Recycled Textile Linters for Low-Carbon Eco-Mortars: Thermo-Physical, Mechanical and Environmental Performance

There have been considerable amounts of waste fibres produced as a result of the rapid expansion of the textile industry, which has led to major concerns regarding the environment and brought to light the necessity of developing recycling systems that are sustainable. To provide lightweight, thermally efficient, and environmentally friendly construction materials, this work valorizes Linters textile waste fibres (LTWF) as reinforcement in cement-based mortars. Thermal conductivity, diffusivity, effusivity, and volumetric heat capacity were determined using the flash method coupled with an inverse identification approach based on a genetic algorithm. The addition of LTWF greatly improved the thermal insulating properties of the mortars. At 7 wt.% LTWF, thermal diffusivity decreased by about 60% and thermal conductivity declined from 0.592 to 0.17 W·m⁻¹·K⁻¹, representing a 71% reduction. The composites also showed increased porosity and reduced density, demonstrating their lightweight insulating properties and ability to minimize building energy use. Mechanical characterization identified 3 wt.% LTWF as the optimal fibre content, producing gains of around 97% in flexural strength and 53% in compressive strength when compared with the reference mortar. From an environmental perspective, The application of LTWF significantly reduced the carbon footprint of the composites, resulting in a maximum 31.7% reduction in CO₂ emissions through partial substitution of cementitious materials and lower clinker consumption. Overall, the developed LTWF-reinforced mortars showed an excellent mechanical performance, outstanding thermal insulation, lightweight behavior, and enhanced environmental sustainability, confirming the strong potential of recycled LTWF as a cost-effective reinforcement for next-generation sustainable composites and circular economy applications.