Experimental and Analytical Study of Flexural Response of RC Beams with Steel Fibers After Elevated Temperature

Abstract

In the present investigation, experimental tests were performed to study the flexural response of normal- and high-strength reinforced concrete (RC) beams with and without crimped steel fibers after exposure to elevated temperature. The RC beams were subjected to 200 °C, 400 °C, 600 °C and 800 °C at an average rate of 5 °C/min for holding period of 3 h. After single heating–cooling cycle of elevated temperature, the RC beams were tested under four-point loading. The flexural behavior of RC beams at first crack load and ultimate load was studied. It has been found that the addition of fibers in RC beams yields ductile failure and delays the initiation of flexural and shear cracks, both at ambient temperature and after exposure to elevated temperatures. The ultimate load-carrying capacity of high-strength RC beams with steel fibers has been found higher than the high-strength RC beams without steel fibers after exposure to 200 °C temperature. An empirical model is proposed to incorporate the effect of temperature and steel fibers in predicting the mid-span deflection of normal- and high-strength RC beams. The model is in very good agreement with the experimental values and predicts the mid-span deflection for normal- and high-strength concrete beams.