Flexural Behavior of Concrete Beams Reinforced with FRP Bars Under Long Exposure to UAE Environment

Abstract

Due to the large research pool of Fiber-reinforced Polymers (FRP) reinforcements, their utilization as main reinforcement in concrete structures has gained the trust of the engineering community. In fact, design codes such as the ACI 440.1R and the CSA S806 have been written due to the extensive research conducted in the realm of FRP reinforcement. The previously stated guidelines, however, do not include provisions for Basalt FRP reinforcements. In addition, research about the impact of harsh environments on the behavior of FRP reinforcement is scarce. In this study the flexural behavior and serviceability performance of Glass and Basalt FRP reinforcement exposed to a combination of ultraviolet rays, humidity, and rain for a period of 28 months were investigated. Specifically, the effects of the UAE climate on the flexural capacity of FRP Reinforced Concrete (RC) beams were examined. Additionally, bond-dependent coefficient (kb) values were evaluated. The study also aims to evaluate the effects of reinforcement ratio, reinforcement surface texture, beam detailing, and reinforcement type on the flexural behavior and serviceability of FRP RC beams. In total, six sand coated GFRP RC beams, six ribbed GFRP RC beams, and nine sand coated BFRP beams were tested. In addition, one Carbon FRP RC beam and one steel RC beam were used as reference beams. It was concluded that exposure had a larger impact on the serviceability performance than it had on the flexural behavior of the beams. The kb factor for all beams in this study was averaged to be 0.82 which is less than the 1.4 kb factor recommended by the ACI 440.1R code. The average kb factor for beams reinforced with exposed ribbed GFRP bars was 7% higher than that of beams reinforced with the unexposed ribbed GFRP bars. However, the kb factor was not affected by exposure variation in the BFRP RC beams. The study concluded that even with harsh exposure to the UAE climate, FRP bars are still resilient enough to be used in construction. Although FRP bars subjected to exposure showed inferior performance to their unexposed counterparts, they still showed superior performance when compared with steel reinforcement.