Behaviour of Fibrous Concrete Two-way Solid Slabs Reinforced with Basalt Rods

This study experimentally investigates the flexural performance of fibrous two-way concrete slabs reinforced with basalt fiber–reinforced polymer (BFRP) bars and dispersed basalt fibers.The research evaluates key structural parameters,including crack propagation, flexural toughness, stiffness, ductility, and ultimate load capacity. All slabs had a clear span of 1200 × 1200 mm and contained a constant basalt fiber dosage, while slab thickness and reinforcement ratio were varied. Seven full-scale slabs were tested in three groups.The control specimen (S1) used conventional steel reinforcement (7Ø10/m) with a 100 mm thickness. Group II (S2 to S4) employed a constant BFRP ratio (5Ø10/m) with thicknesses of 100-, 120-, and 150-mm. Group III (S5 to S7) maintained a 100 mm thickness while increasing the BFRP ratio to 6Ø10, 7Ø10, and 9Ø10/m. BFRP-reinforced slabs showed superior performance compared with the steel-reinforced control. The BFRP bars provided tensile strength about 2.5 times the yield strength of steel. Regarding flexural behavior including cracking load, ultimate strength, deflection, and crack patterns. Slab S7 (9Ø10/m) achieved a 29% enhancement in ultimate load capacity relative to the control, while slab S4 with greater thickness, recorded a 16% enhancement. The experimental results correlated well with theoretical predictions based on the Egyptian Code and ACI 440 provisions. The mean experimental-to-theoretical ultimate load ratio was 0.89, with a coefficient of variation of 0.001 and a standard deviation of 0.03. These findings confirm the reliability of current code-based models for predicting the behavior of fibrous slabs reinforced with BFRP bars and support their use in durable structural systems.