Abstract

Abstract

The local fired brick production technique is the known method of brick making, especially in Jimma Town. Firing of bricks in local brick production method is conducted by burning of much amount of woods. But this method of firing bricks by burning of woods will affect the environment. The locale firing technique is difficult to control the firing temperature, which will result in non-uniform burnt bricks. The major objective of this experimental study was to compare the compressive strengths of locally fired clay bricks and the local unfired cement and lime stabilized clay bricks. Specifically, the index properties of soil used for brick production, the compressive strength of locally fired clay bricks, and stabilized clay bricks had been determined and compare with the standard specifications. This study, it was used contents of the stabilizer for cement and lime of 10%, 12%, and 14%, respectively. The mix ratio applied 1:9, 1:7, and 1:6 by volume of clay with stabilizer 10%, 12%, and 14%. Based on the result on the 28th day, the mean compressive strength test, the 10%, 12%, and 14% cement Stabilized clay bricks have compressive strengths of 2.91Mpa, 3.28Mpa, and 3.79Mpa respectively, which are better than the mean compressive strength of the locally fired clay bricks which is 2.73Mpa. On the other hand, the 28th day means compressive strengths of the lime stabilized clay bricks were 2.19Mpa, 2.51Mpa, and 2.69Mpa, respectively. Therefore, these results showed that the Fired Clay Brick fails the minimum mean compressive strength requirement based on the ES, ASTM, and IS standards. But the Stabilized Clay Bricks fulfill the minimum compressive strength requirements of IS standard for stabilized bricks. Among these three methods, the cement stabilized clay bricks indicated better quality than both locally fired and lime stabilized bricks.

Abstract

Nowadays, metallic fibre reinforced cementitious composites are widely used on many different construction elements: concrete beds, slabs, precast concrete industry, etc. Fibres reduce the crack generation due to the cementitious composite shrinkage and improves its flexural strength, toughness and durability. If metallic waste materials from the industrial manufacturing sector were used instead of using the commercially available metallic fibres, the energy of both the waste recycling process and the manufacturing of the actual commercial metallic fibres would be saved. This paper studies the use of the waste residual brass fibres generated during the electrical discharge machining process as a reinforcement on mortars. With that in mind, two different fibre types (brass covered steel and recycled brass) on two different mix proportions (0.65% and 1.3% by unit volume of mortar) were added to a self-leveling non-reinforced mortar taken as a reference to evaluate their influence on the physical, thermal and mechanical properties of the resulting mortar. According to the results, for both types of fibres studied, the higher the fibre proportion used, the higher were the density, the thermal conductivity, the flexural strength and the compressive strength.of the resulting mortars. Recycled brass fibres increased the thermal conductivity and decreased the volumetric heat capacity of the resulting mortars more than the steel fibres, which is interesting, for example, on self-levelling mortars used on radiant floor heat exchangers. However, less increase was observed on the mechanical properties of the recycled brass fibre reinforced mortars than that of the steel fibre reinforced mortars, due to the shorter length of the former fibres (5-10 mm for the recycled brass fibres, 13 mm for the steel fibres). Therefore, the parameter that controls the cutting frequency of the waste wire of the electrical discharge machine should be modified to adapt the final fibre length to that of the commercially available fibres.

Abstract

Abstract

Cement being the main constituent of concrete plays a vital role in concrete production. In Ethiopia, cement consumption has grown well with a growth rate of about 16.1% per year. Hence, an alternative material to partially replace cement was initiated to reflect the needs of the local community in the study area. The waste quantity of animal bones has impacted the environment which is unusual to see in other Non-African countries. The primary aim of the research is to investigate the effects of varying dosage replacement of cement by animal bone powder (ABP) in normal concrete production. The bone samples collected from the Seka Waste Disposal Site of Jimma town, approximately 10km from the bus station where a quantity of waste animal bones can be found. After cleaning and drying, the bone samples burned in the Furnace. The average required energy to burn the animal bone obtained at a temperature of 340°C. The burnt bone was allowed to cool before grinding in a hammer mill and sieving. There were six proportions prepared to start from 0% (as control specimen), 5%, 10%, 15%, 20%, and 25% dosage increment by weight of bone powder, and evaluated the normal concrete strengths of C-25 grade concrete. The laboratory test results indicated the chemical analyses of a bone powder composed of similar compounds of oxide in cement but slightly lesser in content based on ASTM C-150. Likewise, the effects of replacing animal bone on the properties of cement such as consistency and setting time remained within the acceptable limits of the Standard Specifications. On the other hand, the results of compressive, flexural tensile, and split tensile strengths significantly declined from the control specimen during the dosage increment of the replacement made. Therefore, the optimum dosage of the bone powder indicated 10% by weight to replace cement content in normal concrete mix production.

Abstract