Significance of Sand in Concrete

Sand or the fine aggregates form an important constituent of concrete. It helps to increase the bulk or volume of concrete, which results in the reduction of cost. It helps in the adjustment of the strength of concrete by variation of its proportion with cement. It also increases the resistance to crushing. The aggregates reduce shrinkage and affect economy. Earlier, aggregates were considered as inert materials but now it has been recognized that some of the aggregates are chemically active and also that certain aggregates exhibit chemical bond at the interface of the aggregate and paste. The sand together with the coarse aggregate forms 70–80 per cent of the volume of concrete. The fine aggregate also helps in filling the voids formed by the coarse aggregates.