Conservation of monumental buildings
December 11, 2009
Consolidantes products available in the market (alcoxisilanos), on the one hand, have undoubted advantages (proof of this is that they have not been ousted by no other material) and, on the other hand, certain disadvantages completely ignored by the professionals responsible for implementing them. The main drawback of these products is the occurrence of fractures in the consolidante which has been polymerized in the pores of the altered rock.
The pet-243 project: molecular sieves and other nanomaterials, developed by a research group of the UCA, led by Dr. Maria Jesus Mosquera, studying new nanomaterials fracture-free. To do this, use a surfactant as the pores of the consolidante template, getting a nanomaterial with uniform pore size, in which responsible of these fractures capillary pressures are minimized.
Researchers have designed new amendments in the first phase of the project focused on the synthesis of new consolidantes materials. His strategy was to add a new item to the Sun's departure. In particular, it's an organosiloxano - polydimethylsiloxane (PDMS) - which generates an orgánico-inorgánico hybrid gel.
This option is intended to increase the pore size of the gel, reducing capillary pressure of the material to a greater extent and favouring the Elimination of the surfactant. It also seeks to increase the elasticity of the material, avoiding their break-up, and form an orgánico-inorgánico hybrid gel which confers on the material properties hidrofugantes.
This last point is especially interesting, because the obtaining of a material with application like consolidante and hidrofugante represents a momentous step forward from a technological point of view on the development of materials for protection of stones. The new product allows, through a single application, consolidate the stone and protect it at the same time of the primary responsibility for their deterioration: the water. So far, in the works of restoration of buildings is carried out, first, the consolidation of the altered stone then, treatment of hidrofugación. The reduction in costs of personnel and matériel which would fit with a single application would be considerable.
The image shows a drop of water placed on a rock calcarenite untreated. Less than 90 ° contact angle is typical of post-translational porous materials. In Figure 2 you can see the image of a drop on the surface of the same rock after being treated with the patented product. As you can be seen clearly, the contact angle is increased above 90 degrees, being typical of a waterproof material.