From Waste to Strength (2025-05)¶

This research investigates the utilization of recycled steel fibers (RSFs) derived from waste tires as a reinforcement material in cementitious mortars, focusing on their potential in sustainable 3D printing of cementitious composites. The study systematically examines the effects of incorporating RSFs at various volume fractions on the rheological properties of fresh mortar mixes, the morphological characteristics of the hardened mortar matrix, and the resulting mechanical strength at both early (3 days) and later (28 days) curing stages. Findings demonstrate significant improvements in key mechanical properties, including such as flexural strengths, with an optimal RSF content identified for achieving both high early-age strength and a balanced combination of desirable properties at 28 days. Scanning Electron Microscopy analysis confirms good dispersion of RSFs within the mortar matrix and reveals strong fiber-matrix bonding, contributing to enhanced durability and overall strength. The research extends to exploring the application of RSF-reinforced mortars in 3D printing with cementitious materials, showing improved structural integrity, enhanced flexural strength, and reduced anisotropy and interlayer bonding weaknesses commonly encountered in additive manufacturing processes. This approach offers a promising sustainable solution for developing high-performance mortars suitable for various construction applications, effectively addressing waste reduction, material property enhancement, and advancing the field of 3D printing with cementitious materials.