Degradation Of Glass Fiber Reinforced Polymer (Gfrp) Bars In Concrete Environment

Degradation of tensile, shear and flexure properties of glass fiber reinforced polymer (GFRP) bars is investigated in the paper. Glass fibre reinforced polymer bars, when used in structures exposed to aggressive environments, can significantly increase the lifetime, as compared to structures reinforced with conventional steel. However, the progress in utilization of GFRP bars in concrete structures is hampered due to limited information on durability of these materials. Since long-term durability data are not readily available, accelerated aging tests have been used in this research to study GFRP bar degradation. The bars were kept in a highly alkaline solution heated to 50, 60 and 70 degrees C for 1, 3 and 5 months, respectively, and after each immersion period, bars were taken out and tested in tension, shear and flexure. The experimental results show that immersion in high pH of the alkaline solution reduces the strength of the bars. The speed of degradation depends on the temperature of the solution. The degradation is then studied using the models for solution ingress into the GFRP bars. The conclusions proposed are that the shear test is a good indicator of the tensile strength degradation, bent bars deteriorate faster than straight bars, and smaller diameter bars deteriorate faster than larger diameter bars; finally, bars under flexural (tensile) strength deteriorate faster than those under direct tensile and shear strengths.& nbsp; (c) 2021 Elsevier Ltd. All rights reserved.