EVALUATION OF SILICONE BASED PRODUCTS USED IN THE PAST AS TODAY FOR THE CONSOLIDATION OF VENETIAN MONUMENTAL STONE SURFACES

Abstract

The commercial consolidating siloxane compounds EAS 40, Rhodorsil Consolidante RC90 and RC80, and the

silicone water repellent agents Rhodorsil H224 and Hydrophase were carefully applied to stone specimens and

tested to ascertain their chemical nature and their stability under oxidative stress and degradative

environments. The resins were applied to laboratory samples (Carrara marble and Vicenza white limestone

specimens) and subjected to controlled natural weathering and artificial ageing. The film morphology and

the penetration depth was observed and measured by SEM-EDS determinations, while the stability of the

resins was monitored by FTIR, SEM-EDX, colorimetric measurements and sponge tests. The results were

compared with those obtained from a spread sampling of Venetian surfaces treated in the second half of the

XX c. with Sogesil XR893 and X54-802, silicone resins which are no longer on the market. The overall results

prompted a number of considerations on the effects of the resins applied to stone materials and offered the

authors the opportunity to make a practical contribution to current practices in the consolidation of stone

materials.