Influence of Polypropylene Fibers on Precast Laminated Cement Composites Reinforced with GFRP Bars

The novel application of precast laminated cementitious composite (PLCC) with glass fiber-reinforced polymer (GFRP) bars on the undersides of reinforced concrete beams enhances their bending strength. Unlike traditional steel reinforcements, GFRP provides corrosion immunity and ensures long-term durability in aggressive environments. Integrating fibers into cementitious matrices holds promise for improving the bond strength between polymer bars and cement composites. Polypropylene fibers (PPFs) are lightweight and exhibit corrosion resistance. This study investigates the flexural behavior of PLCC specimens measuring ۵۰۰×۱۲۵×۲۵ mm under a four-point load configuration, encompassing parameters such as first crack occurrence, maximum post-cracking strength, deflection, toughness, and failure modes. Consequently, the experimental examination scrutinizes the impact of PPF presence or absence and the number of GFRP rebars employed. Both monotonic and ultra-low cycle fatigue (ULCF) loading regimes are employed. The findings underscore the substantial enhancement in resistance, strength, and ductility of GFRP-reinforced cementitious composite laminates obtained by the addition of PPFs. Notably, upon subjecting PLCCs to a displacement of ۲۰ mm under monotonic loading subsequent to PPF incorporation into PLCCs featuring one and two GFRP bars, energy absorption increases by ۴۷۰% and ۶۹۰%, respectively. Analogous increases of ۴۳۷% and ۵۵۲% are observed under cyclic loading conditions. Furthermore, a comparison between the maximum post-cracking strength and the first cracking strength reveals a deflection softening behavior in GFRP-reinforced laminates lacking PPFs. In contrast, displacement hardening becomes evident post-PPF incorporation into PLCCs.

کلیدواژه ها:

flexural strength ، laminated cementitious composite ، energy absorption capacity ، Polypropylene fibers ، GFRP bar