Effect of accelerated aging and silica fume addition on the mechanical and microstructural properties of hybrid textile waste-flax fabric-reinforced cement composites

Incorporating eco-friendly substances obtained from recycled resources and industrial by-products is gaining increased acceptance among building materials. In this context, a cementitious matrix containing supplementary cementitious materials (SCMs) reinforced by recycled fibers may be a promising solution from both a durability and sustainability perspective. This study presents an extensive experimental program carried out on a cement-based composite with Silica Fume (SF), reinforced with recycled textile waste (TW) nonwoven fabric. Initially, the mechanical strength (compression and flexure) of the Portland cement paste substituted with variable SF content (0%–30%) was characterized. Based on the results, laminate plates having six TW fabric layers impregnated with three different cement pastes −0%, 15%, and 30% SF− were produced, and both the mechanical (flexural and direct tension) and durability (against wet-dry and freeze-thaw cycles) properties of the composite were assessed through testing. Experimental microstructural techniques including thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning and backscattered scanning electron microscopy (SEM and BSEM) were also used to complement the analysis of the mechanical characterization. The results suggested that the composite modified by 30% SF could protect fibers from embrittlement, thereby offering the greatest durability by increasing flexural and tensile resistances by up to 45% and 55%, respectively, as compared to the sample without SF in the wet-dry cycles. Indeed, the treated composite with 30% SF had almost equal performance in both unaged and aged conditions, showing a flexural strength in the range of 14.5–15.5 MPa and flexural toughness of 8.0–8.7 kJ/m², suitable for the targeted applications including ventilated façades. The results and outcomes of this study may serve as the basis for future research on these composites and their potential use in structural applications in the building construction and housing industries.