海水环境下GFRP筋-海水海砂混凝土黏结行为演化规律

Evolution of bonding behavior of GFRP reinforcement⁃seawater⁃sea sand concrete under seawater conditions

为研究海水环境下GFRP筋与海水海砂混凝土的黏结行为,设计并测试了54个GFRP筋-海水海砂混凝土中心拉拔试件,采用温度加速实验,研究清水和海水环境腐蚀后试件黏结强度的变化,并分析了试件的黏结滑移曲线上升段。结果表明,海水温度的升高加速了GFRP筋-海水海砂混凝土试件黏结强度的退化,在相同浸泡条件下,60℃的黏结强度相较于10℃降低了15%左右;海水环境对试件黏结强度的影响略大于清水环境。分别使用BPE模型、CMR模型和Malvar模型对试件黏结滑移曲线上升段进行分析,结果表明,海水环境下GFRP筋-海水海砂混凝土黏结滑移曲线上升段宜采用Malvar模型。最后根据TSF寿命预测法得出,在20℃海水环境下,GFRP筋-海水海砂混凝土试件使用100年后的黏结强度保留率为65.58%。

To investigate the bonding behavior of GFRP bars and seawater⁃sea sand concrete under seawater environ⁃ment,totally 54 GFRP bars⁃seawater⁃sea sand concrete center pullout specimens were designed and tested.A tempera⁃ture acceleration experiment was conducted to study the changes of bond strength of the specimens after corrosion in the clear water and seawater environments,and the rising section of the bond slip curve of specimens was analyzed.The re⁃sults indicated that the increase of temperature accelerated the degradation of bond strength of GFRP reinforcement⁃sea⁃water⁃sea sand concrete specimens.The bond strength decreased by about 15%at 60℃ compared to that at 10℃.The effect of the seawater condition on the bond strength of the specimens is slightly more significant than that of the clear wa⁃ter condition.The rising section of the bond slip curve of the specimens was analyzed using the BPE,CMR,and Malvar models,and the results indicated that the Malvar model was suitable for the rising section of the bond slip of GFRP rein⁃forcement⁃seawater⁃sea sand concrete under the seawater condition.According to the TSF life prediction,the bond strength of the GFRP reinforcement⁃seawater⁃sea sand concrete specimens presented a retention rate of 65.58%after 100 years of use under the 20℃ seawater condition.