▎ 摘　　要

Used face masks resulting from the COVID-19 pandemic are forming a new waste stream that poses a considerable environmental risk to the ecosystem if not properly disposed of. This work explored an environmentally friendly solution to diverting such waste to a value-added application, i.e., fabricating waste mask microfibers for use in cementitious composites. To improve the interfacial transition zone between mask fibers and cement paste matrix, the microfibers made from recycled medical masks are pre-treated in an aqueous solution of graphene oxide (GO, at 0.05 wt%). In a cement paste with the water/cement ratio of 0.40, the GO-treated mask fibers admixed at 0.1 vol% showed great potential for improving the splitting tensile strength (by 47% at 28 days), even though they slightly decreased the compressive strength of the paste (by 3% at 28 days). Microscopic investigation was also carried out to reveal the enhancement mechanism of GO-treated fibers. This study preliminarily demonstrated the feasibility to upcycle waste masks in the concrete industry and provided a new strategy for disposing of waste masks.