Lightweight plastic waste gypsum composites for sustainable and energy efficient buildings

The buildup of plastic waste (PW) in different ecosystems is a major environmental issue that has detrimental effects on people, wildlife, and their habitats. Our study aims to investigate specific plaster properties while reducing the rate at which end-of-life plastic is rejected in nature. This manuscript explores a gypsum composite reinforced with plastic waste (GPPS), with an emphasis on thermo-physical, chemical, and mechanical characteristics. Ten samples were produced, with varying addition rates (0%, 5%, 10%, and 15%) by weight of GPPS waste, incorporating three different sizes of GPPS aggregates (δ ≤ 1 mm; 1 mm < δ ≤ 1.25 mm; and 1.6 mm < δ ≤ 3 mm). The results demonstrate that the gradual increase in the quantity of GPPS aggregates incorporated into the plaster matrix produced a notable enhancement in thermal properties. However, this resulted in a slight decrease in mechanical performance due to a loss of workability. In general, the material evolution indicated that the inclusion of 15% size 2 GPPS was concluded to be the optimal arrangement for effectively reducing both thermal and mechanical qualities. Specifically, density, conductivity, and thermal diffusivity were decreased by approximately 20.73%, 42.47%, and 53.57%, respectively, while compressive strength decreased by 15.73% (6.64 MPa), a tolerable value according to the EN 13279 standard.