SCOPE OF GRANULATED BLAST FURNACE SLAG AS FINE AGGREGATE IN CONCRETE FOR NORMAL AND FIRE EXPOSURE

Present work experimentally investigates the scope of utilizing granular blast furnace slag (GBFS) in concrete exposed to high temperature. Six series of concrete mixes of Grade M20 including control mix were prepared by replacing natural sand with GBFS in 10, 30, 50, 70 and 100% by weight. Sustainability of GBFS concrete for normal weather condition was ensured by preliminary investigation on mechanical strength for various GBFS concrete mixes at various ages. Later, fire durability of the concrete was evaluated by residual compressive strength, weight loss and surface observation of heat cured specimen through necked eye. Cube compressive strength improves by 2.15-6.31% while cylindrical compressive strength of concrete mix with 30% GBFS marginally improves at all ages. Split strength increases up to 2.9-8.07% up to 50% GBFS replacement while flexure strength increases by 0.81-7.0% at 30% with respect to all the age of curing at room temperature. Residual compressive strengths were 57.3, 55.89 and 54.46 % for 30, 50 and 70% GBFS concrete mixes at 600°C. Surface cracks in specimen were observed after 500°C which continued to grow with the increase in temperature. Furthermore, test results indicate the improvement in the properties of concrete with the incorporation of GBFS even though it exposes to high temperature.