Industrial production of pipe foam insulation generates huge volumes of scrap material, driving to a serious environmental problem. This research studies the potential of adding different size particle proportions of this waste rubber to a plaster matrix. For this purpose, an experimental plan has been elaborated which characterizes the physical and mechanical behavior of the new composite: Shore C hardness, flexure and compressive strength. Furthermore, different particle sizes, weight rates and water/plaster ratios have been analyzed. In view of the results this waste rubber could be incorporated in gypsum based composites forming part of new lightweight products

The quality of secondary materials is imperative to promote a circular economy. In order to improve the way in which the quality of recycled gypsum is assessed, European guidelines on recycled gypsum (RG) quality criteria have been outlined in the framework of the Life+ Gypsum to Gypsum (GtoG) project. Such GtoG guidelines, along with the European Standard on gypsum plasterboard EN 520, provided the basis for this study. During the GtoG project, gypsum recycling and plasterboard manufacturing processes were monitored by testing the gypsum feedstock and the plasterboard produced. The aim of this paper is to discuss the results obtained on relevant parameters that characterize gypsum as a secondary raw material, as well as the resulting product. The minimum requirements were fulfilled by 56% of the RG samples and 86% of the plasterboard with increased RG.