Numerical modeling of transport phenomena in reinforced concrete exposed to elevated temperatures

The objective of this study is to develop a finite difference model that simulates coupled heat and mass transport phenomena in reinforced concrete structures exposed to rapid heating conditions such as fires. A mathematical and computational model for simulating the multidimensional, thermohydrological response of reinforced concrete structural elements is developed and subsequently used to study the effects of steel reinforcement on thermodynamic state variables. Key material parameters describing multiphase fluid flow and thermohydrological behavior of concrete are discussed. Spatial and temporal distributions of temperature, pore pressure, and degree of saturation are illustrated as predicted under extreme thermal-loading conditions. Simulation results indicate that the presence of steel reinforcement impedes moisture movement and produces quasi-saturated zones in cover concrete where significant pore pressures are developed.