Effects of thermal loads on concrete cover of fiber-reinforced polymer reinforced elements: Theoretical and experimental analysis

This paper is devoted to the analysis of fiber-reinforced polymer (FRP) reinforced concrete elements under thermal loads. Nonmetallic reinforcing bars present high values of transverse coefficients of the thermal expansion (CTE) with respect to concrete; as a consequence, when temperature increases, tensile stresses take place within the concrete that may produce splitting cracks and, eventually, the concrete cover failure if the confining action is not sufficient. An analytical model is proposed to determine the values of temperature increase (ΔT) corresponding to the first appearance of the cracking phenomenon and to the concrete cover failure. An experimental investigation carried out on concrete specimens reinforced with FRP reinforcing bars is described, and obtained results are compared with theoretical predictions.