Biomediated Reinforcement of Weathered Calcareous Stones

In this paper a new conservation treatment for the reinforcement of weathered monumental calcareous stones and sculptures, based on bioremediation application, is validated both in laboratory and in a field test site. It is necessary that the reinforcement is achieved without the introduction of material that would irreversibly change the work of art being conserved. To achieve this, calcite crystals are grown in the porous the stone to bridge across the pore and reinforce. Natural and synthetic polypeptides are used to control the crystal growth within the pores. Calcium and carbonate ions for crystal growth are supplied by a saturated solution of calcium bicarbonate, supplemented in some cases by calcite nanoparticles, to maintain a saturated carbonate solution, over a prolonged period, in the pore. Delivery of the protein, calcium ions and nanoparticles into the pores is achieved using a fine spray and the natural capillarity of the stone.