TEOS Nanocomposites for the Consolidation of Carbonate Stone: The Effect of Nano-HAp and Nano-SiO Modifiers.

This study aimed at evaluating the effect of hydroxyapatite (HAp) nanosized structures and nanoparticles of hydrophilic silica as modifiers of both acid- and alkaline-catalysed tetraethoxysilane (TEOS)-based products for the consolidation of carbonate stones. Their initial effectiveness and some compatibility aspects were assessed in a porous limestone (sound and artificially aged Ançã stone samples) and two types of treatment (capillary absorption and brushing). The studied products were examined by scanning electron microscopy (SEM) and micro-Raman spectroscopy.