改性聚丙烯纤维增强混凝土复合材料的研究进展OA

Concrete suffers from high brittleness,low tensile strength,and cracking,limiting its safety and durability and serviceability.Polypropylene(PP)fibers,with advantages like abundant sources,low cost,and excellent corrosion resistance,are commonly used to control plastic shrinkage in concrete.However,the strong surface chemical inertness and high hydrophobicity of PP fibers result in weak bonding at the interface with the hydrophilic cementitious matrix,leading to fiber debonding and limited reinforcement and toughening effects.Therefore,surface modification of PP fibers is crucial for enhancing the comprehensive performance of polypropylene fiber-reinforced concrete(PP-FRC). The modification methods of polypropylene(PP)fibers primarily include physical methods,chemical methods,and hybrid methods.Physical methods,such as high-energy radiation and plasma treatment,enhance mechanical engagement by introducing polar groups and increasing surface roughness.Chemical methods,such as silane coupling agent treatment and graft polymerization,introduce active groups to improve chemical activity.Hybrid modification involves incorporating polar components before spinning to produce fibers with high surface activity.The modification strategy must precisely align with the physicochemical properties of the cement matrix to maximize the interfacial reinforcement effect.After modification,the microstructure of the interfacial transition zone(ITZ)between the fiber and the cement matrix is optimized.Through multi-scale synergistic effects such as physical anchoring,chemical bonding,and dense deposition of hydration products,the originally loose and weak ITZ is transformed into a dense reinforcement phase,enabling efficient stress transfer.Microstructural optimization significantly enhances macroscopic properties:in terms of mechanics,modified PP fibers can effectively inhibit microcrack propagation,stabilize compressive strength,improve failure modes,and significantly enhance tensile and flexural strength;in terms of toughness,the load-deflection curve shows a slow decline after the peak,with significant improvements in ductility and post-crack load-bearing capacity;in terms of durability,the fiber network can inhibit plastic shrinkage and early microcracks,block the penetration of corrosive media,enhance impermeability,and jointly enhance freeze-thaw resistance through the microcapsule effect and dense ITZ,while significantly suppressing drying shrinkage cracks. Modified polypropylene fiber-reinforced concrete,with its enhanced performance,demonstrates broad application prospects in transportation infrastructure and harsh environmental engineering,contributing to achieving long-lasting,highly reliable,and sustainable structures.However,the field still faces challenges in production cost control,process environmental friendliness,and fiber dispersion.Future research should focus on developing green modification technologies,deepening the understanding of multiscale interfacial behavior and long-term performance evolution,and promoting standardized design and engineering application,so as to support the sustainable development of advanced civil engineering materials.