Towards the design of new circular composites for lightweight boards in building: analysis and environmental performance

Over 80 % of raw materials needed for Europe's economy are imported, creating strong reliance on external resources, coupled with the construction sector's high waste output, this underscores the urgent need for circular strategies to promote industry development. In this study, we have characterised and environmentally evaluated a new composite entirely produced by construction waste revalorisation. The recycling process of discarded plasterboard and expanded polystyrene waste in dissolution has allowed the reincorporation of up to 75.3 % of secondary materials in new composite elaboration. Thus, a physico-chemical, physical and mechanical characterisation has been conducted, with special emphasis on the thermal behaviour of the new material, as well as an environmental assessment. We found that the obtained composite shows a reduction in density and thermal conductivity of 44 % and 27 %, respectively, fundamental properties to achieve building sustainability during construction and operational stages. Additionally, the results show how the use of recycled gypsum reduces emissions by 56 %, demonstrating the great potential of reusing discarded materials in the production of new construction products. This research adopts a twofold strategy that implies circular economy principles by recycling and reusing waste, aiming not only to ease the burden on landfills but also to develop construction materials that contribute to lower the energy consumption of buildings throughout their lifespan. • Circular economy applies through recycling to develop energy-efficient composites. • Recycled gypsum and dissolved EPS waste reduces natural raw materials use by 75 %. • A porous and lighter material with 27 % reduction in thermal conductivity was obtained. • Raw materials are a crucial factor in environmental impact of composites production. • Use of recycled gypsum reduced emissions by 56 % in relation to the reference.