Resultados de SEM/EDX en morteros de restauración aplicados a areniscas del Eoceno de Gipuzkoa utilizadas en la construcción de edificios

The restoration of buildings made of sandstones is a critical problem in the Basque Country, because the wide use of Eocene sandstones that appear as a constructing material very frequently affected by weathering processes. The impossibility to recuperate the original material sometimes leads to complete or even replace the masonry stones with mortars which should have the same physical properties and visual appearance than the original stones. Our research is focused to find the better mortars for the Eocene sandstones, and even to synthesize a mortar having the same resistance to weathering than the original sandstone. In order to improve the research, the first step was to accurately know the intimate textures of several types of mortars for furtherly test their physical behaviour under different experimental techniques in the laboratory. We have compared the textures of three commercial mortars (A, B and C) and a fourth one synthesized by Teusa. The mortar A is an amorphous arid-free alite-mortar, whereas the B and C are composed by quartz, alite and calcite. From all the four studied mortars, the A seems to be the most appropriate to rejoin the Igueldo sandstone masonry stones, without exclude its use for completion. The B and C mortars are suitable for completion because their composition and texture is very similar to that of Eocene sandstones. Finally, the uncommercialized Teusa mortar is thought to have by the moment an excessively resistant behaviour when compared to Eocene sandstones. Being relatively-close the textures of all the four studied mortars, we think that both organic additives or catalysts together with the ratio high-Ca-lime/white-cement should play an important role in the final properties of the mortar