Lightweight plasters containing plastic waste for sustainable and energy-efficient building

The reduction of energy consumption in construction, the production of thermally insulating materials, as well as the solution of environmental problems by recycling industrial and municipal waste are key challenges for the next future. For this reason several plasters have been studied, in which virgin raw materials such as natural sand and limestone filler were replaced up to 100% by waste polyethylene terephthalate (PET) particles and pulverized Glass Fibre Reinforced Plastic (GFRP) waste, respectively. Moreover, an attempt was made to combine PET waste particles and wood waste (WW) particles in order to improve functional properties of plasters. As supplementary cementitious material silica fume was employed, which is a further industrial by-product obtained from silicon wafer sawing during the production process of solar panels. Finally, in some mixtures even cement was fully replaced by a combination of lime and hydraulic lime in order to further improve the carbon footprint of these plasters. At the end of the optimisation process, environmentally-friendly plasters have been obtained with 100% waste particles replacing virgin materials, which proved to be energy efficient thanks to the low thermal conductivity values achieved, as well as for their remarkable lightness.