Post-peak compressive response and energy absorption of ternary pozzolanic mortar reinforced with PVA fibers

Abstract Brittleness of concrete and poor post-cracking performance is a big challenge to develop ductile and sustainable cementitious materials. This paper investigates the impact of ternary pozzolanic blend and PVA fiber on mechanical performance and the post-peak behavior of sustainable mortar. A blend of 7 % FA, 5 % MK, 3 % GP was used to replace 15 % of the cement weight, while PVA fibers were incorporated at 0.25–2.25 vol% for investigating dosage-effect on strength vs ductility. From the experimental results, optimized ternary blend increased the density by 5.03 %, reduced water absorption by 20 %, and increased compressive strength by 41.18 % compared to the control Increasing dosage of fiber resulted in a gradual deduction in flowability −4.9 % to −33 %, yet all mixes maintained adequate workability for casting. The mix with 1.0 % PVA fibers showed a balanced performance with 46.5 MPa compressive strength, 75.8 kJ/m3 absorbed energy, and 447 N/m Fracture Energy (G f ) 82 % higher than non-fibrous pozzolanic mix. Mechanical indices such as toughness, Energy Absorption (U), Ductility Index (DI), Fiber Reinforcement Performance Index (FRPI), Softening Ratio (SR) and Stiffness Degradation (SD), which were derived from the stress–strain curve under uniaxial compression, also demonstrated pseudo-ductile response and enhanced dissipation of energy at an optimum dosage of fibers, whereas the possibility of clustering and reduced efficiency of stress transfer was observed in the case of higher fiber dosages ≥1.75 %. Overall, the combination of optimized ternary blend with 1.0 % PVA fibers produced a dense, ductile, and energy-absorbing mortar, applicable for seismic-resistant, impact-resistant, and structural repair works.