Bond characteristics of different FRCM systems

Abstract

© 2018 Elsevier Ltd Fabric-reinforced cementitious matrix (FRCM) composites are usually applied on the concrete surface for the purpose of strengthening reinforced concrete structures. The efficiency of FRCM as a strengthening material is notably affected by the bond between the FRCM and concrete. In view of that, this paper reports on the results of an experimental study to investigate the bond characteristics between FRCM and concrete. Eighteen specimens with different lengths were prepared and subjected to double-shear test. The parameters investigated included (a) fabric type (carbon, polyparaphenylene benzobisoxazole (PBO), and glass); (b) bond length (75, 100, 125, 150, and 200 mm); and (c) number of fabric plies (single or double). The modes of failure observed in carbon-, PBO-, and glass-FRCM bond tests are fabric/matrix debonding, FRCM mortar/concrete debonding, and fabric rapture, respectively. The PBO- and glass-FRCM bond failure was more brittle than that of the carbon-FRCM counterpart. Among the three systems, the PBO-FRCM showed the highest FRCM/concrete bond. The bond capacity and the mode of failure were prone to the number of fabric plies and indeed bond length. Theoretically-predicted values for the FRCM bond capacity were obtained based on a proposed analytical model, and showed a reasonable agreement with the experimental results.