Abstract:
At early ages, considerable concrete restrained stress can be generated once the deformation is restrained by adjoining members or foundation. Concrete will crack when the tensile stress exceeds its tensile strength. Due to the fact that temperature control function can not be achieved by restraint ring and flat plate method, the actual temperature evolution of mass concrete (0.3℃/d) was achieved in the lab based on the newly developed temperature stress testing machine (TSTM). Furthermore, we also investigated the restrained stress of concrete made with different cement compositions with different cooling ages (3 d, 7 d and 14 d) under the rapid temperature variation history (0.5℃/h). The temperature difference criterion was adopted to evaluate the cracking behavior of concrete. Results show that the cracking temperature difference is proportional to the concrete age (strength) and the relaxation degree decreases with the increasing loading age. Finally, stricter surface protection should be carried out for concrete made with low heat cement (LHC).