Effects of Thermal Loads on Concrete Cover of Fiber-Reinforced Polymer Reinforced Elements: Theoretical and Experimental Analysis

This paper analyzes fiber-reinforced polymer (FRP) reinforced concrete elements under thermal loads. Nonmetallic reinforcing bars present high values of transverse coefficients of the thermal expansion with respect to concrete; as a result, when temperature increases, tensile stresses occur 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 values of temperature increase corresponding to the first appearance of the cracking phenomenon and to the concrete cover failure. An experimental investigation conducted on concrete specimens reinforced with FRP reinforcing bars is described, and the results obtained are compared with theoretical predictions.