Mechanical Properties of the Interface between Reactive Powder Concrete and Aggregates at Different Temperatures

To analyze the effect of temperature on the failure of the interface between reactive powder concrete (RPC) and aggregate, a constitutive model based on the elastoplastic theory to describe both tension and shear failure modes at high temperatures is developed. The influence of damage is incorporated in the developed model. A unified yield function is proposed based on the Mohr-Coulomb criterion to describe plastic behavior at the interface. The evolution of damage is distinguished by different energy dissipation potential functions for tension and shear. Microstructure analysis of the failure surface reveals that the interface degraded with increasing of temperature due to the decomposition of concrete hydrates and the formation of cracks. Comparisons between predictions and experimental data validate accuracy of the proposed model, demonstrating that it can effectively describe the mechanical behavior of cement-aggregate interface at different temperatures. In the current study, the authors investigated the mechanical properties of the interface between reactive powder concrete (RPC) and stone materials under high-temperature conditions through experimental and theoretical analysis. The tension and shear constitutive models of the interface at different temperatures are developed based on elastoplastic mechanics model, and the evolution of damage is considered. The developed constitutive models for the tensile and shear behavior of the interface were implemented in user defined subroutine of finite element software ABAQUS, and the predictions exhibited good agreement with experimental results. The developed model can assist engineers in studying the failure of the interface between the matrix and aggregates after a fire incident and analyzing the internal damage of concrete in construction projects. It provides significant assistance in the assessment of building structural fire performance and the analysis of concrete durability.