Towards Green Materials for Cultural Heritage Conservation: Sustainability Evaluation of Products for Stone Consolidation

Formulation of effective stone consolidants for the restoration of weathered carbonate substrates is an active area of research in conservation science. In addition to consolidation performance, sustainability is increasingly taken into account in the selection of the most suitable conservation intervention. Here, a comparative life cycle assessment of three consolidants (a novel product based on a diammonium hydrogen phosphate solution and two commercial alternatives: nanolimes and acrylic resin) was carried out to determine the environmental burdens that might arise from their production, their application processes, and the supply chain of precursors and auxiliary materials. The impacts of the three consolidants were compared considering the respective amounts required to treat 1 m2 of two alternative substrates (limestone and lime mortar), as determined by application until apparent refusal. The results of the study highlight the lower environmental footprint of the phosphate-based treatment compared to the commercial solutions on several impact categories. The analysis allows to point out, for each product, the components that contribute the most to the environmental impact, namely solvents in the case of the commercial consolidants and production of DAP itself in the case of the phosphate treatment.