Upcycling dello scarto di vetro industriale nel settore edilizio: valutazione di impatto ambientale

The chemical-physical properties of glass make it one of the materials that can be completely recycled an infinite number of times. This characteristic helps minimize the use of virgin raw materials that make up the glass (silica, sodium carbonate, and calcium carbonate) and allows for saving energy in the production cycle. Many studies report information on the application of glass cullet as an aggregate in building materials, especially in cement composites. The application of glass foams has recently been developed as the most promising option for the use of glass scrap fractions otherwise destined for landfills. However, recycled materials must also have excellent chemical-physical performance, which is why upcycling is one of the technological challenges of the circular economy. The importance of adopting up-cycling actions is growing in order to avoid forms of circularity with low added value. This project aims to develop more sustainable alkali-activated materials than those already adopted. The new dense and porous structural components would replace building products, such as clay bricks, lightweight concrete, glass foams, and ceramics, already produced by energy-intensive and material-intensive processes. Within this project, the new products are to be subjected to environmental impact analysis to verify their sustainability. The production process of a glass foam through the alkaline activation of industrial glass cullet has been implemented. The performance of the process at laboratory scale has already been evaluated, demonstrating environmental advantages over previous options. Within the European project, this study aims to improve, already in the design phase, the environmental performance of this glass recycling process at the industrial level. The research analyzes three different scenarios in which transport and energy sources are modified. The Life Cycle Assessment (LCA) methodology is used in accordance with the ISO 14040 and ISO 14044 standards. The boundaries of the system include the downstream phases of glass transport, avoiding landfill disposal, the glass foam production process, and the upstream phases, such as transport to the place of use and end of life. The primary data, obtained from the laboratory system, are integrated with those available in the Ecoinvent database. For the impact assessment, the ReCiPe 2016 method is used through the commercial software SimaPro. The sensitivity analysis is conducted to quantify the environmental impacts deriving from reducing distances and modifying the energy source. Distances in the transport of the incoming material (scenario A) and expanded glass to the destination of use (scenario B) are halved. Then the energy source used varies from a non-renewable source to a renewable source from photovoltaics (scenario C).