Failure Localization Analysis of Concrete Subject to High Temperatures

Abstract

Despite the low thermal conductivity that characterizes concrete behavior, high temperatures acting for long periods on reinforced concrete structures could conduce to devastating effects on its overall integrity and stability. The caused damages comprises not only the structural, but also the material level, manifesting as a degradation of the strength and stiffness properties, together with the increase of the porosity and the consequent loss of cohesion. In this work, the influence of high temperatures on the mechanical behavior of concrete is computationally evaluated by means of failure analysis in the form of discontinuous bifurcation. For this purpose, numerical solutions for the acoustic tensor for microplanebased plasticity theory are implemented. The nullity and/or negativity of the acoustic tensor suggests the potential development of localized failure, also allowing to know its orientation for a given stress state, concrete quality and applied high temperature.