Microstructure change and mechanical property variation of high performance concrete with recycled ceramic aggregate as internal curing material under different environmental temperatures

High performance concrete (HPC) is broadly utilised in various building environment because of its excellent properties. Recycled ceramic aggregate (RCA) is employed as internal curing material for HPC in this study, which introduces extra water to maintain internal humidity and support continuous hydration. In particular, the effect of temperature on the curing efficiency of RCA is investigated for the first time. The physical properties and chemical compositions of RCA are firstly analysed. The microstructure and pore distribution of HPC with various RCA replacement ratios affected by three different curing temperatures are then investigated. Finally, the autogenous shrinkage, splitting tensile strength and compressive strength of HPC are tested at various ages. The experimental results show that a higher curing temperature will generate more micro-cracks and larger porosity inside the HPC. The increase in curing temperature will enhance the early strength of HPC, but the mechanical properties will decrease with the growth of curing time. Besides, the increase in curing temperature will cause more significant autogenous shrinkage.