An experimental evaluation of a hybrid bio-composite based on date palm petiole fibers, expanded polystyrene waste, and gypsum plaster as a sustainable insulating building material

Gypsum plaster is essential in construction as a thermal insulator and decorative material. This study aims to protect the environment by valorizing two commonly found wastes in Algeria, namely date palm petiole fibers (DPP) and expanded polystyrene waste (EPS), to produce a gypsum plaster hybrid biocomposite material comparable to, or better than, neat gypsum plaster (NGP). Hand -made samples with different DPP mass loadings (0; 5; 10; and 15%), EPS mass ratios (0.3%), or both were used. Different morphological, mechanical, and thermophysical tests were performed on the produced hybrid composites. FTIR shows the characteristic peaks for gypsum, polystyrene, and fibers. XRD shows that NGP, EPS, and DPP are 71.58, 29.91, and 52.93% crystallinity, respectively. Compression strengths, flexural strengths, and young modulus show that EPS, DPP, or both significantly reduce all mechanical properties of prepared samples. The biocomposites produced had lower thermal conductivity ( lambda ) (0.265 - 0.414 W/(m.K) at 24 degrees C) and bulk density ( rho) (852 - 925 kg/m 3 ) than reference NGP samples witch have 0.425 W/(m.K) in thermal conductivity and 977 kg/m 3 in therm of bulk density. Based on a comparative study, gypsum plaster reinforced with DPP, EPS, or both exhibits potential as a viable alternative to insulation materials, thereby offering a sustainable solution for construction purposes.