Analysis of Strength Hydraulic Concrete Produced with a Mixture ofCrushed Gneiss and Alluvial Sand

In recent years, the construction industry has been faced with a decline in the availability of natural sand due to the growth of the industry. In the present study, effect of gneiss powder as fine aggregate replacement on the compressive strength of concrete was investigated. The percentage of gniess powder added by weight was 0%, 25%, 50%, 75% and 100% as a replacement of river sand used in normal concrete. Tests were performed for compressive strength tests for all replacement levels of gneiss sand at different curing period (7 days, 28 days and 90 days). The results revealed that all the concrete made with different replacement present the good mechanical performance. At 90 days, the maximal values of compressive strength are obtained for conventional concrete CN (37.07 MPa), followed by CG75 concrete made with 25% of river sand and 75% of crushed gneiss (35.09 MPa). Then it is suggested that sand with a partial substitution of 75% can be effectively used in concrete production without affecting the strength and durability properties of the concrete.