Influence of ground granulated blast furnace slag on early-age cracking potential of internally cured high performance concrete

Abstract

High performance concrete (HPC) with low water-to-binder (w/b) ratio has been used widely in the actual project. However, high autogenous shrinkage induced by the low w/b ratio would cause the residual tensile stress in HPC when the shrinkage is restrained. The cracking may occur in HPC if the residual tensile stress exceeds the developing tensile strength. Ground granulated blast furnace slag (GGBFS) has been used widely in the mixture of HPC as a kind of mineral admixture. The influence of GGBFS on the cracking potential of concrete has been studied. However, investigations on the influence of GGBFS on the early-age cracking potential of internally cured high performance concrete (ICC) with super absorbent polymers (SAPs) as an internal curing (IC) agent by using the ring test are still lacking. Investigations on the early-age cracking potential of ICC with different GGBFS contents (0%, 20%, 35%, and 50%) by using the ring test were conducted in the present study. Results and corresponding analysis showed that: (1) the free shrinkage strain, residual tensile stress, stress relaxation, cracking potential parameter, and stress rate of ICC with SAPs decreased with the increase of GGBFS content; (2) the early-age cracking potential of ICC with SAPs based on the cracking potential parameter and stress rate decreased with the increase of GGBFS content. The results in the present study could be used to evaluate the influence of GGBFS on the early-age cracking potential of ICC with SAPs.