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• A Study on the Effect of Time Duration by Vibrating or Tamping Fresh Concrete on the Compressive Strength of C-25 Concrete

  A. Achalu, E. Quezon, G. Macarubbo

  Effect of Time Duration by Vibrating or Tamping Fresh Concrete on the Compressive Strength (Select a year). Afework Achalu, Emer Tucay Quezon, Gerry Bangayan Macarubbo. A Study on the Effect of Time Duration by Vibrating or Tamping Fresh Concrete on the Compressive Strength of C-25 Concrete. American Journal of Construction and Building Materials. Vol. 2, No. 2, 2017, pp. 40-47. doi: 10.11648/j.ajcbm.20170202.11

  
  

  Abstract

  Many years ago, consolidation accomplished by laborers wielding a variety of spades, tampers, and similar tools. In Ethiopia, there is no enough knowledge by the laborers, while the site engineers ignored the correct application due to some constraints. The agreement of acceptable vibration level in fresh concrete to which tamping time duration is optimum is an issue to obtain the desired specific compressive strength. This research study aims to evaluate the maximum time length and techniques used to Vibrating or Tamping fresh concrete and its effect on the compressive strength of C-25 Concrete through internal Rodding. Therefore, to study the effects of the period by vibrating or tamping, the needle-type internal vibrator was used to test new concrete cubes based on ACI309R-96. The quality of concrete is important to make physical tests on materials used before any actual experiments to perform. The fresh concrete samples tested by using internal vibration methods and techniques of compaction with different time duration of 1sec, 2sec, 3sec, 4sec, and 5sec. These tests performed by using steel rod in fresh concrete to know the Optimum time of compaction by internal vibration on the cube test of new concrete. Laboratory experiments had been conducted to check the methods and techniques applied to construction sites, as well as site observation on the effects of the vibration time of fresh concrete on the compressive strength and flexural strength of C-25 Concrete with varying vibration time duration and steel rod tamping. Based on the results of cube tests of compressive strength of Concrete Samples have been checked on the 3rd day, 7th day, and 28th day. This research study found out that the Optimum period of compaction was 3sec to produce an acceptable right quality of the concrete mix. Likewise, the flexural strength of the Concrete Sample, when it tested in the laboratory on the 7th day and 28th day, results revealed that the flexural strength improved when vibration time increased, but the amount of water has to be reduced to obtain the desired strength. Finally, Tamping is needed to place fresh concrete in the mold correctly. Furthermore, new concrete produced should match the properties and avoid improper tamping or vibration applications. This situation must not cause differences in the compressive strength of concrete.

  Abstract
  Many years ago, consolidation accomplished by laborers wielding a variety of spades, tampers, and similar tools. In Ethiopia, there is no enough knowledge by the laborers, [...]

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• Contract claim Analysis on Building Construction Project in Addis Ababa: A case study at Yeka Sub City

  E. Quezon

  International Journal of Scientific & Engineering Research (2016). Zenebe, E.; Quezon, ET.; Mosisa, A. Contract claim Analysis on Building Construction Project in Addis Ababa: A case study at Yeka Sub City. International Journal of Scientific & Engineering Research. 2016; 7(7): 1154-1160

  
  

  Abstract

  Contract claims are an inevitable fact of life in the construction industry. Contract claims are one of the problems that construction projects may face. Claims might cause many effects such as payment delay, an extension of time, and work suspension. The main aim of this research was an analysis of contract claims on building construction projects in Addis Ababa, Yeka Sub City by investigating the causes of contract claims and determining the factors to be considered in the selection of appropriate methodology for contract claims analysis. Literature and survey-based studies were made to provide an overview of the different contribution effects of contract claim analysis on building construction projects at the selected site. Interviews were also conducted with the three parties which have direct involvement in construction activities to get concrete ideas on the subject matter. A total of 75 questionnaires was distributed to respondents in Addis Ababa, Yeka Sub City building construction projects. Out of these 12 for client representatives, 35 for contractors representatives, 20 for consultant representatives, and 8 for other companies in order to identify claim causes that occurred in the study area. The quantitative data were analyzed using Excel and SPSS version 20 software, while qualitative data were analyzed by content analysis. The main factors of contact claim cause in the study area were identified. These factors further categorized into four groups; client-related, contract document-related, contractor related and consultant-related factors. While types of delays, knowing the strength and weakness of the project (project complexity) and conditions of the contract were identified as the factor to be considered in the selection of appropriate methodology for contract claim analysis. It is recommended that the three main contracting parties (Owner, Contractor, and Consultant) have responsibility for the effective accomplishment of the project. So each party would take part in their homework on time by developing technical knowledge about the effects of Contract claims on the progressive construction projects. Index Terms— causes, claim analysis, Contract claims, construction project, and risks.

  Abstract
  Contract claims are an inevitable fact of life in the construction industry. Contract claims are one of the problems that construction projects may face. Claims might cause [...]

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• Evaluation of Health and Safety Practice in Building Construction: A Case Study in Addis Ababa

  E. Quezon

  International Journal of Scientific & Engineering Research (2016). Fekele, L.; Quezon, ET.; Macarubbo, YC. Evaluation of Health and Safety Practice in Building Construction: A Case Study in Addis Ababa. International Journal of Scientific & Engineering Research. 2016; 7(10): 122-131

  
  

  Abstract

  The construction industry has been seen as one of the hazardous industries. This is because the industry has a poor health and safety performance record compared to other industries all over the world. Labor law in every nation provides that it is the duty of an employer to ensure that every worker employed works under satisfactory, safe and healthy conditions. The research is focused on evaluating the health and safety issues in building construction projects in Addis Ababa, Ethiopia. The roles of the Client, Consultant and Contractor in health and safety consideration during project implementation were examined. It also determined the factors affecting health and safety performance of laborers. Whether, safety is used as criteria in selecting a contractor during the prequalification phase of public bidding was also identified. Building Construction Companies were involved in the sampling. All the information that could help in attaining the study objectives were collected, reviewed and formalized from the literature review. Data were collected and evaluated and the Relative Importance Index for each factor affecting health and safety was determined. The study determined the practical situation of building construction projects in consideration of health and safety, which was evaluated as low to medium. Relative Importance (RII) index of 12 factors affecting health and safety performance of labors were calculated. The top three factors identified were: (1) Non availability of a clear company Health and safety policy (0.85); (2) Inadequate enforcement of the existing building rules and regulations (0.82); and (3) Safety awareness of the company's top management (0.80). To improve the safety and health performance of building construction projects, the following major recommendations were proposed: each building, construction projects should have their own safety and health policy; include safety as a pay item in contract document; and allocate budget and time frames for health and safety in the contract document. Index Terms— Addis Ababa, Company Policies, Hazards, Health and Safety Practices, Rules and Regulations .

  Abstract
  The construction industry has been seen as one of the hazardous industries. This is because the industry has a poor health and safety performance record compared to other [...]

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• Assessment on the effects of weather change on road construction planning at some selected projects in Addis Ababa and Oromia

  E. Quezon

  International Journal of Scientific & Engineering Research (2016). Befkadu, A.; Quezon, ET.; Busier, M. Assessment on the effects of weather change on road construction planning at some selected projects in Addis Ababa and Oromia. International Journal of Scientific & Engineering Research. 2016; 7(12): 134-145.

  
  

  Abstract

  Road construction in Ethiopia is in high demand to meet its short and long-term goals in infrastructure development programs. The road network is constructed radiating outwards North-South and East-West direction of the Capital City. Some projects are experiencing weather malady due to changing weather conditions in project locations. The study area of this research was focused on some selected projects in Addis Ababa and Oromia. The research had been addressed the effects of changes in weather in the three project planning phases, namely conception planning, design planning, and construction planning. A quantitative research design was used in this study. A literature review was undertaken and the result of which showed that the effects of weather changes are not extensively researched in the construction industry and there are limited references on the effects of weather change within the road construction industry. Sample data were obtained from sixty-three (63) construction practitioners through questionnaires, which were mailed to prospective respondents to assess their opinions. Questions were subdivided into three relevant areas covering demographics, experience with weather change factors, and the effects of weather change on road construction project planning. The study found that the effects of weather change on road construction project planning are similar to those found in other construction industries. The effects of weather change factors on road project planning vary with planning phases. These weather change factors as well as their effects were listed and ranked based on their frequency of occurrence and mean score. An independent sample t-test was used to compare respondents’ opinions on weather change effects between the two sample groups taken in Addis Ababa and part of Oromia. A partial correlation was also employed to identify the relationship between weather change factors and their effect on road construction project planning using SPSS-20. Delay of site preparation activities as a result of weather change on road project conception planning phase has a mean score of 4.30 Addis Ababa and 4.00 in for Oromia, while the influence of weather change on the selection and specification of construction materials for road project design planning phase has the highest mean score of 4.23 for Addis Ababa and 4.03 for Oromia. The effect of weather change on road workers' physiological comfort and quality of work for the road project construction planning phase has the highest mean score of 4.80 and 4.58 in Addis Ababa and Oromia, respectively. The study concludes with recommendations for potential research and with useful information and considerations on the effects of weather change on road construction project planning for construction professionals and project managers.

  Abstract
  Road construction in Ethiopia is in high demand to meet its short and long-term goals in infrastructure development programs. The road network is constructed radiating outwards [...]

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• PARAMETRIC MODELLING ON THE RELATIONSHIPS BETWEEN ATTERBERG LIMITS AND COMPACTION CHARACTERISTICS OF FINE-GRAINED SOILS

  P. Quezon, E. Quezon

  International Journal of Advanced Research in Engineering and Applied Sciences (2019). Worku Firomsa, Prof. Emer Tucay Quezon; (2019). “PARAMETRIC MODELLING ON THE RELATIONSHIPS BETWEEN ATTERBERG LIMITS AND COMPACTION CHARACTERISTICS OF FINE-GRAINED SOILS.” International Journal of Advanced Research in Engineering and Applied Sciences, 8(7), 1-20. https:// www.garph.co.uk

  
  

  Abstract

  Compaction is one of the essential engineering techniques, performed to assure the stability of soils based on specified strength. However, in most construction projects such as large-scale projects, obtaining the desired compaction characteristics, namely optimum moisture content (OMC) and maximum dry density (MDD), becomes time-consuming. In this case, predicting the compaction characteristics from the Atterberg's limits that involve a more straightforward and quicker method of testing becomes a vital task. This study focused on obtaining valid correlations between Atterberg's limit parameters and compaction characteristics of fine-grained soils. A series of laboratory tests for 50 samples conducted for the investigation. Statistical relationships of all the parameters were analyzed. The laboratory test results indicated that both OMC and MDD showed a strong correlation with LL and PL together using multiple linear regressions than with single parameters from single linear regression. Therefore, the study concluded that during the prediction of OMC and MDD from Atterberg's limits, the combined parameters of Atterberg's limits should be used rather than single parameters. It is recommended, the result of this research could be applied in different civil engineering practices, directly related to the parameters to be known.

  Abstract
  Compaction is one of the essential engineering techniques, performed to assure the stability of soils based on specified strength. However, in most construction projects such [...]

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• Evaluation on the Performance of Lowest Responsive Bid Contract and the Quality of Materials Used on Governmental Building Projects in Jimma Town

  E. Quezon

  International Journal of Scientific & Engineering Research (2016). BinyamLetarge, Emer T. Quezon, Yolente C. Macarubbo. Evaluation on the Performance of Lowest Responsive Bid Contract and the Quality of Materials Used on Governmental Building Projects in Jimma Town. International Journal of Scientific & Engineering Research. 2016; 7(12): 60-73

  
  

  Abstract

  Construction industry participants have started recognizing that accepting the least bid price does not guarantee maximum value. Continuous problems of inferior quality of constructing facilities, high incidence of claims and litigation, frequent cost overruns, and use of poor quality of materials have become the main features of Ethiopian’s public construction work contracts. This research was undertaken to evaluate the performance of publicly owned construction projects awarded on a lowest bid awarding system, to determine the effect of advance payment on the contractor’s performance, compare lowest and average bid systems, and check the quality of local construction materials use by lowest price won contracts. A literature review was carried out to identify different practices and floated questionnaire survey and laboratory test was conducted for selected and expected materials. Two alternative bid evaluation methods were discussed and suggested the better one from a performance point of view. The questionnaire was distributed to contractors, clients, consultants, and other related professionals. Additionally, interviews were conducted with them. A total of 88 questionnaires were distributed, including laboratory test results for selected and expected materials found in Jimma town. The data were collected and 80 valid questionnaires were analyzed by using SPSS-20, Excel, and laboratory test results requirement. The study identified that the causes of the poor performance of contractors were won projects with the lowest price; therefore more of the respondents do not like the lowest bidding method. Advance payment is the main solution to support the financial problems of contractors, but instead of paying in cash, purchasing the necessary construction materials is seen as an alternative to protect contractors from using the money for other uses. Obviously known that in the current bid awarding method of Ethiopia, most of the time, in order to be the winner of the bid price should be lesser. This leads the bidder not to get adequate profit, this pushes them to use poor quality of local construction materials. Finally, this work provides valuable information to the Ethiopian government, clients, consultants and contractors, and other stakeholders who desire to improve bidding methods; usage of advance payment; ways to improve performance of contractors, and to protect the project from contractors using poor quality of construction materials. 

  Abstract
  Construction industry participants have started recognizing that accepting the least bid price does not guarantee maximum value. Continuous problems of inferior quality of [...]

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• A Study on the Effect of Time Duration by Vibrating or Tamping Fresh Concrete on the Compressive Strength of C-25 Concrete

  A. Achalu, E. Quezon, G. Macarubbo

  American Journal of Applied Scientific Research (2017). Vol. 3, No. 6: pp. 72-79. doi: 10.11648/j.ajasr.20170306.11

  
  

  Abstract

  Many years ago, consolidation accomplished by laborers wielding a variety of spades, tampers, and similar tools. In Ethiopia, there is no enough knowledge by the laborers, while the site engineers ignored the correct application due to some constraints. The agreement of acceptable vibration level in fresh concrete to which tamping time duration is optimum is an issue to obtain the desired specific compressive strength. This research study aims to evaluate the maximum time length and techniques used to Vibrating or Tamping fresh concrete and its effect on the compressive strength of C-25 Concrete through internal Rodding. Therefore, to study the effects of the period by vibrating or tamping, the needle-type internal vibrator was used to test new concrete cubes based on ACI309R-96. The quality of concrete is important to make physical tests on materials used before any actual experiments to perform. The fresh concrete samples tested by using internal vibration methods and techniques of compaction with different time duration of 1sec, 2sec, 3sec, 4sec, and 5sec. These tests performed by using steel rod in fresh concrete to know the Optimum time of compaction by internal vibration on the cube test of new concrete. Laboratory experiments had been conducted to check the methods and techniques applied to construction sites, as well as site observation on the effects of the vibration time of fresh concrete on the compressive strength and flexural strength of C-25 Concrete with varying vibration time duration and steel rod tamping. Based on the results of cube tests of compressive strength of Concrete Samples have been checked on the 3rd day, 7th day, and 28th day. This research study found out that the Optimum period of compaction was 3sec to produce an acceptable right quality of the concrete mix. Likewise, the flexural strength of the Concrete Sample, when it tested in the laboratory on the 7th day and 28th day, results revealed that the flexural strength improved when vibration time increased, but the amount of water has to be reduced to obtain the desired strength. Finally, Tamping is needed to place fresh concrete in the mold correctly. Furthermore, new concrete produced should match the properties and avoid improper tamping or vibration applications. This situation must not cause differences in the compressive strength of concrete.

  Abstract
  Many years ago, consolidation accomplished by laborers wielding a variety of spades, tampers, and similar tools. In Ethiopia, there is no enough knowledge by the laborers, [...]

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• Influence of Subsurface Courses Materials On Pavement Performance: A Case Study in Yebu-Agaro Road

  E. Quezon

  International Journal of Scientific & Engineering Research (2016). Anteneh Geremew, Prof. Emer T. Quezon, Getachew Kebede. Influence of Subsurface Courses Materials On Pavement Performance: A Case Study in Yebu-Agaro Road. International Journal of Scientific & Engineering Research. 2016; 7(10): 1252- 1260.

  
  

  Abstract

  The properties of subsurface materials would vary from place to place while it is true the performance of pavement along the route also differs. The research study had been undertaken at the Yebu-Agaro road section with the main objective to determine the Influence of Subgrade Soil on pavement performance. In order to realize the desired objective, a systematic methodology was adopted which includes field investigation, field test, and laboratory tests. While the purposive sampling method was used to extract soil samples from the road section that are severely damaged showing different failure types and non-distress surfaces. Those severe types of failures observed along the road section are reflective crack, pothole, rutting, alligator crack, and block crack. From these failure types, five representative samples were extracted at different locations along the failures section and one non-distress pavement of the road section using a manual hand auger. The analyses of soil samples were carried out based on the Geotechnical properties such as wash gradation, Atterberg limit, and Modified proctor test, California Bearing Ratio (CBR) and field test, as well as Axle load analysis. It was found out that the liquid limit of subgrade soil varies from 33% -60.5% and the plasticity index from 20.3% -30.1% while there was a significant increase in moisture content at the field and observed beyond the OMC in the laboratory result due to the distress of pavement affected by water infiltration through cracks, that tend to reduce the dry density. The recorded soaked CBR values of subgrade soil materials range between 8% -13%, which was below the 15% minimum value specified by the ERA manual. However, the existing CBR values of the subgrade soils indicate a poor material used for pavement structures. According to ASSHTO, the soil is classified as A-2-6 and A-7-6 category which means the existing soils are fair to poor as a sub-grade material while USCS classification shows that the soil falls into the SC group. In addition, the failures that are frequently observed on the road surface were significantly influenced by subgrade soil. For the sub-base layer materials, it was noted to have satisfied the minimum requirements as compared with standard specification, except deficiency of its thickness. For the base course materials, inferior qualities of material were used in some sections. The overall results showed that heavy vehicles or traffic loads are one of the major causes of road failure along the study road section. Hence, the influence of other factors such as poor drainage courses, level of groundwater table, variety of geologic materials along the road route, and poor construction materials should be thoroughly addressed before the start of the rehabilitation of the road section in the future. Finally, a possible remedial measure is recommended for every observed failure or distress on the pavement condition of the study area in order to sustain the design life of the pavement. 

  Abstract
  The properties of subsurface materials would vary from place to place while it is true the performance of pavement along the route also differs. The research study had been [...]

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• Investigation of Traffic Accident Prone Areas Related to Existing Road Condition and Driver’s Behavior along Menagesha- Ambo Road Section

  E. (MSc), P. (MSc), E. Quezon

  World Journal of Engineering Research and Technology (2018). Eyob Mekonnen (MSc), Prof. Emer Tucay Quezon and Murad Mohammed (MSc). Investigation of Traffic Accident Prone Areas Related to Existing Road Condition and Driver’s Behavior along Menagesha- Ambo Road Section. World Journal of Engineering Research and Technology. wjert, 2018, Vol. 4, Issue 2, 64-81

  
  

  Abstract

  Traffic accidents worldwide are increasing due to pragmatic vehicle ownership, acquisition, which necessitates daily activities. The primary objective of this research work was to identify the most hazardous location and provide countermeasures that will minimize traffic accident at the designated sites. The scope of the study was limited to Ambo-Ginchi- Addis Ababa road, a total length of the study road section of 87kms. The traffic accident data collected from each Wededa Police station covering the period of 2012-2015. It was analyzed using a Priority value formula for EjereWereda and Holota town, and accident frequency for Ambo wereda, Dendiwereda, and Welmeraweredato rank the traffic accident areas. Based on the results of the analysis, thirteen locations of the road stretch were found to be accident-prone areas. Out of these sites, three of them are in Ambo Wereda, two in Ejerewereda, one in Welmerawereda, and seven in Holota town. The time when most of the accidents occurred from 3:00 PM-6: 00 PM. The primary causes of the accidents were overspeeding, driving without attention, and some unknown reasons. Also, it showed that the drivers’ age group who caused most of the accidents composed of 25-34 years old. Based on the findings of the study, it is concluded that there was a significant increase in the number of crashes in the afternoon. Young drivers are believed to cause more accidents than older ones due to aggressiveness. To minimize the occurrence of accidents along the study road section, it is recommended that provision of speed limit signboards and warning signs at the strategic locations where traffic accident areas are identified to forewarn the overspeeding drivers. It is also recommended that the road agency should have to undertake to widen the lane width of the road, provision of sufficient climbing lane, installation of roadside Delineator, conduct roadside improvements, and repaint faded pavement markings.

  Abstract
  Traffic accidents worldwide are increasing due to pragmatic vehicle ownership, acquisition, which necessitates daily activities. The primary objective of this research work [...]

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• Engineering Properties of Mechanically Stabilized Subbase Material Using Natural Gravel around Jimma Quarry Sites for Unpaved Road Construction

  E. Quezon

  Global Scientific Journals (2017). Almaz Ejeta, Emer Tucay Quezon, Kabtamu Getachew. Engineering Properties of Mechanically Stabilized Subbase Material Using Natural Gravel around Jimma Quarry Sites for Unpaved Road Construction. Global Scientific Journals. GSJ: 2017; 5(5): 93-102

  
  

  Abstract

  Unpaved roads are designed with a small input and are constructed from the nearest available materials as possible. It requires routine and periodic maintenance, and its condition can be significantly affected by a period of excessive traffic volumes or inclement weather conditions. The accurate estimation of maintenance cost is difficult. Many problems occur in the economic analysis of unpaved roads in comparison with paved roads. D effects that may affect unpaved roads are dusty, potholes, stoneness, corrugations, and rutting. Hence, it needs to apply a sufficient stabilization method to strengthen and increase the durability of the unpaved road. Mechanical stabilization is an important application in engineering for different types of construction to improve the performance of road construction materials. The objective of this research was to determine the Engineering properties of natural gravel materials by mechanical stabilization method to be used in subbase material for the unpaved road. The methodology carried out in this research study includes: (a) field visual inspection and sampling of natural gravel materials from three quarry sites around the Jimma area; and (b) laboratory tests to identify the physical and mechanical properties of natural gravel. Based on the laboratory test results, natural gravel materials from the Seka quarry site has an excellent Abrasion resistance of 35.26%, Plasticity Index of 13% a little bit above the upper limit, and good gradation (coarser and less subtle or binder materials), right CBR value. While the Jiren quarry site has a little Abrasion resistance of 52.09%, medium plasticity index, poor gradation (moderate fine material), CBR value of 28.90% which was below 30% minimum requirement, but had good MDD. On the other hand, the Merewa quarry site comprised of a very poor Abrasion resistance of 78.3 4%, Plasticity Index of 2 3.90% which was beyond the upper limit plasticity index of 1 2%, and poor gradation (more fine materials), poor CBR value and poor MDD. Therefore, it is concluded that the natural gravel from the Seka quarry site is suitable for the subbase course. But since road construction around Jimma is booming, the natural gravel from this quarry site would be soon depleted. About this, mechanical stabilization is recommended by blending the natural gravel from the Seka quarry site with 54% by weight with Jiren natural gravel of 46% by weight to meet the minimum requirements for subbase materials.

  Abstract
  Unpaved roads are designed with a small input and are constructed from the nearest available materials as possible. It requires routine and periodic maintenance, and its condition [...]

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