Redesigning lightweight gypsum with mixes of polystyrene waste from construction and demolition waste

Abstract

Perlite and vermiculite are commonly used aggregates for lightweight gypsums, but they cause negative environmental impacts due to the high energy demand needed during their manufacture. Therefore, this paper studies the physical and mechanical behavior of lightweight gypsums using incorporating mixes of polystyrene wastes, both extruded (XPS) and expanded (EPS) polystyrene, in order to substitute perlite and vermiculite and achieve new materials complying with circular economy criteria. For this, and experimental plan was designed and 33 series of gypsums were prepared containing different percentages of EPS and XPS waste and also reference samples (with no additions). These samples were tested in the laboratory and the following tests were developed: dry density, superficial hardness, mechanical strengths and thermal behavior. A comparative analysis evidenced that it is viable to obtain lightweight gypsum when adding mixes of XPS and EPS waste. These gypsums containing polystyrenes comply with the current standards and have lower density than currently used lightweight gypsums and similar mechanical strengths. © 2019 Elsevier Ltd