混凝土构件直接粘贴CFRP加固的腐蚀界限研究

为弥补现有规范不足、解决不同腐蚀等级构件碳纤维加固效果参差不齐的问题,在氯化钠溶液中通电模拟海洋腐蚀环境,加速腐蚀出不同腐蚀程度的RC梁,粘贴CFRP加固后进行加载试验,通过分析不同腐蚀程度构件承载力损失和直接粘贴、凿除粘贴两种CFRP处理方式的加固效果,研究腐蚀等级对海工RC梁CFRP抗弯加固的影响,并探讨直接粘贴CFRP加固的腐蚀界限。结果表明,在低腐蚀等级条件下,直接粘贴CFRP加固能有效减小腐蚀梁在荷载作用下的主裂缝宽度,减缓梁开裂的时间,提高抗弯承载力和整体刚度,但随腐蚀等级的增加,这些作用越来越弱,当梁腐蚀裂缝宽度超过1 mm、主筋锈蚀率达15%时,直接粘贴CFRP加固已不再适合。

Corrosion threshold for concrete structures bonded directly strengthened with CFRP

To compensate for the existing norms lack in technology applications of harbor concrete structures strengthened by CFRP and solve the spotty problem of components with different corrosive grades strengthened with CFRP,powered by NaCl solution to simulate the corrosive marine environment,RC beams were accelerated corroded to different grades,and the comparison tests of corrosion beams flexural strengthened with CFRP were carried out.By analyzing capacity loss and reinforcement effects of the beams with different corrosion degrees,the effects of corrosion grades on RC beams flexural strengthened with CFRP were studied in this paper and the corrosion threshold between bonded directly with CFRP and bonded after chiseling off in the strengthening of RC Beams were discussed.The results showed that,within a certain corrosion threshold,the corrosion grades had significant effects on the flexural strengthening of corrosion RC beams bonded with CFRP,and bonded directly with CFRP can effectively reduce the width of the main cracks,decrease the cracking time,and improve the capacity and overall stiffness of corrosion beams.However,such strengthening effects became more and more insignificant with the increase of corrosion grade.As the RC beams corroded to a certain level,the directly bonded with CFRP was no more suitable for the strengthening,and the corrosion crack width 1 mm and corrosion section loss rate 15% as the threshold between directly bonded with CFRP and bonded after Chiseling off for the strengthening were determined.