The effect of exposure to alkaline solution and water on the strength–porosity relationship of GFRP rebar

This study examined the accelerated degradation of E-glass fiber/vinylester resin composite rebar in alkaline solution and water and analyzed the relationship between the reduction in mechanical performance and the test conditions using microstructural degradation analysis. In this study, a pH of 12.6 was chosen for the alkaline test group, while water was used for the control group. After immersion for up to 300 days, the tensile strength of the glass fiber-reinforced plastic (GFRP) rebar was tested. In addition, the deformation of the GFRP rebar surface was evaluated under scanning electron microscopy (SEM) and the change in the internal pore distribution was measured using mercury intrusion porosimetry (MIP). The mechanical performance decreased as the exposure time and temperature increased. The SEM analysis showed that the internal pore distribution in the GFRP rebar increased as degradation progressed, reducing the mechanical performance. Moreover, the pore distribution increased with temperature, also reducing the mechanical performance.