PP staple fiber is mainly a material for improving the durability of concrete. If the fatigue resistance is regarded as a durability index of concrete for pavement deck, the above understanding is of course correct. In addition, the improvement of concrete performance by polypropylene fiber also includes: by reducing the bleeding of concrete, the quality of surface concrete is improved, so that the wear resistance of concrete is improved, and the crack resistance effect can significantly improve concrete. Anti-leakage performance, etc. Polypropylene fibers have no adverse effects on other durability indexes of concrete such as resistance to permeation, frost and salt resistance, and chemical resistance, but the degree of improvement remains to be further studied.

    1、PP staple fiber can eliminate or reduce the number and scale of primary cracks in concrete. This effect can not only effectively prevent plastic cracking of concrete, but also beneficial to the performance of hardened concrete.

   2、 Although the PP staple fiber can not significantly improve the quasi-static load strength of the hardened concrete, the performance of the pavement bridge concrete can be improved by improving the impact resistance and fatigue resistance of the concrete.

    3、 Due to the difference in fiber fineness, elastic modulus and other properties, the effect and mechanism of PP staple fiber and steel fiber on concrete performance are different, and both have their own advantages.

    4 、Due to the test evaluation method, indoor small test pieces can not fully display the effect of polypropylene fiber in actual engineering, resulting in an underestimation of the actual use effect of PP staple fiber.