Polypropylene fiber, as a micro-scale reinforcement material, has been widely recognized for its ability to effectively inhibit crack propagation during the service life of concrete, thereby enhancing both its crack resistance and durability. This study presents an experimental investigation of the mechanical properties of polypropylene fiber-reinforced concrete specimens. The primary objective of this study was to assess the influence of varying fiber lengths and volumetric fiber contents on the load-bearing behavior of concrete. Seven sets of concrete specimens with different polypropylene fiber parameters (dosage and length) were prepared and subjected to a series of tests, including compressive strength, splitting tensile strength, flexural strength, and axial compressive stress–strain behavior. Specifically, coarse polypropylene fibers with two lengths (30 mm and 50 mm) and three dosages (0.5%, 1%, and 1.5%) were investigated. Experimental results facilitated the identification of the optimal fiber dosage and length at which the mechanical properties of the concrete specimens were maximized. Subsequently, a constitutive model for polypropylene fiber-reinforced concrete was established. The analysis elucidated the relationships between the parameters within the constitutive model, axial compressive strength of the concrete, and characteristic fiber parameters. The derived formulations provide a theoretical foundation for subsequent finite element analyses of polypropylene-fiber-reinforced concrete.
Li et al. (Thu,) studied this question.