Mechanical and Durability Performance of Concrete Road Slabs Incorporating Microsilica and Basalt Fiber Reinforcement

This study investigates the combined effects of microsilica modification and basalt fiber reinforcement on the mechanical performance, microstructure, and durability of concrete developed for precast road slab production. Concrete mixtures were optimized using locally available raw materials from the Turkestan region of Kazakhstan, and the influence of different microsilica dosages and basalt fiber contents was experimentally evaluated. The manufacturing process was improved at the industrial facility of Atina LLC, with a low water–cement ratio (w/c = 0.40–0.48) adopted to achieve a dense and durable concrete structure. Specimens were cured under controlled conditions at 20 ± 2°C for 3, 7, 14, and 28 days. The results showed that 4% microsilica increased the 28-day compressive strength by 15%, while basalt fiber reinforcement improved strength by 18% compared with conventional concrete. These enhancements were attributed to pore refinement, additional calcium silicate hydrate (C–S–H) formation, and crack-bridging effects of basalt fibers. The developed concrete mixture demonstrated improved strength, durability, and potential for application in precast road slabs exposed to aggressive environmental conditions.