Effects of partial replacement of river sand with stone dust in concrete production.

Abstract

This paper investigates the effects of partial replacement of conventional river sand with crushed rock dust in concrete production. To achieve this, different preliminary tests were performed on the two sources of aggregate (river sand and crushed rock dust) to determine their physical properties before using in the production of concrete cubes and beams to determine their compressive and flexural strengths. Hence, the percentage replacement of conventional river sharp sand with crushed rock dust at 0%, 10%, 20%, 30%, 40%, 50%, and 100% to evaluate the optimum compressive and flexural strengths of concrete produced. The water-cement ratio used is 0.5 while the mix ratio is 1: 1.397:3.419. To determine the compressive and flexural strengths, concrete cubes and beams of sizes (150 x 150 x 150) mm and (100 x 100 x 500) mm respectively were prepared and cured for 7days and 28days and its compressive and flexural strengths determined. The result shows that concrete produced with 0% replacement of conventional river sand with crushed rock dust attain the highest compressive strength at 7 and 28days curing ages while concrete produced with crushed rock dust has a lower compressive strength. Also, the optimum compressive strength was achieved at 40% replacement of conventional river sharp sand with crushed rock dust while the concrete attains its maximum flexural strength at 30% replacement level. At 28day, the concrete produced with river sharp sand attain its optimum compressive and flexural strengths of 31.72% and 6.72N/mm2 respectively, while the maximum compressive and flexural strengths was achieved at 40% replacement level.