Cusatis Group Research

Discrete Modeling of Concrete Thermo-Hydro-Chemical-Mechanical Coupling Behavior at High Temperature

Thermal spalling can significantly increase the risk of concrete structure and so far its mechanism still remains in dispute. To gain a better understanding, a discrete hydro-thermo-chemical (HTC) model of concrete at high temperature is proposed and a two-way coupling scheme between the discrete HTC model and lattice discrete particle model (LDPM) is performed. This two-way coupling scheme is featured with the effect of pore vapor pressure and temperature on mechanical response and the impact of cracking behavior on mass and heat transport. The good agreements achieved in the calibrations of high-performance concrete and ordinary concrete indicate the precision of this model. Interestingly cracking behavior is found to have a significant effect on the local pore pressure built-up. Based on this coupling model, the spalling phenomenon is successfully reproduced and the mechanism study shows that thermal stress relatively plays a more important role in thermal spalling, although pore vapor pressure can form a macro-crack parallel to the heating surface.

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