Abstract:Based on uniaxial tensile test on 21 plain and polypropylene fiber concrete specimens with the dimensions of 100 mm × 100 mm × 250 mm with epoxy paste method, the influence of the different scales of polypropylene fiber and hybrid fiber on concrete uniaxial tensile strength is investigated, and the uniaxial tensile stress strain whole curves of the different scale polypropylene fiber reinforced concrete is analyzed. Single doped and blended polypropylene fiber can improve the tensile strength of concrete by 11% to 27%、 The strain hardening of low stress occurs during the uniaxial tensile for the single doped crude polypropylene fiber and blended polypropylene fiber concrete, and the surrounding area of the descent stage of single doped and blended polypropylene fiber concrete stress strain curves is larger than the plain concrete stress strain curve of the package area. The tensile toughness enhancement effect of different scales of polypropylene fiber concrete is illustrated as blended fiber concrete> single doped coarse fiber concrete > single doped fine fiber concrete> plain concrete.