Abstract
Stress analysis of RC structures that have been retrofitted by an externally bonded layer of Polymer Cement Mortar (PCM) based materials requires the development of a constitutive model of the PCM-concrete interface under static and fatigue loading. In this paper, the bending fatigue and shear fatigue tests were conducted to determine the interface fatigue degradation properties by using the J-integral method based on the energy equivalence. Substrate concretes with four different compressive strengths and interface roughness were applied to understand the effects of substrate concrete and interface roughness on the fatigue degradation properties. It was found that the failure characteristics of the PCM-concrete interface is similar to those of cementitious material and the failure modes of PCM-concrete interface has an important effect on the interface tensile and shear degradation relation and S-N relation under fatigue loading. The degradation relation is similar in the case that the failure mode is identical, regardless of the type of substrate concrete. The fatigue resistance of the PCM-concrete interface is inferior to that in the concrete cohesion layer.
