Improving bonding behavior between basalt fiber-reinforced polymer sheets and concrete using multi-wall carbon nanotubes modified epoxy composites

Premature debonding failure is a critical problem in the reinforcement of concrete structures using fiber reinforced polymer (FRP) sheets with externally bonded reinforcement (EBR) technique. The usual anchoring methods are likely to cause damage to the concrete. The effect of incorporating various amounts of carboxyl (COOH)-functionalized MWCNTs in the epoxy resin on the bonding behavior of the basalt fiber-reinforced polymer (BFRP)-concrete joints was detailed studied by single-shear tests and the digital image correlation (DIC) technique. Experimental results indicated that adding the functionalized MWCNTs into the epoxy considerably enhanced the bonding properties. In comparison with the BFRP-concrete joints using neat epoxy, the effective bond length, bond strength, ultimate global slip, interface fracture energy, and BFRP strain of the BFRP-concrete joints using 0.8 wt% MWCNTs modified epoxy increased by 96 %, 55 %, 39 %, 172 %, and 114 %, respectively. The scanning electron microscope (SEM) images of debonded BFRP surface revealed that the MWCNTs could penetrate into concrete along with epoxy resin, and the MWCNTs pull-out and crack-bridging could indicate a reinforcing effect to prevent premature adhesive failure. This study demonstrated the great promise of the MWCNTs modified epoxy composites toward practical engineering application in reinforced concrete (RC) structures. Data availability statement: The raw/processed data required to reproduce these findings cannot be shared at this time as the data also forms part of an ongoing study.