STUDY OF GRANULATED BLAST FURNACE SLAG AS FINE AGGREGATE IN MORTAR AND MASONRY

Fine aggregate is one of the important constituents of mortar and concrete and plays a significant influence on the properties of mortar and concrete. Fine aggregates occupy thrice the volume of cement which affects the performance of mortar. In general, as demand of natural sand is quite high in developing countries like India consumption of river sand is increasing day by day due to mass production of concrete and mortar in construction activities. The excessive quarrying of sand from river beds resulting in vast depletion of natural resources, causing a serious threat to future generations and in some parts of the country there is an increase in the cost of sand due to growing restrictions on quarrying and non-availability of sand lead to scarcity of sand. In this situation, construction industry and researchers are looking for a cheap and alternative materials to natural sand. Latest innovations in concrete technology are focusing on sustainable development by using industrial by-products possessing similar properties of fine aggregate. The various alternative materials available for replacement of river sand are manufactured sand, gold mine tailing, stone powder, quarry saw dust, foundry sand, demolished waste, municipal incineration waste ash, bottom ash and granulated blast furnace slag (GBFS) [1]. Generally, the use of granulated blast-furnace slag as a fine aggregate in cement mortar and concrete provides environmental and economic benefits. GBFS is a by-product obtained from quenching molten iron slag from the blast furnace in water or steam to produce a glassy, granular product. GBFS is glassy particle and is granular in nature having similar particle size range like sand. GBFS is available in huge quantity as an industrial by product in Visakhapatnam at very low cost and 63,000 tonnes of steel slag is produced every year [2]. The particle size distribution of the GBFS in present work was found to be within the permissible limits of Indian standards. Present study explores the possibility of using GBFS as replacement of natural sand in mortar and its applications. In this work, cement mortar mixes 1:3 & 1:4 were selected for 0, 25, 50, 75 and 100% replacements of natural sand with GBFS for w/c ratios of 0.45 and 0.56 respectively.