PERFORMANCE EVALUATION OF BEAMS STRENGTHENED WITH MECHANICALLY ANCHORED CARBON FIBER-REINFORCED CEMENTITIOUS MATRIX (FRCM)

Abstract

Textile reinforced mortar (TRM), more popularly known as fiber-reinforced cementitious mortar (FRCM), has unique characteristics such as an excellent bond with the concrete substrate, applicability in a wet environment, and resistance to high temperatures. It is now considered a substitute for the fiber-reinforced polymer (FRP) due to the vast progress in FRCM and the increasing complexity of FRP-concrete or FRP-masonry debonding. Strengthening beams with FRCM can be implemented using direct wet layup, Near-surface mounted (NSM), etc. Observed failure modes in the literature show fiber-fiber slip and fiber-matrix debonding as dominant modes. Some authors also studied mechanical anchorages to improve these interfacial limitations. Anchorage in FRCM includes adding transverse layers at the end and intermediate locations, winding the fabric around the bar, and embedding it into the substrate or fan-type anchorage as used in FRP. The present study, 12 beams were strengthened using an indigenously developed unidirectional carbon FRCM system with anchorage. The study parameters include the number of layers and strengthening strategies such as mechanical anchoring and pressure impregnation. For the study, a novel yarn-based mechanical anchorage is developed suitable for Indian site conditions. It is found that the developed mechanical anchorage strategy improves the ultimate load-carrying capacity of the beam by about 16% compared to conventional cement-matrix impregnation. Fiber-rupture failure was observed for anchored specimens, whereas fiber-fiber slip was observed for impregnated specimens.