Strength in concrete reinforced with recycled CFRP pieces

This paper presents strength in concrete reinforced with recycled and crushed carbon fiber reinforced plastic (CFRP) pieces. Mechanical properties such as compressive and flexural strength of CFRP reinforced concrete (CFRPRC) were evaluated and its fracture behavior was characterized. First, compressive and flexural tests of CFRPRC were conducted to investigate the effect of size and content of CFRP pieces on compressive and flexural strength and work of fracture in the flexural tests. Secondly, pull-out and peel tests were performed to estimate the adhesion strength at the interface. Finally, fracture surfaces were observed with an optical microscope and an electron probe micro analyzer to characterize fracture behavior and adhesion at the interface between CFRP and cement. Flexural strength increases and compressive strength increases slightly with increasing CFRP content. In the load-displacement curves in the flexural tests of CFRPRC specimens, large displacement is observed after maximum load. As a result, work of fracture of reinforced specimens is much higher than that of blank specimens. Good bonding at the interface due to anchoring effect was confirmed through the microscopic observation and the pull-out and peel tests. It is concluded that addition of CFRP pieces with appropriate size to concrete improves the flexural strength and work of fracture due to bridging effect.