GFRP筋在海洋环境下的耐久性研究

EXPERIMENTAL STUDY ON THE DURABILITY OF GFRP BARS UNDER MARINE ENVIRONMENT

为研究GFRP筋在海洋环境下的耐久性,GFRP筋被置于60℃的海水、碱、碱+海水三种腐蚀液中进行加速腐蚀试验,并选取对GFRP筋耐久性影响最大的碱+海水溶液,进行干湿循环和应力/腐蚀试验。通过拉伸试验法和扫描电子显微镜的测试方法,研究了不同条件下GFRP的耐久性和腐蚀机理。试验结果表明,由于纤维中的硅氧键分别与水分子和氢氧根离子发生离子交换或化学反应,使硅氧键断裂,并且在遭受化学破坏的纤维和树脂界面处促进水化产物的生成,因此碱离子对GFRP筋的耐久性影响最大。加速腐蚀试验中,在碱+海水溶液中浸泡6个月后GFRP筋的抗拉强度损失接近30%,弹性模量的损失较小,为12%;在干湿循环和应力腐蚀条件下GFRP筋的抗拉强度和弹性模量保持率都接近90%,显示出良好的耐久性。

Accelerated aging test under seawater,alkaline solution and alkaline ＋ seawater solution（ solution mixed with seawater and alkaline） at 60 ℃ was carried out to investigate the mechanical performance of GFRP bars under marine environment. Solution mixed with seawater and alkaline was selected in dry / wet and stress / corrosion conditions. Tensile tests and SEM method were used to study the durability and corrosion mechanism of GFRP bars under different conditions. The test results show that alkali ion has the largest influence to the durability of GFRP,because the chemical reaction between silicon-oxygen bond of fiber and water molecule or hydroxide ion lead to silicon-oxygen bond rupture,and promote the formation of hydration product. But in accelerated aging test,the degradation of tensile strength of GFRP bars immersed in alkaline＋seawater solution for 6 months is nearly 30%,and the degradation of elasticity modulus is 12%. GFRP bars show good anti-corrosion performance under dry / wet and stress / corrosion conditions,the tensile strength and elasticity modulus retention is both nearly 90% under the two conditions.