An Improved Constitutive Statistical Damage Model of a Multisize Polypropylene-Fiber-Reinforced Concrete Under Compression

To study the effect of multisize polypropylene fibers on the compression characteristics of concrete cubes, ten sets of polypropylene fiber-reinforced concrete test pieces were designed and fabricated to obtain their stress–strain curves and mechanical parameters at different ratios of coarse and fine fibers. Results for the cubes with multisize fibers were better than for those with to single-size ones. Based on test results, an improved statistical damage constitutive model for such a material is proposed.