Valorisation of Polyurethane Waste in Gypsum Mortar to Improve Its Circular Economy

Abstract

The study of the behaviour of polymeric waste in building materials is of great interest. Both sectors are important and have a significant impact on the environment, so more sustainable alternatives that drive the circular economy are needed. A multi-criteria assessment on gypsum mortar with polyurethane waste from eight different industries has been carried out to analyse in depth the influence of this polymer on building materials. The methodology used studies the physico-mechanical properties of the mixtures. A “cradle to gate” Life Cycle Assessment at laboratory level is also included to evaluate and compare their environmental performance. The dosage evaluated is the one that recovers the greatest amount of waste possible while maintaining its performance above the values established in the regulation. The results of the study show that the incorporation of polyurethane waste in gypsum mortars decreases their bulk density by 2–22% in the fresh state and 7–24% in the hardened state, while flexural and compressive strengths are reduced by about one third. The environmental impact assessment of the innovative materials shows that some samples are 15–22% more environmentally friendly than the conventional one. It is concluded that the incorporation of polyurethane waste in gypsum mortar products is a viable alternative to landfill disposal or incineration, given its good technical and environmental performance. © The Author(s) 2025.