Load–deflection behavior of RC beams strengthened with GFRP sheets subjected to different environmental conditions

An investigation to examine the durability of reinforced concrete beams strengthened with glass fiber reinforced polymer (GFRP) laminates is performed. A total of 84 beam specimens were prepared for this study. The performance of these specimens was assessed through evaluating the flexural capacity and load–deflection relationships of the beams after placing them in different environments directly or indirectly with simulated field condition for a specified period of time. The specimens were divided into six categories which include controlled laboratory environment (unexposed category), outside environment (direct exposure to hot–dry field conditions), wet–dry normal water environment, wet–dry saline (NaCl) water environment, and wet–dry alkaline (NaOH) environment. Each category consisted of unstrengthened and strengthened beams. Furthermore, some of the specimens of the hot–dry field exposure were coated with protection paint against ultra violet (UV) rays. The specimens of different wet–dry environments were exposed to a time cycle of two weeks inside the solution and two weeks outside the solution. The test results carried out after 6, 12 and 24 months of exposure to different environmental conditions, show that none of the aforesaid environmental conditions have a noticeable influence on the flexural strength of the beams.