Early-age tensile creep and cracking potential of concrete internally cured with pre-wetted lightweight aggregate

High-performance concrete (HPC) is widely used in practice due to its potential long-term benefits, such as high strength and low permeability. However, high self-desiccation and high temperature rise occur due to the low water-to-cement (w/c) ratio of HPC, both of which would increase the cracking potential of concrete at early age. Although the creep and cracking potential of early-age HPC have been investigated, studies on the tensile creep and cracking potential of internally cured concrete with pre-wetted lightweight aggregates (LWAs) at early age under adiabatic condition at various w/c ratios remain lacking. In present study, the tensile creep and cracking potential of concrete at early age were experimentally investigated under adiabatic condition using the temperature stress test machine. Test results and corresponding analysis showed that: (1) a model for predicting the compressive strength of concrete was presented in consideration of the influence of pre-wetted LWAs; (2) the adding of pre-wetted LWAs reduced the autogenous shrinkage of concrete with different basic w/c ratios; (3) the basic tensile creep/shrinkage and absolute value of basic tensile creep of internally cured concrete were lower than that of normal concrete when the basic w/c ratios were the same; (4) the basic tensile creep/shrinkage and absolute value of specific basic tensile creep of normal and internally cured concrete at the age of cracking both increased with the decrease of basic w/c ratio; (5) the cracking potential of normal and internally cured concrete both increased with the decrease of basic w/c ratio and the adding of pre-wetted LWAs reduced the cracking potential.