Effect the silica sand percentage as subtitution of fine agregate on the concrete compressive strength

Abstract

This study uses silica sand, which has a high SiO2 content and micron size as a substitute for normal sand with control specimens with compressive strength of fc′ 45 MPa. Two types of silica sand gradations were used, namely 80-100 mesh(0.177 mm - 0.149 mm) in size and 325 mesh (0.044 mm) in size from Bangka as the fine aggregate. There were 45 cylindrical specimens sized 15 cm in diameter, 30 cm in height, and age of7, 14, and 28 days. The tests carried out were absorption test and compressive strength test based on SNI 1974: 2011, which explained the testing method of the compressive strength of concrete with cylindrical specimens. Based on the test results, the optimum compressive strength was 53.07 MPa in the specimen with a composition of 50% sized 80-100 mesh (0.177 mm - 0.149 mm) (+) 50% sized 325 mesh (0.044 mm) silica sand, which can increase 4.12% of the compressive strength from normal concrete. On the other hand, the lowest compressive strength was obtained in a specimen with a composition of 25% sized 80-100 mesh (0.177 mm - 0.149 mm) (+) 25% size325 mesh (0.044 mm) silica sand, which was 48.43 MPa at 28 days.