Experimental Investigation of Fiber-Matrix Bond Behavior in Carbon, Basalt, and Glass Fabric-Reinforced Cementitious Matrix (FRCM) Composites.

Fabric-Reinforced Cementitious Mortar (FRCM) systems offer a promising alternative to epoxy-based Fiber-Reinforced Polymers (FRPs) for structural strengthening and repair interventions. By replacing the organic matrix with an inorganic cementitious mortar, FRCMs provide superior compatibility, vapor permeability, reversibility, and fire resistance compared to FRPs. This study investigates the bond performance of three FRCM systems: dry (uncoated) carbon and styrene-butadiene rubber (SBR) coated basalt and glass fabrics, embedded in a cementitious mortar matrix. A total of 27 specimens were tested across three fiber types at three embedment lengths: short (40 mm), medium (80 mm), and long (120 mm), with three replicates per configuration for statistical analysis. Pull-out tests were conducted under displacement-control mode at a rate of 0.2 mm/min to quantify peak bond forces, bond-slip relationships, and failure modes. The results showed that the SBR-coated glass and basalt fabrics achieved the highest peak loads showing also better ductility, despite having lower tensile properties than carbon. In contrast, dry carbon fabric exhibited the lowest peak loads due to poor matrix-fabric penetration, resulting in characteristic telescopic failure mode. Bond strength increased with embedment length for all fiber types. Pull-out was the predominant failure mode for short and medium embedment lengths, while fabric rupture occurred at longer embedments. These findings demonstrate the importance of fiber-matrix bond behavior on the performance of FRCM composites.