Characterization of the pore space of crystalline monumental stones

• Autores: Rosa María Esbert Alemany, T. Kovacs, Modesto Montoto San Miguel
• Localización: IX Congreso Internacional de Rehabilitación del Patrimonio Arquitectónico y Edificación: (9. 2008. Sevilla), Vol. 1, 2008, ISBN 978846123459z, págs. 63-68
• Idioma: español
• Texto completo no disponible (Saber más ...)
• Resumen

  • One of the most serious deteriorating agents of building materials, such as monumental stones, is water. The weathering, caused by water, depends on the external conditions and the intrinsic characteristics, above all on the hydric properties of the material, which are determined by the structure of its void space. The crystalline stones � widely used as monumental stones (marbles, granites etc.) � have a void space structure of fissure type, very different from that exhibited by cemented stones (sandstones, limestones, etc). Because of the typical features of this pore space � low porosity values, channelled water pathways etc. � the characterization of these stones requires a special methodology or the special use of the methods so effective in the case of cemented rocks or of larger porosity. And even within the group of crystalline rocks the characteristics of the pore space and, as a consequence, the effective methods examine it may vary significantly. The three examined stones � the Macael marble (open porosity: ~0,4%;

    average pore radius: ~0,01 ìm), the Silvestre Porrisal granite (open porosity: ~4,4%; average pore radius: ~0,1ìm) and the Szobi andesite (open porosity: ~4,6%; average pore radius:

    ~0,01ìm) � all belong to the mentioned group, - used as monumental stones for example in the Alhambra, (Spain), the cathedral of Santiago de Compostela (Spain), and in several fortresses of North-Hungary, respectively -, but still there are serious differences in their porous network and therefore in their hydric properties. The study aimed at finding the most useful methods for the characterization of the mentioned stones taking into account some typically used techniques - from the classical methods using water (water absorption, capillary uptake, etc.) till the instrumental (Hg intrusion, N2 adsorption) and microscopic techniques (SEM, FM, CLSM).