Tensile Mechanical and Stress-Strain Behavior of Recycling Polypropylene Fiber Recycled Coarse Aggregate Concrete

Abstract

To effectively recycle waste petroleum products and construction waste, recycling polypropylene fiber (RPF) and recycled aggregate can be mixed into concrete to make RPF recycled coarse aggregate (RCA) concrete. In this study, the RPF recycled from a polypropylene (PP) packaging belt was used as the test material and manually cut into the shape required for the experiment. The effects of RCA and RPF on the tensile mechanical behavior of concrete are researched. The failure modes and constitutive relationship of the specimens under axial tension and splitting tension are further investigated. The results show that the axial tensile strength of RPF RCA concrete first increased and then decreased with the increase in fiber volume content, and was the largest when the fiber volume content was 1.5%, and its strength increased by 21.14% compared with that of recycled concrete. Its lifting rate relative to recycled concrete is between 13.14–21.41%. The change trend of axial tensile strength with the substitution rate of RCA is that it decreases with the increase in substitution rate, and the substitution rate decreases by 9.64% when the substitution rate is 100% compared with 0%.The peak strain first increased and then decreased with the increase in fiber volume content, and the maximum fiber volume content was 1.5%, which increased by 28.19% compared with that of recycled concrete. The peak strain first increased and then decreased with the increase in fiber length-diameter ratio, and the maximum length-diameter ratio was 47.85, which increased by 18.22% compared with that of recycled concrete. The peak strain increased with the increase in the replacement rate of RCA, and the peak strain at 30%, 60% and 100% was 96.22%, 102.45% and 118.09% when the replacement rate was 0%, respectively.