Flexural strengthening of RC beams using basalt textile reinforced mortar: experimental and analytical investigation

This study investigates the flexural behavior of RC beams strengthened with Basalt Textile Reinforced Mortar (BTRM), focusing on the influence of the number of textile layers, mesh size, and anchorage techniques. Six full-scale RC beams were tested under four-point bending, comprising one unstrengthened control specimen and five beams strengthened using different BTRM configurations. The experimental results demonstrated that increasing the number of BTRM layers from three to five enhanced the ultimate load capacity by up to 18% compared to the control beam. Nevertheless, debonding was identified as the predominant failure mode across most strengthened specimens. The influence of mesh size was examined by comparing an eight-layer specimen using 5 mm mesh size with a three-layer specimen using 34 mm mesh size; both configurations exhibited comparable flexural performance. Variations in mesh size (34 versus 5 mm) had a negligible effect on load capacity. The incorporation of basalt bars resulted in a marginal improvement in flexural strength, whereas mechanical anchorage provided limited enhancement in overall performance. These findings highlight the critical need to improve bond behavior and anchorage efficiency in order to fully benefit from the strengthening potential of BTRM systems. In addition, an analytical study was conducted to assess the accuracy of existing predictive models, including those proposed in current design guidelines and previously published analytical approaches, against the experimental results. A modified predictive equation derived from an existing analytical model demonstrated good agreement with both the experimental data and results reported in the literature.