An experimental study on mechanical behaviors of carbon fiber and microwave-assisted pyrolysis recycled carbon fiber-reinforced concrete

In the last decade, waste carbon fiber-reinforced plastic (CFRP) products have not been properly recycled and reused, and they sometimes cause environmental problems. In this paper, the microwave-assisted pyrolysis (MAP) technology was utilized to remove the resin from the CFRP bicycle frame, which was recycled into carbon fiber. A scanning electron microscope (SEM) and single filament tensile test were used to observe and compare the difference between recycled carbon fiber and normal carbon fiber. The mechanical performances of carbon fiber-reinforced concrete (CFRC) were investigated with static and dynamic tests under three different fiber/cement weight proportions (5‰, 10‰, and 15‰). Three different kinds of carbon fiber were used in this study, normal carbon fiber, carbon fiber without coupling agent, and recycled carbon fiber. The experimental program was tested according to ASTM C39-01, ASTM C293, and ACI 544.2R standards for compression, flexural, and impact test, respectively. From the experimental results, addition of 10‰ of carbon fiber into the concrete exhibited maximum compressive and flexural strength. The impact performance of recycled carbon fiber improved the highest impact number compared with normal carbon fiber under different impact energy.