Improving bonding performance of PCM-concrete interface under elevated temperatures by using different adhesives

Abstract

Polymer cement mortar (PCM) has been widely utilized in engineering practice for the repair and strengthening of damaged concrete. However, the bond strength of PCM-concrete interface can deteriorate under high temperatures. To enhance bonding performance, a new interface treatment method needs to be explored. This study aimed to investigate the bond performance between concrete and PCM after adding a layer of epoxy bonding agent (EP) or carbon fiber-reinforced polymer (CFRP) to the interface, as well as to investigate the effect of temperature. The bond behavior was evaluated by interfacial split tensile tests. The experimental results show that the splitting tensile strength of the specimens decreased as the temperature increased. After being exposed to a temperature of 100 °C, the splitting tensile strength of specimens without interface reinforcement, EP- and CFRP-reinforced interface specimens decreased by 35.42%, 58.90%, and 63.39%, respectively. When the ambient temperature exceeds 80 °C, bonding with epoxy or CFRP does not improve the bond performance due to the decomposition of epoxy. Finally, the relationship between the splitting tensile strength of the three types of specimens and temperature was clarified, and a model was developed to predict the strength degradation under elevated temperatures. The results are useful for improving the durability and safety of concrete structures repaired with PCM.