Development and Characterization of Gypsum Plaster Composite Incorporated with Sheep Wool

Abstract

This study aimed to develop and characterize a sustainable gypsum plaster composite incorporating sheep wool fibers to enhance thermal insulation properties while maintaining adequate mechanical performance. Samples with varying sheep wool concentrations (1%, 2%, and 3% by weight) were prepared using a layering technique. Thermal properties were evaluated using a heat flow meter method following BS EN 12667:2001, while mechanical performance was assessed through three-point bending tests according to BS EN 13279-2:2014. Results demonstrated significant improvements in thermal insulation, with thermal conductivity reduced by up to 51% in the 2% wool composite (0.122 W/m·K) compared to the reference sample (0.246 W/m·K). However, flexural strength decreased with wool fiber addition, with reductions ranging from 45-54% across reinforced samples, though all maintained values above the minimum requirement of 1.0 MPa for building applications. Microstructural analysis revealed that 2% wool content represented an optimal balance between thermal and mechanical properties, as higher concentrations led to fiber agglomeration and clustering that negatively affected performance. This research contributes to sustainable construction by demonstrating that sheep wool, a renewable material, can effectively enhance the thermal insulation of gypsum plaster while maintaining structural integrity for building applications.