Assessment of cracking risk of concrete due to restrained strain based on zero-stress temperature and cracking temperature

Cracking of high performance concrete due to restrained volume change has been a rising concern in the last few decades. The present study investigated this topic from a different point of view based on two novel feature temperatures, namely, the zero-stress temperature (T_z) and the cracking temperature (T_x). In this study, the evolutions of T_z and T_x over time, as well as the gradients of T_z and T_x inside a concrete wall were demonstrated. Based on the modeled T_z results, parts of the concrete wall subject to compression and tension were identified, and the corresponding transition time when compressive stress turned into tensile stress was predicted. According to the determined T_x results, the zones of the concrete wall with high cracking risk were described, and the appearance time of cracking was approximated. For the concrete wall investigated, the influences of the drying shrinkage gradients inside the cross-section of the wall on T_z, T_x, and the cracking risk of concrete were assessed quantitatively. Besides, the influences of the proportional height of the concrete wall above the base on the degree of restraint, T_x, and cracking risk were also studied. In the final analysis, a comprehensive yet practical program for evaluating the cracking risk of concrete induced by restrained strain was built based on the proposed T_z and T_x models. Some research gaps in the determination of T_z and T_x that require further research were also identified and analyzed.