Initiative to Increase the Circularity of HDPE Waste in the Construction Industry: A Physico-Mechanical Characterization of New Sustainable Gypsum Products

Abstract

The annual production of plastic waste worldwide has doubled in just two decades, with approximately 390 million tonnes of plastic waste now being generated. In this context, the construction industry must move towards the development of new, more sustainable materials made under circular economy criteria. In this work, a physico-mechanical characterisation of gypsum composites with the incorporation of high-density polyethylene (HDPE) waste, replacing 2–4–6–8–10% by volume of the original raw material, has been conducted. The results show how the incorporation of these plastic wastes improves the water resistance of the gypsum material without additions, as well as producing a decrease in thermal conductivity and greater resistance to impact. On the other hand, it has been found that, as the percentage of recycled raw material added increases, the mechanical resistance to bending and compression decreases, leading to fracture due to a lack of cohesion between the matrix and the waste. Nevertheless, in all the cases studied, mechanical strengths higher than those established by the EN 13279-2 standard were obtained. Thus, the results confirm the viability of these secondary raw materials to be used in the development of new products for sustainable building, especially in the design of prefabricated panels for false ceilings.