Mechanical performance of cementitious composites reinforced with weft-knitted spacer fabrics under static flexural and impact loading

Though weft-knitted spacer fabric made from high-performance continuous fiber offers great potential for lightweight composite with high energy absorption characteristic, it has yet to be substantially studied in the field of cement-based structural materials. In this paper, a series of newly developed aramid weft-knitted spacer fabrics were applied to reinforce the eco-friendly cementitious matrix. The mechanical properties and failure behaviors of composites were investigated via the three-point bending test and impact test systematically. XCT was then performed to reveal the underlying damage mode of composites. The experimental results indicated that aramid weft-knitted spacer fabrics were highly beneficial reinforcements for cementitious composites due to their great bonding and mechanical anchoring with matrix. The larger ductile deformation and higher damage tolerance of composites were obtained by the increase of spacer yarn density and surface yarn density. The asymmetrical structure corresponding to the different density of surface layer could further enhance bearing capacity by altering the stress transfer.