Documents published in 2023 : Scipedia

ESSENTIAL CHARACTERISTICS OF PEDAGOGICAL SUPPORT CHILDREN IN DIFFICULT LIFE SITUATIONS IN RUSSIA AND ABROAD
I. Popova

RUSSIAN PRESIDENTIAL ACADEMY OF NATIONAL ECONOMY AND PUBLIC ADMINISTRATION (2023). 186

Abstract
The relevance of the study we determine the need to study pedagogical support as a factor that can have a significant impact on the formation of conditions for the development and positive socialization of children in difficult situations. Addressing this issue is associated with the solution of problems of the state level in terms of prevention of destructive phenomena in children and adolescents. The subject of the study is the specifics of the conditions of pedagogical support for children in difficult life situations in Russian and foreign practice. The purpose of the study: analysis of scientific approaches and developments that provide theoretical and methodological justification and effectiveness of practical activities to provide pedagogical support for children in difficult life situations as a condition for preventing victimization of the child population and the development of destructive phenomena in the child and adolescent environment. The basis of the study were the results of content analysis of Russian dissertations for the period 1996-2019 years and foreign scientific articles in the framework of the stated problems. Research methods: content analysis of dissertation studies and scientific publications, systematization, analysis and synthesis of the information obtained. Scientific novelty of the study is to assess the current state and development of the problems of pedagogical support for children in difficult situations in contemporary Russian scientific research. As a result, we found that Russian scholars in their dissertations widely presented the areas of study of pedagogical support. The study examined 340 Russian dissertations for degrees in pedagogy and psychology. Among the angles of scientific development of the problems of pedagogical support are the varied aspects of support for children with difficulties in the educational process (56%), issues of support for students (27%), and families (17%). However, Russian researchers have reflected the specifics of pedagogical support for children in difficult situations in a small number of works (14%), usually focused on children with disabilities. Among the deficient aspects of studying pedagogical support are such areas as research on comparative basis (2%), development of methodological and technological support of pedagogical support (14%), addressing the problem of teachers' readiness to provide pedagogical support to children in the educational process (13%). Russian scholars in their dissertation studies have not sufficiently disclosed the potential of the participatory approach in solving the problems of pedagogical support (14%). Based on the results obtained, the main conclusion is that the study of the essential characteristics of the phenomenon of pedagogical support for children of socially vulnerable categories is important for the development of pedagogical science. Currently, science and practice are in demand to develop promising scientific directions for the methodology of designing conditions of support for various groups of children in difficult life situations, not focusing only on children with disabilities. There is a particular need to develop scientific research on this issue in the direction of supporting children from low-income families, from migrant families, from families with socially destructive educational content. Recommendations: at a time of global geopolitical transformation, in order to create conditions for the development and positive socialization of children in difficult situations, it is necessary to disseminate among practicing teachers the results of scientific developments in the field of pedagogical support for children of socially vulnerable categories. The model of resistant schools, which has proven effective in working with children from families with low socio-economic and cultural status, should now be widely implemented in the Russian education system. In the conditions of Russian reality, the application of an empathic and participatory approach and facilitation. Implementation of these recommendations is possible if teachers and heads of educational organizations are better prepared to master modern evidence-based approaches and evidence-based practices in solving the problems of pedagogical support for children of socially vulnerable categories.
Abstract
The relevance of the study we determine the need to study pedagogical support as a factor that can have a significant impact on the formation of conditions for the development [...]
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LABIOPLASTIA DE LABIOS MENORES CON LÁSER DIODO EN ADOLESCENTE, A PROPÓSITO DE UN CASO
A. Renaud

Revista Latinoamericana de Ginecología Regenerativa (2023). Renaud A. Labioplastia de labios menores con láser diodo en adolescente, a propósito de un caso. Rev Latinoam Ginecol Reg. 2023; 1(1): 79-81. https://doi.org/10.5281/zenodo.8197050

Abstract
Labia hypertrophy is a completely normal condition, six out of ten patients have labia minora hypertrophy, but not all are surgical, it is related to hormonal factors, trauma, and hereditary factors, however, a large percentage is of unknown cause. In the present case, the labia minora labiaplasty with diode laser applied to an adolescent is briefly described.
Abstract
Labia hypertrophy is a completely normal condition, six out of ten patients have labia minora hypertrophy, but not all are surgical, it is related to hormonal factors, trauma, [...]
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LÁSER DIODO COMO INSTRUMENTO DE CORTE VERSUS BISTURÍ EN PRESENCIA DE PÓLIPO FIBROEPITELIAL VULVAR: REPORTE DE DOS CASOS
J. Freytez, R. Márquez, A. Renaud

Revista Latinoamericana de Ginecología Regenerativa (2023). Freytez J, Márquez R, Renaud A. Láser diodo como instrumento de corte versus bisturí en presencia de pólipo fibroepitelial vulvar: reporte de dos casos. Rev Latinoam Ginecol Reg. 2023; 1(1): 71-77. https://doi.org/10.5281/zenodo.8196827

Abstract
Benign tumors of epithelial connective tissue located in the vulvar region have a very low incidence; the most frequent of these is fibroepithelial polyp, also known as acrochordon. The vulvar fibroepithelial polyp is extremely rare before menarche and after menopause, predominantly in obese and diabetic women. Descontrol hormone may facilitate its development as well as the high level of estrogen and progestogen during pregnancy. There are no reports regarding their relationship with human papillomavirus infections. They are histologically composed of fibrovascular stroma rich in collagen and fibrous tissue which sometimes has a mild chronic inflammatory reaction in the stroma. It is covered with keratinizing epithelium that can be thick with acanthosis, papillomatosis and hyperkeratosis. With the objective of reporting the benefits of diode laser in the treatment of benign tumors of epithelial tissue in the vulvar area and at the same time; To document the presence of this pathology and its ambulatory surgical approach comparing the aesthetic results of the excision with scalpel and laser diode, two cases are presented to which of acrochordon cutting off were performed, comparing surgical time, scarring, blood loss and better aesthetic gynecological outcome. Patients were followed up for 8 months without complications or recurrences. A better adhesion to the diode laser therapy was obtained, demonstrated in a fast recovery, null blood loss, effective healing and very favorable immediate cosmetic gynecological results.
Abstract
Benign tumors of epithelial connective tissue located in the vulvar region have a very low incidence; the most frequent of these is fibroepithelial polyp, also known as acrochordon. [...]
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LABIOPLASTIA OFICINAL CON LÁSER DIODO 30 WATTS, 980NM: INDICACIONES Y RESULTADOS
F. Bolívar, G. Marinello, F. Vera, A. Renaud

Revista Latinoamericana de Ginecología Regenerativa (2023). Bolívar F, Briceño G, Vera F, Renaud A. Labioplastia oficinal con láser diodo 30 watts, 980nm: indicaciones y resultados. Rev Latinoam Ginecol Reg. 2023; 1(1): 65-70. https://doi.org/10.5281/zenodo.8196784

Abstract
Objective: To evaluate the indications for labiaplasty with 30 watt, 980nm diode laser performed in the office in the period 2016-2017 and the results obtained in terms of postoperative pain scale, sexual satisfaction scale and associated complications. Methods: A retrospective, descriptive and analytical study of the results obtained from labiaplasties performed in the office by surgeons was carried out, with a sample of 23 patients, in the period between 2016 -2017 in Caracas, Venezuela. The Trim technique with a 30-Watt Laser Diode was used in a continuous mode with a 980 Nm fiber. The patients were classified according to reason for consultation, degree of hypertrophy according to González's classification and pain scale, index of sexual satisfaction and associated complications. Results: The age range prevailed in patients between 29 and 39 years, the reason why all the patients underwent surgery was primarily discomfort referred to as 'discomfort', one patient also referred functional disorders, specifically dyspareuria. 65.2% of the cases presented generalized hypertrophy, followed by central asymmetric in 34.7%. On the analogue scale of postoperative pain, only 8.6% reported pain II to III; there were no intraoperative complications and postoperative complications were absent in 82.6% of them, 8.6% presented labial dehiscence, 4.3% pruritus and 4.3% granuloma, all complications had secondary resolution and the post-procedure sexual satisfaction index 10 / 10 pts. 100%. Conclusion: after surgery the patients achieved symmetrical lips, with a good aesthetic appearance.
Abstract
Objective: To evaluate the indications for labiaplasty with 30 watt, 980nm diode laser performed in the office in the period 2016-2017 and the results obtained in terms of [...]
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BENEFICIOS DEL TENSADO VAGINAL CON LASER CO2 PARA EL BIENESTAR SEXUAL FEMENINO. EXPERIENCIA EN CONSULTA PRIVADA
T. Pichardo

Revista Latinoamericana de Ginecología Regenerativa (2023). Valdez Pichardo TP. Beneficios del tensado vaginal con láser co2 para el bienestar sexual femenino. experiencia en consulta privada, septiembre 2018- febrero 2019. Rev Latinoam Ginecol Reg. 2023; 1(1): 51-63. https://doi.org/10.5281/zenodo.8196771

Abstract
Female sexual dysfunction is a disorder that occurs when there is a change in a woman's usual sexual response. The reasons for consultation are more frequent, are the problems related to the sexual part, we have, in 80%, problems, errors, pathologies of pelvic floor dysfunction, such as obesity, childbirth, age, Physical activity, sedentary lifestyle, menopause, etc. Methodology: a descriptive, prospective, observational, and experimental study was conducted in 15 patients aged between 35 and 45 years, who attended the consultation from September 2018 to February 2019, presenting signs and symptoms compatible with sexual dysfunction. A vaginal test with Japanese co2 laser of 15w was performed, with a handpiece designed for vaginal tension with a power of 4ww and amplitude of 0.30, they were assessed with controls at 21 days and 6 months, applying 3 sessions of vaginal tenses. Results: of 67% of sexual dysfunction in patients, carrying out the PISQ-12 survey of sexual dysfunction and physical examination with manual manometry with a Kegel perinometer. The predominant symptomatology was
Abstract
Female sexual dysfunction is a disorder that occurs when there is a change in a woman's usual sexual response. The reasons for consultation are more frequent, are the [...]
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LASER DIODO 980 NM ASOCIADO A FIBRINA RICA EN PLAQUETAS, EN PACIENTES CON FISURA VULVAR RECIDIVANTE. BARQUISIMETO, ESTADO LARA
A. Renaud

Revista Latinoamericana de Ginecología Regenerativa (2023). Renaud A. Laser diodo 980 nm asociado a fibrina rica en plaquetas, en pacientes con fisura vulvar recidivante. Barquisimeto, estado Lara, marzo-junio 2021. Rev Latinoam Ginecol Reg. 2023; 1(1): 41-49. https://doi.org/10.5281/zenodo.8196741

Abstract
Las disfunciones sexuales son consideradas como un problema de salud pública que afecta la calidad de vida de la mujer en cualquier etapa de su vida adulta, y entre las asociadas al dolor destaca la dispareunia asociada al vaginismo, en la que figura como manifestación clínica la fisura vulvar recidivante, la cual es infradiagnosticada en la consulta ginecológica, y el manejo y/o tratamiento es tardío. De acuerdo al grado, la resolución puede llegar a ser quirúrgica, en este sentido, con la finalidad de evidenciar la eficacia del Láser Diodo 980nm, asociado a fibrina rica en plaquetas en el manejo de la fisura vulvar recidivante, se desarrolló un estudio cuasiexperimental, en una muestra de 45 pacientes entre 23 a 76 años, que acudieron a una consulta privada. El motivo principal de consulta estuvo asociado a sequedad vaginal o atrofia, seguido de infecciones urinarias y dispareunia. Se realizó diagnóstico clínico e histológico, y se practicó la perineoplastia con láser Diodo 980 nm asociado a fibrina rica en plaquetas (PRF) con la finalidad de corregir la fisura vulvar recidivante. Tras un periodo de seguimiento de 4 meses se constató la curación de la patología, con toma activa de la función sexual, reflejado a través del IFSF (índex de función y satisfacción sexual femenina). Se concluye que, la perineoplastia con Láser asociada a PRF, constituye una técnica mínimamente invasiva, ambulatoria, con menos recidiva y excelente resultado funcional, regenerativo y estético. Se espera que este estudio sea de utilidad para el Ginecólogo en el manejo no convencional en la consulta ginecológica, esta técnica mínimamente invasiva y que mostró ser efectiva en el tratamiento de fisura vulvar recidivante
Abstract
Las disfunciones sexuales son consideradas como un problema de salud pública que afecta la calidad de vida de la mujer en cualquier etapa de su vida adulta, y entre [...]
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LIPOLÁSER DEL MONTE DE VENUS CON LÁSER DIODO 980-nm
D. Vizcaíno, 1. Renaud, J. Gaviria

Revista Latinoamericana de Ginecología Regenerativa (2023). Vizcaíno D, Renaud A, Gaviria J. Lipoláser del monte de Venus con láser diodo 980-nm. Rev Latinoam Ginecol Reg. 2023; 1(1): 35-40. https://doi.org/10.5281/zenodo.8196713

Abstract
Objective: Evaluate the safety of the technique: Laser-assisted liposuction Diode 980-nm, presenting the rate of complications obtained in our interventions. Methods: A retrospective, descriptive and analytical study was carried out that included ten (10) patients selected with inclusion criteria between the months of January and September 2018, using a 980-nm Diode Laser (SixLáserDuo®) equipment whose energy used was 12 to 15 watts through a 600 μm fiber. Results: The average age of the patients was 29.6 years (range: 18 to 42 years), the complication was the hematoma 10% (1/10 patients) due to omission of medication and ecchymosis by 3% (3/10 patients). Pain control time of 1 to 2 days. Conclusions: The Lipoláser of mons pubis with the Laser Diode 980-nm, is a less traumatic proven technique, without major complications and with a low rate of minor complications reducing the recovery period of patients.
Abstract
Objective: Evaluate the safety of the technique: Laser-assisted liposuction Diode 980-nm, presenting the rate of complications obtained in our interventions. Methods: A retrospective, [...]
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LABIOPLASTIA CON LÁSER CO2: BENEFICIOS Y COMPLICACIONES
M. Ponce, N. Delysqui, A. Renaud

Revista Latinoamericana de Ginecología Regenerativa (2023). Azuaje Ponce M, Cedillo Delysqui N, Renaud A. Labioplastia con láser co2: beneficios y complicaciones. Rev Latinoam Ginecol Reg.. 2023; 1(1): 25-34. https://doi.org/10.5281/zenodo.8196684

Abstract
La labioplastia es un procedimiento quirúrgico que se emplea para mejorar el aspecto funcional, estético y psicosocial de la vulva, cada día aumenta su demanda debido a los múltiples beneficios que conlleva. Han sido descritas diversas técnicas, con el objetivo de obtener mejores resultados, así como disminuir las complicaciones intra y postoperatorias. Objetivo: evaluar los beneficios del uso del Láser CO2 en las labioplastias. Método: se realizó un estudio observacional, longitudinal y retrospectivo en 50 pacientes quienes acudieron a consulta privada, en el periodo comprendido entre los años 2014-2016, con diagnóstico de hipertrofia de labios menores grado II - III según la clasificación de Motakef. Se les realizó labioplastia en consultorio con Láser CO2 y seguimiento a dos años, donde fue evaluada la evolución de las mismas y la presencia o no de complicaciones. Resultados: la edad promedio de solicitud de la intervención fue de 30 años, donde el 80% de las pacientes tenía entre 20 y 39 años. En el 86% de los casos el grado de hipertrofia de labios fue Grado III y el motivo de consulta más frecuente el Disconfort, con un 44 % de prevalencia. El 4% presentó complicaciones a causa del procedimiento. Conclusiones: La labioplastia con Láser CO2 es un procedimiento seguro, realizado por manos expertas con amplios conocimientos de la tecnología Láser, con una baja tasa de complicaciones y una alta tasa de satisfacción.
Abstract
La labioplastia es un procedimiento quirúrgico que se emplea para mejorar el aspecto funcional, estético y psicosocial de la vulva, cada día aumenta su [...]
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ADIESTRAMIENTO EN EL USO DEL LÁSER, PARA EL TRATAMIENTO DE PATOLOGÍAS DEL TRACTO GENITAL INFERIOR, ASOCIADAS AL VIRUS DEL PAPILOMA HUMANO (VPH)
R. Márquez, A. Rodríguez

Revista Latinoamericana de Ginecología Regenerativa (2023). Márquez R, Renaud A. Adiestramiento en el uso del láser, para el tratamiento de patologías del tracto genital inferior, asociadas al virus del papiloma humano (VPH). Rev Latinoam Ginecol Reg. 2023; 1(1): 15-24. https://doi.org/10.5281/zenodo.8196107

Abstract
El Virus del Papiloma Humano (VPH), causa cáncer del cuello del útero, la mayor parte de las infecciones por VPH son asintomáticos y categorizados, de alto o bajo riesgo. En la actualidad una de las técnicas, “mínimamente invasivo” en las patologías del tracto genital inferior, es el uso de láser CO2 de 15 ww y Diodo de 30 ww. El conocimiento y práctica de la Medicina Fotónica, no está incluida en el pensum del Programa de Postgrado de Obstetricia y Ginecología, UCLA, por lo que, se elaboró un plan de adiestramiento y se adquirió las técnicas y protocolos, para el uso adecuado de los equipos láser CO2 de 15 ww y Diodo de 30 ww, como herramienta en la consulta ginecológica, y método terapéutico, en pacientes con patologías del tracto genital inferior, asociadas a VPH. Se identificaron y evaluaron 20 pacientes con patologías del tracto genital inferior, asociadas a VPH, al 60% (12) de las pacientes diagnosticadas de condilomatosis vulvoperineal, se trató con la técnica láser CO2 de 15 ww, y se fotovaporizaron las lesiones menores de 0,5 cm y las lesiones mayores de 0,5 cm, se realizó exceresis; el 30% (06) de pacientes con diagnóstico citohistológico de neoplasia intraepitelial cervical de bajo grado, se realizó la técnica de láser Diodo de 30 ww, fotovaporizando las lesiones en cuello uterino y al 10% (02) de las pacientes diagnosticadas con neoplasia intraepitelial cervical de alto grado, se le realizó la técnica tipo cono, de láser Diodo de 30 ww. Los resultados del plan de entrenamientos obtenidos, indican un conocimiento teórico apropiado, con una concordancia alta, alcanzando un puntaje de 28/30 en relación al criterio del tutor, clasificado como Aprobado; en la evaluación práctica, se obtuvo una concordancia alta, en relación al criterio del tutor, con un puntaje de 37/40 clasificado como Aprobado.
Abstract
El Virus del Papiloma Humano (VPH), causa cáncer del cuello del útero, la mayor parte de las infecciones por VPH son asintomáticos y categorizados, de [...]
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EFECTIVIDAD DE LA APLICACIÓN DE PLASMA RICO EN PLAQUETAS EN LABIOPLASTIA REALIZADA CON LÁSER DIODO
D. González, C. Vázquez

Rev Latinoam Ginecol Regen (2023). Vol. Revista Latinoamericana de Ginecología Regenerativa. Volumen 1, número 1, 4

Abstract
In recent years, the usefulness of PRP (Platelet Rich Plasma) for soft tissue healing has been published. In the gynecological area, it is used to stimulate vaginal and clitoral rejuvenation to recover its function globally, contributing to improving the patient's self-esteem, as well as improving the sexual experience. In the case of labiaplasty, it is indicated in labia minora hypertrophy. Another non-invasive gynecological aesthetic method is the use of Diode laser because it does not require incisions, it is ambulatory and has a fast recovery. At present there are few studies and literature on the matter. Hence, a clinical study was carried out with 28 patients to determine the effectiveness of the application of PRP in labiaplasty performed with Diodo laser, with patients between 20 and 46 years old, who attended consultations due to discomfort, pain in relationships and low self-esteem. 54% presented grade 3 hypertrophy of the labia minora and the remaining 46% grade 2 hypertrophy. After the application of the treatment, 86% did not present complications, only 14% manifested dehiscence. The recovery period was 5 weeks in 50% of the patients. Obtaining a degree of satisfaction in all patients between 9 to 10. PRP has been gaining relevance among gynecological aesthetic treatments, however, due to its recent use there are still few studies that deepen and corroborate its effectiveness. It is necessary to carry out studies in which the clinical evolution, healing and repair of vaginal tissues are evaluated.
Abstract
In recent years, the usefulness of PRP (Platelet Rich Plasma) for soft tissue healing has been published. In the gynecological area, it is used to stimulate vaginal and clitoral [...]
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Tuning the incompatibility between recycled plastic aggregates and cement matrix with polymer-nano silica hybrids
Q. Zeng, A. Al-Mansour

DBMC 2023.

Abstract
Use of recycled waste plastics as the aggregates in construction materials has attracted increasingly gained attention for sustainable construction industry with great environmental benefits. However, the soft plastics and rigid cement matrix can naturally induce the great aggregate-matrix incompatibility, which results in the degradation of engineering properties of cement-based materials containing recycled plastic aggregates (RPAs). To overcome this shortage, this work reports a strategy of tuning the cement matrix with polymer-nano silica (P-nS) hybrids. Ethylene vinyl acetate (EVA) and recycled polypropylene (PP) were selected as the coating polymer and RPA, respectively. Density, strength, water sorptivity and carbonation resistance were measured to assess the physical and mechanical properties of the mortars with recycled PP particles. Microstructure was analyzed using scanning electron microscopy (SEM) with backscattered electron (BSE) and energy-dispersive X-ray spectroscopy (EDS). Results showed that the addition of P-nS hybrids into cement decreases density, mitigates strength reduction, obstructs water sorption, but have positive and negative effects on carbonation resistance of the cement mortars with RPA. The P-nS hybrids build the organic–organic links between the cement matrix and RPA, and coordinate their deformations. The findings of this work proof the proposed strategy of tuning the compatibility between soft aggregates and rigid matrix with the engineered microstructure towards enhancing the recyclability of waste plastics in construction materials.
Abstract
Use of recycled waste plastics as the aggregates in construction materials has attracted increasingly gained attention for sustainable construction industry with great environmental [...]
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Recycling of Polypropylene Fibre Reinforced Concrete: Use of Recycled Aggregate and Recovered Fibre in New Concrete
G. Liu, N. Tošić, A. de la Fuente

DBMC 2023.

Abstract
The study aims at investigating the feasibility of using recycled aggregate (RA) and recovered fibres (RF) obtained from recycling of polypropylene fibre reinforced concrete (PPFRC) in new concrete production. The mechanical properties were compared between a parent concrete, polypropylene fibre reinforced recycled aggregate concrete (PPRAC), and recovered polypropylene fibre concrete (Re-PPRFC). All concretes were designed to have the same compressive strength and slump. The parent concrete was produced with 9 kg/m3 of polypropylene fibre. After recycling, the RA and RF were collected and new concretes with RA and RF, PPRAC and PPRFC, respectively, were produced with the same fibre content as the parent concretes. The strain-stress relationship in compression and residual tensile strength were tested. The results obtained for PPFRC, PPRAC and rePPRFC were compared. The results show that the RA and RF obtained by PPFRC recycling can benefit new concrete production.
Abstract
The study aims at investigating the feasibility of using recycled aggregate (RA) and recovered fibres (RF) obtained from recycling of polypropylene fibre reinforced concrete [...]
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Numerical Simulation on the Influences of Wind Pressure on Jet Characteristics of Shotcrete
S. Zhang, Y. Zhang, K. Wu, X. Kong

DBMC 2023.

Abstract
A gas-liquid two phases model of shotcrete was developed to simulate the whole process from the spouting of concrete from nozzle, the scattering in the flow field to its colliding with a wall based on computational fluid dynamics theory, in which concrete was regarded as a Bingham fluid. The influences of wind pressures、 pumping speeds、 air incident angles and rheological parameters on five characteristic parameters including spouting velocity, jet velocity, jet trajectory, collision velocity and distribution of shotcrete on the wall were analyzed in depth. Results showed that concrete was gradually mixed well with air in the nozzle with an increasing average velocity, and the increase of velocity was most pronounced in the contraction section of nozzle. With the increases of wind pressures and pumping speeds, the spouting velocity and spouting mass of concrete both increased. Higher wind pressure and pumping speed led to larger jet velocity and more concentrated distribution, resulting in significantly longer jet distance, higher collision velocity and larger distribution area. The collision velocity and volume fraction of concrete on the wall were distributed symmetrically along Y axis, shifting towards the direction of gravity. With the increases of air incident angles, the spouting velocity and spouting mass of concrete both decreased, the shifting to gravity is weakened and the volume fraction decreased first and then increased. When plastic viscosity decreased, the spouting velocity and spouting mass of concrete both increased, accompanying with a higher jet velocity, a longer spraying distance and a larger distribution area.
Abstract
A gas-liquid two phases model of shotcrete was developed to simulate the whole process from the spouting of concrete from nozzle, the scattering in the flow field to its colliding [...]
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Effect of Pre-calcination of Lead-zinc Tailings on the Activation of Blast Furnace Slag
J. Ou, Z. Luo, Y. Mu

DBMC 2023.

Abstract
Blast furnace slag and lead-zinc tailings (LZTs) are solid wastes from the iron-making and mining industries, respectively. In order to reuse these solid wastes, the LZTs were pre-calcined at different temperatures and then explored whether it is capable of being the activator of slag. The effects of pre-calcination on the phase composition of LZTs were elucidated by XRD. The compressive strength of LZTs-activated slag pastes was investigated, and the mineral composition and microstructure of the pastes were detected by XRD and SEM. The results imply that with the elevating of heating temperature from 500 ℃ to 1000 ℃, the dolomite in LZTs decompose into CaO and MgO, and the oxidation of pyrite resulted in the formation of Fe2O3 and gaseous SO3, then SO3 reacted with a part of formed CaO to produce CaSO4. The resulting CaSO4 and CaO can become the sulfate activator and alkaline activator of slag, respectively. The LZTs-activated slag pastes prepared with the LZTs preheated at 800 ℃ exhibit the highest strength at 90 d, which yield 24 MPa. The hydration products of LZTs-activated slag were ettringite and calcium silicate hydrates (C-S-H gel). Large amounts of dense C-S-H gel bond together, connecting most of the ettringite networks into a whole, thus forming a dense structure and effectively improving the strength of LZTs-activated slag. The outcome of this study provides a potential disposing or reusing approach of the large amounts of LZTs.
Abstract
Blast furnace slag and lead-zinc tailings (LZTs) are solid wastes from the iron-making and mining industries, respectively. In order to reuse these solid wastes, the LZTs [...]
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Probability Durability Assessment of Existing Concrete Structures in Carbonation Environment
H. Gu, J. Yao, Z. Meng

DBMC 2023.

Abstract
In a particular service environment, the calculation models used to determine the durability of existing concrete structures differ from those employed in the design phase. This paper presents a methodology for assessing the probability durability of existing structures, taking into account the nondestructive testing results and the target reliability index. The initial step involves introducing a correction coefficient into the carbonation and corrosion development theory model. This coefficient is necessary to account for the correction associated with the corrosion monitoring of steel. The values of this coefficient should be determined based on the actual testing results, specifically considering the presence of reinforcing steel corrosion. Next, a probability expression is proposed using the measured results of probability characteristics and the target reliability index. This approach takes inspiration from the design-value method and the existing theory of structure reliability. It also takes into account the specific variables of concrete protective cover thickness and the compressive strength as the fundamental random variables. The residual working life can be calculated as the outcome of a durability assessment through quantitative analysis. This calculation can serve as a valuable reference for the maintenance program.
Abstract
In a particular service environment, the calculation models used to determine the durability of existing concrete structures differ from those employed in the design phase. [...]
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Overview on Testing Method of Internal Damage to Special-shaped Stone Components in Palace Museum
Y. Qian, F. Qi, K. Niu

DBMC 2023.

Abstract
Irregular historic stone components are very important parts of the ancient architecture in the Palace Museum. They have been subjected to deteriorations from surface to interior under the combined effects of many factors such as wetting and drying, salt dissolution and recrystallization, selfload, external load, and environment action. The internal damages in these stone components are difficult to detect but are crucial for the assessment of the intact of these components. In order to detect the internal damage of stone components, especially the special-shaped stone components, which cannot be tested by comment methods. Taking evaluation on preservation status of stone components in a qualitative and quantitative way， with application of ultrasonic computerized tomography and regular inspection, a convenient, safe, economical, efficient, and readable method for detecting the internal damage of irregular stone components can be established in order to detect any safety hazards as early as possible and provide data support for assessment and conservation, achieving a better preventive conservation.
Abstract
Irregular historic stone components are very important parts of the ancient architecture in the Palace Museum. They have been subjected to deteriorations from surface to interior [...]
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Evaluating the Future Moisture Performance of the Stucco-Clad Wall Assembly in Selected Canadian Cities
O. Zhe, X. Xiao, H. Ge, M. Lacasse

DBMC 2023.

Abstract
Due to climate change, it is expected that the amount of precipitation in most parts of Canada will increase in the coming decades. Consequently, the building envelope exposed to such climate could experience a higher moisture load than in the past, which could have a negative impact on its performance in the long run. The stucco-clad wall assembly, which has been widely employed in the construction of low-rise residential buildings throughout Canada may not be adequately designed to be resilient to the future climate. Thus, in the study described in this paper, the future moisture performance of the stucco-clad wall assembly located in two Canadian cities with different levels of moisture load, i.e., Vancouver and Calgary, subjected to projected future climate is investigated. The analysis includes two phases: conducting watertightness for a full-scale stucco wall specimen to determine the relationship between the climate data and the moisture load in the wall assembly and implementing hygrothermal simulations using the relationship obtained from the watertightness test for the performance assessment. Mould growth index at the exterior surface of the oriented strand board of stucco-clad wall assembly for the historical and projected future time periods is compared and discussed.
Abstract
Due to climate change, it is expected that the amount of precipitation in most parts of Canada will increase in the coming decades. Consequently, the building envelope exposed [...]
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UN PASO FIRME EN LOS ESTUDIOS DE LA GINECOLOGÍA REGENERATIVA
A. Renaud

Rev Latinoam Ginecol Regen (2023). Vol. Revista Latinoamericana de Ginecología Regenerativa. Volumen 1, número 1, 3

Abstract
El área de la ginecología regenerativa data de más de tres décadas en el mundo, y en nuestro país, Venezuela, tiene sus inicios desde el 2007, a través, del Dr. Jorge E. Gaviria, quien inicia con los primeros avances en esta ciencia, continuando ese legado hasta la actualidad, donde se ha mantenido una formación continua en, talleres, diplomados y training, sistematizados, donde los que trabajamos en el área, queremos la mejor formación para el discípulo. Hoy decidimos reforzar con un espacio abierto para la publicación, las experiencias que hemos desarrollado, no solo en Venezuela, sino en toda Latinoamérica, específicamente en este maravilloso campo de las ciencias médicas. El área de la ginecología regenerativa, enfoca de manera integral el manejo de nuestras pacientes, para el mejoramiento de su función sexual y por ende de su calidad de vida. Nuestra revista, representa el vehículo expedito de difusión, en el avance científico, en esta área emergente, constituyendo el medio de expresión de las distintas especialidades entre los grupos de investigación que desarrollan esta disciplina. Igualmente, constituirá un elemento inestimable para la formación continua de los profesionales que practican o desean incursionar en esta área, tanto por la actualización, como por las pautas que puedan ser recomendadas a través de los diversos trabajos de investigación. Es para nosotros, un logro indescriptible a través de la logística y organización de nuestro comité editorial, en especial del Dr. Traviezo, por haber abierto las puertas a un área emergente, que solo va en pro de la mejora de su calidad de vida y del esmero en la construcción de su femineidad. Esta revista tendrá como eje central la ginecología regenerativa, pero no será excluyente de todos los profesionales de áreas y temas afines, que tengan el propósito de acompañarnos. La Revista Latinoamericana de Ginecología Regenerativa, tiene ya proyectada su inclusión en los distintos y mejores índices y plataformas electrónicas internacionales, para garantizarle a autores y usuarios en general, la mayor y mejor visibilidad de los artículos, las 24 horas del día, los 365 días del año, con el respaldo DOI de cada artículo y garantizando el acceso gratuito y oportuno a todos, para contribuir, desde nuestra humilde tribuna, al acceso libre a la información, en esta importante área de las ciencias de la salud. La revista recibirá manuscritos durante todo el año y tendrá una regularidad semestral (dos números al año, junio y diciembre) e igualmente podrá contar con suplementos especiales, por volumen, los cuales dependerán de la misma dinámica que exista entre la revista y sus colaboradores. No me queda más que, en nombre de todo el comité editorial, darles la bienvenida a nuestra revista, la cual está abierta a todas sus contribuciones y sugerencias, para que juntos, naveguemos en este bello río de conocimientos científicos, que nos unen en la ginecología regenerativa, sin olvidar que, la investigación continua, es el camino para el aprendizaje a lo largo de la vida y la perfección en el acto médico.
Abstract
El área de la ginecología regenerativa data de más de tres décadas en el mundo, y en nuestro país, Venezuela, tiene [...]
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Analysis of Thermal Bridges in Concrete and Cross-Laminated Timber (CLT) Constructions: A Numerical Study
A. Zegeye, F. Tariku

DBMC 2023.

Abstract
The thermal efficiency of a building envelope relies on various factors, including insulation resistance, continuity, the thermal conductivity of structural materials, and the presence of thermal bridges. This study focuses on studying the thermal performance of thermal bridge details in two construction types: concrete and Concrete and Cross-Laminated Timber (CLT). For the study, two common building envelope details with significant thermal bridges are considered, balcony and intermediate wall-to-floor connections. Utilizing the finite element program COMSOL Multiphysics, hourly transient simulations were conducted over a one-year period to assess the heat loss/gain associated with thermal bridges, considering daily, seasonal, and annual heat flow for two diverse climatic conditions (hot weather Houston-Climate Zone 2 and cold weather Toronto-Climate Zone 6). The findings demonstrate that thermal bridges constructed from CLT outperformed those made of concrete. In Toronto, the annual heat flow for the concrete balcony was 146% higher compared to CLT, while in Houston, it was 67% higher. However, this trend was significantly reduced for the wall-to-floor detail, with a concrete detail showing a 13% increase in heat flow for Toronto and a 7% decrease in annual heat flow for Houston. Furthermore, the dynamic analysis revealed notable heat flow magnitude changes in the balcony detail, highlighting the importance of thermal conductivity, while the wall-to-floor detail exhibited dampening fluctuations in heat flow, emphasizing the material's heat capacity importance in this context.
Abstract
The thermal efficiency of a building envelope relies on various factors, including insulation resistance, continuity, the thermal conductivity of structural materials, and [...]
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Use of Machine Learning in Processes Optimization for Drinking Water Treatment Plant Butoniga (Istria, Croatia)
G. Volf, S. Zorko, I. Čule

DBMC 2023.

Abstract
Drinking water treatment plant Butoniga is located in central Istria (Croatia) downstream of the Butoniga reservoir. The Butoniga reservoir is an artificial lake created in 1987 with two main objectives: 1) protection from adverse water impacts, and 2) drinking water supply. The operation of the drinking water treatment plant is mainly related to the tourist season, and the 5.000.000 m3 of produced and distributed drinking water annually, 3.000.000 m3 is produced and distributed during June 15 to September 15, when the raw water quality in the Butoniga reservoir is the worst. Regarding this, main problem with Butoniga reservoir and thus drinking water treatment plant appear in summer months when water temperature is the most critical parameter and raw water for the treatment process must be captured from the lowest layer of the reservoir which have increased concentrations of Mn, Fe, NH4 and lower pH values and thus influence on the treatment processes. To deal with this problem, model predicting Mn, seven days in advance is build using machine learning approaches. Build model have high accuracy compared to the measured data, with a good prediction of the peak values. As such, obtained model can help in optimization of the treatment processes which are depending on the quality of raw water, and overall, in sustainability and management of the drinking water treatment plant Butoniga.
Abstract
Drinking water treatment plant Butoniga is located in central Istria (Croatia) downstream of the Butoniga reservoir. The Butoniga reservoir is an artificial lake created in [...]
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Proposal of Soundness Index for Existing RC Apartment Building for Proper Management Through Visual Monitoring
N. Tsuchiya, N. Mishima, K. Nemoto, K. Matsuzawa, K. Nakada, T. Kage, H. Tanano

DBMC 2023.

Abstract
A numerical index for housing complexes of reinforced concrete maintained properly was proposed. First, based on the literature review, deterioration grade and a method for evaluating soundness for RC housing complexes, which determined by visual inspection, was proposed. And then, accelerated deterioration experiments of small RC wall and investigation of existing buildings were conducted. From the study, a correlation between the deterioration grade determined visually and rebar corrosion grade was confirmed. By using building health H(t), that is proposed as index of soundness for existing RC housing complexes, RC housing complexes whose age were 46 to 69 years were evaluated. From the study, it was confirmed how much deterioration the evaluation value indicates.
Abstract
A numerical index for housing complexes of reinforced concrete maintained properly was proposed. First, based on the literature review, deterioration grade and a method for [...]
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Effect of Moderately Elevated Temperatures on Performance of Portland Cement Concrete
S. Gao, M. Liu, Q. Kong, K. Li

DBMC 2023.

Abstract
High temperature is one of the critical factors leading to the change in concrete performance since it affects the physical structure and chemical components of concrete. However, some concrete structures are continuously subjected to moderately elevated temperatures (typically less than 200 ℃) when operating, such as chimneys for the metallurgical industry and structures in nuclear power plants. The deterioration process of these structures could be caused and accelerated by a high-temperature environment. Thus, the safety and performance of these concrete structures at elevated temperatures during service life are crucial. This paper aims to investigate the change in concrete performance exposed to sustained moderately high temperatures. The concrete cured for 56 days was subjected to temperatures ranging from 65℃ to 200 ℃ for 28 days. The mechanical properties of concrete at different heating temperatures were tested, including compressive strength, splitting tensile strength and modulus of elasticity. Meanwhile, concrete’s durability after heating was evaluated using the concrete electrical resistivity test. The concrete elevated-temperature performance was compared to identical concretes at room temperatures, and the evolution of each property was analyzed. Based on experimental results, the long-term performance of concrete in a moderately elevated temperature environment is predicted.
Abstract
High temperature is one of the critical factors leading to the change in concrete performance since it affects the physical structure and chemical components of concrete. [...]
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Heavy Metals Immobilization Property and Mechanisms of LDHs-modified Cementitious Materials
L. Chi, C. Huang

DBMC 2023.

Abstract
Layered double hydroxide (LDH) has a positive effect on the adsorption and immobilization of heavy metals. The compressive strength and the heavy metal ions Pb2+ immobilization of CaAl-LDH modified cement paste were studied in this paper. Through research, it was found that compared with the cement paste sample with a Pb2+ content of 1% after curing for 7d and 28d, the addition of CaAlLDH to the cement paste sample increased the compressive strength by 6.1% and 1.6%, respectively, demonstrating the enhancing effect of CaAl-LDH on the strength of cement paste. Compared with the sample containing only Pb2+, the addition of CaAl-LDH to the cement increased the immobilization rate by 0.3% after 12 hours of leaching time and showed varying degrees of improvement at different leaching times. The immobilization mechanism of heavy metals in LDH blended cement paste was revealed by microstructure characterization. It was founded that Pb2+ can replace Ca2+ in AFt, AFm, and LDH, and can co-precipitate with OH-.
Abstract
Layered double hydroxide (LDH) has a positive effect on the adsorption and immobilization of heavy metals. The compressive strength and the heavy metal ions Pb2+ immobilization [...]
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Chemo-physical Analysis on Corrosion Initiation of Offshore Structures under Chloride Attack
B. Dong, Y. Yu, W. Gao

DBMC 2023.

Abstract
Chloride ingress has been recognized as a main factor inducing the corrosion of offshore reinforced concrete structures. It is acknowledged that the chemical attack can lead to concrete property deterioration, which inevitably affects the reinforcement corrosion. Herein, the influence of the concrete aging on the chloride-induced corrosion initiation is systematically evaluated by a novel numerical framework. In this framework, the chemo-physical analysis is conducted based on coupled NernstPlanck model and Gibbs energy minimization model. The proposed method is first validated against reported experimental results. It is found that the chloride ingress is always accompanied by leaching of hydrates near the exposure surface, leading to the porosity enlargement. Moreover, due to chemical binding of chloride to monosulfoaluminate, ettringite continuously precipitates under the function of released sulfate ions. Through a series of numerical analyses, it is revealed that the newly formed hydrates impose competitive effects on chloride transportation due to the simultaneous pore-clogging and expansion-induced microcracks. Chloride-induced corrosion occurs earlier in the situation that the effect of microcracks overcomes that of pore clogging, otherwise, the corrosion is delayed.
Abstract
Chloride ingress has been recognized as a main factor inducing the corrosion of offshore reinforced concrete structures. It is acknowledged that the chemical attack can lead [...]
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Carbonation-induced Early Corrosion Propagation Based Service Life Assessment Model (CECP-SAM)
L. Chen, R. Su

DBMC 2023.

Abstract
Supplementary cementitious materials (SCMs) are widely used for sustainable concrete. However, this is challenged due to the deteriorated resistance towards carbonation-induced corrosion. This paper introduces the establishment of a novel carbonation-induced early corrosion propagation based service life assessment model (CECP-SAM). This model is characterized by considering the early corrosion propagation (incipient cracking) and the use of supplementary cementitious materials. Based on experimental and numerical methods, the effects of binders, water/binder (W/B) ratio, exposure condition, cover thickness, rebar diameter, semi-carbonation zone, cathode-anode ratio on service life are investigated by CECP-SAM. The model is justified by using the results from a field investigation in Hong Kong. Performance-based service life equations are also given based on CECP-SAM.
Abstract
Supplementary cementitious materials (SCMs) are widely used for sustainable concrete. However, this is challenged due to the deteriorated resistance towards carbonation-induced [...]
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Service Life Prediction of Concrete Against Freezing and Thawing Based on Water Absorption Results
L. Xu, J. Wang, C. Zhang, Z. Li, Q. Yang

DBMC 2023.

Abstract
Freezing and thawing resistance performance of concrete is a critical issue when evaluating the durability performance of concrete. This paper aims to predict the freezing and thawing resistance performance of concrete based water absorption indexes, meanwhile, five groups of experiments on porosity, short-term water absorption, long-term water absorption, MIP and pore structure scanning were respectively carried out for concrete. According to the experimental results, the important indexes such as porosity, water absorption, gas content and bubble spacing coefficient were obtained, which provided the basis for the prediction of durability and service life. The concept of equilibrium time ratio is introduced to simplify the calculation process. Based on the critical saturation theory, the service life of concrete against freezing and thawing is predicted by combining the environmental parameters and the indexes measured in experiments. The calculated results verified that the freeze-thaw durability life of air-entrained concrete is significantly increased compared with that of concrete without air-entrained concrete. In addition, a wide range of the service life was predicted for the 5 mixes, and the results could provide a guidance for selecting a proper mix design of concrete subjected to freezing and thawing.
Abstract
Freezing and thawing resistance performance of concrete is a critical issue when evaluating the durability performance of concrete. This paper aims to predict the freezing [...]
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Microstructure of Cement Paste with Expansive Additives under Free and Restrained Conditions
M. Gupta, G. Igarashi, Y. Takahashi, T. Ishida

DBMC 2023.

Abstract
Expansive additives (EAs) have been widely used to reduce the risk of cracking due to shrinkage. Such additives cause early age expansion of concrete due to the formation of Portlandite and Ettringite in the pores of the cement paste, which affects the cement paste's microstructure. The presence of external restraints in the form of reinforcement and support affects the expansion and, ultimately the microstructure of cement paste. In the current study, the microstructure of cement paste with expansive additives is studied using mercury intrusion porosimetry (MIP). A free lime-based EA, with 10 and 15% (by weight) cement replacement ratios, is studied in the current study. The porosity and pore size distribution of the cement paste with EA were studied under free and restrained conditions. Results show that the under the stress-free condition, the porosity of the paste increased, while under the restrained condition, the porosity remained much similar to the reference case of OPC. Further, the pore size distribution of the cement paste with EA under free and restrained conditions is explained, and the effect of EA and restraint on the microstructure is discussed.
Abstract
Expansive additives (EAs) have been widely used to reduce the risk of cracking due to shrinkage. Such additives cause early age expansion of concrete due to the formation [...]
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Study on Release Performance of Concrete Release Agent
S. Lu, Z. Jie, W. Liya, Y. Maoqian, L. Tongwei

DBMC 2023.

Abstract
In this paper, the effects of types of concrete release agent, the amount of brushing per unitarea and the 1d's strength of concrete on the release performance were studied. The adhesion and filmforming ability of O/W emulsion release agent was improved by adding high polymer. The results showthat the 1d's strength of concrete has no effect on the release performance of the release agent. The mostimportant factors affecting the release performance are brushing amount per unit area and the type ofrelease agent. O/W emulsion release agent with polyacrylamide and polyethylene glycol all stick mold. The more they are added, the heavier the stickiness is. While, the release performance with polyethyleneglycol is very close to blank sample.
Abstract
In this paper, the effects of types of concrete release agent, the amount of brushing per unitarea and the 1d's strength of concrete on the release performance were studied. [...]
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Properties of Mineral Powders Modified Foamed Concrete
Q. Liu, H. Chen

DBMC 2023.

Abstract
In order to improve the stability of lightweight foamed concrete, the particle-stabilized foam (PSF) has been proposed because of its high stability. However, most PSFs added particles to foams, and few researchers have investigated whether the stabilization effect exists when particles are added to the paste. In this study, a new type of foamed concrete was prepared by adding different kinds of mineral powders to cement and using ionic surfactants to prepare foam. The influence of different mineral powders on the mechanical properties and durability of foamed concrete was investigated. Results showed that mineral powders decreased the drainage and disproportionation of foam, which stabilizes the foam. The excellent stability is attributed to the interaction between the mineral powders and ionic surfactants, which allows the mineral powders to adhere to the foam surface and form a dense granular film layer. Moreover, due to the interaction between mineral powders and ionic surfactants, hardened foamed concrete has a robust pore structure, which improves its properties.
Abstract
In order to improve the stability of lightweight foamed concrete, the particle-stabilized foam (PSF) has been proposed because of its high stability. However, most PSFs added [...]
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Influence of Alkali-resistant Glass Fibers Distribution on Properties of Cementitious Composites
B. Mrduljaš, A. Pranjić, M. Štefančić, K. Didulica, A. Baričević

DBMC 2023.

Abstract
The waste hierarchy establishes a prioritized framework for effective waste management, where higher levels such as prevention, re-use, and recovery are associated with the conservation of primary resources and the retrieval of secondary resources. This approach aligns with the objectives of the construction industry, which aims to promote the efficient utilization of resources by treating raw materials in an environmentally responsible manner. In this context, utilizing waste fibers to reinforce cementitious composites becomes more logical than producing new fibers with similar properties. These waste fibers typically originate from the production of high-performance technical textiles used for structural repair and rehabilitation. By reusing these waste materials, the construction industry contributes a circular economy in its own sector and fosters cross-sectoral industrial symbiosis. Although the potential benefits and positive environmental impact of utilizing such materials are recognized, their influence on the properties of composites requires further investigation. This study examines the impact of production waste glass fibers on the properties of the mortar in both the fresh and hardened states. The study focusses on properties such as compressive strength and toughness. To gain a better understanding of the fibers’ contribution to the matrix properties, an investigation was conducted using µCT. The study focuses on investigating the effects of waste fibers with lengths of 5 and 10 mm and different dosages (0.2, 0.6 vol.%) on the properties of high-strength mortar, comparing them with factory fibers.
Abstract
The waste hierarchy establishes a prioritized framework for effective waste management, where higher levels such as prevention, re-use, and recovery are associated with the [...]
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Study on Natural Passivation Behavior of Corrosion-resistant Steel Rebars in the Mortar
G. Liu, D. Zhang, H. Chen, Z. Fan, Q. Wu

DBMC 2023.

Abstract
The passivation behavior of HRB400 carbon steel rebar, 304 austenitic stainless steel rebar and 2304 austenitic-ferritic duplex stainless steel rebar during curing stage of mortar was studied by electrochemical testing techniques such as open-circuit potential, electrochemical impedance spectroscopy and linear polarization curve, and the corrosion resistance of the passivation film of the three rebars was compared to provide a reference for the practical engineering application of corrosion-resistant steel rebars. The study shows that all three types of steel rebars can be passivated during the 28 days curing stage of mortar, and 2304 duplex stainless steel rebars have the best passivation film corrosion resistance, followed by 304 stainless steel rebars, and HRB400 steel rebar was the worst.
Abstract
The passivation behavior of HRB400 carbon steel rebar, 304 austenitic stainless steel rebar and 2304 austenitic-ferritic duplex stainless steel rebar during curing stage of [...]
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Property and Environment Evaluation of Cement Replaced with Treated Reclaimed Concrete Slurry Waste
R. Jun, X. Yunqiu, L. Birunxuan, Z. Ji, L. Min

DBMC 2023.

Abstract
The development of the cement industry consumes piles of natural resources and generating huge amount of waste and causing serious pollution, which can be partially solved by replacing with other cementitious materials, in particularly, solid waste. Reclaimed concrete slurry waste (RCSW), a corrosive and hazardous the residues from the reclaimed system for retrieving the aggregates from the returned concrete or cleaning the concrete mixer and trucks in the ready-mixed concrete plant, could that cannot be used to manufacture reclaimed concrete. However, the pre-hydration limits the hydraulic property of RCSW, which requires the proper treatment. This paper investigated the effect of three different treatment methods in improving the performance of RCSW and its feasibility of replacing cement under different substitution ratio in manufacturing reclaimed concrete. The treatment included sieving, shearing and ball-milling, and the substitution ratio was set as 15%, 30% and 45%, respectively. In addition to compressive strength and hydration properties, the environment impact of the cement paste replaced with RCSW were investigated as well. The results showed that compared within three methods, the shearing and ball-milling generated the treated RCSW with smaller particle size and high roundness. For the RCSW substituted cement paste, the substitution with 15% of treated RCSW provided the highest strength, meanwhile, while at a higher substitution ratio significantly reduced the compressive strength. The 15% of ball milling treated RCSW produced more products during the hydration process, resulting in a denser structure. According to the economic and environmental calculations, RCSW substitution reduced CO2 emissions, in which, the ball-milling method showed a lower carbon footprint.
Abstract
The development of the cement industry consumes piles of natural resources and generating huge amount of waste and causing serious pollution, which can be partially solved [...]
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Oxygen Diffusion Property of Fatigue Damaged Concrete under Drying-wetting Cycle
J. Zhilu, H. Sheng, F. Chuanqing, Y. Wenjie

DBMC 2023.

Abstract
Oxygen diffusion has an important influence on the corrosion process of reinforced concrete structures. In the marine environment, concrete is subject to both fatigue loads and periodic drying-wetting conditions. In this study, the oxygen diffusion performance of damaged concrete due to fatigue is studied under drying-wetting cycle condition, which is of great significance to the development of concrete durability theory. The pore structures of concrete specimens with different damage degrees after drying-wetting cycle were measured by nuclear magnetic resonance (NMR). The effects of drying-wetting cycle and damage degree on pore structure were studied, and the oxygen diffusivity of damaged concrete before and after drying-wetting cycle was compared and analyzed. The results show that the pore size distribution curves of concrete specimens move to the smaller pores and the peaks decrease after 28 days of drying-wetting cycle. The proportion of gel pores (< 10 nm) increases and the proportion of medium and large capillary pores (10 - 1000 nm) decreases. After the drying-wetting cycle, the porosity of the damaged concrete specimens all decreased to certain degrees. It shows that the microstructure of the specimen is improved and the internal structure of concrete becomes more complex in the early stage of drying-wetting accelerated erosion. After the drying-wetting cycle, the oxygen diffusivity of all concrete specimens decreased, and the oxygen diffusivity of undamaged concrete decreased the most, about 10 times, but with the increase of damage degree, the reduction effect generally decreased.
Abstract
Oxygen diffusion has an important influence on the corrosion process of reinforced concrete structures. In the marine environment, concrete is subject to both fatigue loads [...]
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Optimal Amorphous Oxide Ratios and Multifactor Models for Binary Geopolymers from Metakaolin Blended with Substantial Sugarcane Bagasse Ash
L. Jing, T. Ye

DBMC 2023.

Abstract
As a potential precursor, the utilization of sugarcane bagasse ash imparts enormous technical and environmental benefits to human society. However, its rich crystal content challenges the mix design of sugarcane bagasse ash-involved geopolymers. The present study is aimed to contribute toward the substantial utilization of sugarcane bagasse ash in geopolymers and develop a guideline for designing binary geopolymers from metakaolin and sugarcane bagasse ash. The experimental results show that when suitably designed, the compressive strength of metakaolin-sugarcane bagasse ash geopolymers satisfied the structural use in building engineering, and the sugarcane bagasse ash proportion could substantially reach up to 50%. Moreover, through a combination of mechanical, economic and environmental assessments, the optimal mixing proportions fall into the following ranges: SiO2/Al2O3=4.63~5.60, Na2O/Al2O3=1.5~2.0 and H2O/Na2O=8~10. Further, multi-factor models are proposed to regulate the mix design of binary geopolymers, with a R2 value beyond 0.9 .
Abstract
As a potential precursor, the utilization of sugarcane bagasse ash imparts enormous technical and environmental benefits to human society. However, its rich crystal content [...]
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Negative Emission Potentials Using Biogenic Building Materials - A Case Study from Denmark
R. Torben Valdbjorn, T. Emil Engelund, B. Niclas Scott, N. Thomas, J. Uffe, B. Annette, G. Stefan Christoffer

DBMC 2023.

Abstract
Significant reductions in carbon footprint can be achieved by increasing the use of biogenic materials in construction. In biogenic materials, carbon is embedded as long as the materials are not biologically degraded, and they consequently act as carbon reservoirs that keep CO2 out of the atmosphere. The reservoirs of carbon are maintained if the biogenic materials during maintenance and renovation are replaced by similar ones. Buildings containing more wood, straw, and other biogenic materials and less concrete, steel, and mineral wool are therefore part of the way forward for a sustainable restructuring of the construction industry. Until now, the main focus has been on reducing energy consumption of buildings, while less focus has been on energy consumption and the climate impact from the production of materials and the construction process itself. This paper examines the potential carbon reservoir in the building stock in Denmark for the next 100 years. In detail the paper describes potential building components made from biogenic resources, outlines the necessary amounts and qualities of biogenic materials, and summarizes the available biogenic resources. The article is based on the conditions for construction in Denmark and the opportunities Denmark has as an industrialized agricultural country with a long coastline, which can be utilized in the production of biogenic resources for manufacturing of building materials.
Abstract
Significant reductions in carbon footprint can be achieved by increasing the use of biogenic materials in construction. In biogenic materials, carbon is embedded as long as [...]
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Molecular Dynamics Study between Amine Solution and Calcium Hydroxide
T. Pan, R. Kitagaki, Y. Yoda

DBMC 2023.

Abstract
Carbon dioxide can be captured by amines and carried into calcium hydroxide to generate calcium carbonate. In this study, molecular dynamics simulations were performed to study the interaction energy and structure between amine solution and calcium hydroxide crystal slab at the molecular level. MDEA was chosen as a representative amine. According to the one-dimensional concentration function, it was found that at a low ratio of MDEA, it was preferentially distributed close to the calcium hydroxide. And as the content in the solution increased, MDEA was gradually distributed equally throughout the aqueous solution. Compared to water, the interaction energy between MDEA and calcium hydroxide is greatly reduced and gradually decreases with increasing amine content. This means that the interaction between the two is reduced, and the reaction is more difficult to occur. In addition, the system of carbon dioxide dissolved in a solution of amine and water was simulated. The distribution of carbonate and bicarbonate was found to be relatively uniform at MDEA ratios of 5% and became irregular above 20%.
Abstract
Carbon dioxide can be captured by amines and carried into calcium hydroxide to generate calcium carbonate. In this study, molecular dynamics simulations were performed to [...]
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Laboratory and Pilot Investigation on Properties of precast Engineered Cementitious Composites (ECC) Subjected to Carbonation Curing
Z. Duo, E. Brian R., L. Victor C.

DBMC 2023.

Abstract
The concrete industry is facing an increasing challenge for sustainability. Besides the large embodied carbon, the intensive operational carbon associated with repetitive repair becomes the main hurdle for lifecycle emission reduction. In this study, the feasibility of sequestering CO2 into durable engineered cementitious composite (ECC) through early-age carbonation curing was investigated. The goal is to demonstrate a simultaneous reduction of the material’s embodied carbon (by CO2 sequestration) and lifecycle emissions (by ECC’s superior durability). The material was processed at both lab and pilot scales and was demonstrated on precast pedestrian pavement slabs. Results show that ECC was highly reactive to CO2 at lab scale, with 26.5% CO2 uptake by cement mass after 24-hour carbonation. However, the early-age carbonation was subjected to a significant size effect and attained a 4.3% CO2 uptake for pilot-scale specimens with a low specific surface area. Despite this reduction in carbonation efficiency, the calcite precipitation through carbonation curing was found to densify the fiber/matrix interface and improve the composite ultimate tensile and flexural strength by up to 28.8%. Carbonation curing also enhanced ECC’s crack width control, thus mitigating sulfate attack and lowering surface salt scaling on freeze-thaw exposure. It is suggested that producing ECC through carbonation curing is technically viable, and the carbon-sequestered ECC is recommended for small-scale precast components for enhanced durability and sustainability.
Abstract
The concrete industry is facing an increasing challenge for sustainability. Besides the large embodied carbon, the intensive operational carbon associated with repetitive [...]
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Impact of the Thaumasite Sulfate Attack on the Pore Structure and Gas Permeability of Cement Mortar
R. Bo, H. Tingyu, H. Xiaobin, L. Kefei

DBMC 2023.

Abstract
In this study, the impact of the thaumasite sulfate attack (TSA) on cement mortar was investigated by comparing it to the ettringite sulfate attack (ESA). Mortar specimens with three binders, corresponding to the blank, ESA, and TSA, were exposed to sulfate solution. The evolutions of thaumasite and ettringite formation, pore structure, and gas permeability on the mortar specimens were characterized through XRD, 1H NMR, and CemBureau device. The experimental results show that: (1) both ettringite and thaumasite were formed in TSA; (2) ESA reduces the capillary pore space, whereas TSA decreases both the capillary pore and interlayer pores; and (3) ESA decreases the gas permeability while TSA significantly increases it.
Abstract
In this study, the impact of the thaumasite sulfate attack (TSA) on cement mortar was investigated by comparing it to the ettringite sulfate attack (ESA). Mortar specimens [...]
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Fracture Process of In-situ Polymerization Modified Cementitious Materials
X. Chengji, Z. Qiang

DBMC 2023.

Abstract
By regulating cement hydration reaction and organic monomer polymerization, the strength and deformability of in-situ polymerization modified cement-based materials are greatly improved. However, the fracture processes of this type of organic-inorganic composites have not been systematically investigated. In this work, sodium acrylate (SA) monomer in-situ polymerization modified cementitious composites (iPSA) were fabricated. Three-point bending (TPB) test was conducted with digital image correlation (DIC) technique for characterizing the fracture process zone (FPZ). Microscopic test was conducted to unravel the crosslinked organic-inorganic composite structures in the iPSA matrix. Results showed that an obvious strain concentration region occurred and grew at the notch tip of the iPSA beams with load. The gradually expanding width of FPZ was normally distributed. Microscopic test suggested that the physical interlinks between the cement hydrates and sodium polyacrylate may resist again the FPZ development of iPSA. The findings of this work would deepen the understandings of fracture process of polymer modified cementitious composites with broad engineering applications.
Abstract
By regulating cement hydration reaction and organic monomer polymerization, the strength and deformability of in-situ polymerization modified cement-based materials are greatly [...]
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Evaluation of Carbonation Degree of Hardened Cement Paste with Different Water-Cement Ratio in Wet-Dry Cycle
Z. Zhao, D. Oh, Y. Wang, R. Kitagaki, T. Masuo

DBMC 2023.

Abstract
One of the global environmental problems, CO2 emissions from cement production intensifies in these decades. To solve this problem, countermeasures for CO2 emissions using waste concrete, which has ability to absorb CO2 due to contain calcium-silicate-hydrate (C-S-H) and portlandite (Ca(OH)2), are in the spotlight recently. However, considering the limited time before recycling as roadbed materials, it is important to increase CO2 absorption efficiency so that as much CO2 as possible reacts with waste concrete. In this study, hardened cement paste powders (HCPWs) with the water-to-cement ratios of 0.4, 0.5 and 0.6 were evaluated for the degree of carbonation under various humidity conditions. HCPWs were pulverized to a particle size of 0.6 to 1.18mm and put in desiccators keeping constant humidity condition of RH60 and RH80. In addition, desiccators were prepared with RH60-80 cycle (wet-dry cycle) of 30 minutes, 1 hour, 2 hours and 4 hours to determine the degree of carbonation promotion according to periodic humidity changes. The degree of carbonation of HCPWs were measured by thermogravimetric analysis (TGA). The result shows that the degree of carbonation was improved as the water-cement ratio increased, because the higher the water-to-cement ratio, the more open pores were contained. In addition, vaterite and aragonite caused by the decomposition of C-S-H were the most produced under RH60-80 cycle conditions. This is considered to be because the reaction area with CO2 was increased by weakening the C-S-H by repeating drying and wetting.
Abstract
One of the global environmental problems, CO2 emissions from cement production intensifies in these decades. To solve this problem, countermeasures for CO2 emissions using [...]
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Evaluate the Ability to Determine the Carbonation Depth of Concrete by Hyperspectral Imaging
Y. Wang, D. Oh, R. Kitagaki

DBMC 2023.

Abstract
In recent years, using concrete to absorb CO2 in the atmosphere has attracted attention as one of the global warming countermeasures. In general, destructive methods have been used to evaluate the amount of CO2 absorption in concrete buildings and civil engineering structures. However, it needs to sample a portion of the concrete, and it is impractical to conduct continuous disruptive sampling of the structures in use. Therefore, it is necessary to develop non-destructive tests to evaluate the amount of CO2 absorption in concrete. In this study, Multi-spectral imaging, which are the methods of non-destructive tests, were used to visualize the presence of calcium carbonate with depth-axis from surface of the concrete specimen which have been the preliminary drilled holes. In addition, moistened cotton swabs were used to extract the pore solution by pressing the inner wall of the hole and to test it for determination of the distribution of pH with depth. The results indicate that Multi-spectral imaging can evaluate different carbonation depths of concrete samples. Moreover, PH of each point examined in the specimens can evaluate as the depth distribution of calcium carbonate. Results were compared and discussed with each other depending on each methodological characteristic.
Abstract
In recent years, using concrete to absorb CO2 in the atmosphere has attracted attention as one of the global warming countermeasures. In general, destructive methods have [...]
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Effects of Multi-scale Siliceous additives on Hydration and Microstructure of Hardened Cement Pastes
X. Zhang, Y. Zhang, J. Zeng, K. Wu

DBMC 2023.

Abstract
Siliceous materials are commonly used in concrete with physical filling and higher pozzolanic reactivity, such as silica fume (SF) and nano-silica (NS). Investigations were conducted into the effects of SF, hydrophobic silica fume (HSF), and synthesized NS on the mechanical properties and microscopic characteristics of hardened cement pastes (HCPs). The surface of silica fume was hydrophobically modified using isooctyltriethoxysilane. Fourier infrared spectrometer (FTIR), X-ray diffractometer (XRD), and energy spectrometer (EDS) were used to evaluate the hydration, while mercury intrusion porosimetry (MIP) and scanning electron microscope (SEM) were used to analyze the pore structure and microscopic morphology of HCPs. The results demonstrated that HSF has better dispersion in cement pore solution. The addition of HSF exhibits the higher pozzolanic reactivity, weakens CH diffraction peaks, generates higher levels Q3 C-S-H gels, and significantly lowers the Ca/Si ratio of C-S-H gels. Due to the hydrophobicity, HSF increases the volume of micro-pores in range of 10-100 nm, resulting in a decrease in strength. Compounding HSF and NS further weakens the CH diffraction peak, decreases the Ca/Si ratio of C-S-H gels, and reduces the micro-pore volume to refines the pore structure.
Abstract
Siliceous materials are commonly used in concrete with physical filling and higher pozzolanic reactivity, such as silica fume (SF) and nano-silica (NS). Investigations were [...]
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Effect of Sulfate Attack on Compressive Strength of Foamed Cement Paste under Static Cyclic Loading
Y. Guanbao, X. Yiling, Z. Zhen, S. Honghui

DBMC 2023.

Abstract
Foamed cement paste has been increasingly used as backfill material in roadways and railway embankments due to its advantages of adjustable density and strength. The embankments constructed by foamed cement paste in coastal regions is subjected to both traffic loading and chemical erosion in service life. This paper conducted a series of durability tests to investigate the reduction of static and dynamic strength of foamed cement paste after the specimens were immersed in sodium sulfate solutions.The specimens were prepared with densities of 800 and 900 kg/m3. The influence factors of specimen density, concentration and cation type of sulfate solution on the strength degradation of the specimens were discussed. The results showed that the corrosion resistant coefficient of the specimens was reduced with the increase of immersion time and concentration of sodium sulfate solution. The degradation of the compressive strength under cyclic loading is more serious than that under static loading. The high density specimens perform better durability than low-density specimens, as the specimens with 900 kg/m3 under 28 and 56 days of sulfate attack had smaller reduction in both dynamic and static strengths than the specimens with 800 kg/m3.
Abstract
Foamed cement paste has been increasingly used as backfill material in roadways and railway embankments due to its advantages of adjustable density and strength. The embankments [...]
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Effect of Endogenous Chloride Ion on Corrosion of Rebar in Sea-sand Ultra-high Performance Concrete
H. Lian, H. Wei, C. Zhendong, C. Rong, W. Jiangang, C. Baochun

DBMC 2023.

Abstract
Ultra-high performance concrete (UHPC) is an innovative cement-based composite material characterized by extremely high durability and mechanical properties, which provides a potential possibility of using non-desalted sea-sand as aggregate. However, the long-term steel corrosion behavior in UHPC prepared by simulated sea-sand under different immersion environments remains unclear. In this study, the pore structure of sea-sand UHPC matrix was measured using nitrogen adsorption/desorption method. The corrosion behavior of rebar in sea-sand UHPC with different endogenous chloride ion contents soaking in pure water and NaCl solution was characterized by electrochemical workstation. The experimental results show that the initial UHPC pore structure is refined by incorporation ofsea-sand, and is similar to that of ordinary UHPC at the later hydration. Regardless of the endogenous chloride ion content and immersion environment, the corrosion rate evaluated by corrosion current density (icorr) and polarization resistance (Rp) of reinforcement in UHPC is extremely low. The measurement of EIS shows that UHPC group has higher matrix resistance (Rc) and charge transfer resistance (Rct), while lower electric double layer capacitance (CPEdl) of reinforcement, which indicates that the steel in UHPC made of sea-sand is still in a state ofpassivation. However, the steel bar in comparison specimen OPC soaking in NaCl solution is in the corrosion stage. Furthermore, sea-sand UHPC possesses of excellent ability of anti- pitting corrosion ofreinforcement after 180 days ofimmersion in NaCl solution.
Abstract
Ultra-high performance concrete (UHPC) is an innovative cement-based composite material characterized by extremely high durability and mechanical properties, which provides [...]
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Carbonation of Concrete Cured Under Different Conditions
O. Kolawole A., A. Nafisat M.

DBMC 2023.

Abstract
Concrete is cured under different conditions to preserve the moist state of the concrete matrix for continuous hydration as it is done on most construction sites. In this study, the effect of different curing techniques on the carbonation depth of concrete mix is presented. Concrete matrix of mix ratio 1 :2 :4 with a water-cement ratio of 0.5 was prepared and cast into cubes of sizes 150 mm. After 24 hours, the concrete cubes were removed from moulds and cured using different techniques for 3, 7, 28, 56, and 91 days. Thereafter, the compressive strength of the concrete cubes and carbonation depths were determined for each curing day. The curing techniques investigated were immersion in water (IM), sprinkling (SP), polyethylene membrane (PM), damp sand (DS), indoor (OI), outdoor (OT), and saturated wet covering (SWC). The results indicated that carbonation depth differed with each of the concrete cured in different techniques. It was observed that concrete exposed outside was worst affected by carbonation followed by those cured indoor, while those cured with polythene showed the least carbonation depth. It was concluded that the polythene membrane curing technique was the best curing technique to limit the effect of carbonation of concrete.
Abstract
Concrete is cured under different conditions to preserve the moist state of the concrete matrix for continuous hydration as it is done on most construction sites. In this [...]
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Biomimetic Organic-Inorganic Hybrid Magnesium Oxychloride Cement as Green Adhesive for Biomimetic Organic-Inorganic Hybrid Magnesium Oxychloride Cement as Green Adhesive for Wood Industry
H. Yufei, K. Xiangming

DBMC 2023.

Abstract
Benefiting from the negative carbon footprint of wood, wood composites have been considered as eco-friendly alternative building materials. However, adhesives for bonding wood components are mainly formaldehyde-based resins, which are highly combustible and continuously release volatile hazardous substances during service. Therefore, the development of magnesium oxychloride cement (MOC) as wood adhesive is highly compliant with environmental regulations and green material requirements. Unfortunately, the extensive application of MOC adhesive is hindered by poor water resistance and weak interfacial interaction with wood. Herein, an oyster-inspired organic-inorganic hybrid strategy was proposed to develop MOC with high adhesion strength and excellent water resistance. Specifically, the renewable chitosan (CS) and tartaric acid (TA) were selected as organic reinforcing constituents to construct a dense double chelating network in MOC, which induced the structural regulation at the bonding interface, thus enhancing the cohesion strength and interfacial properties. Thanks to the biomimetic organic-inorganic hybrid structure, the dry and wet shear strength of the MOC-CS-TA reached 3.08 MPa and 1.77 MPa, making increases of 27.27% and 53.91% compared to the control sample, respectively. Meanwhile, the MOC-CS-TA adhesive presented excellent flame-retardant properties compared with urea-formaldehyde resin adhesives and soy protein adhesives. The design path presented here provides workable guidance for the preparation of eco-friendly cementitious materials and green wood composites in further applications.
Abstract
Benefiting from the negative carbon footprint of wood, wood composites have been considered as eco-friendly alternative building materials. However, adhesives for bonding [...]
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Application of Nanomaterials for Enhancing the Performance of Recycled Aggregate Concrete-A Short Review
X. Caihong, Z. Qingxin

DBMC 2023.

Abstract
Incorporation of recycled concrete aggregates (RA) produced from construction and demolition wastes in concrete contributes to the sustainability from two perspectives: reducing environmental pollution and reserving natural resources by reducing the consumption of natural aggregates (NA). However, comparing to NA, RA has lower mechanical properties and higher water absorptivity due to the old mortar attached on RA surface, resulting in weakened interfacial transition zones (ITZs) in the concrete and the consequent reduced durability of concrete when RA was used to replace NA for producing recycled aggregates concrete (RAC). Therefore, extensive research work had been devoted to the enhancement of RAC performance and nanomaterials have demonstrated great potential in this regard. This paper reviews recent progress on the application of various nanomaterials for improving the microstructure as well as nano/mechanical properties of ITZs in RAC, and special attentions were given to the dispersion strategies for nanomaterials which determines the amount of nanomaterials required to achieve reliable improvement in RAC performance and thus the cost of using nanomaterials in RAC.
Abstract
Incorporation of recycled concrete aggregates (RA) produced from construction and demolition wastes in concrete contributes to the sustainability from two perspectives: reducing [...]
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Modification of Recycled Cement with Different Additives
L. Xu, J. Wang

DBMC 2023.

Abstract
The unmodified recycled cement (RC) paste has unfavorable properties (like fast setting, high water demand and low strength) restricting application. This paper intends to rectify these shortcomings and improve RC with different additives. A comprehensive experimental program combining flowability, setting time, isothermal calorimetry and mechanical tests of modified recycled cement (M-RC) paste with different proportions were conducted. The results indicate that adding TEA and pectin could significantly improve the early flowability of RC and delay its setting, but it will have adverse effects on the mechanical properties of RC paste. Adding 0.5% TEA or 0.075% pectin can increase the fluidity by 240% and 293%. For the 0.5% TEA and 0.075% pectin groups, the 3-day compressive strengths were reduced by 44.3% and 49.5%, respectively.
Abstract
The unmodified recycled cement (RC) paste has unfavorable properties (like fast setting, high water demand and low strength) restricting application. This paper intends to [...]
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Influence of Waste Fibers on the Total Porosity of Cementitious Composites
K. Didulica, A. Pranjić, M. Štefančić, B. Mrduljaš, A. Baričević

DBMC 2023.

Abstract
The amount of water is essential to explain the shrinkage process. It is determined by the water-cement ratio, but also by the moisture content. Water in hydrated cement paste occurs in various forms: chemically bound, interlayer, adsorbed, free water and water vapor. During cement hydration, the balance between various forms of water changes. For example, the amount of physically bound water diminishes, and the moisture content changes at similar environmental conditions. Moisture changes occur first in the larger pores and then in the smaller pores. The air pores are larger than the hydration pores (capillary pores, gel pores) and have a greater effect on strength and permeability properties, while the cement hydration pores have a greater effect on shrinkage. At early ages, when composite properties are not fully developed, higher shrinkage influences the development and propagation of cracks. These (micro)cracks represent weak points and affect durability. To reduce shrinkage and bridge the cracks, fibers are added to the cementitious composite. Depending on the type and geometry, the fibers can reduce shrinkage and bridge the cracks. To reduce the environmental impact of fiber production, the use of waste fibers in cementitious composites is proposed. The main objective of this study was to investigate the influence of alkali-resistant glass fibers from production waste on the development of the microstructure of cementitious composites, i.e., the influence on the total porosity. The pore content was determined on fresh cementitious composites after mixing, while the total porosity of the material was measured after 28 days using a mercury intrusion porosimeter. Results were complemented by X-ray computed microtomography (micro-CT). The influence of production waste fibers is presented as a function of length and fiber content. In addition to the reference mixture, results were also compared with mixtures containing factory-produced fibers.
Abstract
The amount of water is essential to explain the shrinkage process. It is determined by the water-cement ratio, but also by the moisture content. Water in hydrated cement paste [...]
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Effect of Current Modes on Electrochemical Chloride Extraction Treatments for Concrete
C. Song, C. Jiang, X. Gu, Q. Zhang

DBMC 2023.

Abstract
The current mode plays an important role in the Electrochemical Chloride Extraction (ECE) treatment for concrete. In this study, the experiments were conducted to investigate how the ECE process would be affected by different current modes (continuous and intermittent current modes). The results showed that there were remaining amounts of chloride ions that were hard to be removed by both current modes. Additionally, the porosity under the two current modes showed the same upward trend compared to the initial value, and the chloride diffusion coefficient increased by 1 - 2 times. Also, the chloride-contaminated concrete subjected to the continuous current mode had a higher cumulative chloride extraction content than that subjected to the intermittent mode. The intermittent current mode could not increase the effectiveness of extracting chloride when the current density was not greater than 3 A/m2 and the on-off ratio was not less than 3.2.
Abstract
The current mode plays an important role in the Electrochemical Chloride Extraction (ECE) treatment for concrete. In this study, the experiments were conducted to investigate [...]
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Comparison of Non-calcined and Calcined Red Muds from Different Sources as Potential Supplementary Cementitious Material
S. Chen, A. Ghani Razaqpur

DBMC 2023.

Abstract
Red mud (RM) is a hazardous by-product of alumina refining processes. Due to its high alkalinity, large specific surface area, and complex and variable composition, RM is hard to treat or utilize on a large scale. To date, more than 4 billion tons of RM have been stockpiled globally and is still growing by more than 120 million tons annually. Many investigations have focused on the largescale utilization of RM as a construction material, either in its virgin form or after heat treatment. However, the huge differences among the chemical/mineralogical compositions of RMs due to differences among bauxite ores from different sources and/or different refining processes, it is difficult to prescribe a unique process for activating RM cementitious/pozzolanic properties. The present study aims to identify the key chemical and process-dependent factors that influence the cementitious/pozzolanic properties of RM. Two types of RM from different sources are investigated to determine the effects of the chemical/mineralogical composition, the alumina refining process, and calcination on the mineralogical phases and compressive strength of mortar cubes made with ordinary Portland cement (OPC)- RM blended cement. Mortar made with 15 wt.% OPC replaced by one type of virgin RM produced by the Bayer’s process was found to have better strength than a control mortar made with 15% OPC replaced by sand, which indicates that this RM had cementitious/pozzolanic property without requiring heat treatment. On the other hand, the RM produced by the bauxite calcination method needed heat treatment to improve its pozzolanicity, but, despite the improvement, mortar made with its optimally treated form had lower 91-day compressive strength than the companion control mortar made with extra sand as RM replacement. The compressive strength of mortars made with calcined RM was not only affected by the phase changes of the virgin RM properties brought about by calcination but also by changes to its physical.
Abstract
Red mud (RM) is a hazardous by-product of alumina refining processes. Due to its high alkalinity, large specific surface area, and complex and variable composition, RM is [...]
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Rebar-matrix Interface in Extrusion Molded Cementitious Filaments
R. Yang, Q. Zeng, Z. Wang

DBMC 2023.

Abstract
Extrusion molding enables automatic construction through the pattern of material addition. The unique molding would result in several features that are different from those in conventional framework molding, such as weak interlayer bonding and a laminar structure with high anisotropy. To strengthen the interlayer bonding, reinforcement is often implanted to penetrate through the extrusion molded filaments (EMF). However, different from the pre-implantation of reinforcement before concrete casting, the post-implantation of reinforcement in EMF may trigger the problems concerning the interface bonding between reinforcement and material matrix. In this work, saddle stitches, a type of Ushape rebar or fiber, are taken as an example to demonstrate the effect of the post-implantation of reinforcement on the interfacial structure between the rebar and EMF matrix. X-ray computed tomography (XCT) is employed to non-destructively probe the post-implanted saddle stitches as well as the surrounded EMF materials. Regions of interest (ROI) are set on the rebar-matrix interfaces to elaborately analyze the material or defect distributions around the saddle stitches. Results demonstrate that insufficient material filling is observed at the outboard of the U-shape rebar, while material pressing is shown at the inboard. Large defects unevenly form in the rebar-matrix interface. Mechanisms of the observations may be ascribed to the low flowability of EMF materials that can hardly migrate to the rebar-matrix interfacial gaps spontaneously. The findings would deepen the understandings in rebar-matrix interfacial structure of EMF with post-implantation of reinforcement.
Abstract
Extrusion molding enables automatic construction through the pattern of material addition. The unique molding would result in several features that are different from those [...]
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Effectiveness of Paraffin-based Curing Compound for Mitigation of the Plastic Shrinkage and Related Cracking of the 3D-printed Concrete Elements
S. Markin, V. Mechtcherine

DBMC 2023.

Abstract
3D-printed concrete elements are highly vulnerable to early-age shrinkage and cracking compared to conventionally cast concrete elements. Material compositions of printable concretes and complete renunciation of shuttering are responsible for accelerated capillary pressure build-up, leading to volumetric constructions of the 3D-printed layers at a very early age after extrusion and enhanced shrinkage at a later age. Shrinkage-induced cracks can severely impair the durability and appearance of 3D-printed concrete structures. The study at hand analyses the efficacy of the paraffin-based curing agent for reducing the shrinkage and cracking of 3D-printed elements and structures. Development of the temperature and capillary pressure, as well as shrinkage strains, were reported for the cured and uncured specimens. The study results show that applying paraffin-based curing agents can considerably reduce shrinkage-indued deformations of the 3D-printed elements produced even under extreme environmental conditions.
Abstract
3D-printed concrete elements are highly vulnerable to early-age shrinkage and cracking compared to conventionally cast concrete elements. Material compositions of printable [...]
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Effect of Delayed Addition of TEA on the Performance of Cement with Different Sulfate Carriers
Z. Lu, X. Peng, Z. Sun, D. Stephan

DBMC 2023.

Abstract
Concrete 3D printing is one promising technique used for future construction. However, a bottleneck limiting this technology's rapid development and practical application is the conflicting requirements for concrete properties before and after printing. Hence, the application of the accelerator and a deep understating of its working mechanism is becoming more and more important. As one commonly used accelerator, triethanolamine (TEA) has the advantage of low dosage and high efficiency to reach a fast setting. However, it is still unclear how the delayed addition of TEA affects the performance of cementitious materials. Besides, it is found that the different types and combinations of sulfate carriers can significantly affect the performance of TEA on cement hydration. However, the combined effect of different sulfate carriers and different addition times of TEA on the hydration process of cement paste is also unclear. The effect of different TEA addition times on the hydration and setting performance of cement pastes containing different types and combinations of sulfate carriers were thoroughly investigated in this study. It is found that, depending on the types of sulfate carriers inside, the different addition times of TEA can significantly affect the hydration and setting performance of cement paste. Specifically, to artificial cement (ArC) prepared with hemihydrate (HH), the different TEA addition times do not affect the setting performance of cement paste. To ArC with the two sulfate carriers of anhydrite (AH) and HH, a flash setting was observed when the TEA was added simultaneously. However, a delayed addition of TEA for just 5 min can make the setting performance back to normal. To ArC with only AH, a longer addition time of 15 min is needed to eliminate the flash setting behavior. This phenomenon could be originated from the competed interaction of sulfate ions released from sulfate carriers and TEA with the aluminate phase contained in the clinker.
Abstract
Concrete 3D printing is one promising technique used for future construction. However, a bottleneck limiting this technology's rapid development and practical application [...]
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Adapting Construction and Demolition Waste to Circular Building Materials and Evaluation of Life Cycle Environmental Impacts
A. Kul, E. Ozcelikci, B. Furkan Ozel, G. Yildirim, A. Ashour

DBMC 2023.

Abstract
Upcycling of construction and demolition wastes (CDWs) into value-added building materials that can be used for rapid construction and housing in developing countries and disasterprone areas is important and offers a fast, cost-effective, and eco-friendly solution. The objective of this study is to investigate the feasibility of using different-size recycled concrete aggregates (RCAs) in geopolymers made entirely from CDW-based masonry components including hollow brick (HB), red clay brick (RCB), and roof tile (RT) as precursors. To improve the strength development, thermal curing was applied to the developed geopolymer mortars. Compressive strength test was used for mechanical characterization. To assess the environmental impact of geopolymer mortars, a cradle-to-gate life cycle assessment (LCA) was carried out. Findings revealed that RT-based geopolymer mortars were with the highest compressive strength level reaching 66.2 MPa based on different mixture and curing parameters. Compressive strength increased with the reduction in the maximum RCA size. According to LCA analysis, CDW-based geopolymer mortars resulted in similar strength but significant reduction in CO2 emissions (up to 60%) and are with comparable energy consumption to the Portland cement-based mortars.
Abstract
Upcycling of construction and demolition wastes (CDWs) into value-added building materials that can be used for rapid construction and housing in developing countries and [...]
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A Conceptual Model for Assessing Circularity Potential of Building Materials at the Product Manufacturing Stage
N. Tharaka Dharmasiri Pathberiyage, E. Delzendeh, F. Cheung, M. Mateo Garcia

DBMC 2023.

Abstract
The construction industry presently accounts for 30% of natural resource extraction and 25% of solid waste generation. The prevailing economy is “Linear” which is summarised as take-makedispose. On the contrary, the “circular economy” model is a systematic model to restore, regenerate and expand the lifecycle of materials. Most of the existing circularity assessment methods are focused on the end-of-life wastage of building materials while neglecting resource consumption and wastage at the product manufacturing stage. Further, these methods only consider direct material flows for assessing the circularity potential of building materials and overlook the indirect material flows associated with product manufacturing. There is a need to develop metrics to assess the circularity performance of building materials more holistically. Therefore, this study proposes a conceptual model to assess the circularity potential of building materials by analysing both direct and indirect material flow processes of the product manufacturing stage including raw material extraction, transportation, and manufacturing. The method used to design the conceptual model includes a comprehensive literature review in two stages. First, the existing circular assessment methods are reviewed to identify the methods used for assessing the circularity potential of building materials. Secondly, the circularity options are explored to develop the circularity metrics. According to the findings of this study, in the absence of a comprehensive method to assess the circularity potential of building materials, the life cycle assessment and material flow analysis are the most prominent circularity assessment methods used. Furthermore, circularity options such as industrial waste (by-products), biodegradability, biofuels, renewable energy, reusability, recoverability, recyclability and product life span are identified as the circularity metrics for building materials at the product manufacturing stage.
Abstract
The construction industry presently accounts for 30% of natural resource extraction and 25% of solid waste generation. The prevailing economy is “Linear” which [...]
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State-of-Art of Construction 4.0: An Academia Vs Industry Comparative Study
W. Ahmad, S. Azhar

DBMC 2023.

Abstract
The manufacturing industry is experiencing the 4th Industrial Revolution, also known as Industry 4.0. It encapsulates cyber-physical systems (i.e., combining sensing, computation, control and networking into physical objects and infrastructure) integrated towards digitalization and automation of the manufacturing sector. The construction industry has also benefited from these technologies, which go by Construction 4.0. Despite the construction industry often being blamed for its reluctance to implement emerging technologies and non-traditional management methods, recent research attempted to integrate Industry 4.0 emerging technologies to keep up with the manufacturing sector. This shows that academia and industry need each other’s hand-in-hand support in order to implement these technological advances. This study investigates the status of Construction 4.0 technologies adoption in academia and industry in the United States of America (USA) and measures the level of collaboration. Relevant data is collected via web-based questionnaire surveys that are distributed to academia and industry professionals within the USA to inquire about the status of construction 4.0 technologies and their adoption rate. The collected data are analyzed and important findings are reported in this paper. The results show that around 61% of the professionals from academia and 33% from industry are fully or somehow familiar with the term – ‘Construction 4.0’. There has been significant adoption of BIM, laser scanners, and drones in each sector. The rest of the technologies show potential in upcoming years, and academia and industry have methods in place of updating the workforce on new technologies. However, a lack of collaboration has been observed as 50% of the respondents reported no ongoing or past research projects between academia and industry in this domain. It is hoped that the findings of this research will help both academia and industry to join forces to modernize the construction industry.
Abstract
The manufacturing industry is experiencing the 4th Industrial Revolution, also known as Industry 4.0. It encapsulates cyber-physical systems (i.e., combining sensing, computation, [...]
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Reality Capture (RC) Technology for Drywall Installation: A Scan-toPrefab Approach
S. Alathamneh, J. Liu, S. Azhar, R. Burt

DBMC 2023.

Abstract
Drywall, also known as gypsum board, sheetrock, or plasterboard, is a widely used building sheathing material in the US and Canada to create interior walls and ceilings. Typically, the design and construction documents of a project exclude detailed information about the layout of drywall sheets on interior surfaces. Such information is left to the drywall installation crews to determine solely based on their experience. This inconsistent approach often results in substantial rework and waste of material in the field. The construction industry has seen a significant increase in the adoption of Reality Capture (RC) technology in recent years, with the goal of improving the quality and productivity of various construction activities. This research aims to investigate the implementation of RC technology, explicitly Terrestrial Laser Scanning (TLS) and Structure from Motion (SfM, also referred to as photogrammetry), in drywall installation. The research team has developed a framework that utilizes RC tools to capture the as-built information of the framing members of interior walls and penetrations of the MEP systems and uses these RC data to develop prefabricating shop drawings in a Building Information Modeling (BIM) platform for drywall cutting and installation. This framework has been tested and studied on active construction project sites. The preliminary findings indicate that this framework has the potential to lead to a more precise and efficient drywall installation process. This paper also proposes a process model for the execution of the proposed framework for improving drywall installation.
Abstract
Drywall, also known as gypsum board, sheetrock, or plasterboard, is a widely used building sheathing material in the US and Canada to create interior walls and ceilings. Typically, [...]
- 97
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Lateral Behavior of Modular Steel Buildings with Diaphragm Connections
X. He, Y. Wei

DBMC 2023.

Abstract
Modular steel buildings are increasingly popular due to their high level of industrialization. Corner-supported modular steel buildings are typically connected by inter-module connections at the corners of each module without continuous diaphragm slab. Therefore, rigid diaphragm assumption could not be adopted when designing modular steel buildings as in-plane deformation of the slab level is significant. To address this issue, the present study introduces diaphragm connections along the edges of modules at the floor slab levels. Then the lateral behavior of modular steel buildings with and without diaphragm connections is evaluated, as well as when a rigid diaphragm is assumed in the structures. The effect of diaphragm connection on lateral behavior of modular steel building under different parameters is discussed, including modular aspect ratio, number of modules in one storey, bracing system, and number of storeys. It is concluded that using diaphragm connections could improve the lateral behavior of modular steel buildings and simplify the design process.
Abstract
Modular steel buildings are increasingly popular due to their high level of industrialization. Corner-supported modular steel buildings are typically connected by inter-module [...]
- 3
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Investigation of the Initial Quality of Robotic Tile Installation Based on Coupled Eulerian-Lagrangian Approach
K. Wu, Y. Zhang, X. Kong, S. Zhang

DBMC 2023.

Abstract
In this study, the initial quality of robotic tile installation under various construction parameters and material properties of adhesive were investigated based on the fluid–structure coupling construction models for the first time. First, the models of adhesive application and tile leveling were developed based on the coupled Eulerian–Lagrangian approach. Then, on the basis of these models, various patterns of adhesive application, types of tile leveling loads, numbers of adhesive strips and yield stresses of adhesive were simulated and their influence laws on the initial quality of robotic tile installation were analyzed. Finally, the influence mechanisms of these parameters on the installation quality were revealed in terms of the spacing between adhesive strips, tile rebounding, contact areas and defect distribution. Results showed that the adhesive with horizontal application possessed smaller plastic deformation, kept stable shape of strips and distributed at equal spacing, compared with the one with vertical application. In contrast to a single compression load, its couplings with vibration loads were beneficial to the reduction of tile rebounding. Among the coupling loads, the coupling of shear vibration with compression considerably increased the tile–adhesive contact area until no interfacial defect appeared. The increase of the number of adhesive strips exerts few effects on the installation quality, including slight increases of contact areas as well as diminished interfacial defects. In the case of relatively low and high yield stresses of adhesive, the shear vibration effects were respectively large and small which decrease the installation quality.
Abstract
In this study, the initial quality of robotic tile installation under various construction parameters and material properties of adhesive were investigated based on the fluid–structure [...]
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Intelligent Construction via Digital Twin Approach
M. Lauria, M. Azzalin

DBMC 2023.

Abstract
The paper presents the results of an ongoing research activity dealing with Digital Twin (DT) approaches for Intelligent Construction, optimizing Operation and Maintenance of buildings and urban areas. DT is an essential technological node of Industry 5.0, which leads to the growth of a Collaborative Industry based on the cooperation between machines and human beings to give added value to processes that meet the needs of users. DT realizes the synchronization between two realities: physical objects in real space, virtual objects in virtual space, remaining connected through the mutual exchange of data throughout the entire life cycle of the object. The construction sector is also adopting the new DT perspective to enforce innovative, responsible, and sustainable governance of the life cycle of buildings improving their durability and reducing environmental impacts. Due to IoT, AI, and virtualization, DT approaches permit prediction of future performance in-use, prevent anomalies, downtime, and inefficiencies, to experiment improvements or changes without having to test them on the construction itself or on special mock-ups. The research assumes the aforesaid considerations and states as its principal operational and experimental assets as-built virtual models in OpenBIM connected with Geographic Information Systems and an IoT infrastructure. They realize intelligent constructions integrated with an analytical data communication network for control and performance simulations. Through the study cases analyzed, the paper also introduces arguments for a critical literature review on current statements and future challenges of the DT approach for Intelligent Construction.
Abstract
The paper presents the results of an ongoing research activity dealing with Digital Twin (DT) approaches for Intelligent Construction, optimizing Operation and Maintenance [...]
- 1
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Influence of Temperature Increase on the Degradation Evolution of Rendered Façades
J. Barrelas, A. Silva, J. de Brito, A. Tadeu

DBMC 2023.

Abstract
Climate change could alter the natural degradation pattern of buildings and their components. Façade claddings are directly exposed to the action of environmental agents, thus being particularly vulnerable to climate change impacts. Determining the expected degradation of the façades’ external layer, according to climate parameters’ projections, could be useful in the context of maintenance planning and adaptation to climate change. The present study intends to deepen the knowledge about the influence of temperature on the degradation evolution of rendered façades, considering the analysis of possible correlations between variables, based on observed and recorded climate data. It covers the degradation evolution of a sample of 26 rendered façades located in Lisbon, Portugal, based on the mean triennial degradation rate (∆Sw,mt) for periods of three years between 1990 and 2020. The severity of degradation index (Sw) of each façade, assessed through visual inspections in two moments in time, is used to model the individual degradation of the respective case study, necessary to calculate the sample’s ∆Sw,mt of to each triennium. The correlation between the dependent variable ∆Sw,mt and the independent variable ‘maximum temperature’ is significant, with a Pearson correlation coefficient of approximately -0.89. The negative trend shows that the degradation of the sample tends to decelerate with the increase of maximum temperature. Therefore, the temperature warming projected for the end of the century could contribute to lessen the rate of rendered façades’ degradation in the future, in Portugal or in analogous areas of the Mediterranean. The present study is part of a methodology that is being developed to quantify the impact of changes in climate parameters on the future degradation of rendered façades. Further research is necessary regarding the degradation projections, based on the climate change signal for maximum temperatures.
Abstract
Climate change could alter the natural degradation pattern of buildings and their components. Façade claddings are directly exposed to the action of environmental agents, [...]
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Impact of High-resolution Regional Climate Conditions on the Moisture Performance of Wood-frame Building Envelopes
C. Aggarwal, L. Wang, M. Junginger, M. Defo, A. Gaur, H. Ge, M. Lacasse

DBMC 2023.

Abstract
Climate data is one of the most important inputs for hygrothermal simulations and significantly influences the simulation results that are used for moisture performance assessment of building envelopes. Conventionally, climate data from representative weather stations are used for hygrothermal simulations to assess the moisture performance of the buildings. Recently, the Construction Research Centre of the National Research Council Canada generated historical and future climate data for 564 locations across Canada. In this paper, the climate data of four urban locations within Vancouver (a humid and warm coastal city in Canada) were selected for hygrothermal simulations. These include an open area at the airport, a city center, an area surrounded by plants, and an area surrounded by a water body. The 31-year-long simulations were performed for a typical woodframe wall assembly complying with moisture protection designs as provided in the National Building Code Canada (NBCC 2020) but rain penetration was assumed considering the deficiency of exterior cladding. The differences in its hygrothermal response across the four locations were analyzed. It was found that some climate parameters are significantly different among the selected locations, although the values for moisture indices given in the NBCC 2020 for these locations are all similar. The results show that high values of WDR are the dominant factor that drives the moisture performance but there is no indication that the design of the assembly could be different among the tested locations.
Abstract
Climate data is one of the most important inputs for hygrothermal simulations and significantly influences the simulation results that are used for moisture performance assessment [...]
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Hygrothermal Performance of External Wall Systems Under Current Climatic Conditions and Future Climate Projections of Turkey
C. Baş, A. Türkeri, M. Lacasse

DBMC 2023.

Abstract
External wall failures caused by rainwater ingress are very common in Turkey. External wall systems that fail to meet the expected watertightness performance may cause premature deterioration of building components, create health hazards for users, and lead to a financial burden for building owners and in respect to the premature deterioration of public buildings, this also has repercussions on the national economy. In addition to the current climatic conditions, thermal and moisture loads that effect the buildings are expected to increase in the future due to climate change. In regards to climate change mitigation strategies, as have been emphasized for the building sector in Turkey, the national government is promoting the use of thermal insulation. However, given that the thermal performance of the most commonly used thermal insulation materials in Turkey are affected by moisture, it is important to evaluate the hygrothermal performance of external wall systems to help ensure the effectiveness and longevity of any proposed measures to mitigate the effects of climate change on building performance. In this paper, the state of the art is presented in respect to investigations of the hygrothermal performance of external wall systems. The research is analyzed based on climatic conditions to which the wall is exposed, the type of external wall assembly investigated, and the method of investigation described in the studies reviewed. The results indicate that the hygrothermal performance of external walls has been extensively investigated; however, there is relatively little research focusing on the hygrothermal performance of external walls subjected to the current climatic conditions of Turkey. In those studies that focused on evaluating the hygrothermal performance of external wall systems under future climate projections, these have been conducted for the cold climate regions of Canada, USA, Norway, and Finland. The hygrothermal performance of external walls under future climate projections for any region of Turkey has not yet been explored.
Abstract
External wall failures caused by rainwater ingress are very common in Turkey. External wall systems that fail to meet the expected watertightness performance may cause premature [...]
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Evaluation of Defects Incidence and Severity on Building Façade: A Case Study
H. Yasemin Cakir, S. Emanet, Z. Melis Oguz

DBMC 2023.

Abstract
20th century buildings are referred to as modern heritage and suggested to be conserved them because they reflect the particular characteristics of the period. To conserve and sustain modern buildings against agents of degradation, such as the inherent quality characteristics, environmental agents, and operational conditions, an important consideration is the observation, from inspection, and documentation of building defects as may reflect the current condition state of the building. In the scope of the study, façade defects of one of the modern period buildings located in the Fatih district of Istanbul/Turkey – the Istanbul Esnaf Hospital was inspected and analyzed. This building was constructed between 1955-1963 with T-shaped plan which consists of eight façades, for which defects, located on six of the building’s façades, were evaluated. The aim of the study is the evaluation of defects in relation to: the orientation of the façade; the location defects on the façade; the façade material, that consisted of a rendered and painted façade, incorporating a mosaic of ceramics, and; the perceived causes of defects. The study consists of three stages (i) data collection, (ii) analysis of defects, and (iii) comparative evaluation of defects. In the first stage, environmental, architectural, and material data are presented. After which, defects on the building façade were detected through a field inspection and were systematically classified. In the final stage, the findings from comparative evaluations of defects and their relation to the orientation of the façade, location on the façade, material, and causes are given. The analysis shows that the incidence of defects is primarily related to design decisions, i.e., the architectural features of the building. Dirt/stain and cracking are two of the most observed defects. Stain/dirt defects are mostly observed under windowsills and recessed areas due to architectural features typical of this modern period. Whereas it was observed that cracks were generally locate around openings and balconies. Material loss and detachment were generally related to impact from vehicles and were concentrated on two of the façades having high usage. On the other hand, biological growth, and efflorescence were principally caused by outdoor environmental conditions.
Abstract
20th century buildings are referred to as modern heritage and suggested to be conserved them because they reflect the particular characteristics of the period. To conserve [...]
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A Comparison of Nature-based Solutions and Related Policies for UrbanEnvironment in China and Canada
Z. Xiao, H. Ge, M. Lacasse

DBMC 2023.

Abstract
Nature-based solutions (NBS) are considered and implemented in many places around the world as a means to mitigate the impact of climate change on the urban environment. NBS can provide useful approaches to mitigate the urban heat island effect, reduce energy consumption of buildings, sequestrate carbon from the atmosphere, as well as improve comfort to pedestrians in the urban environment. However, the implementation of NBS usually requires extra resources, i.e., valuable land within the urban fabric, additional funds for the design and construction of buildings that incorporate NBS, and additional operational costs for maintaining relevant systems, which may conflict with individual building owner’s interests, but nonetheless, be beneficial for the public at large. Under these circumstances, relevant policies should be established to set minimum performance requirements and incentives be introduced to encourage the implementation of relevant practices. China and Canada have set a target of achieving carbon neutral, by 2060 and 2050, respectively. Implementing such policies is critical for realizing the contributions of NBS in the building sector and helping achieve carbon neutrality in urban areas. For the study described in this paper, polices related to the implementation of NBS as issued by selected cities in China and Canada are reviewed. Scopes and limitations of policies from these two countries are summarized and compared. Suggestions and requirements provided in the policies are discussed in conjunction with the findings and conclusions from scientific articles related to the NBS.
Abstract
Nature-based solutions (NBS) are considered and implemented in many places around the world as a means to mitigate the impact of climate change on the urban environment. NBS [...]
- 2
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How Environmental Circumstances Influence Water Repellent Treatment Efficiency – A Case Study of Bentheim Sandstone
X. Chen, T. De Kock, V. Cnudde, N. Van Den Bossche

DBMC 2023.

Abstract
Water repellents are widely applied directly to the outer surfaces of existing buildings to increase the hydrophobicity and durability of historic facades. Nevertheless, there is little control over the initial moisture content inside masonry and boundary conditions in practice. The fluctuating temperature and moisture content of a wall are inevitable when applying the treatment under natural climatic conditions, therefore the efficiency under realistic application approaches may not be as optimal as in the lab. This research aims to understand how application circumstances affect the hydrophobic efficiency of a siloxane-based water-repellent solvent on sandstone. Samples with different moisture content were treated and cured under different temperature to simulate various field climate conditions in practical applications. The experiments indicate that application temperature and relative humidity have little effect on water-repellent efficiency. The water-repellent product is also effective on saturated walls.
Abstract
Water repellents are widely applied directly to the outer surfaces of existing buildings to increase the hydrophobicity and durability of historic facades. Nevertheless, there [...]
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Holism vs. Sustainability in Construction
T. Szkuta

DBMC 2023.

Abstract
Introduction, motivation: almost 40 years of observation, work and cooperation with investors, designers, contractors, manufacturers, distributors, authorities directly in the construction, rescue of monuments, problem solving, design, implementation, maintenance of facilities is a field of research. I have been there to see how and why construction facilities are implemented, used and protected. The title holism is a good method for analyzing problems but also a tool for predicting the necessary characteristics of what we want to create. Holism is a way of thinking about a problem. Where it is applied it gives good results, especially in the long term. It allows one to see the consequences of the flow of time more easily than reductionism. The study of the causes of a problem is broader which allows us to better diagnose and solve it. It makes you always analyze the effects on the whole object and its environment. It places each problem in the context of nearer, farther, sometimes very far and the passage of time. An important element is the analysis of human behavior during the creation and life of the object. Most of the ways to research and determine the condition of objects are obviously known and used. The problem is to determine them (almost) all and the details. Understanding Aristotle's "The more you know, the more you realize you don't know." is crucial here. The point is to explore and come to a conclusion without "closing the door" to more sometimes diametrically opposed knowledge as you go along. Holism in construction can be formulated, describing principles so as to facilitate broader analysis. Such an approach is desirable, which will give the opportunity to benefit from the results to people with different levels of competence, that is, the majority. The purpose of the paper is to try to systematize the approach and show, with examples, why it is worth using. Method: shown in the table are the elements of the research method used in the appraiser's practice. Some areas and elements should be analyzed for the recognition and determination of conditions, impacts and behaviors of construction objects are described. It was determined how to situate the problem in the broadest possible context, with particular attention to typical human behavior. As it turns out, this context is underestimated here. Due to the small volume of the text, examples were limited to the analysis of two relevant elements: lime mortar brick masonry and monolithic reinforced concrete. Objects from the appraiser's practice were selected. For masonry, a school building from the early 20th century and a farmhouse from the mid-19th century. For reinforced concrete, the school swimming pool erected in 1968 and the building of the printing house from 1972, both in emergency condition. Results: The time caesura is important for the results of the conducted research. The indicated errors in the selection of repair methods and materials are due to simplistic methods of analyzing problems. Overlooking the longevity of existence under different conditions and the most important influence of human behavior at each stage of the establishment, use and existence of building structures prove to be crucial.
Abstract
Introduction, motivation: almost 40 years of observation, work and cooperation with investors, designers, contractors, manufacturers, distributors, authorities directly in [...]
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Corrosion Initiation Period for Stainless Steel Reinforcement in Concrete Structures
L. Abreu Araujo, I. Helices Arcila, N. Rebolledo Ramos, J. E. Torres Martín, S. Chinchón-Payá, J. Sánchez Montero, B. B. Raggiotti, V. Matres

DBMC 2023.

Abstract
The designed service life of reinforced concrete structure is often shortened when disposed in aggressive environments. In certain situations, stainless steel reinforcement may be an appropriate replacement to attain a higher level of durability. This paper presents the findings of an experimental study conducted to determine the critical chloride threshold for two types of stainless steel reinforcement (UNS S40977 and UNS S32001). For each steel grade, a prediction model for the corrosion initiation period was obtained, applying the electrochemical test data in a Monte Carlo analysis. Results show that if the initiation period is taken as the corresponding for a 7% corrosion probability, that will occur at 6.5 years of age for carbon steel and over 150 years for UNS S32001 stainless steel.
Abstract
The designed service life of reinforced concrete structure is often shortened when disposed in aggressive environments. In certain situations, stainless steel reinforcement [...]
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Assessing Different Insulation Strategies for Historic Wooden Facades Based on Modeled Mold Growth Risk
M. Zhao, H. M. Künzel

DBMC 2023.

Abstract
Wood makes up a considerable proportion of applied construction materials in Chinese historic building envelopes. With increasing awareness of preserving historic heritage by promoting their further use and occupation, it becomes necessary to improve the current poor indoor thermal environment in abundantly existing historic buildings in southern China. One common approach for improvement is to install insulation materials on historic building envelopes, which can additionally improve their sustainability by reducing buildings’ energy demand for heating and cooling. However, this measure of deep retrofits requires cautious design regarding the hygrothermal performance of insulated wooden facades, since an improper construction way would lead to mold growth in wooden materials, causing problems of durability and indoor hygiene. Therefore, this study investigates the mold growth risk of different insulation systems for historic wooden facades in the Chinese HotSummer-Cold-Winter zone based on a parameter study. The considered parameters are internal and external insulation systems, vapor-open (mineral wool) and vapor-tight (XPS) insulation materials, a U-value of 0.8 W/(m²K) as well as a lower U-value of 0.24 W/(m²K) for the insulated walls, different capabilities and positions of an additional vapor control layer, as well as different cooling/dehumidification conditions in the warm period of a year. The hygrothermal performance of insulated wooden facades is simulated with WUFI®Plus software, while the mold growth risk is assessed with mold index values of the Viitanen mold model. The results of this paper will provide a quantitative evaluation of different insulation strategies for historic buildings in southern China regarding the mold growth risk in wooden materials, which is of essential importance for the durability of construction materials. This study can also give instructions for deeply retrofitting wooden historic buildings in China.
Abstract
Wood makes up a considerable proportion of applied construction materials in Chinese historic building envelopes. With increasing awareness of preserving historic heritage [...]
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A Dose-response Approach for Predicting Frost Damage with Hygrothermal Simulations
K. Janssens, C. Feng, V. Marincioni, N. Van Den Bossche

DBMC 2023.

Abstract
Freeze-thaw degradation is one of the most prominent degradation risks of brick facades. Considering the difficulties of repairing freeze-thaw damage without replacing the materials, which may not always be an option due to heritage values, it is highly important to quantify the risk of frost damage in advance. Hygrothermal simulations have proven to be a valuable tool to assess the risk of deterioration of building facades. The performance criterion method generally applied today quantifies the number of critical freeze-thaw cycles (FTCcrit) as described by Mensinga et al (2010). This method is based on frost resistance tests that adopt high moisture contents and extremely low frost temperatures. However, building facades often experience milder frost temperatures and lower moisture contents rather than these extreme conditions. A journal article published by Feng et al. (2019) investigated the relationship of frost damage with temperature and moisture content, which enables a dose-response approach that goes beyond the existing threshold level criteria. The experimental study tested freezing temperatures from -2°C to -20°C and moisture saturation degrees from 0.1 to 1.0. This paper studies freeze-thaw risk using this advanced approach, and investigates whether the dose-response approach can lead to a clarification at what number of FTCcrit actual deterioration occurs and how this can be predicted by the use of hygrothermal simulations. Thereby, an attempt is made to derive a more representative performance criterion for frost damage.
Abstract
Freeze-thaw degradation is one of the most prominent degradation risks of brick facades. Considering the difficulties of repairing freeze-thaw damage without replacing the [...]
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Why the Quality of Concrete Construction for Infrastructure Contracts Must Not be Undermined by Inappropriate Design Code Assumptions
S. R. Curtis

DBMC 2023.

Abstract
The concept of a draft international project specification (DIPS) has long been under consideration in relevant fib Task Groups, - even before the framework Standard, ISO 22966 (Execution of concrete structures) was published (2009). However, the quality requirements of ISO 22966 were developed from the product quality inspection principles of the Eurocodes and ISO 9001:2000; and the author has explained why these principles cannot be applied directly to contract works. Furthermore, these principles do not demand the necessary level of high-performance concreting and supervision to produce defect-free structures and the 100 plus year service life which Owners expect. The original ISO 9001:1987 was a simple, contractually effective model quality system specification which “aimed primarily at preventing nonconformity,” (the fundamental purpose of quality assurance). Its most powerful element was ‘process control’ (including ‘special processes’), and it demanded that all processes which could adversely affect quality must be addressed by effective documented preventive procedures in the Contractor’s Project Quality Plan (PQP). The Contractor had to document exactly how he would perform each (special) concreting process and then demonstrate that his proposed procedures worked. Since 2000, this powerful combination of mandatory quality planning requirements has been removed from most specifications for concrete works; but this is precisely what needs to be restored if Owners’ and Designers’ durability expectations are to be consistently achieved. The author now proposes an amended draft version of the International Project Specification, - hoping that it will soon be used on a trial basis on selected construction contracts for reinforced and prestressed concrete bridgeworks in China, Australia, United States and Europe.
Abstract
The concept of a draft international project specification (DIPS) has long been under consideration in relevant fib Task Groups, - even before the framework Standard, ISO [...]
- 2
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Validation Exercise at European Level on Natural Chloride Diffusion Test and Natural and Accelerated Carbonation Testing
C. Andrade

DBMC 2023.

Abstract
The work summarizes the results of the interlaboratory testing made in the committee CEN/TC51/WG12 on the standardized procedures for carbonation (EN 12390 – 10 and part 12) and chloride diffusion (EN 12390-12). The exercise was made by 13 different laboratories on 8 different concrete compositions with w/c ratios of 0.4, 0.5 and 0.6. The results indicated repeatability of 10-22% for natural carbonation (outdoors protected from rain and controlled chamber respectively), of around 5% for accelerated carbonation (at 4% of CO2 concentration), and 23% in the Apparent diffusion coefficient for natural chloride diffusion and 13% for the chloride surface concentration.
Abstract
The work summarizes the results of the interlaboratory testing made in the committee CEN/TC51/WG12 on the standardized procedures for carbonation (EN 12390 – 10 and part [...]
- 1
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Link between Durability Defects and Construction Failures
S. R. Curtis

DBMC 2023.

Abstract
Over thirty years ago enthusiastic and dedicated materials scientists and structural engineers initiated a series of research projects and draft International Standards which has now revolutionised the design approach to durability of concrete structures. Concrete mix design is dominated by the contractual requirement for the concrete supply not to exceed specified limiting values of the nationally favoured durability criteria. The specifying Authorities are striving to ensure that structures achieve their design service life (ideally 100 years+). Concrete research and development is their primary hope. During the 1990s, the concrete construction industry was also working hard to develop better specifications and contract management procedures to address the pressing problems of not only durability but also safety. Central to all the work of the construction industry was the principle that all concreting operations were ‘special processes’ (as universally acknowledged for welding processes), and therefore they had to be documented, trialled, verified and implemented in compliance with the process control requirements of ISO 9001:1987/1994. Procedures had to be prepared, approved and implemented for all processes which were identified as being potentially ‘adverse to quality’ (which included most processes involved in concreting and prestressing operations (including grouting)). The critical question to answer in preparing a procedure is HOW the process will be carried out and verified. However, equally critical questions may be WHEN, WHERE and BY WHOM. The Project Specification must ask these questions in the tender documents and the Owner and/or his Designer must satisfy themselves that all the identified problems have been resolved – both technical and administrative – before relevant design/construction commences. These questions must be answered by all subcontractors, including designers and checkers of falsework structures. Example are given, based on recent fatal bridge collapses largely caused by Owner and Designer failings to control subcontracting of temporary works design and checking.
Abstract
Over thirty years ago enthusiastic and dedicated materials scientists and structural engineers initiated a series of research projects and draft International Standards which [...]
- 2
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Electrical Resistivity Measurements on Hardened Concrete Exposed to Various Curing Conditions
S. Gao, R. Douglas Hooton, K. Li, T. Hao, X. Feng

DBMC 2023.

Abstract
Evaluating concrete quality and performance, especially determining the resistance of concrete to fluid and ion ingress, is fundamental to estimating concrete’s durability and predicting the service life of concrete structures. Both bulk and surface electrical resistivity tests have gained increasing interest as rapid and repeatable indicators of concrete’s resistance to fluid ingress. In this study, concrete electrical resistivity was measured at the ages of 56 and 91 days on specimens from five concrete mixtures exposed to different curing environments and storage solutions. Both bulk and surface resistivity of concrete in each curing condition are compared, and the effect of curing methods on electrical resistivity is discussed. The results show that conditioning in a highly-conductive storage solution, such as a simulated pore solution, led to a lower concrete resistivity measurement than when stored in saturated limewater. The effect of mixture compositions on measured resistivity revealed that for the same cementitious materials, the electrical resistivity increased as the w/cm ratio decreased, and a linear correlation between the w/cm ratio and concrete electrical resistivity was obtained.
Abstract
Evaluating concrete quality and performance, especially determining the resistance of concrete to fluid and ion ingress, is fundamental to estimating concrete’s durability [...]
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Application of Service Life Planning to Existing Buildings – Perspectives on Condition Appraisal, Performance and Cost
K. P. Bourke, A. Silva, P. L. Gaspar

DBMC 2023.

Abstract
ISO 15686 on Service Life Planning of Constructed Assets provides guidance which is applicable to both new and existing constructed assets and their parts. However, there has been limited exposition of the applicability of the guidance to existing buildings. This paper provides perspectives on practical application of the principles to condition assessment (survey and appraisal) of the long-term performance of existing buildings, in particular in respect of the building envelope and how maintenance interventions and life cycle costs are predicted or estimated. The authors are currently actively involved through CIB W080 and ISO TC59/SC14 in preparing for the revision of the ISO 15686 standards to take account of experience over the last 20 years, including the development of the factor method and its applicability, and guidance on life cycle costing of existing buildings. The paper will develop key themes from the series of ISO 15686 standards, which are particularly relevant to assessment of existing buildings and other constructed assets.
Abstract
ISO 15686 on Service Life Planning of Constructed Assets provides guidance which is applicable to both new and existing constructed assets and their parts. However, there [...]
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Prediction and Ranking of Moisture Severity of Climate Years Using Supervised Projection to Latent Structures Applied to Tall Wood Buildings
M. Defo, M. Lacasse, T. Moore

DBMC 2023.

Abstract
Hygrothermal simulation tools are commonly used to assess the moisture performance of building envelope components. Owing to the computational costs required to complete simulations over the long-term, one approach to reduce simulation time when undertaking hygrothermal design analysis is to select representative year(s) amongst sets of long-term climate data. To properly select these moisture reference year(s), a method is required to rank or predict the moisture severity of climate years for sets of long-term climate data. Several methods are used in the literature for this purpose, but none seems to be sufficiently accurate. In this study, the supervised projection to latent structures, also known as partial least squares regression, was trained and validated on data obtained from hygrothermal simulations of tall wood building wall assemblies for several cities across Canada. Models developed at the city level, for a given greenhouse gas emission scenario or time period, or encompassing historical and future time periods, showed comparable scores for ranking. In respect to prediction of the moisture severity of climate year sets, models developed at the city level were shown to be more accurate.
Abstract
Hygrothermal simulation tools are commonly used to assess the moisture performance of building envelope components. Owing to the computational costs required to complete simulations [...]
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Opportunity-Based Maintenance of Buildings’ Envelope
C. Ferreira, J. de Brito, A. Silva

DBMC 2023.

Abstract
More than half of the building’s life-cycle costs correspond to maintenance costs. Nevertheless, maintenance actions are, generally, conditioned by subjective criteria and carried out at inopportune times, which implies that one third of the maintenance costs are improperly incurred. Buildings are multi-component systems and, therefore, the adoption of opportunistic maintenance policies allows reducing the maintenance costs and the number of interventions, while maximizing the service life and the efficiency of the resources available. In this study, an opportunistic maintenance plan is proposed for the buildings’ envelope, combining the maintenance needs of four elements: rendered facades; ceramic claddings; window frames; and pitched roofs ceramic claddings. For this purpose, a condition-based maintenance model is used. The maintenance model is based on stochastic degradation models for the individual components of the system. The optimization of these policies will identify the best maintenance schedule and combination of maintenance activities, finding the optimal trade-off between disruption of the buildings’ use, maintenance costs and their service life. The application of these opportunistic maintenance policies in the building envelope elements allows mitigating the degradation of these elements over the buildings’ life cycle and, consequently, increasing the economy, quality, and aesthetic perception of our cities. This methodology will change the way that maintenance plans are defined, and interventions are prioritized.
Abstract
More than half of the building’s life-cycle costs correspond to maintenance costs. Nevertheless, maintenance actions are, generally, conditioned by subjective criteria [...]
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Flexibility and Adaptability: A Review on Assessment Methods and Tools and Their Applicability
G. Cignachi, P. Gaspar, H. Farias

DBMC 2023.

Abstract
In this paper, the existing methods for the assessment of flexibility and adaptability in buildings are reviewed. These methods have been tentatively proposed for a number of building types / uses - notably for residential buildings - and generally propose sets of indicators, variables and weights that combine into a score of flexibility. In spite of the limited practical applicability of these methods so far, they provide a stimulating approach to greater use and incorporation of the concepts and strategies of flexibility and adaptability, aiming at an increased performance of buildings.
Abstract
In this paper, the existing methods for the assessment of flexibility and adaptability in buildings are reviewed. These methods have been tentatively proposed for a number [...]
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Durability and Long-term Performance Assessment in Eco-efficient Concrete Mixtures Towards a More Sustainable Cement Industry - A Critical Review
Z. Xia, C. Londero, S. R.A.Dantas, L. F.M.Sanchez

DBMC 2023.

Abstract
In the current need to fulfill a Net-Zero goal to offset greenhouse gas emissions by 2050, the cement industry deeply needs to renovate its process and products. The amount of concrete, and consequently ordinary Portland cement (OPC) used worldwide, far exceeds other industrial materials, contributing to around 8% of global emissions. A recognized solution would be to partially replace clinker with limestone, an available material in many countries with the potential to improve the particle packing of a concrete mixture. Even though several studies have been carried out on the application of Portland limestone cement (PLC) concrete, there is a need for further investigation regarding durability performance. Problems include alkali-silica reaction (ASR), delayed ettringite formation (DEF), sulphate attack, steel corrosion, and freeze/thawing, whose deteriorating effects tend to be maximized in harsh climate countries such as Canada and should be evaluated when introducing distinct materials into concrete. Therefore, this paper aims to review previous assessment of the durability of PLC concrete mixtures. The use of an advanced mix-design method (particle packing model and mobility parameters - PPM+MPs), will also be discussed on its ability to enhance the durability performance of the mixtures. It is expected that novel guidelines to design more eco-efficient concrete mixtures using PLC can be developed to reduce concrete’s cost and carbon footprint, achieving a more sustainable industry.
Abstract
In the current need to fulfill a Net-Zero goal to offset greenhouse gas emissions by 2050, the cement industry deeply needs to renovate its process and products. The amount [...]
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Changes in Educational Buildings at Very Early Stages of Their Life Cycle
G. Cignachi, P. Gaspar, H. Farias

DBMC 2023.

Abstract
Changes always occur in buildings at any stage of their life cycle. In this paper, particular attention is paid to changes that occur very early on this process, sometimes between bidding and very initial construction stages, in the context of public procurement and building. The research is based on the total building stock of the Federal Institute Sul-rio-grandense, in Brazil, which holds presently 14 campuses and more than 120 buildings. Accumulated experience has demonstrated that the prototypical buildings - educational or administrative - designed to be repeated often undergo alterations. The reasons for such changes are identified, along with their impact on the functionality, service life and future maintenance of such assets.
Abstract
Changes always occur in buildings at any stage of their life cycle. In this paper, particular attention is paid to changes that occur very early on this process, sometimes [...]
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Analysis of the Repassivation of Corroded Bars in Cementitious Materials Subjected to Realkalisation
G. R. Meira, P. R. R. Ferreira, A. A. Meira

DBMC 2023.

Abstract
The effect of concrete realkalinisation on reinforcement repassivation was evaluated by means of electrochemical measurements considering different previous corrosion degrees of reinforcements and different environmental conditions. Reinforcements obtained from a real concrete structure which were activated due to concrete carbonation were used for this purpose. Five different corrosion degrees were considered. All these reinforcements after being classified, were embedded in fresh mortar specimens and were cured in wet chamber for 7 days. After that, they were sequentially subjected to two different environmental conditions; laboratory environment (65% of relative humidity) and 80 % of relative humidity environment. Along all the testing period, reinforcements were monitored on corrosion potential and instantaneous corrosion current density by linear polarisation measurements. Results show that as the previous corrosion degree increases it becomes harder to reach the repassivation condition for reinforcements. This shows that the effectiveness of concrete realkalisation on reinforcement repassivation depends on the previous corrosion degree of reinforcements. The influence of the relative humidity was not significant under the experimental conditions adopted in this work.
Abstract
The effect of concrete realkalinisation on reinforcement repassivation was evaluated by means of electrochemical measurements considering different previous corrosion degrees [...]
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Durability Assessment and Maintenance Planning of Concrete Structures in Ningbo-Zhoushan Port Main Channel Sea Link Project
L. Li, K. Li

DBMC 2023.

Abstract
This paper performs the durability assessment and maintenance planning of concrete structures during construction phase in the ongoing Ningbo-Zhoushan Port Main Channel (NZPMC) sea link project with a service life of 100 years. The background of this project is first introduced and the durability design at preliminary study phase is recalled; the chloride-induced corrosion of reinforcement steel was considered as the most critical process that controls the design. Then, the durability model for assessment is established for this durability limit state and the statistical properties of the model parameters are given. From the collected data on the concrete cover thickness and modified chloride diffusion coefficients, the statistical properties of these parameters are updated. With the design options adopted in design phase and the updated parameter properties, taking one non-navigable bridge as an example, the achieved reliability levels and failure probabilities are calculated for structural elements under different exposure conditions by using full probabilistic approach. On the basis of the achieved reliability level of durability, a preliminary maintenance planning is performed for the concrete elements in the concrete structures, and the corresponding recommendations are given.
Abstract
This paper performs the durability assessment and maintenance planning of concrete structures during construction phase in the ongoing Ningbo-Zhoushan Port Main Channel (NZPMC) [...]
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Damaged Swedish Buildings
P. Wallentén, S. Olof Mundt-Petersen, K. O. Anders Joelsson, M. Kläth

DBMC 2023.

Abstract
Damages with a negative influence on the indoor environment often become linked to high costs. Detailed facts about buildings with damages need to be collected and analyzed in order to be able to reduce the number of damages. This paper presents basic facts, such as design, property ownership and year of construction in buildings where 1105 damages were found. In general, the study gives qualitative indications and cross-comparing to other parameters considering damages and causes of damages needs to be done to obtain better results. Buildings with indoor air ventilated or heated crawlspaces have less damages compare to non- or outdoor ventilated crawl spaces. Damages are more common in buildings with poor exterior insulation in the foundation or a no-drainage and poorly ventilated cladding. In the buildings in the study, schools and local authority owned buildings have a high frequency of damages. A higher number of damages were also found in condominium association owned multi-family houses compared to public tenancy owned multi-family houses.
Abstract
Damages with a negative influence on the indoor environment often become linked to high costs. Detailed facts about buildings with damages need to be collected and analyzed [...]
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Classification Systems for the Built Environment: A Cornerstone for the Long-term Performance Analysis
C. Serrat, V. Royano, V. Gibert, J. Rapinski

DBMC 2023.

Abstract
In the long-term performance analysis of the built environment, classification systems are seen as a key consideration. When classifying residential building objects, characteristics such as accuracy, exhaustivity, and consistency are required. It is noticeable that while organizations around the world are working to develop an internationally agreed standard classifier, the use of national classification systems remains widespread. Therefore, this paper focuses on reviewing the most popular classification systems such as CoClass, Uniclass 2015 and OmniClass®, among others, and discusses their strengths and weaknesses, in order to be useful both to the research and technical communities. Based on this, two main contributions are derived. On the one hand, the paper points out that there is no international consensus to use a common classification system. On the other hand, some recommendations are given and illustrated to meet the challenges of classifying existing buildings, in particular under a functional assessment approach.
Abstract
In the long-term performance analysis of the built environment, classification systems are seen as a key consideration. When classifying residential building objects, characteristics [...]
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Causes of Damages in Swedish Buildings
S. Olof Mundt-Petersen, P. Wallentén, I. J. Edskär, K. O. Anders Joelsson

DBMC 2023.

Abstract
Damages, failures and functional defects in buildings create high cost for the owner and the society. It is important to determinate the causes of damages in order to limit the costs. This paper presents the causes of 1105 different damages from a technical perspective from 265 real damage investigations. In general, the results show that; 1. Rain and snow was the most common moisture source cause damages, 2. The number of damages caused by wet concrete and PVC or linoleum flooring may be overestimated. 3. A significant number of damages were caused in details where different materials connect to each other, 4. A high number of damages were linked to wear and tear and poor maintenance. 5. Causes of damages occurs in all phases of the building process but most of them were deemed to occur in the management and on-site construction phase. 6. Most of the damages were caused by building owner or their facility trustees.
Abstract
Damages, failures and functional defects in buildings create high cost for the owner and the society. It is important to determinate the causes of damages in order to limit [...]
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Assessment of the Impressed Current Cathodic Protection System after 4 Years Operation: Evolution Over Temperature and Time of the Applied Current and Tension on Anodic Zones of the Saint-Cloud Viaduct (France)
J. Ducasse-Lapeyrusse, V. Bouteiller, O. Lesieutre, E. Marie-Victoire, M. Bouichou, G. Damien, V. Martinet, C. Annede-Villeau

DBMC 2023.

Abstract
This paper presents the feedback of the Impressed Current Cathodic Protection (ICCP) system implemented on a road bridge, the Viaduct of Saint-Cloud, constructed in the 1970s in France. After a test trial in 2012, the full-scale ICCP system was energized in 2018. It consisted of 44359 discrete titanium anodes implemented on the lateral segment webs on both sides of the Viaduct, distributed in 212 anodic zones on one side and 153 anodic zones on the other side. The four years monitoring data include the variations of the applied current and tension on anodic zones, their polarization, etc. This paper focus on the global resistance of the circuit for the different anodic zones. The circuit resistance shows first the influence of the temperature. The differences between anodic zones and their evolution over time also bring more information about the environment of the anodes and the reinforcements. The analysis of the response of the circuit reveals the heterogeneity of an actual and large-scale ICCP system and provides important feedback to an appropriate ICCP design for durable cathodic protection.
Abstract
This paper presents the feedback of the Impressed Current Cathodic Protection (ICCP) system implemented on a road bridge, the Viaduct of Saint-Cloud, constructed in the 1970s [...]
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Analytical and Experimental Service Life Assessment of Ningbo-Zhoushan Port Main Channel Sea Link Project
L. Li, K. Li, R. Torrent

DBMC 2023.

Abstract
The Ningbo-Zhoushan Port Main Channel (NZPMC) sea link is one of the most important projects undertaken by the People's Republic of China. The main factors that determine the service life of these marine structures, exposed to chloride-induced corrosion, are the "penetrability" and thickness of the concrete cover that protects the steel reinforcement. In an initial design phase, these factors are defined by modeling the penetration of chlorides with analytical tools (based on the Duracrete approach). In the construction phase, data are collected from the in-site laboratory for concrete chloride diffusivity, and from non-destructive tests for the concrete cover thickness and air permeability for the prefabricated bridge piers. On the basis of these data, two model-based approaches are used to predict the service life of the bridge. The first model is an analytical one based on the solution of Fick’s 2nd diffusion law, for chloride ingress into concrete using the corrosion initiation as durability limit state.The second model uses the “Exp-Ref” model, using the concrete cover thickness and air permeability as input parameters and calibrated by the EuroCode specifications on structural concretes in marine environments. Both approaches use Monte-Carlo simulations and consider the statistical properties of the input parameters. A comparison of the analytical and experimental predictions is made, showing compatibility with 100 years of service life. The convenience of verifying the analytical predictions with those obtained from site experimental data is discussed.
Abstract
The Ningbo-Zhoushan Port Main Channel (NZPMC) sea link is one of the most important projects undertaken by the People's Republic of China. The main factors that determine [...]
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An In-situ Method for Assessing the Kinetics of Acid Attack on Iron-richAlkali-activated Materials
Z. Yu, R. Oliveira-Silva, E. De Oliveira, N. Wen, Y. Pontikes, D. Sakellariou

DBMC 2023.

Abstract
In iron-rich alkali-activated materials (AAMs), iron is present in both the ferrous and ferric states. Fe3+ is considered to be present in a silicate network and the dissolution of Fe3+ under acid attack can be taken as an indication of the deterioration of the AAMs framework. Conventional methods for evaluating the acid resistance of AAMs are based on the durability standards for OPC concrete with indicators such as mass change and dimensional change, or by measuring the corroded depth. All of these methods are measured based on solid samples and many samples have to be prepared to obtain different points in a time profile. Here we propose nuclear magnetic resonance (NMR) relaxometry measurements as an in-situ method for the direct determination of dissolution kinetics of Fe3+ ions in an acid solution with high temporal resolution. The leaching kinetics of iron-rich AAMs in (sulfuric) acid can be described by the Real Physical Picture (RPP) kinetic model, which was originally used to describe the gas-solid interaction. The fitting results show that the leaching process is controlled by chemical reactions at the beginning and by diffusion over time.
Abstract
In iron-rich alkali-activated materials (AAMs), iron is present in both the ferrous and ferric states. Fe3+ is considered to be present in a silicate network and the dissolution [...]
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Experimental Study of the Development of Stresses in Prestressing Strandsunder Different Environments
D. Xu, C. Chen, Y. Zhao

DBMC 2023.

Abstract
This paper presents findings from an experimental study on the effects of different environmental factors on post-tensioned prestressed concrete beams. The study included four different environments: outdoor shielded, drying-wetting cycles with tap water, drying-wetting cycles with NaCl solution, and drying-wetting cycles with NaCl solution and energized longitudinal rebars. A vibratingstring anchor cable dynamometer was used to measure the stress variation in prestressing strands. The results indicate that ambient temperature affects the trend of stresses in the prestressing strands. The increasing humidity caused by drying-wetting cycles and increasing salinity caused by NaCl solution led to the expansion of the concrete and increased stresses in the prestressing strands. Additionally, the corrosion of longitudinal rebars caused by the impressed-current accelerated corrosion method results in concrete damage and cracking, and continuously decreases the stresses in the prestressing strands. The study is ongoing, and further observations and reports will be made to evaluate the effects of different environmental factors on stresses in prestressing strands of post-tensioned beams.
Abstract
This paper presents findings from an experimental study on the effects of different environmental factors on post-tensioned prestressed concrete beams. The study included [...]
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Exploring Moisture Performance of Two Distinctive Solid Bricks underCurrent and Future Climate in London
B. Xu, S. Zhang, T. Cambray, V. Marincioni

DBMC 2023.

Abstract
The increasing concerns surrounding climate change have raised apprehension about the heightened frequency and intensity of extreme weather events, globally as well as in the UK. Historic solid brick buildings, due to their construction materials and prolonged exposure to changing climate conditions, are vulnerable to the impacts of climate change, resulting in increased moisture risks that undermine their durability. Understanding the moisture behaviour of solid bricks facing climate change is therefore significant. This study aims to investigate the moisture performance, with a specific focus on moisture content, of two distinct types of bricks: handmade bricks from the 19th century and more recent – early 20th century - bricks, under current and future climate scenarios in London. The results reveal that the more recent bricks can have greater susceptibility to climate changes, providing valuable insights for the implementation of effective moisture control strategies and informed decision-making in the retrofitting of solid brick buildings in the UK.
Abstract
The increasing concerns surrounding climate change have raised apprehension about the heightened frequency and intensity of extreme weather events, globally as well as in [...]
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Freeze-thaw Damage Mechanism and Cracking Behaviour of PerforatedPlateau Concrete Structure
J. Mao, K. Fang, L. Mi, H. Jia

DBMC 2023.

Abstract
The harsh environment and poor quality of building materials used in plateau concrete projects adversely affect the ability of such structures to withstand the damaging impact of freeze-thaw. A fast-freezing test with a single variable control was carried out and the process of microstructural changes in the plateau concrete was traced. The results also showed that the plateau curing environment led to an increase in width and porosity of the interface transition zone (ITZ), and that clay content in building materials significantly impacted the microstructure of paste. The frost resistance of plateau concrete was found to be far lower than that of plain concrete. Perforated concrete structures are common in engineering, and concrete members can easily experience frost cracking in cold regions. This study conducts frost heave tests on perforated concrete, aiming at the problem of the frost heave cracking risk of perforated concrete structures in cold regions. The cracking characteristics of concrete with holes under freeze-thaw cycles are mastered by performing rapid freeze-thaw tests on concrete with holes and observing the cracked section. Finally, hydrophobic filling materials were adopted to alleviate the frost heave stress on concrete.
Abstract
The harsh environment and poor quality of building materials used in plateau concrete projects adversely affect the ability of such structures to withstand the damaging impact [...]
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Hygrothermal Performance of CLT Subjected to Rain Loads duringConstruction in Belgium
K. Habtie, B. Vanderschelden, X. Jiang, L. De Ligne, J. Van Den Bulcke, N. Van Den Bossche

DBMC 2023.

Abstract
As the use of CLT is increasing, it is important to understand how to deal with moisture during construction. Throughout the construction phase it is often not feasible to shield every component and detail from direct rain impingement. This paper investigates what happens to CLT, and spruce wood in general, when it is exposed to rain events, and how fast it dries out afterwards. Subsequently, the implications of incorporating a wetted component into a finished wall system is also investigated. The moisture behaviour of both plain spruce and CLT samples that are exposed outdoors is investigated using the continuous moisture measurement (CMM) setup at the UGent Woodlab in combination with hygrothermal simulations in Delphin 6. Pieces of solid wood and CLT are mounted on load cells that record the weight every 5 minutes, to study the wetting and drying behavior. Hygrothermal simulations are done in Delphin 6 using a climate file that is made from the recorded weather data. This way, the CMM experiments can be recreated in simulations. The goal here is to understand what is happening in the simulations and to look at what influence different parameters have on the moisture content of the samples. Risks of mould and wood decay are investigated, and recommendations are made concerning practical moisture management and risk mititagion for these types of constructions.
Abstract
As the use of CLT is increasing, it is important to understand how to deal with moisture during construction. Throughout the construction phase it is often not feasible to [...]
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Numerical Simulation on the Pouring Process of Self-compacting Concretein CRTS III Slab Track
H. Zhang, Y. Zhang, K. Wu

DBMC 2023.

Abstract
In this study, a fluid-solid coupling model describing the pouring process of self-compacting concrete (SCC) in CRTS III ballastless slab track in straight section was established based on a coupled Eulerian-Lagrangian method, which realized the simulation of the whole pouring process of SCC. The influence law and mechanism of different construction parameters on the pouring process of SCC were studied theoretically. The effects of height and number of funnels on some key indices including the filling rate of SCC, the vertical and lateral displacements of slab track and the forces of withhold were mainly analyzed. The study was aimed at providing theoretical guidance for the intelligent pouring of SCC and the development of intelligent pouring equipment. Results indicated that the higher funnel and double-hole pouring both reduced the pouring time and improved the construction efficiency, and the latter one demonstrated a significant effect. The maximum vertical displacement of track slab was appeared in the middle of slab edge during single-hole pouring but was found in the vicinity of observation hole during double-hole pouring. The maximum lateral displacement of track slab was appeared near the withhold during the pouring process. A higher funnel led to greater pressure of SCC to track slab, which brought about larger vertical and lateral displacements of slab track and higher forces of withhold. Compared to single-hole pouring, the final floating dis-placement and lateral displacement of slab track and the force of withhold were greater during double-hole pouring
Abstract
In this study, a fluid-solid coupling model describing the pouring process of self-compacting concrete (SCC) in CRTS III ballastless slab track in straight section was established [...]
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Modeling the Sulfate-induced Damage of Concrete
P. Dangla, Y. Gu, Y. Omikrine-Metalssi, R. Martin

DBMC 2023.

Abstract
The degradation of concrete due to sulfate attack from internal or external sources is a serious problem. The cause of this degradation is the formation and growth of ettringite, which results from the reaction of cement hydrates with sulfate ions in the pore network. This crystal growth leads to a pore pressure that can exceed the concrete’s strength. This paper presents a modeling of concrete’s sulfate-induced stress-strain behavior based on damage poromechanics and two kinetic laws for ettringite growth. Free expansion of cement paste samples exposed to sulfate solutions were measured, and mercury porosimetry tests were conducted at different expansion stages. The pore size distribution was analyzed to locate the dissolution of hydrates and precipitation of ettringite at the pore scale. Results support the theory that ettringite first precipitates in larger capillary pores and spreads to smaller ones. A heat-based dissolution test was performed at different expansion stages, revealing ettringite formed in the pore size range of 4-30 nm. The model was implemented in a finite volume code and applied to four experimental cases from the literature: ESA and DEF in confined and free conditions. The kinetic coefficients were calibrated to fit the observed strains in some experiments and used to blindly test the model in others. Diffusion was neglected due to the small sample size. All simulations showed that the calibrated kinetic parameters had the same order of magnitude, supporting the right physics involved
Abstract
The degradation of concrete due to sulfate attack from internal or external sources is a serious problem. The cause of this degradation is the formation and growth of ettringite, [...]
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MARS – A Multiphysics Framework for the Analysis of Cast and PrintedConcrete
A. Cibelli, R. Wan-Wendner, J. Vorel, D. Pelessone

DBMC 2023.

Abstract
Predicting the time-dependent responses of concrete and concrete structures remains a challenging task in the construction sector. While experimental investigation serves as an essential cornerstone for concrete research, by itself it only offers limited insights into the complex time-dependent behaviour of concrete. The complexity is due to the multiple coupled hygro-thermo-chemo-mechanical processes. In the last two decades MARS, a special purpose computational software developed by ES3, has shown the capability of turning such insights accessible. This paper aims to provide a state-of-theart of the MARS capabilities in concrete modelling, enriched with a discussion of some meaningful examples. The multiphysics framework today available in MARS already allows to simulate a wide range of complex phenomena, featuring the long-term performance of ordinary and advanced cementitious materials.
Abstract
Predicting the time-dependent responses of concrete and concrete structures remains a challenging task in the construction sector. While experimental investigation serves [...]
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Effects of Surface Layer on Moisture Transport in Cementitious Materials:Experimental Evidence and Simulation Results
Z. Zhang, U. Angst

DBMC 2023.

Abstract
Moisture in concrete is the essential factor of many degradation mechanisms to reinforced concrete structures, such as carbonation, chloride ingress, and frost attack. Therefore, it is important to arcuately determine and predict moisture state and moisture distribution inside the material. Most moisture transport models generally view concrete as a homogeneous material, which might be appropriate for the large scale. However, it is commonly found that the properties (chemical and microstructure) of the concrete surface layer are different from the bulk concrete. When considering the moisture exchange with the surrounding environment, this surface layer may unavoidably affect the process of moisture transport. In this study, water absorption tests were performed to investigate moisture transport in uncarbonated cement pastes and mortars. The results show that during the process of sample preparation, the microstructure of the surface layer was altered, leading to anomalous moisture transport, in which the conventional models can not predict the measured mass change. Based on the experimental results, the non-homogeneous simulation domain was created to represent the more realistic microstructure of concrete. The numerical simulation results show a similar trend of the mass change due to moisture transport to the experimental results. Therefore, the nonhomogeneous microstructure of concrete, in particular the different microstructure of the surface layer from the bulk concrete, can be one of the reasons that cause the anomalous moisture transport in cementitious materials. This also emphasizes the importance of sample preparation in the lab, which must avoid creating a surface layer with the different microstructure from the bulk concrete
Abstract
Moisture in concrete is the essential factor of many degradation mechanisms to reinforced concrete structures, such as carbonation, chloride ingress, and frost attack. Therefore, [...]
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Degradation Behavior of GO-ternary Blended Nano-concrete Compositesunder Accelerated Sulfuric Acid Attack
A. Anwar, X. Liu, L. Zhang

DBMC 2023.

Abstract
Biogenic corrosion of concrete in wastewater sewer systems is caused by the in-situ production of sulfuric acid (H2SO4) formed by the bacterial action is considered the principal cause of structural degradation. The intense corrosive environment disintegrates the service lifespan of concrete structures significantly sooner in its advanced state, resulting in structural collapse within 10-20 years and jeopardising its durability. Thus, the degradation of concrete structures in the aggressive acidic environment of sewerage systems remains a global concern for industries and stakeholders, resulting in economic losses of several billion dollars annually. This research experimentally investigates the degradation behavior of developed ternary blended nano-concrete composites reinforced with graphene oxide (GO-TBNCCs) under accelerated H2SO4 exposure (pH 1.0) for 28 days and 90 days. The experimental results revealed that TBNCCs reinforced with GO are more resistant to aggressive acidic attack in contrast to its control composites, hence increasing its acidic resistivity performance with lower degradation depth that may cater to the durability problem of concrete structures in the wastewater sewer systems.
Abstract
Biogenic corrosion of concrete in wastewater sewer systems is caused by the in-situ production of sulfuric acid (H2SO4) formed by the bacterial action is considered the principal [...]
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An Experimental and Numerical Study of the Effect of Heat and ThermalShock in Precast Concrete Wall System
C. Cremonesi, G. Akyo, O. Oliveira, L. Alves de

DBMC 2023.

Abstract
The aim of the paper is to analyse the performance of a precast concrete wall system under heat and thermal shock (physical phenomena). The understanding of thermal shocks in building systems is a challenge because of the requirements and complexities of the phenomena behaviour through cycles of heating and cooling provided by the environment (sun followed by suddenly rain). The period of duration of the phenomenal during the cycles makes changes in the systems responses in terms of mechanical and physical aspects. The responses of the building system to heat and thermal shock were analysed during the monitoring of the changes in temperature and deformation using sensors in a scalable prototype of a precast concrete wall system. In addition, a numerical simulation based on the finite element method (FEM) in commercial software was conducted to verify and analyse the variables in a digital model of the wall as a complementary study of the effects of heat and thermal shock. The results demonstrated the feasibility to use numerical simulation to analyses the phenomenal of heat and thermal shock on the behaviour of a precast concrete wall system.
Abstract
The aim of the paper is to analyse the performance of a precast concrete wall system under heat and thermal shock (physical phenomena). The understanding of thermal shocks [...]
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Effect of Repeated Loading on the Flexural Load Carrying Capacity ofMarine Concrete Beams Exposed to Chloride Environment
C. Lu, C. Feng, Y. Zheng

DBMC 2023.

Abstract
To investigate the effect of repeated loading on the flexural load carrying capacity of marine concrete beams suffering from chloride attack, a total of 10 marine concrete beams and 27 concrete cubes were designed for flexural performance test and compressive strength test, respectively. Three damage mechanisms, including repeated loading with a stress level of 0.4, chloride salt dry-wet cycles and coupling action of repeated loading history and chloride salt dry-wet cycles, were applied for concrete beams and cubes. Test results show that the effect of repeated loading on the degradation of compressive strength of concrete is significantly higher than that on the flexural properties of concrete beams, and the corresponding degradation ratio between them is maintained at about 1.5. The effect of chloride salt dry-wet cycles on concrete compressive strength is 1.8 times higher than that on the flexural load carrying capacity of test beams. Combined with the test data proposed in this paper and some existing studies, the influence of compressive strength loss on the flexural load carrying capacity of marine concrete beams was discussed. The analysis shows that the compressive strength loss rate can effectively reflect the remaining flexural load carrying capacity of marine concrete beams and there is an exponential relationship between them.
Abstract
To investigate the effect of repeated loading on the flexural load carrying capacity of marine concrete beams suffering from chloride attack, a total of 10 marine concrete [...]
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