Influence of copper slag and metakaolin on the durability of self compacting concrete

Abstract

Now-a-days, researchers are endeavoring to discover new substitute materials to elucidate the scarcity of natural aggregates in the construction industry. One such alternative is copper slag (CS) obtained as byproduct during the matte smelting process of copper metal. The present investigation is aimed to assess the durability of self compacting concrete (SCC) incorporating copper slag (CS) as fine aggregates and metakaolin (MK) as substitute to fly ash (FA). A total of seven concrete mixes were prepared. The control concrete contains 60% ordinary portland cement (OPC), 40% FA and 0% CS whereas other six mixes contains constant percentage of 60% OPC, 30% FA, 10% MK with different proportions of CS from 0% to 100%. Results revealed that fresh properties declined with inclusion of MK although escalated with increment of CS content. All SCC mixes exhibited higher compressive and splitting tensile strength in comparison to control concrete. The minimum carbonation depth was marked for 100% CS substitution with 10% MK as replacement to FA. The maximum electrical resistivity and resistance to sulfate attack were obtained for 20% CS substitution while UPV values of whole mixes were under the excellent quality of concrete beyond 7 days of curing. On full replacement of sand by CS with 10% MK, initial surface absorption and sorptivity were significantly lower than control concrete at each curing period. This study suggests that CS together with MK can be a potential substitute to natural sand in the construction sector to overcome the scarcity.