Abstract: Glass Fiber Reinforced Polymer (GFRP) bars is a new type of building materials which has been used as an alternative steel bar. It has been used in concrete structure. In this paper, by studying in the alkaline environment of simulated concrete, the corrosion mechanism, failure modes and tensile strength, elastic modulus and other tensile properties of GFRP bars of different matrix materials during 90 days immersion period were investigated. The results show that the two forms of damage typical matrix material GFRP bars is substantially the same, and brittle strands are shaped blasting. The tensile strength of the GFRP bars with a base material for the Unsaturated polyester resin is reduced, elastic modulus have a slight growth in the early and reduced later. When the final soaking period reaches 90 d, the attenuation of tensile strength and elastic modulus is lower than the minimum requirement of the standard. The tensile strength of the GFRP bars with a base material for the vinyl ester resin is reduced. But the decay-rate is lower than the base material of the unsaturated polyester resin GFRP bars. And the elastic modulus changes are not obvious. When the final soaking period reaches 90 days, the tensile strength and elastic modulus fulfill the minimum requirements of the standard.

Key words: glass fiber reinforced polymer bars, matrix resin, alkaline environment, tensile mechanical propertie