scholarly journals Assessing the weathering of granitic stones on historical urban buildings by geochemical indices

2016 ◽  
Vol 20 (3) ◽  
pp. 1 ◽  
Author(s):  
Jorge Sanjurjo-Sánchez ◽  
Carlos Alves ◽  
Juan Ramón Vidal Romani
Keyword(s):  
Chemical Weathering ◽  
Building Materials ◽  
Building Stone ◽  
Urban Environments ◽  
Granitic Rocks ◽  
Chemical Components ◽  
Original Structure ◽  
Salt Weathering ◽  
Weathering Rates ◽  
Weathering Indices

Weathering involves important processes that alter the original structure, texture and chemical components of rocks and minerals. Bulk changes produced by weathering in granitic rocks have been studied by several methods, including chemical weathering indices. They are based on the assumption that some ions are more easily leached from minerals in relation to others. Such methods have also been briefly tested on building stone but not in urban environments, where fast stone weathering rates are typically observed, mainly due to interaction of minerals with several pollutants and where other specific processes, such as salt weathering, can occur. The aim of this work is to discuss the use of weathering indices in the study of weathering rates on granitic stones applied in four historical buildings of an urban area. Results suggest that some factors can cause scatter of results in the relation indices vs. exposition age in the built environment, namely previous weathering degree in rock massifs and the quarry, different orientation of façades and different exposure to urban pollutants. Indices that consider some highly mobile cations that are present in other building materials (namely Ca that is related to leaching from mortar joints) should be avoided due to the uptake of such elements by the stone pores or used to assess this some types of weathering. Moreover, the use of some indices shows more reliable results. Evaluación de la meteorización de rocas graníticas en edificios históricos urbanos por medio de indices geoquímicos  ResumenLa meteorización implica importantes procesos que alteran la estructura, textura y componentes químicos originales de las rocas y minerales. Los cambios producidos por la meteorización en rocas graníticas han sido estudiados por varios métodos, incluyendo los índices de meteorización química. Éstos se basan en la suposición de que algunos iones son lavados de los minerales más fácilmente que otros. Tales métodos también se han probado, aunque en pocos casos, en rocas de edificios, pero no de ambientes urbanos, en donde se han observado típicamente elevadas tasas de meteorización, principalmente por la interacción de los minerales con varios compuestos contaminantes y en dónde otros procesos específicos, tales como la erosión por sales, pueden producirse. El objetivo de este trabajo es discutir el uso de índices de meteorización en el estudio de las tasas de meteorización de rocas usadas en cuatro edificios históricos de un área urbana. Los resultados sugieren que algunos factores pueden causar la dispersión de los resultados obtenidos a través de los índices en relación al tiempo de exposición en el ambiente construido, principalmente por el grado de meteorización previo de la roca en los macizos rocosos y en la cantera, la orientación de las fachadas y la diferente exposición a compuestos contaminantes. Los índices que consideran algunos cationes altamente móviles que están presentes en otros materiales de construcción (principalmente el Ca que se relaciona con la meteorización de morteros en las juntas) deben ser evitados debido a que penetran en los poros de las rocas de edificios o deben ser usados para evaluar algunos tipos de meteorización. Por otra parte, el uso de algunos índices muestra resultados más fiables.

Fingerprinting the provenance of building stones: a case study on the Louvigné and Lanhélin granitic rocks (Armorican massif, France)

2014 ◽  
Vol 185 (1) ◽  
pp. 13-31 ◽  
Author(s):  
Claudine Malfilatre ◽  
Erwan Hallot ◽  
Philippe Boulvais ◽  
Marc Poujol ◽  
Annick Chauvin ◽  
...  
Keyword(s):  
Building Stone ◽  
Granitic Rocks ◽  
Magnetic Characteristics ◽  
Building Stones ◽  
Intrinsic Variability ◽  
Geological Unit ◽  
Qualitative Variables ◽  
Identity Cards ◽  
Armorican Massif

Abstract Two examples of granitic stones from Brittany (western France) commercialized under the names of “gris-bleu de Louvigné” and “bleu de Lanhélin” were characterized in order to explore how the provenance of a building stone can be traced back with a maximum of confidence. For this purpose, petrographical, geochemical and magnetic characteristics, representing more than 70 quantitative and qualitative variables, were compiled for a total of 32 samples. We have defined two reference populations for these building stones and have extracted their discriminative characteristics. We have then compared four randomly selected samples and two foreign commercial counterparts of these stones to the reference populations. Discriminative variables differ from one case of comparison to the other, which indicates that a combination of various tools and variables will be generally required to unequivocally fingerprint the origin of a given granitic stone. Where several quarries are mining a single geological unit within a composite intrusion, the provenance of a granitic rock can be defined at the scale of the intrusion. In addition, stones coming from two different intrusions from the same batholith can be distinguished. We conclude that the provenance of any granitic building stone is identifiable, especially if the intrinsic variability of a population of samples representative of that stone has been previously circumscribed. This study underlines that the compilation of databases for building stone identity cards is an essential first step toward the creation of official labels guaranteeing stone provenances.

scholarly journals The Plaka Bridge in Epirus: An Evaluation of New Building Materials for Its Restoration

Heritage ◽  
2019 ◽  
Vol 2 (2) ◽  
pp. 1136-1159
Author(s):  
Maria Apostolopoulou ◽  
Ioannis Nikolaidis ◽  
Iakovos Grillakis ◽  
Myrto Kalofonou ◽  
Vasileios Keramidas ◽  
...  
Keyword(s):  
Cultural Heritage ◽  
Heavy Rainfall ◽  
Building Materials ◽  
Structural Integrity ◽  
Mechanical Performance ◽  
Building Stone ◽  
Historical Building ◽  
Historical Materials ◽  
Important Landmark

The sustainable preservation of monuments requires the use of performing materials which are at the same time compatible with the monument’s historical building materials to ensure structural integrity, adequate performance of the structure in earthquake stresses, and resilience of both restoration and historical materials. This is especially true for cultural heritage assets that have experienced major destruction, demanding extensive reconstruction. The Plaka Bridge in Epirus, Greece, partially collapsed after a heavy rainfall in 2015. It was a supreme example of traditional stone bridge architecture of the region and an important landmark. In the present study, a potential restoration stone from a nearby quarry was examined in terms of compatibility in relation to the dominant historical building stone of the bridge, as well as in terms of mechanical performance, through a variety of in lab techniques. In addition, criteria were set for restoration mortars, taking into account the characteristics of the historical materials, as well as the environment of the bridge. The results of the study regarding the restoration stone and mortars are presented and assessed, in order to select the most appropriate restoration materials for Plaka Bridge in its upcoming restoration, aiming to enhance the overall resilience of the structure.

scholarly journals Natural Radioactivity, Radiological Hazard and Petrographical Studies on Aswan Granites Used as Building Materials in Egypt

2021 ◽  
Vol 11 (14) ◽  
pp. 6471
Author(s):  
Nasser M. Moghazy ◽  
Amira M. El-Tohamy ◽  
Mona M. Fawzy ◽  
Hamdy A. Awad ◽  
Hesham M. H. Zakaly ◽  
...  
Keyword(s):  
Natural Radioactivity ◽  
Building Materials ◽  
Gamma Ray ◽  
Natural Radionuclides ◽  
Polarized Light ◽  
Environmental Parameters ◽  
Mineralogical Composition ◽  
Eastern Desert ◽  
Granitic Rocks ◽  
Gamma Ray Spectrometry

The present study was carried out on commercial types of Aswan granite used as building and decorative materials. Nearly 29 granitic rocks samples from 11 classes (black Aswan, red Aswan, dark Rosa, light Rosa, yellow Verdi, grey Shirka, Gandolla, Forsan, red Nefertiti, Royal, and white Halayeb) were collected from three stations near Aswan city for petrographical description and assessment of natural radioactivity. The petrographical study of granites was conducted by polarized-light microscope in order to determine their mineralogical composition and investigate their texture; the activity of the natural radionuclides 238U, Ra226, 232Th, and 40K was measured by gamma-ray spectrometry with a NaI(Tl) detector. The average values of the activities, 52.2 Bq kg−1, 57.8 Bq kg−1, 31.2 Bq kg−1, and 1055.7 Bq kg−1 of U-238, Th-232, Ra-226, and K-40, respectively, were higher than that the world average values of 35 Bq kg−1, 30 Bq kg−1 and 400 Bq kg−1 for 226Ra, 232Th, and 40K, respectively, according to the recommended levels from UNSCEAR reports. The minimum and maximum values obtained were compared with the value ranges from other locations in the Eastern Desert, highlighting the fact that that the maximum values obtained in this work are higher than those in other areas. According to the radiological hazards indices results, most samples lie in the permissible level ranges, suggesting their favorability for use as building materials. In contrast to that, some samples have some environmental parameters higher than the international levels, indicating their unsuitability as building materials.

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