Influencia de tratamientos de hidrofugación en las propiedades de morteros de cal y cal y puzolana

The influence that water-repellent products can have on physical and micro-structural properties of lime mortars, and lime plus pozzolan mortars has been studied. Three water repellent products have been used. Mixes of the previously mentioned three water repellents plus a biocide product were also applied. Treatments make the total porosity and saturation coefficient of both mortars to decrease, while colorimetric coordinates bear little alteration. All treatments with water repellent products provided mortars with a hydrophobic property index close to 100%. Durability of such mortars has been also studied: salt crystallization test, frost-thaw and dry-wet cycles, as well as ultraviolet radiation test were carried out. Relationship between mortars behavior and their porosity and saturation coefficient were found.En el presente trabajo se ha estudiado la influencia de la aplicación de productos hidrofugantes a morteros de cal y morteros de cal y puzolana sobre sus propiedades físicas y microestructurales. Se han estudiado tres productos hidrofugantes. También han sido estudiados dichos productos junto con un biocida. La porosidad total y el coeficiente de saturación de ambos tipos de morteros se ve reducido por el efecto de los tratamientos mientras que las coordenadas colorimétricas se ven poco alteradas. Todos los tratamientos confieren un índice de hidrofobicidad a los morteros próximo al 100%. Asimismo, también se ha estudiado la durabilidad de dichos morteros frente a la cristalización de sales, hielo-deshielo, los ciclos de humedad-sequedad y radiaciones ultravioleta. Se relaciona el comportamiento de los morteros con su porosidad y el coeficiente de saturación

29Si and 1H NMR study of waterproofing polymerization

6 pags. ; 5th International Conference: Youth in Conservation of Cultural Heritage ; Madrid, 21st-23rd September 2016Lime mortar, a construction material used by the ancients and still in use today, is characterized by its vulnerability to physical, chemical and biological attack, in which water plays an instrumental role. Surface coatings may be used to enhance its durability. As such coatings are applied to the outermost surface; they are the materials most liable to deteriorate. Due to the tiny amounts involved, however, it is difficult to judge when they are in need of restauration and/or replacement. Spectroscopic techniques are generally non- and at most semi-destructive, as they require only small amounts of sample; moreover, they are very useful for studying surface coatings. 29Si and 1H NMR were used in the present study to characterize different waterproof coatings before and after their application into lime mortars. Polymerization reactions were studied over an evaporating dish, without interaction with the substrate. Interaction and polymerization of the coating over the lime mortar was also studied by the same spectroscopic technique. Two waterproofing materials were used (¿Hydrophase superficii¿ and ¿RC-80¿). The first one was found to be a mixture of tert-butyl-trimethoxysilane partially polymerized (31%) and ethyl silicate. The second product proved to be a mixture of poly-methyl-siloxane and ethyl silicate. Initially 86% of the ethyl silicate and 100% of the poly-methyl-siloxane were in monomeric form. The two initial compounds in Hydrophase superficii polymerized on evaporating dish to different degrees, with 43% of the tert-butyl-trimethoxysilane and 33% of the ethyl silicate reaching maximum polymerization at the end of the test. They polymerized more fully when that product was applied on lime mortar surface, with 60% of the tert-butyl-trimethoxysilane and 40% of the ethyl silicate reaching maximum polymerization. Poly-methyl-siloxane failed to polymerize on evaporating dish, whereas 86% of the ethyl silicate formed polymers. When the product was applied to lime mortar, 80% of the ethyl silicate polymerized to the highest possible degree and poly-methyl-siloxane began to polymerize (20% to the maximum degree)