To prevent premature debonding of fiber reinforced polymer (FRP) from concrete surface and achieve rapid repair of flexural members, magnesium phosphate cement-based ECC (MPC-ECC) with many advantages of early strength, multi-cracking and steady-state cracking was combined with carbon fiber reinforced polymer (CFRP) to explore the feasibility of strengthening flexural members. The bonding properties of the concrete/MPC-ECC/CFRP composite interface were investigated in this study. Results showed that the higher composite interface bearing capacity can be obtained by using the MPC-ECC as a binder compared to the use of epoxy resin adhesive, which can reach 15.9 kN. In addition, it was found that a good bonding between the high-pressure water gun treated concrete and the MPC-ECC was obtained, which could ensure that the concrete/MPC-ECC interface does not fail before the MPC-ECC/CFRP interface fails. Compared with the concrete/CFRP interface, the maximum effective bond length, slip value of CFRP, and energy consumption of the concrete/MPC-ECC/CFRP composite interface are greatly improved, all of which increase with the increase of MPC-ECC thickness. Furthermore, the composite interface has obvious residual stress in the failure stage, which can avoid the sudden failure of specimens. However, the increase of curing age from 7 days to 28 days does not significantly improve the bonding performance, which reflects that the bond strength of the composite interface mainly develops within 7 days, that is, possessing good early strength characteristics.

中文翻译：

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混凝土/磷酸镁水泥基ECC/CFRP板复合界面粘结性能


为了防止纤维增强聚合物（FRP）从混凝土表面过早脱粘，实现受弯构件的快速修复，结合了具有早强、多次开裂和稳态开裂等诸多优点的磷酸镁水泥基ECC（MPC-ECC）利用碳纤维增强聚合物（CFRP）探索增强受弯构件的可行性。本研究研究了混凝土/MPC-ECC/CFRP复合材料界面的粘结性能。结果表明，与使用环氧树脂粘合剂相比，使用MPC-ECC作为粘合剂可以获得更高的复合材料界面承载力，可以达到15.9 kN。此外，发现高压水枪处理的混凝土与MPC-ECC之间获得了良好的粘结，这可以确保混凝土/MPC-ECC界面在MPC-ECC/CFRP界面失效之前不会失效。与混凝土/CFRP界面相比，混凝土/MPC-ECC/CFRP复合界面的最大有效粘结长度、CFRP滑移值和能耗都有较大提高，且均随着MPC-ECC厚度的增加而增加。此外，复合材料界面在破坏阶段具有明显的残余应力，可以避免试件的突然破坏。然而，固化龄期从7 d增加到28 d并没有显着改善粘结性能，这反映出复合材料界面的粘结强度主要在7 d内发展，即具有良好的早期强度特性。