Flexural behavior of carbon-textile-reinforced concrete I-section beams

In the present work, the flexural behavior of carbon textile reinforced concrete (TRC) I-beams is investigated. Four-point bending tests were performed in I-beams, considering SBR-laminated textile and the following conditions: (a) plain cementitious matrix; (b) plain matrix and sand-coated textile; and (c) strain hardening cement-based composite (SHCC) matrix. The main goal of the research was to correlate the improvements on interface and matrix properties with the crack pattern, failure mode and ductility. For a comprehensive discussion, full mechanical characterization was performed and a design model is proposed for a better evaluation of the experimental results. Cracking behavior was greatly improved for conditions (b) and (c) with respect to (a), due to enhanced bonding between reinforcement and matrix in the former and due to fiber bridging mechanism in the latter. Beams with plain matrix exhibited brittle failure, whereas the beam having SHCC matrix showed premature local failure near load application point, resulting in an apparent ductility due to concrete softening mechanism. The reduced cracking load and the premature flange detachment along web-flange junction for condition (a) are also discussed. The proposed model is also validated through comparison with experimental results available in the literature.