Preliminary Evaluation of Coating Hydrophobization of Natural Stone from Repedea - Iasi area (Romania)

Abstract

Given the need for the development of interdisciplinary studies and research, including in the Engineering field and in the Building sector, this paper suggests a multidisciplinary approach to the maintenance of lithic surfaces, by analyzing some high-performance building materials and products, such as hydrophobization coating films. As it has been determined and acknowledged by the scientific community worldwide, the main aggression factor affecting the geomaterials used in the construction of heritage assets is represented by water and/or excessive humidity, especially in the case of the use of porous limestone, such as those available in the Repedea -Iasi area (Romania). Therefore, in order to ensure better maintenance of a lithic calcareous material of this type, it is necessary to use a hydrophobic preventive treatment. The findings of the research conducted and described in this paper represent one of the first steps on the path to standardization regarding the confirmation of the efficiency of the hydrophobization products, which have been increasingly present on the Romanian specialized market lately. Thus, this paper is addressed to all the specialists interested in maintaining the lithic surfaces exposed to various environmental factors, as it is useful for both historical and civil constructions.Although natural stone is considered a construction material that stands the test of time, the degradation and deteriorate rate of architectural surfaces has been increasing over the last decades, especially due to anthropic causes, mainly to atmospheric pollution [1-3], but also due to intrinsic factors, by using low quality indigenous lithic materials, which favor the rapid onset of the aforementioned alterations. Such a situation is often encountered in the case of numerous historical buildings in Iasi area, erected between the XVth and the XIXth centuries, as well as during the first decades of the twentieth century, the most sought after building stones being the porous limestone in the Scheia, Pietrarie and Paun -Repedea areas located south of Iasi City.For the stone constructions in the city of Iasi, most of the building materials were found in the surrounding areas of the city [4], where the geological context allowed the formation of porous sedimentary rock deposits [5,6]. Therefore, as lithic materials used in constructions, sedimentary rocks in Iasi area have relatively low strength and durability [7-10], and for this reason their use in the maintenance and/or restoration processes of historical buildings requires a series of in-depth studies and research, with reference to the choice of stone and the development of an appropriate protocol that clarifies a number of issues, such as [11]: a) spot/area in the building requiring restoration works; b) extent of current (active) damages and degradations; *