Predicting post-fire behavior of crumb rubber aggregate concrete

An efficient technique to recycle crumb rubber is to use it in concrete. The general stress-strain relationship for the concrete exposed to fire is required to provide specific fire-performance criteria for designing concrete structures. In this research, the residual stress-strain behavior of concrete containing crumb rubber as a natural sand replacement (by 0, 15, and 30%) under axial compression after exposure to elevated temperature (200, 400, 600, and 800 degrees C) was studied. For this purpose, the physicomechanical properties of the concrete specimens including compressive strength, tensile strength, modulus of elasticity, strain at peak stress, ultimate strain, toughness, stress-strain curve, and weight loss as well as their visual characteristics were examined after thermal exposure, and a number of empirical models were then proposed for the prediction of mechanical properties. Furthermore, a comparison was conducted between the experimental results and the prediction results of the ACI 216, EN 1994-1-2, ASCE, EN 1992-1-2, and CEB-FIP 1990 codes. Finally, using the empirical equations obtained for the mechanical properties, a stress-strain model was developed to predict the compressive performance of concrete containing crumb rubber under elevated temperatures, which demonstrated a good agreement with the experimental results. The results showed a notable degradation of the physicomechanical properties of the specimens with temperature increase. (C) 2019 Elsevier Ltd. All rights reserved.