Synergistic effect of textile ratio, grid configuration, and hybrid mortar composition on the tensile behaviour of basalt textile reinforced composites

Over time, critical infrastructure deteriorates due to operational demands and extreme events, necessitating innovative approaches for rehabilitation and retrofitting. Textile-reinforced composites (TRCs) have emerged as a promising solution for strengthening and repairing existing structures. Since conventional cement composites possess limited tensile capacity, different reinforcement strategies are employed to enhance their performance. This study focuses on the development and evaluation of tensile behaviour of Basalt Textile-Reinforced Hybrid Composites (BTRC) under direct tension in accordance with ACI 434 guidelines. Thirty groups of specimens were tested to evaluate the influence of different types of mortar, including non-fibrous, mono AR glass, mono basalt, and hybrid fiber reinforced mortar, on tensile behaviour, along with the effects of textile configuration (unidirectional B5 and bi-directional B25 Fabrics) and textile reinforcement ratio. The results revealed that fiber hybridization significantly enhanced the ultimate tensile capacity from 3.45 to 5.10 MPa, an improvement of 47.83 % for the composite with B5 fabric and improved from 5.59 to 9.32 MPa, enhanced by 66.73 % for the composite with B25 Fabric compared to control specimens. Composite with B25 fabric showed the highest improvement in strength is attributed to the greater textile area and superior stiffness of yarn. The strength utilization coefficient (K) improved from 0.44 to 0.65 for B5 and improved from 0.38 to 0.64 for B25 hybrid composites compared to the reference composite, Hybrid fibers consistently enhanced the K value compared to mono and non-fibrous composites. Furthermore, increasing the number of fabric layers (textile ratio) enhanced both ultimate tensile capacity and strain, owing to improved fabric-matrix bonding. Distinct failure modes were identified: unidirectional fabrics exhibited wide single cracks that predominantly failed by fabric rupture, whereas bi-directional fabrics exhibited multiple cracking before failure. Composite reinforced with Hybrid fiber (B25–3-A10HY) showed finer crack patterns, with the number of cracks increasing from 4 to 6 and crack spacing reducing from 6 to 3 cm compared to the reference composite (B25–3-A0) due to improved ductility, and a stronger matrix–fabric bond. Based on regression analysis of the experimental results, an empirical formula was developed to calculate the ultimate tensile strength of BTRC based on the strength utilization coefficient (K), considering the combined effects of textile reinforcing ratio and short fibers, showing good agreement with experimental results, thereby providing valuable insight into the tensile behaviour of textile-reinforced composites for retrofitting applications. Future studies are recommended to investigate the durability, long-term performance, and large-scale structural applicability of BTRC systems to further validate and extend the proposed findings.