41 / 2022-03-24 17:53:38

Recycling, regeneration and reuse of carbon fibers in carbon fiber reinforced cementitious composites

Recycled carbon fiber,Carbon fiber reinforced concrete,Electrochemical catalysis,Graphene nanofluid additives

In recent years, the recovery and reuse of waste FRP composite materials in civil engineering has become a research focus in the field of green building materials. The carbon fiber in carbon fiber reinforced polymers (CFRP) waste generally reserves splendid physical and chemical properties, which possessing towering value of recovery and reuse. Meanwhile, carbon fiber reinforced cementitious composites (CFRC) exhibits excellent mechanical properties and functionality, however, the high cost of the reinforced phase carbon fiber is not conducive to the large-scale application of CFRC. In this study, the binding material epoxy resin in CFRP waste was depolymerized by electrochemical catalysis, and carbon fiber was thus recovered. The effects of different electrolyte solution systems and reaction conditions on the removal rate of epoxy resin, mechanical strength and microstructure of recycled carbon fibers (rCFs) were studied. The mechanism of electrochemical reaction was thereby revealed. On the basis of the revealed mechanism, the experimental conditions were optimized to realize the integration of recovery and surface oxidation modification. Hydrophilic groups were formed on the surface of rCFs at the same time of recovery, so as to enhance the interfacial bonding strength between rCFs and cement matrix. Moreover, the surface modified rCFs and graphene nanofluid additives were combined to form the composite modified CFRC with micro- and nano-carbon materials. The mechanical and piezoelectric properties of the composite modified CFRC were significantly improved compared with the original CFRC. This work is not only expected to solve the environmental pollution caused by the CFRP waste, but also can break the cost bottleneck of large-scale application of carbon fiber in civil engineering, promoting the interdependent benefits of resources and environment.