碱性环境下不同基体材料GFRP筋的拉伸性能试验研究

EXPERIMENTAL STUDY ON TENSILE PROPERTIES OF GFRP BARS WITH DIFFERENT BASE MATERIALS IN ALKALINE ENVIRONMENT

玻璃纤维增强聚合物(Glass Fiber Reinforced Polymer,简称"GFRP")筋作为一种替代钢筋的新型建筑材料已在混凝土结构中开始使用,研究在模拟混凝土的碱性溶液中,不同基体材料的GFRP筋在90 d浸泡周期内的腐蚀机理、破坏机理及拉伸强度、弹性模量等拉伸力学性能的变化规律。试验结果表明:两种基体材料GFRP筋的典型破坏形式大致相同,均为丝束状炸开的脆性破坏;基体材料为不饱和聚酯树脂基的GFRP筋的拉伸强度会不断降低,弹性模量前期稍有增长,后期也不断降低,最终浸泡周期达到90 d时,其拉伸强度和弹性模量的衰减均低于标准的最低要求;基体材料为乙烯基酯树脂的GFRP筋的拉伸强度会不断降低,但衰减速率要低于基体材料为不饱和聚酯树脂的GFRP筋,而弹性模量变化并不明显,最终浸泡周期达到90 d时,抗拉强度和弹性模量均满足标准规定的最低要求。

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.