Laboratory Evaluation of Nanoparticles for Consolidation of Limestone in Archaeological Site of Jerash

Limestones have been widely used in the construction of archaeological and heritage structures in Jordan. These stone structures are facing degradation due to many deterioration factors. Exposure to atmospheric conditions results in deterioration in historic monuments. Limestone conservation identifies emerging issues and challenges that have to be investigated in detail. In this study, limestone deterioration and the development of its consolidation treatments by synthesizing nano-sized particles of calcium hydroxide that dispersed in an alcoholic medium were investigated through an examination of limestone from the archaeological site of Jerash and another fresh limestone sample. Many properties were observed before and after the treatment, to examine the performance of nano-lime as a consolidant. All of the tests were conducted in laboratory conditions. When most of the conservation interventions relied on using organic materials, which were later proven to be harmful to stone on long term, a pressing demand is calling on representing new smart materials by using nano-lime for limestone consolidation; due to their improved mechanical properties, their physicochemical compatibility as consolidant materials follow the principle of authenticity of historic monuments (Wharton 1995). Results have shown that the application of nano-lime prepared in propanol-1 significantly improved the mechanical properties of the treated limestone. Compressive strength increased about 48% for archaeological and 38% for fresh samples, while the drilling increased by 500% for fresh and 84% for archaeological limestones; it has no significant change on porosity, although water uptake value (w-value) decreased 20%.