Physico-mechanical properties of plastic waste-containing gypsum composites exposed to elevated temperature

•Physico-mechanical properties of gypsum composites with polypropylene and nylon waste.•Influence of high temperature on plastic waste-containing gypsum composites’ performance.•Plastic waste-containing gypsums classified as A2 non-flammable material.•Higher dependence of residual properties on thermal gypsum reaction than on plastic content. This study presents the characterization of residual physico-mechanical performance of gypsums incorporating two types of plastic waste (i.e. polypropylene and nylon), after exposure to high temperature (23 °C–300 °C). The bulk density, ultrasonic pulse velocity, young’s modulus and mechanical strength were analysed. Furthermore, the fire reaction performance was evaluated according to standards. Also, an experimental toxicity assessment of gases released during combustion was conducted. As a results, the residual properties of the composites present a higher dependence on the reactions that take place in the gypsum matrix than on plastic waste content. Moreover, plastic-containing composites could be classified as A2 non-combustible material.