FRP筋在不同腐蚀环境下的层间剪切性能劣化试验

Experimental study on the degradation of interlaminar shear performance of FRP bars in different corrosive environments

本文研究了玄武岩纤维、玻璃纤维及碳纤维增强聚合物(BFRP、GFRP和CFRP)筋在水、强碱溶液(pH=12.8)、弱碱溶液(pH=11)、模拟海水及酸溶液(pH=1.5)这5种腐蚀溶液环境下的性能劣化情况。通过层间剪切强度测试、水吸收试验、DMA、FTIR和SEM探究了不同老化温度(20、40和55℃)与腐蚀时间(1、2、3、6和9月)下FRP筋的纤维-树脂界面粘结性能、微观结构及化学成分等的劣化规律。试验结果表明:FRP筋的层间剪切强度受腐蚀环境的影响显著,在强碱溶液中的劣化速率远高于其他溶液,其原因是高浓度的OH−离子加速了FRP筋的水解和刻蚀反应,导致大量纤维与树脂发生脱粘,最终导致层间剪切强度降低;与BFRP筋和GFRP筋相比,CFRP筋的耐久性相对优异,在相同老化条件下具有更高的层间剪切强度保留率。

In this paper,the performance deterioration of basalt-,glass-and carbon-fiber reinforced polymer(BFRP,GFRP and CFRP)bars in five kinds of corrosive solution environments,i.e.,water,strong alkali solution(pH=12.8),weak alkali solution(pH=11),simulated seawater and acid solution(pH=1.5),was investigated.The deterioration patterns of fiber-resin interfacial bonding properties,microstructure and chemical composition of FRP bars at different aging temperatures(20,40 and 55℃)and corrosion periods(1,2,3,6 and 9 months)were investigated by interlaminar shear strength,water absorption,DMA,FTIR and SEM tests.The test results show that the interlaminar shear strength of FRP bars is significantly affected by the corrosive environment,and the deterioration rate of FRP specimen in the strong alkali solution is much higher than the other four solutions.The reason is that the high concentration of OH−ions accelerates the hydrolysis and etching reaction of FRP bars,causing a large number of fibers and resin debonding,which eventually leads to the reduction of interlaminar shear strength.Compared with BFRP bars and GFRP bars,CFRP bars have relatively excellent durability and higher interlaminar shear strength retention ratio under the same aging conditions.