Experimental study on interface bonding fatigue behavior of C-FRCM composites in ICCP

摘要

This paper mainly deals with interface fatigue behavior of Carbon-Fabric Reinforced Cementitious Matrix (C-FRCM) composites in Impressed Current Cathodic Protection (ICCP) system. Fatigue pull-out tests were launched on a total of 18 C-FRCM composites. Two bonding lengths of 60 and 125 mm, three current densities of 0, 100 and 150 mA/m(2) and three cyclic stress ratios of 0.55, 0.65 and 0.75 of the specimens are considered. The interface slip versus cycle number and load amplitude versus fatigue life relationships of the specimens are presented. The interface stiffness and its damage evolution are further analyzed with simplified models, wherein key parameters are calibrated against experimental results. It is found that C-FRCM composites with higher stress ratio showed less fatigue life due to a pre-matured damage accumulation. The interface fatigue performance at high stress level significantly varied when it suffered from different current densities in ICCP system. A linear relationship between the load amplitude and common logarithms of the cycle number is found for C-FRCM composites in the fatigue pull-out tests. Moreover, the relationship between the fatigue damage index at the carbon fiber (CF) yarn-cementitious matrix interface and cycle number is tri-linear. The damage mainly developed at the early stage and the cycle number in the stable damage development stage accounted for great proportion of the whole fatigue life for the C-FRCM composites. (C) 2020 Elsevier Ltd. All rights reserved.