AbstractThree types of textile fabric waste, namely Kevlar, Nomex, and Cordura Nylon, were investigated in this study. The effects of the fiber parameters: volume fraction (0.1%, 0.3%, and 0.5%), length (6, 12, and 24 mm), and use of 1D fiber (width of 0) versus 2D woven fabric fiber (width of 3 and 6 mm) on strength properties, flowability, and shrinkage were studied to determine the optimum textile parameters. The pore structure, microstructure, and fiber-matrix interfacial properties of the optimised mixtures were then characterized by means of X-ray micro-CT, SEM, and nanoindentation at 7, 28, and 90 days. Results showed that the optimized parameters for three types of fabric fibers are 1D fiber (width of 0), length of 12 mm, and volume fraction of 0.3%. This optimized design provided an enhancement of strength and shrinkage resistance. Pore refinement was pronounced in the case of hydrophilic Kevlar and Nomex fibers. However, this also correlates to inferior performance in shrinkage resistance of mortar compared to hydrophobic Cordura Nylon. The fiber-matrix ITZ thickness was dependent on fiber size, while the wettability of fibers (i.e., hydrophobicity or hydrophilicity) was observed to affect the phase distribution in the vicinity of the fiber surface. Furthermore, a large volumetric proportion of the structure is porous in nature (more than 50%) in the region of the fiber-matrix interface after 7 days. With the increment of curing age, the microstructure at the fiber interface becomes denser due to the hydration of the clinker phase facilitating the growth of CSH and CH phases.