Influence of curing temperature on autogenous shrinkage and cracking resistance of high-performance concrete at an early age

Abstract

High-performance concrete (HPC) is widely used in practice. The water-to-cement ratio of HPC is low, and self-desiccation occurs which will induce marked autogenous shrinkage. Autogenous shrinkage usually increases the risk of cracking if the concrete is restrained from shrinking freely at early age. The autogenous shrinkage and cracking resistance of early-age concrete is influenced by curing temperature. However, the effect of curing temperature on autogenous shrinkage of early-age concrete is not in consistency and how the curing temperature affects the cracking resistance of concrete remains lacking. Thus, investigation on the effect of curing temperature on cracking resistance of early age concrete must be further studied. In this study, experimental studies on early-age cracking of concrete under 100% restraint and different curing temperatures were carried out using Temperature Stress Test Machine (TSTM). The present study investigated autogenous shrinkage of early-age HPC cured at different curing temperatures. The experimental results indicate that (1) the ratios of cracking stress to tensile strength for HPC specimens were all lower than 1.0; (2) the autogenous shrinkage of HPC increased with the increase of curing temperature; (3) a prediction model for autogenous shrinkage of HPC was presented considering the effect of curing temperature; (4) cracking temperatures and stress reserves were selected as the main cracking evaluation indicators of TSTM, and the HPC specimen cured at isothermal 20°C showed better cracking resistance than that at isothermal 45°C and adiabatic condition.