人工海水环境下GFRP筋抗拉性能加速老化试验

Accelerated Aging Tests for Evaluations of Tensile Properties ofGFRP Bars under Artificial Seawater Environment

摘要:

根据ASTM D665规定的试验方法，开展了40，60，80℃人工海水环境中玻璃纤维塑料（GFRP）筋抗拉性能的加速老化试验.GFRP筋试件数量共90根，直径为16mm，侵蚀时间分别为3.65，18.00，36.50，92.00，183.00d.结果表明：在40，60，80℃人工海水环境中侵蚀183.00d后，GFRP筋的抗拉强度分别下降了17.71%，24.89%和28.65%，而弹性模量仅分别下降了6.57%，4.40%和-3.77%.采用扫描电子显微镜（SEM）对腐蚀前后GFRP筋的微观形貌进行了观测，发现在GFRP筋的腐蚀劣化区域，环境温度为60℃的GFRP筋其纤维和树脂之间的界面变得松散（与环境温度为40℃筋相比），而环境温度为80℃的GFRP筋内部则出现了孔洞.GFRP筋吸湿试验结果表明：在侵蚀初期，GFRP筋的吸湿曲线近似为线性；随着侵蚀时间的增加，吸湿曲线变缓并趋于水平；GFRP筋在人工海水溶液中的吸湿过程符合Fick定律.最后，在分析了环境温度、侵蚀时间等参数对GFRP筋抗拉性能影响的基础上，基于Fick定律提出了人工海水环境下GFRP筋抗拉强度的退化模型.

Abstract:

According to ASTM D665, the tests of 90 glass fiber reinforced plastic（GFRP） bars were conducted at 40, 60，80℃ in artificial seawater environment for 3.65, 18.00, 36.50, 92.00，183.00d to evaluate the tensile properties of GFRP bars. The results reveal that after being exposed to the artificial seawater environment for 183.00d at 40, 60，80℃, tensile strength of GFRP bars decreases by 17.71%, 24.89% and 28.65%, while tensile elastic modulus of GFRP bars decreases by 6.57%, 4.40% and -3.77%, respectively. The micro morphology of the GFRP bars surface was observed under scanning electron microscopy（SEM）, and it indicates that the bonds between fibers and resin in GFRP bars in the erosion region become loose, and as the temperature rises, the interfacial debonding between fiber and resin in GFRP bars becomes more significant. The results of moisture absorption test show that the absorption kinetics can be satisfactorily described by Ficks law, the absorption curve were leveled off after reaching to saturation. In addition, based on the Ficks law, tensile strength degradation model of GFRP bars under the artificial seawater environment is proposed.