Effects of the liquid rubber modified adhesive on the bond-slip response of the CFRP-steel interface

This paper presents an experimental and analytical study, purposely exploring the effects of the liquid rubber incorporation into epoxy resin on the bond performances between the carbon fiber reinforced polymer (CFRP) plate and steel. The experiment consisted of 36 double-shear bonded joints, and the investigated variables were the liquid rubber contents (i.e., 0, 5%, 10%, and 15% by weight) and adhesive thickness (i.e., 0.5 mm, 1.0 mm, and 2.0 mm). The failure mode, ultimate load, strain distribution, as well as the load-slip response were compared and discussed between specimens using the non-modified and liquid rubber modified epoxy adhesives, respectively. On the basis of the experimental results, a bi-linear bond-slip model considering the influence of liquid rubber content was proposed, and the critical parameters including the maximum interfacial shear stress, initial slip, fracture energy, and the maximum slip were identified, respectively. The present study lays a foundation for the subsequent research on the long-term bond enhancement for the CFRP-steel interface under freeze-thaw environment.