Influence of aluminum waste on the thermo-mechanical properties of lightweight composite mortars based on sand and recycled high-density polyethylene

The development of new construction materials must take into consideration several factors, including the environmental impact, cost price, mechanical performance and thermal comfort. The present study falls within this context. It essentially aims to valorize high-density polyethylene plastic waste as a fine aggregate in substitution of sand at 10% and 30% in order to produce lightweight composite mortars. The incorporation of aluminum waste (powder), which is as an expansive agent, was made at 0.5% and 1% of cement weight in order to further lighten the products that are primarily intended for thermal insulation. This study also seeks to investigate properties in the fresh state such as the workability of mortar, and other properties in the hardened state such as the density, the compressive strength and tensile strength by bending, and finally the thermal conductivity. The results obtained showed that the density of the product obtained decreased as a function of the rate of replacement of natural fine aggregates by high-density polyethylene and also of the aluminum content. In addition, it was observed that the mechanical strengths decreased while the thermal conductivity of the composite mortars obtained improved significantly by approximately 48% in comparison with that of the control mortar.