Effects of chemically treated coconut fibers on the hydric, physico-mechanical and thermal properties of plaster materials resulting from hydrated clay-lime mixtures

The present study investigated the use of coconut fibres derived from agricultural waste, treated with a sodium bicarbonate solution, to enhance the properties of thermal insulating plasters made from hydrated clay-lime mixtures. The investigation focused on the effects of treated fibres on the hydric, physico-mechanical, and thermal properties of the plaster. Plasters were prepared using clay stabilized with 4 wt% hydrated lime and varying proportions of treated coconut fibres (0, 2, 4, 6, 8, and 10 wt%). Flexural strength, compressive strength, and hydric tests were conducted on the samples. The results revealed that the inclusion of 4% treated fibres yielded the highest compressive strength of 13.11 MPa. Additionally, the use of coconut fibres treated with a 5 M sodium bicarbonate solution improved the thermal conductivity to 0.31 W/m·K, compared to 0.6 W/m·K for samples without fibres. These findings demonstrate that chemical treatment of fibres significantly enhances both the mechanical and thermal properties of the plaster, suggesting its potential for eco-friendly construction applications.