Mechanistic insights into eco-efficient high-performance concrete with basalt powder: Microstructural refinement, durability modeling, and finite element validation

• Basalt powder assessed as eco-friendly sand replacement in HPC. • 20% BP improved compressive, tensile, and flexural strengths. • Service-life modeling showed nearly doubled corrosion resistance. • SEM, XRD confirmed pore refinement and secondary C–S–H gel. • BP saves ∼130 kg sand per m³ and valorizes quarry by-products. This study investigates the eco-efficient potential of basalt powder (BP), a quarry by-product, as a partial replacement for natural sand in high-performance concrete (HPC). A multi-scale framework was employed, combining experimental testing, service-life prediction, and finite element analysis (FEA). BP enhanced compressive, tensile, and flexural strengths by ∼12% compared to the control, while durability indicators confirmed nearly double the corrosion initiation time and reduced carbonation depth. Microstructural analyses (SEM, XRD, ITZ quantification) validated pore refinement and secondary C–S–H formation all analytical tools used to emphasize multi-scale validation. At 20 % replacement, basalt powder enhanced compressive, tensile, and flexural strengths by ≈ 12 %, 13 %, and 12 %, respectively. Service-life modeling projected an extension from ∼22 years (control) to ∼55–60 years for the BP20 mix. Beyond technical improvements, incorporating BP conserves ∼130 kg of natural sand per m³ and valorizes quarry waste, providing dual sustainability benefits. The findings highlight BP as a practical and eco-efficient solution for durable HPC, with direct implications for sustainable construction practices in line with international and Saudi building codes.