Experimental study for the consolidation of stone of old fortifications

摘要

For the construction of fortifications large amounts of stone pieces from nearby deposits have been used. Serpentines, gneiss, schist, limestones and marbles are the most commonly found stones. Most of them present decay which is not only surfacial but goes deeper to the interior of the stone. The problem is that their replacement is not always easy and there is a need for cleaning and consolidating them. Since fortifications are usually exposed to extreme climatic conditions because of their position, the question is which consolidant will be more effective in protecting the stones. In this paper the results of a study concerning the characteristics of serpentines, schist and gneiss are presented. Strength, porosity and pore size distribution as well as microscopic observations have been measured before and after the application of commercial consolidants on those stones. The methodologies followed for the determination of the above mentioned characteristics are the recommended ones by NORMAL 26/87 (Group M). Based on the measurements, it seems that ethyl silicate combined with methyl resin is more effective than the other consolidants used.