The effectiveness of ethyl silicate as consolidating and protective coating to extend the durability of earthen plasters

Abstract

In the heritage protection, one of the most interesting scenarios is the preservation of the original materials. In this case, the surfaces are generally treated to consolidate them. The aim of this paper is to evaluate the effect of ethyl silicate coatings on surface consolidation, water absorption and porosity of earthen materials. Peeling tests, water absorption measurements (capillary and Karsten) and textural alteration analyses were conducted by optical microscopy. In addition, the protective role of the ethyl silicate coatings against rainwater, HCl rain and H2SO4 rain was evaluated to compare the durability of coated and control samples. It was found that ethyl silicate substantially improved the above properties as well as microstructural features of the samples. Scanning Electron Microscopy and EDX mapping revealed the coating was not regularly spread on the surface. Despite this, Mercury Intrusion Porosimetry tests showed the total porosity of samples coated with ethyl silicate was clearly reduced.