Non-invasive techniques in consolidation study of dolomitic lime plasters: application to wall paintings

The consolidation of lime-based plaster materials plays a vital role in preservation of built heritage. Wall paintings are particularly vulnerable due to the fragile nature of lime-based substrates and their susceptibility to deterioration. While calcium lime plasters are frequently studied, there seem to be few studies on the consolidation of wall paintings produced with dolomitic lime. This research evaluates the effectiveness of three carbonate-based consolidants — calcium acetoacetate (CFW), Nanorestore (NR), and NanoLaq (NL) applied individually and in combinations, to assess their mechanical and aesthetic effects on dolomitic lime models. Non-invasive methods included microhardness testing, ultrasonic velocity measurements and micro-invasive method as the drilling resistance measurement system (DRMS) to measure penetration depth and change in mechanical properties. Spectrophotometry was used to monitor colour changes after the application of consolidants. This research emphasizes the significance of using advanced diagnostic tools for evaluating and improving conservation treatments for wall paintings. Results showed that combined applications of CFW with nanolimes improved cohesion and depth performance significantly more than individual treatments. The findings contribute to sustainable practices in heritage preservation and align with ongoing efforts to refine consolidant formulations for better performance.