Studies on the concrete with composite cement and alccofine: from use of OPC towards low-carbon quaternary binder

In recent days, there is an increased interest in using alternative materials in cement to produce concrete with improved properties. Supplementary cementitious materials (SCMs), which are the alternative materials used in the production of cement, are mainly industrial wastes like fly ash (FA), ground-granulated blast furnace slag (GGBS) and silica fume, giving rise to sustainable construction practices. Numerous investigations have been performed on the utilisation of alternate materials in the production of cement that is used in concrete, and an enhancement in the performance of concrete has been reported. Composite cement, a novel material, finds application in construction in which a certain percentage of cement clinker is replaced by GGBS, FA and silica fume during its production. The drawback of the composite cement containing GGBS and FA is that it attains a lower strength at earlier ages. Alccofine, an ultrafine slag-based material collected as a residue from the iron industry, has also been utilised as an SCM in the production of cement. In this study, the effect of a partial replacement of composite cement (COC) with alccofine is examined. It was observed that 10% replacement of COC by alccofine increases the maximum compressive strength (CS), modulus of elasticity (MOE), split tensile strength (STS) and flexural strength (FS) of concrete, respectively, by 12.67%, 16.95%, 11.4% and 21.42% at 28 days. The formation of closely packed structure due to the finer particles of alccofine contributes to an improvement in the strength of concrete.