Influence of Polypropylene Fiber on Metakaolin-Based Concrete: A Comprehensive Review

This comprehensive review examines the influence of polypropylene fiber (PPF) on the mechanical and durability properties of metakaolin-based concrete, highlighting its potential for improving strength, ductility, and long-term performance. The integration of metakaolin as a supplementary cementitious material enhances the pozzolanic reactivity of concrete, refining the microstructure and reducing porosity. However, metakaolin-based concrete tends to exhibit brittleness, which can be effectively mitigated by incorporating polypropylene fibers. The review analyzes experimental findings from recent studies, focusing on key parameters such as compressive strength, tensile and flexural behavior, impact resistance, shrinkage, and permeability. Results indicate that optimal PPF dosages—typically ranging from 0.1% to 0.4% by volume—significantly improve crack resistance, energy absorption, and overall toughness without compromising workability. Furthermore, the combined use of metakaolin and PPF enhances durability by reducing water absorption, chloride ion penetration, and microcrack propagation, making the composite suitable for harsh environmental conditions. Despite these advantages, challenges such as fiber dispersion, bonding efficiency, and optimal mix design remain areas for further investigation. Overall, this review underscores the synergistic effect of polypropylene fiber and metakaolin in producing high-performance, sustainable concrete with improved mechanical integrity and durability for modern construction applications.