Flexural fatigue performance and damage evolution analysis of multiscale polypropylene fiber‐reinforced concrete

Abstract

AbstractAs an excellent concrete reinforcement material, polypropylene fiber has a high potential for bulk‐scale applications. In this study, a comprehensive experimental campaign was carried out to assess the flexural fatigue performance of multiscale polypropylene fiber‐reinforced concrete (MPFRC). Two types of fine polypropylene fiber (FPF) and one type of coarse polypropylene fiber (CPF) were selected for single doping or hybridization into concrete. The fatigue deformation damage mechanism of polypropylene fiber reinforced concrete (PFRC) was analyzed through acoustic emission (AE) and scanning electron microscopy. Results indicated that the incorporation of polypropylene fibers could significantly improve the strength of concrete, with the best results for MPFRC, where the compressive, tensile, and flexural strength were increased by 13.12%, 20.59%, and 25.49%, respectively, compared to the plain concrete. The fatigue life of PFRC obeyed the Weibull distribution at different stress levels, with the mean fatigue life of MPFRC increasing by up to 6.37 times. The fatigue strain‐to‐cycle ratio curves coincided with the cumulative AE ringing count‐to‐cycle ratio curves, both showed that the fatigue damage process of MPFRC underwent three distinct stages, accounting for 5%, 85%, and 10% of the total fatigue life, respectively. By forming a three‐dimensional mesh structure inside the concrete, polypropylene fibers effectively mitigated internal damage and improved the fatigue performance of the concrete.