EFFECT OF PARTIAL REPLACEMENT OF CEMENT WITH BENTONITE ON COMPRESSIVE STRENTH OF CONCRETE

Abstract

Environmental concerns both in terms of damages caused by the extraction of raw material and CO2 emissions during cement manufacture, have brought about pressures to reduce cement consumption by use of supplementary materials. The mixture of ordinary Portland cement (OPC) and pozzolan have proven to be beneficial in concrete production. This study investigates the range of ordinary Portland cement - bentonite mix proportion that can be found useful in concrete and block production. Tests were carried out to obtain the Compressive strength, workability and water absorption of the cement –bentonite concrete mix . This involves the partial replacement of cement with (2-10) % of bentonite for 1:2:4 mix ratio using 0.5 w/c ratio. Twelve cubes of concrete were casted for each percentage replacement including the control mix and tested for 7, 14, 28 and 50days curing ages. It was discovered that 10% replacement of cement with bentonite gave the highest sump value. The compressive strength of concrete decreased on addition of bentonite as compared to control cubes, but at 50days curing age, the compressivestrength of the concrete with up to 10% bentonite gained strength that is approximate to the control mix at 28days. It was also observed that concrete cube with 10% bentonite at 50days absorbed more water.