Study of Effectiveness of Treatment by Nanolime of the Altered Calcarenite Stones of the Archeological Site of Volubilis Site (Morocco)

Volubilis is the major archaeological site of North Africa, built in the 3rd century B.C. Unfortunately, the city, classified as a UNESCO world heritage, is affected by several forms of degradation that threaten its sustainability and durability. The main stone of the site, the calcarenite stone, shows many deterioration patterns (sanding, scaling and alveolization) that require immediate interventions of consolidation. In this paper, we subjected stone samples to artificial aging to simulate actual alteration. Then, degraded samples have been treated with commercial nanolime (CaloSil). Nanolime treatment proved to be efficient to recover most of the damage resulting from artificial aging, but also generated a change in color. Using a less concentrated nanolime could limit the aesthetic impact of the treatment.