The Effect of Fineness Modulus of Fine Aggregate on Concrete Compressive Strength

Abstract

Concrete is the major material used for most civil engineering constructions like buildings, bridges, culvert, rigid road pavement, dam spillway and so on. Concrete is made from a mixture of cement, fine aggregate (sand), coarse aggregate (granite or gravel), and water. The fineness modulus is one of the physical properties of fine aggregates (sand). The Fineness Modulus (FM) of fine aggregates (sand) is obtained from the grading size distribution test as summation of percentage cumulative retained by series of sieves and divided the sum by 100. The fineness modulus of sand differs for each sand quarry. The purpose of this research is to analyze the effect of fineness modulus of fine aggregate (sand) from three different sand quarries on concrete compressive strength. The sand for the study were taken from three quarries (Ayegun, Akufo and Awotan) in Ibadan, Oyo state, Nigeria. The specimens of concrete used in the form of the cube measuring 150x150x150 mm amounted to 36 specimens. The compressive strength of concrete (fc’) targeted is 21 N/mm2 with W/C ratio 0.5. Concrete mix ratio of 1:2:4 was batched by weight. The results showed that the fineness modulus of sand strongly influence the compressive strength of concrete. The classification of sand type is differentiated based on the results of fineness modulus test on each sand sample. Sand fineness modulus (FM) of Ayegun quarry is 2.64 called medium sand (zone 2). Sand fineness modulus of Akufo quarry is 2.35 called mild sand (zone 3), and, sand fineness modulus of Awotan quarry is 1.57 called fine sand (zone 4). Concrete compressive strength values of Ayegun, Akufo and Awotan quarries sand were 21.3 N/mm2, 22.4 N/mm2, and 20.5 N/mm2, respectively. The value of sand fineness modulus does not affect the increase in the concrete compressive strength. The best classification of fine aggregate to increase concrete compressive strength is mild sand (Akufo quarry) and all the sand samples meet the planned concrete compressive strength of 21 N/mm2.