Combined effects of saline solution and moist concrete on long-term durability of GFRP reinforcing bars

This paper presents the mechanical, durability, and microstructural characterization of unstressed glass–fiber-reinforced-polymer (GFRP) reinforcing bars exposed to concrete environment and saline solutions under accelerating conditions. These conditionings were used to simulate the effect of seawater or deicing salts on GFRP bars. The pre- and postexposure tensile strengths of the bars were used for long-term property predictions based on the Arrhenius theory. The results revealed no significant differences in the durability of the concrete-wrapped GFRP bars whether immersed in salt solution or tap water and the very high long-term durability of the GFRP bars in salt solution. According to the predictions, even after a service life of 100 years, the tensile-strength retention of the tested GFRP bar would still be 70% and 77% for mean annual temperatures of 50 °C (the mean annual temperature and the marine environment of the Middle East and warm regions) and 10 °C (mean average temperature of northern regions), respectively, which are higher than the design tensile strength according to the ACI 440.1R.