Effects of Sodium Chloride and Sulfate on Glass Fiber-Reinforced Polymer Bars

This study focuses on environmental degradation of glass fiber-reinfinved polymer (GFRP) bars after ingress of 1) salt water; or 2) solution of chlorides and sulfates and characterization of observed damage along 1 year of immersion of both bare bars and bars embedded in concrete and lime mortar: Published results on these topics are scarce. This study employed techniques more common in areas other than structural engineering, such as scan electronic microscopy, X-ray fluorescence, porosimetry, and diffusion, supplemented by impact tests at low velocity. Results showed: 1) approximately Fickian behavior for GFRP and protective mortars until 1600 hours; and 2) importance of ionic diffusivity and radii in mass gain due to sorption of the solutions, especially in the mortars. It was found that contamination affected the distribution of pore sizes and decreased the relative number of larger pores. Average open porosity decreased 17% after 5800 hours in salt water; and 15% in the sodium chloride and sulfate solution. Vitreous glass temperature transition experienced negligible changes. Bars' energy absorption for impact was especially reduced after saltwater exposure and linked to severe degradation of the resin matrix.