Evaluation the Effects of Coarse Aggregates Size on Concrete Properties

Abstract

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.