Improvement of CFRP-concrete interfacial performance by resin pre-coating method

doi:10.19936/j.cnki.2096-8000.20250228.015

Abstract

Abstract: Although carbon fiber reinforced composites (CFRP) are widely used in strengthening of concrete structures, the strengthening effectiveness is often reduced, primarily due to premature damage in the weaker sub-surface of concrete. To address this issue, the study employed resin pre-coating (RPC) solutions with different concentrations to treat the concrete surface and improve its mechanical properties. The effects of RPC treatment with volume concentrations from 10% to 50% on the load-carrying capacity, interfacial shear stress distribution and bond-slip relationship were analyzed. Besides, the enhancing mechanisms were elucidated. The results demonstrated that the epoxy resin can efficiently penetrate into the microcracks and voids in the concrete sub-surface based on the RPC treatment. The cured epoxy resin created interlocking action between the epoxy and concrete, effectively enhancing the mechanical properties of the CFRP-concrete interface and modifying the failure mode. For the C40 concrete tested in this paper, the RPC treatment with the volume concentration of 30% effectively prevented premature concrete destruction, maximizing the adhesive layer’s strength. This resulted in a 78.4% increase in the load-carrying capacity compared to the control group with no RPC treatment. Additionally, the interfacial shear strength and interfacial shear fracture energy increased by 71.7% and 3.66 times, respectively.

Key words: resin pre-coating, surface treatment, interfacial reinforcement, CFRP-concrete interface, externally bonding method, composites

CLC Number:

TB332

FANG Enhui, YANG Shutong, PANG Ruiyang, SUN Zhongke, LAN Tian. Improvement of CFRP-concrete interfacial performance by resin pre-coating method[J]. COMPOSITES SCIENCE AND ENGINEERING, 2025, 0(2): 117-128.

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