真实海水环境下海水海砂混凝土内FRP筋性能退化研究

Degradation of FRP Bars Covered with Seawater and Sea Sand Concrete in a Real Marine Environment

为得到真实海水环境下海水海砂混凝土(SWSSC)内纤维增强复合材料(FRP)筋的性能退化规律,在真实海水浸泡下对SWSSC内的玄武岩纤维增强复合材料(BFRP)筋和玻璃纤维增强复合材料(GFRP)筋的拉伸性能退化进行了试验研究,同时,用扫描电子显微镜(SEM)对两种筋材进行了微观观察.试验参数包括筋材种类(BFRP筋和GFRP筋)、腐蚀龄期(30 d、50 d、60 d和90 d),测试性能为不同腐蚀龄期下两种筋材的拉伸强度和弹性模量.另外,对试验所处海域年平均相对湿度下SWSSC内的BFRP筋拉伸强度保留率进行了预测.结果表明:SWSSC内BFRP筋拉伸强度退化速度快于GFRP筋,两种筋材弹性模量无明显退化;SWSSC内的BFRP筋和GFRP筋,其拉伸强度退化主要是由树脂的水解或纤维-树脂界面性能退化引起.通过预测,在海南省海口市真实海水环境下,SWSSC内的BFRP筋拉伸强度保留率在50年后的预测值为75.6%(环境相对湿度为82%).

In the report,in order to obtain the performance degradation trend of fiber-reinforced polymer(FRP)bars in seawater and sea sand concrete(SWSSC)under a real seawater environment,the tensile performance degradation of basalt fiber reinforced polymer(BFRP)bars and glass fiber reinforced polymer(GFRP)bars in SWSSC was investigated experimentally under a real seawater immersion,at same time,the scanning electron microscopy(SEM)was used to observe the fracture surface. The test parameters included the type of FRP bars(BFRP and GFRP)and corrosion periods(30,50,60,and 90 d),the tensile strength and Youngs,moduli of BFRP bars and GFRP bars were tested at different zero periods. Additionally,the tensile strength of BFRP bars in the SWSSC under the annual average relative humidity of the sea area where the test was conducted was predicted. The results showed that the tensile strength degradation rate of BFRP bars was faster than that of GFRP bars in SWSSC,and the Youngs,moduli of the two kinds of FRP bars have no obvious degradation. The tensile strength degradation of BFRP and GFRP bars in SWSSC is mainly caused by the hydrolysis of resin and the degradation of fiber-matrix interface properties. The predicted retention of tensile strength of BFRP bars in SWSSC under a real seawater environment in Haikou,Hainan Province is 75. 6% after 50 years(ambient relative humidity was 82%).