Environmental impact of roof tiles using recycled waste glass coatings: A Life Cycle Assessment approach

The integration of recycled materials as secondary resource in the fabrication of sustainable and resilient construction materials helps reduce the environmental impacts and highlights the importance of using sustainability assessment tools, such as Life Cycle Assessment (LCA). In this context, the objective of this study is to perform an LCA analysis of the use of waste glass (WG) coatings for roof tiles, and to evaluate its potential for cool roofs applications. The assessment was based on a comparison between three scenarios: (i) conventional roof tiles without recycled WG coating, (ii) roof tiles with soda-lime-silica WG coating, and (iii) roof tiles with lead silicate WG coating. This work followed the steps defined by ISO 14,040 and 14,044 standards to carry out a gate-to-gate analysis for the production phase, supplemented by a cooling energy simulation assessment for the use phase. The findings showed that the recycling process of WG has a relatively small contribution to the overall environmental impact with regard to the tiles production process, accounting for less than 5 % regardless of the type of WG. Furthermore, the implementation of roof tiles with lead silicate WG coatings used for flat roofs reached the highest cooling energy savings, up to 13 %, particularly in climate zones with severe summer conditions. This study demonstrates the potential benefit of using roof tiles with WG coatings for cool roof applications, which helps offset the environmental impact associated with the production of recycled WG coatings through the cooling energy savings achieved in the operational phase.