Comparison of the Effect of Different Sizes of Aggregate (Granite) on the Compressive Strength of Concrete

Abstract

The need for more understanding of the behavior and response of constituent materials of concrete used in construction projects to loadings and imposed stresses cannot be overemphasized. This paper investigates the effect of different coarse aggregate sizes on the compressive strength of concrete using different sizes ranging from 0-5mm, 5-14mm, 14-20mm, 20-28mm, >28mm and a combination of all the sizes. A nominal mix ratio of 1:2:4 batched by weight with 0.60 water-cement ratio was used. Tests conducted on the aggregates include moisture content, specific gravity, bulk density, sieve analysis, porosity and void ratio. On the other hand, the workability test (slump test) and compressive strength tests were carried out on fresh concrete and hardened concrete respectively. A total of 54 concrete cubes (150mm x 150mm x 150mm) were cast and tested at 7days, 14days and 28days. The result showed that the compressive strength and density increased with days of curing. The aggregate size range 14-20mm gives the highest compressive strength but for optimal and economic reasons the combined aggregate is recommended for construction work.