Spalling and cracking modelling of high-performance concrete exposed to elevated temperatures

摘要

Concrete spalling and cracking play an important role in the mechanical behaviour of concrete structures subjected to thermal loading. However, the spalling and cracking of concrete has still not been sufficiently modelled. Based on the theory of poroelasticity, an anisotropic fixed smeared crack model is proposed for modelling the spalling and cracking of heated high-performance concrete. In the model, the permeability and Young's modulus of cement paste are estimated as a function of heating history based on the thermal decomposition analysis. The vapour pressure build-up and moisture transport in concrete are modelled in a numerical manner. The constitutive relation with the effects of thermal stress and vapour pressure is derived for the non-linear mechanical analysis. Finally, the proposed model is verified with experimental results obtained from the literature.