Mechanical and Microstructural Behavior of Foamed Concrete with Polypropylene Fibers and Mineral Admixtures

This study investigates the mechanical strength and microstructural properties of foamed concrete, which is made to a density of 1200 kg/m³ and enhanced with 10% mineral admixtures (fly ash, metakaolin, or silica fume) in place of cement and 0.8% polypropylene (PP) fibers by volume. To improve matrix cohesiveness, three improved mixes were compared to a baseline mix of cement, water, foam, superplasticizer, and natural sand. Compressive, flexural, and split tensile strengths were evaluated at 7, 14, 28, 56, and 90 days. Refined pore architecture and uniform fiber dispersion in changed mixtures were revealed by scanning electron microscopy (SEM).The silica fume mix showed the greatest strength gains and microstructural improvements, thanks to its fine particles and strong pozzolanic activity. Combining PP fibers with mineral admixtures improves durability, strength, and crack resistance, making foamed concrete more suitable for structural applications. These advancements offer lightweight, sustainable construction options while minimizing structural dead loads. Ongoing study is recommended to investigate long-term durability and alternate fiber types to improve performance.