Preparation and performance analysis of recycled PET fiber reinforced recycled foamed concrete

Construction waste and waste fabric are two major types of solid waste that lead to landfill issue and environmental pollution. Considering the need for more efficient handling method by simultaneously handling both solid waste materials, this study reports an innovative solution to transform waste concrete and waste polyester fabric into environmentally friendly product, recycled foamed concrete (RFC). The dry density, compressive strength, water absorption, frost resistance and chemical erosion resistance of plain RFC (PRFC), PET fiber reinforced RFC (PETRFC) and recycled PET fiber reinforced RFC (RPETRFC) were evaluated. The results indicated that the added recycled powder (RP) can improve the compressive strength of foam concrete. Moreover, the addition of PET fiber (0.1 wt.% content and 6 mm length - optimum) improved the compressive strength (especially the early strength) and durability but had no significant effect on dry density and water absorption. Recycled PET fiber presented a better enhancement effect than PET fiber. The dry density and 28-day compressive strength of RPETRFC were 5.2% and 5.1% higher than those of PETRFC, respectively, and water absorption was 10.7% lower than that of PETRFC. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis indicated that recycled PET fiber had a multifilament structure, which can effectively improve the pore structure of RFC without changing the hydration mechanism. This study demonstrates a new direction for recycling waste concrete and polyester fabric with excellent economic and environmental benefits, and the findings provide reference for the development of lightweight RFC with improved physical properties and durability.