Fire Performance of Concrete: Effect of Temperature Gradients?

Abstract

This paper first presents analytical and numerical solutions for the temperature within a φ100mm×200mm cylinder subject to a uniform heat flux boundary condition. The concrete temperature and its gradients are shown to be strongly dependent on the heat flux, which unfortunately can hardly be controlled accurately and consistently in conventional furnace/oven tests. As a result, the effect of temperature gradients within concrete on its fire performance has not been properly addressed and included in currently available constitutive models; neither has the influence of critical processes linked with temperature gradients, including thermal stresses, moisture transport, and pore pressures. Through addressing major shortcomings of current “standardized†tests by establishing heat flux as a parameter of study, an ongoing research at The University of Queensland aims to develop more realistic constitutive models for concrete at elevated temperatures. Key features of this research are also briefly outlined