Effect of Polypropylene Fibers on GFRP BarReinforced Precast Laminated Cement Composites

The novel application of precast laminated cementitious composite (PLCC) with glassfiber-reinforced polymer (GFRP) bars on the undersides of reinforced concrete beamsenhances their bending strength. Unlike traditional steel reinforcements, GFRP providescorrosion immunity and ensures long-term durability in aggressive environments.integrating fibers into cementitious matrices holds promise for improving the bondstrength between polymer bars and cement composites. Polypropylene fibers (PPFs) arelightweight and exhibit corrosion resistance. This study investigates the flexuralbehavior of PLCC specimens measuring ۵۰۰×۱۲۵×۲۵ mm under a four-point loadconfiguration, encompassing parameters such as first crack occurrence, maximum postcrackingstrength, deflection, toughness, and failure modes. Consequently, theexperimental examination scrutinizes the impact of PPF presence or absence and thenumber of GFRP rebars employed. Both monotonic and ultra-low cycle fatigue (ULCF)loading regimes are employed. The findings underscore the substantial enhancement inresistance, strength, and ductility of GFRP-reinforced cementitious composite laminatesobtained by the addition of PPFs. Notably, upon subjecting PLCCs to a displacement of۲۰ mm under monotonic loading subsequent to PPF incorporation into PLCCs featuringone 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 firstcracking strength reveals a deflection softening behavior in GFRP-reinforced laminateslacking PPFs. In contrast, displacement hardening becomes evident post-PPFincorporation into PLCCs.

کلیدواژه ها:

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