Valorisation of gypsum boards with polyurethane waste to promote their circular economy

The new European environmental policies for construction focus on sustainability, promoting energy efficiency, recyclable materials and circularity, with an emphasis on waste management. This study enhances gypsum board circularity by recycling polyurethane gypsum ceiling tiles waste into a new precast material for suspended and demountable ceilings. The process treats the waste as a whole, without separating the original raw materials: gypsum, polyurethane foam waste and fiberglass. The objective is to determine a gypsum mixture, incorporating the maximum amount of waste, with suitable mechanical properties, workability and consistency for industrial replication. The research studies the physical and mechanical properties of the new products. During the manufacturing phase of the new plasters, it is reported that citric acid needs to be added to the mixtures to ensure good workability and to delay the setting time. Without pre-calcination, gypsum mortars with recycled ceiling tile show a 7 to 10 % reduction in bulk density, compared to the reference plaster. Only two of the four samples tested meet the mechanical requirements, with strengths 35 and 60 % lower than those of the control mixture. Finally, the thermal conductivity of the innovative mortars is on average 16 % lower, improving the insulating properties of the material. The results conclude the feasibility of valorising polyurethane gypsum boards waste, promoting sustainable recycling practices.