Slip-Bond Behavior of Carbon Textile-Reinforced Concrete in Warp and Weft Directions

This study investigates the slip-bond behavior and the associated failure mechanisms of carbon textile-reinforced concrete (C-TRC), with a focus on the effects of embedment length, yarn orientation, and yarn grouping configurations of a gridlike carbon textile. A comprehensive experimental approach was adopted that incorporated yarn pullout tests to evaluate the slip-bond mechanical performance, as well as the use of advanced high-resolution 3D scanning, to precisely characterize the yarn geometry. Results show that yarn orientation (warp versus weft) measurably affects bond response and the embedment length required for effective load transfer. Weft yarns, which have a larger perimeter and greater waviness, achieved maximum bond efficiency at a shorter embedment length of 100 mm. In contrast, warp yarns required a longer embedment length of 150 mm to develop sufficient bonding. Yarn geometry and waviness influenced the governing failure mode. Elliptical cross-sections, derived from 3D scanning, yielded more accurate bond strength estimations than conventional circular assumptions. Moreover, scanning electron microscopy revealed orientation-dependent interfacial behavior, with warp yarns showing debonding and pullout, while weft yarns exhibited interfacial delamination and enhanced anchorage. Last, although yarn grouping enhances overall pullout capacity, it induces nonuniform stress redistribution, diminishing the load-carrying efficiency of individual yarns.