Degradation of Tensile Load-Bearing Capacity of Molded Composite Reinforcement Due to Alkaline Environment

The main reason for replacing the commonly used concrete reinforcement with composite reinforcement is its high resistance to aggressive environments. For direct reinforcement, this issue has been well described and investigated. In the case of shaped (bent) reinforcement, structural changes in the cross-section occur during the bending process, which can significantly affect its tensile capacity. The research work described in this paper was aimed at investigating changes in the tensile load-bearing capacity of bent glass fibre and epoxy matrix composite reinforcement. The reinforcement was placed in three types of baths, which simulates different environments or reinforcement ages. The paper describes the comparison of straight and bent reinforcement, comparison of calculation relationship, methods of reinforcement failure and variables affecting the resulting tensile load-bearing capacity of reinforcement. The research results confirm the high resistance of (straight) reinforcement to aggressive environments. A reduction in tensile strength was observed for the shaped (bent) reinforcement. The reduction rate for the most exposed specimen exceeded up to 33%, indicating that the calculation relationship according to the Japanese JSCE cannot be used to calculate the tensile load-bearing capacity of composite reinforcement exposed in aggressive alkaline environments