Thermal and mechanical performance of gypsum composites with waste cellulose acetate fibres

•Physico-mechanical properties of gypsum compounds with waste cellulose acetate (CA).•Waste CA fibres were extracted from discarded cigarette filters.•Slightly lighter composites were obtained by adding waste CA fibres.•Mechanical strength increased for most of the waste CA-containing composites.•Composites with waste CA fibres presented a lower thermal conductivity. The influence of waste cellulose acetate (CA) fibres in the physico-mechanical (i.e. density, surface hardness - Shore C, flexural and compressive strength) and thermal properties (i.e. thermal conductivity coefficient) of gypsum-based composites was evaluated in this study. Furthermore, complementary stereomicroscopy and scanning electron microscopy analysis were carried out. Lighter composites were obtained with ensuing incorporation of waste CA fibres. In comparison to the control material, an improvement on flexural and compressive strength, up to ∼9 % and ∼1 %, respectively was observed. Moreover, a slight declining trend in thermal conductivity was found with increasing replacement level (up to ∼16 % decrease).