Abstract:

“Surface consolidants” enclose products and methods such as water repellents, emulsions, anti-graffiti surface coatings, salt inhibitors, oxalate coatings, lime wash for surface protection, colloidal silica, biocides, bioremediation treatments and surface coatings by using nano-technological products such as titanium dioxide. Nano-technological products form a coating with approximately 1μ thickness over the surface. This coating may dissolve by crumbling or powdering of the surface due to weathering. Moreover, the presence of water soluble salts under the coating may cause internal stresses caused by salt crystallization and this eventually prompts surface erosion. Aside from these occasions, nano-technological surface coatings prevent soiling over the surface by means of photo catalytic activities.This paper aims to present the results of the research on the efficacy of titanium dioxide coatings as a surface consolidant on limestone. Experimental research was followed up on samples with and without coating that were 20x20x2cm in dimensions in order to determine the coefficient of capillarity, water vapor diffusion permeability and their salt content. Coated and uncoated samples were inspected by SEM-EDX. The samples were also observed during aging tests by wetting-drying cycles in de-ionized water, %2 KS0 and %3 HS0 solutions. The samples were tested under UV light for 28 days after the application of %3 HS0 + ‰1 C solution over their surface. The results present that the titanium-dioxide surface coating does not prevent water transmission in liquid and gas form. The application did not make any changes on the physical properties of the samples. The coating does not cause any discoloration under UV light. The application of TiO appears to be efficient on sound and clean surfaces of limestone or marble, whereas this can not be said for decayed surfaces

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