MECHANICAL PROPERTIES AND MICROSTRUCTURES OF GFRP REBAR AFTER LONG-TERM EXPOSURE TO CHEMICAL ENVIRONMENTS

摘要

This study describes accelerated degradation tests on glass fi bre-reinforced polymer (GFRP) rebar to evaluate itsnlong-term durability. The tests used simulated building acid, sulphate and de-icing environments. We measurednthe resulting reduction in the mechanical properties of the rebar and performed a microstructural degradationnanalysis of the rebar. The acidic environment consisted of a 0.6% acetic acid solution at a pH of 2.92, whereasnthe sulphate environment contained 3% sodium sulphate solution, and the de-icing environment was composednof 4% calcium chloride solution.nTensile strength tests were performed to measure the mechanical properties of the rebar after it was immersionnin one of the environments for 50 to 100 days. We also measured the change in the internal pore distributionnand in the shape of the rebar surface morphology using mercury intrusion porosimetry (MIP) and scanningnelectron microscopy (SEM) technology to observe the microstructure degradation. The tests demonstrated thatnGFRP rebar exposed to degradation environments exhibited only slight reductions in mechanical propertiesnwith time. Areas of surface degradation were diffi cult to observe in the SEM analysis, and the MIP pore valuesnwere very small, indicating a dense structure. Since the durability of GFRP rebar was not adversely affected tonan appreciable degree by exposure to the degradation environments, it was deemed suitable for use in concretenreinforcements