Parametric Study for Replacement of Sand by Fly Ash for Better Packing and Internal Curing

Abstract

The use of fly ash as replacement of sand is an economical solution for making green and denser concrete. The paper presents a concrete mix design procedure for partial replacement of sand with fly ash. Present method could produce additional compressive and flexural strength for concrete with partial replacement of sand with fly ash over control concrete, with higher slump. Addition of 0.5% super plasticizer could further improve compressive and flexural strength with higher slump over control concrete. Concrete with sand replaced by fly ash was also found to be economical without and with super plasticizer, when cost per N/mm 2 was compared. The beneficial effect may be attributed to better packing, pozzolanic activity of fly ash and internal curing by fly ash as partial replacement of sand. Based on experimental results, correlations are developed to predict compressive strength, flexural strength and cost per N/mm2 for percentage sand replacement with fly ash.