Thermophysical characteristics of cement-based mortar incorporating spent coffee grounds

This work aimed to evaluate the efficacy of recycling Spent Coffee Grounds (SCGs) in cement to prepare bio-based mortars with improved thermal insulation. Different SCGs weight concentrations ranging from 0 to 40wt% were considered as partial replacement ratios for the development of cement mortar composites. The thermophysical performance of prepared formulations was studied experimentally using the hot disk method. In addition, the optimal incorporation rate for suitable SCG-based cement mortars was determined. The results indicated the possibility of recycling up to 30% by weight of coffee waste for mortar production. A significant enhancement in thermal insulation was observed in mortar composites incorporating SCGs. Replacing 30wt% of cement by SCGs showed a decrease of about 70.8% in the mortar's thermal conductivity and 45.7% in the thermal diffusivity. The experimental investigation revealed that 5wt% SCGs was to be the optimal incorporation rate for designing eco-efficient mortars. Adding only 5wt% SCGs can improve the thermal insulation of mortars by 58% and reduce their thermal diffusivity by 34%. Therefore, SCGs present a promising bio-waste aggregate for developing thermally insulating mortars with low environmental impact at an industrial scale.