Theoretical Modeling and Evaluation of Thermal Stress Evolution of Concrete at Early Age by Temperature Stress Testing Machine

Abstract

Early-age cracking of concrete can significantly affect the durability performance of concrete structures. Thermal stress evolution during hydration is the main contribution to early-age cracking of concrete materials, which associates with interacted chemical and physical processes. To control thermal cracking in practice, experience-oriented mix design is usually implemented, which may become ineffective and lose extensibility from one to another case since the thermal stress evolution is usually coupled with different environmental factors in reality (e.g., humidity conditions, temperature rise conditions and restraint degrees). In this case, the thermal stress evolution of concrete materials become sophisticated to be accurately modeled. Though related research has been widely studied, a constitutive model that can simulate thermal stress evolution of concrete with reliable experimental validation has been seldom reported. Recently, the temperature stress testing machine (TSTM) developed by this laboratory has been found to provide reliable evaluation for thermal stress of concrete with varied temperature rise conditions and restraint degrees. In view of that, this research presents a theoretical model to understand the interactive behavior between cement matrix and aggregate on the basis of TSTM, which traces the thermal stress evolution of concrete with varied temperature rise conditions and correlates the free deformation with restrained stress under full restraint degree.KeywordsConcreteCrackingThermal stressTemperature stress testing machineConstruction