Dynamic compressive behaviors of polyethylene terephthalate fiber reinforced recycled aggregate concrete

Polyethylene terephthalate (PET) fibers are green, environmentally friendly materials. They mainly come from recycled plastic bottles and other products. The addition of PET fibers to recycled aggregate concrete (RAC) has the potential to reduce concrete damage and increase specimen toughness. In this study, the influences of recycled coarse aggregate (RCA) replacement ratio and fiber volume ratio on the impact response of PET fiber reinforced RAC at various strain rates were experimentally investigated. It was found that the compressive strength, critical strain, and toughness grew with the increasing strain rate, followed by the aggravation of the concrete damage. Owing to the strain rate effect, the failure mode of concrete specimen at a high strain rate was different from that under a quasi-static loading. This led to the reduction of differences in the dynamic compressive strength between the natural and recycled aggregate concrete at a high strain rate. Although the replacement of natural coarse aggregates with RCAs resulted in the decrease in the dynamic compressive strength, it increased the critical strain of the specimen. To reduce the brittleness of concrete materials, flexible fibers, PET fibers were added into the concrete matrix. It was found that the addition of PET fibers increased the critical strain and significantly reduced concrete damage. The empirical equations were proposed to describe the rate-dependent dynamic compressive strength, critical strain, and toughness based on experimental data.