Environmental effects on the mechanical properties of E-glass FRP rebars

Due to their unique properties, fiber reinforced plastics (FRPs) are becoming increasingly popular among researchers and engineers in the construction industry. FRP rebars in particular present an attractive alternative to steel rebars in reinforced concrete. Among the features of this type of rebar are the high strength-to-weight ratio and potential resistance to aggressive environmental factors. This paper presents the results of an experimental and analytical study on the durability of E-glass FRP rebars. A total of 160 rebar samples were placed in corrosive chemical solutions that simulated exposure in the field. Tests were performed at temperatures of 25 C and 60 C. Test variables included one type of fiber (E-glass), two matrix materials (polyester and vinylester), seven chemical solutions, and ultraviolet radiation. Rebar specimens were constructed from E-glass fibers embedded in polyester or vinylester resin matrix. Rebar sizes were 10 min (3/8 in.) and 19.5 mm (3/4 in.) in diameter. Changes in weight and physical appearance were recorded over a one-year period. In addition, ten beams each reinforced with two 10-mm (3/8 in.) E-glass/polyester or E-glass/vinylester FRP rebars to failure after one-year and two-year periods, and the load versus mid-span deflection relationships were recorded. Test results of rebars and beams indicate that significant loss of strength can result from the exposure of E-glass FRP rebars.