Experimental investigation of using slag as an alternative to normal aggregates (coarse and fine) in concrete

These paper present results of experimental investigations carried out to evaluate effects of replacing aggregate (coarse and fine) with that of slag on various concrete properties. The basic objective of this study was to identify alternative source of good quality aggregates which is depleting very fast due to the fast pace of construction activities in India. Use of slag -a waste industrial byproduct of iron and steel production provides great opportunity to utilize it as an alternative to normally available aggregates (coarse and fine). In this study, concrete of M20, M30 and M40 grades were considered for a WIC ratio of 0.55, 0.45 and 0.40 respectively for the replacements of 0, 30, 50, 70 and 100% of aggregates (Coarse and Fine) by slag. Whole study was done in two phases, i.e. replacement of normal crushed coarse aggregate with crystallized slag and replacement of natural fine aggregate with granular slag. The investigation revealed improvement in compressive strength, split tensile and flexure strength over control mixes by 4 to 8%. The replacement of 100% slag aggregate (coarse) increased concrete density by about 5 to 7% compared to control mix. Based on the overall observations, it could be recommended that slag could be effectively utilized as coarse and fine aggregates in all the concrete applications.