An overview of nanolime as a consolidation method for calcareous substrates

Ca(OH)2 particles with submicrometric dimensions (nanolimes) represent one of the most promising consolidants for the conservation of calcareous substrates. The nanolime treatment is similar to the limewater technique, traditionally used for its durability and high compatibility with the calcareous matrix but requiring a large number of applications and not always yielding a highly effective consolidation. Since 2001, alcohol-based dispersions of Ca(OH)2 nanoparticles have been synthesised to overcome the limitations of the limewater treatment. Nanolimes present the same high compatibility and durability of the traditional technique but superior properties in terms of higher consolidation, penetration and reactivity, and fewer side effects. Since their discovery, nanolimes have been investigated by several research groups with the aim of refining their synthesis process, properties and applications. This paper presents an overview of the most relevant literature about nanolime as a consolidant for calcareous substrates.