Sustainable Fired Clay Composites with Root Palm and Diss Fibers for Energy-Efficient and Healthy Indoor Environments

This work presents a low-impact building material designed for hot arid climates, combining traditional fired clay with natural fibers derived from root palm and Diss plants native to southern Tunisia. The objective is to enhance thermal performance while promoting indoor environmental quality (IEQ). Clay mixtures containing 4% fiber content (by weight) were fabricated and tested for thermal conductivity, mechanical strength, bulk density, and water absorption. Results show that incorporating 4% Diss fibers reduced thermal conductivity to 0.281 W/mK, while 4% root palm fibers reduced it to 0.352 W/mK, offering notable insulation gains. Mechanical performance of the root palm fibers reaches 3.2 MPa in compressive strength. Hygric properties improved through reduced porosity and increased vapor permeability, supporting effective moisture buffering and potentially reducing risks of dampness and mold key factors for healthy indoor air. By utilizing locally available agricultural residues, these composites offer a climate-responsive, resource-efficient alternative to conventional masonry. The findings indicate strong potential for use in passive design strategies that simultaneously lower energy demand, regulate indoor humidity, and improve occupant well-being.