Evaluation the Effects of Coarse Aggregates Size on Concrete Properties

摘要

Concrete is the most generally used construction material in buildings,pavements,and infrastructures.Concrete is a construction material composed of cement as binder,fine aggregates and coarse aggregates mixed with water which hardens with time.Concrete is a versatile construction material within the housing industry of the planet.The standard of the concrete is tormented by various factors and from those various factors which may have an effect on the concrete quality are,the coarse combination size has its own nice role on the standard of concrete production.A laboratorial experiment was conducted to work out the results coarse aggregates size on recent and hardened concrete properties.For this study totally different crushed volcanic rock aggregates sizes were collected from almost Jimma city for determination of the results of coarse aggregate sizes in concrete production.Three coarse aggregate nominal sizes of 10 mm,14 mm and 20 mm were used for samples production to envision the scale effects on concrete properties.For this study the procedures that was followed,the types and quantity of materials for concrete creating were similar whereas sizes of nominal basaltic coarse aggregate were different.The fresh concrete has a slump value of 67 mm,72 mm and 83 mm for 10mm,14 mm and 20 mm aggregate sizes respectively.A total of thirty six concrete cube samples were ready and tested using compressive strength testing machine at totally different ages of the cube 7 days,14 days,and 28 days,to know their strengths.The compressive strength was 23.524 Mpa,22.643 Mpa and 22.41 MPa for aggregate sizes of 10 mm,14 mm and 20 mm respectively.The laboratory results show that 10mm coarse aggregate size gave the most effective compressive strength and comparatively lowest slump at similar water/cement ratio of 0.6.At 28th day 10mm coarse aggregate size gave 23.524 Mpa compressive strength which is the maximum compressive strength from the remainder coarse aggregates so,the optimum maximum size of coarse aggregate for this study was 10mm.