Artificial weathering and non-destructive tests for the performance evaluation of consolidation materials applied on porous stones

Abstract

The evaluation of consolidation treatment efficiency in terms of improving the resistance of treated lithotypes to deterioration phenomena caused by soluble salts crystallisation, is taking place through dynamic artificial weathering accelerated tests of marine salt spray. Quarried biocalcarenites from Greece and Cyprus have been treated with four consolidation materials (diversified according to their deposition mechanism). The materials applied are colloidal dispersion of silica, pre-hydrolysed ethyl silicate with amorphous silica, ethyl silicate in ethanol and acrylsiliconic resin in organic solvents. The treated stone samples are placed in an artificial weathering chamber, where they remain for nearly two months, being attacked by severe quantities of marine salt spray. The application of non-destructive techniques (weight and ultra sonic velocity measurements, deteriorated surface analysis by a camera-laser scanning system) during the salt spray simulations verified the improvements presented to the consolidated biocalcarenite samples in comparison to the untreated ones. Consolidated samples present weight stability during the tests, increase in ultra sonic velocity and minor fluctuations on it, and less roughness increase and grain detachment during the simulations. Deductions among the consolidants are made indicating the superiority of ethyl silicate as an appropriate consolidant for those biocalcarenites, as it has arisen from these certain tests.