Effect of rubber toughening modification on the tensile behavior of FRP composites in concrete-based alkaline environment

This study focuses on the tensile behavior of fiber-reinforced polymer (FRP) composites in a concrete-based alkaline environment. Because basalt/glass FRP (BFRP/GFRP) composites exhibit relatively poor alkaline resistance compared with carbon FRP (CFRP) composites, a rubber toughening modification method has been proposed to mitigate microcracking and decrease the diffusion of the alkaline solution in the resin matrix. Different proportions of liquid rubber toughening agents were added into the epoxy resin, on the basis of which different FRP composites were made and then subjected to tensile tests after alkaline exposure. Test results indicated that the rubber toughening modification approach can significantly reduce the tensile strength degradation of the BFRP and GFRP composites in the alkaline solution. Moreover, no degradation of the elastic modulus for the FRP composites was observed. The weight gain and microstructure of the FRP composites were also investigated before and after the alkaline exposure to determine the corrosion mechanisms of the FRP composites in the alkaline environment and interpret the mechanical test results.