Polypropylene Fibers in Pavement Concrete: Mechanical, Durability, and Sustainability Review

Polypropylene fibers (PPF) are attracting growing interest as a reinforcement for concrete pavements, where their low cost, corrosion resistance, and chemical inertness address several of the intrinsic weaknesses of plain Portland cement concrete. This review consolidates laboratory, field, and standardized-test evidence on how PPF influence the mechanical performance, durability, and sustainability of pavement concrete. Across the collected studies, PPF contribute only modest gains in compressive strength but substantial improvements in flexural and tensile behavior, fracture toughness, and energy absorption, together with marked reductions in plastic and drying shrinkage and enhanced resistance to impact, abrasion, skid wear, and freeze–thaw and chemical exposure. These effects are most pronounced within an effective dosage range of roughly 0.3%–1.0% by volume, beyond which reduced workability, dispersion difficulties, and the low elastic modulus of polypropylene begin to offset the benefits. Collectively, they extend service life and lower maintenance demand, particularly under the repeated and moving loads characteristic of pavements, and can permit thinner sections at equivalent load capacity. Hybrid systems combining PPF with steel, basalt, nano-silica, or recycled constituents recover complementary properties and perform well in high-demand applications such as airport runways, bridge decks, and tunnel linings. From a sustainability standpoint, PPF reduces plastic waste and carries lower embodied energy and carbon than steel reinforcement, and life-cycle assessments report emissions and cost savings at optimized dosages. The review identifies fiber surface treatment, mix-design optimization, and machine-learning-based performance prediction as the principal routes to overcoming current limitations, and highlights hybrid and multi-scale composites, self-monitoring fiber systems, and improved PPF formulations as priorities for future research toward durable, low-impact pavement infrastructure.