“…The values of bulk density of the present study were looked similar to the findings obtained by (Alzahrani el al. 2022) 7 in the range of 2582 to 2644 kg/m 3 , (Török and Török 2015) 64 in the range of (2.58–2.68 g/cm 3 ), (Rashwan et al 2023) 32 in the range of 2590 to 2748 kg/m 3 , (Dionísio et al 2021) 66 in the range of 2.48–2.63 g/cm 3 and (Freire-Lista et al 2022) 65 2461–2649 kg/m 3 .…”
The present study aims to explain the geochemical and mineralogical details of the granitic rock types in Gabal EL-Faliq area, South Eastern Desert of Egypt, in relation to geotechnical engineering and their suitability as dimension stones. The objective of the current research was achieved through two steps; the first step involved geological studies such as the petrographic, geochemical, and mineralogical investigations. The second and applicable step involved the geotechnical assessment of the studied rocks by measuring their engineering properties such as physical, mechanical, and thermal expansion properties. The petrographic investigation revealed that the studied granitic rocks are divided into two main classes: (1) gneissose granites (Biotite–Perthite) of medium to fine-grained size and (2) alkali-feldspar granites of coarse to medium-grained size. Mineralogically, the studied rocks are composed mainly of albite, orthoclase and quartz in varying proportions, along with some accessory minerals such as apatite and rutile in addition to some minor quantities of iron-group minerals such as hematite and ilmenite. The engineering properties showed that the maximum water absorption and apparent porosity values are 0.34% and 0.77%, respectively, while the minimum bulk density is 2604.03 kg/m3. The compressive strength ranges from 999.68 to 2469.10 kg/cm2, while the abrasion resistance varies from 29.67 to 54.64 Ha. The increase in albite content led to an increase in water absorption while a decrease in bulk density and compressive strength. The increase in the grain size led to an increase in apparent porosity and a decrease in mechanical properties. A Great variation in the expansion coefficient as well as the length change, occurs under changes in temperature, mineral composition, and physical properties. The increase in heating temperatures caused an insignificant increase in linear thermal expansion with a maximum value of 0.0385% at 100 °C. These results indicated the suitability of the studied granites as dimension stones for use in indoor and outdoor decorative purposes (cladding/paving) under variable temperature conditions.
“…The values of bulk density of the present study were looked similar to the findings obtained by (Alzahrani el al. 2022) 7 in the range of 2582 to 2644 kg/m 3 , (Török and Török 2015) 64 in the range of (2.58–2.68 g/cm 3 ), (Rashwan et al 2023) 32 in the range of 2590 to 2748 kg/m 3 , (Dionísio et al 2021) 66 in the range of 2.48–2.63 g/cm 3 and (Freire-Lista et al 2022) 65 2461–2649 kg/m 3 .…”
The present study aims to explain the geochemical and mineralogical details of the granitic rock types in Gabal EL-Faliq area, South Eastern Desert of Egypt, in relation to geotechnical engineering and their suitability as dimension stones. The objective of the current research was achieved through two steps; the first step involved geological studies such as the petrographic, geochemical, and mineralogical investigations. The second and applicable step involved the geotechnical assessment of the studied rocks by measuring their engineering properties such as physical, mechanical, and thermal expansion properties. The petrographic investigation revealed that the studied granitic rocks are divided into two main classes: (1) gneissose granites (Biotite–Perthite) of medium to fine-grained size and (2) alkali-feldspar granites of coarse to medium-grained size. Mineralogically, the studied rocks are composed mainly of albite, orthoclase and quartz in varying proportions, along with some accessory minerals such as apatite and rutile in addition to some minor quantities of iron-group minerals such as hematite and ilmenite. The engineering properties showed that the maximum water absorption and apparent porosity values are 0.34% and 0.77%, respectively, while the minimum bulk density is 2604.03 kg/m3. The compressive strength ranges from 999.68 to 2469.10 kg/cm2, while the abrasion resistance varies from 29.67 to 54.64 Ha. The increase in albite content led to an increase in water absorption while a decrease in bulk density and compressive strength. The increase in the grain size led to an increase in apparent porosity and a decrease in mechanical properties. A Great variation in the expansion coefficient as well as the length change, occurs under changes in temperature, mineral composition, and physical properties. The increase in heating temperatures caused an insignificant increase in linear thermal expansion with a maximum value of 0.0385% at 100 °C. These results indicated the suitability of the studied granites as dimension stones for use in indoor and outdoor decorative purposes (cladding/paving) under variable temperature conditions.
“…Vale das Gatas granite outcrop is located to the east of the church. It is a two-mica granite porphyroid of coarse-medium crystal size, characterised by the presence of elongated and oriented feldspars (Freire-Lista et al 2022a). Lamares granite is Fig.…”
The Romanesque church of Nossa Senhora de Guadalupe of Mouçós e Lamares is located in Vila Real (North of Portugal). The exterior part of its nave is preserved almost unaltered. Most of the granite ashlars and corbels that make up this church have a mason’s mark in the centre of their faces. The building granites (Sanguinhedo and Vale das Gatas) have been identified and characterised petrographically and petrophysically. The mason’s marks have been as well identified; all the ashlars with visible mason’s marks have been mapped, and a glyptographic study has been carried out. In addition, the surface roughness of ashlars was measured. All these analyses have made it possible to locate the main historical quarry, to calculate the number of stonemasons who worked in the construction of the church, and to determine its construction phases. There are eight main types of mason’s marks on the nave façades. The quarrymen extracted the main building granite (Sanguinhedo granite) from the same quarry, or from nearby quarries. Although the most experienced stonemason has been identified, most stonemasons worked as a team during all construction phases of the church. Techniques such as petrography, ultrasonic P wave velocity, colourimetry, roughness and the determination of hydric properties will guarantee the quality and durability of the heritage stone for restorations. In addition, the glyptographic analysis revealed important historical and ethnographic findings that will be very useful for the appreciation of the monument. Therefore, the knowledge of built heritage, such as mason’s marks contribute to the conservation of historical quarries and traditions, as well as help understand the close cultural association societies have had with heritage stones. In this way, the scientific corpus of historical-cultural heritage can face for the development of tourism in Galicia-North Portugal Euroregion in a long-lasting sustainable way.
“…However, in the current classification system, it is considered that a colour heterogeneity is caused by the formation of secondary minerals (e.g. Pires et al 2014 ; Dias et al 2020 ; Freire-Lista et al 2022a , b ; Vazquez et al 2022 ). As this type of alteration should be described (EN 12407: 2019 ), we recommend linking the nature of mineral inclusions (e.g.…”
Section: Classification System For Natural Stone Heterogeneities and ...mentioning
confidence: 99%
“…5 f), which correspond to weathered and oxidised varieties (Sousa and Lourenço 2015 ; Freire-Lista et al 2022a ). Moreover, this type of granite is more affected by cracking (Freire-Lista et al 2022a ), which increases its colour variation (Sousa and Gonçalves 2012 ), and decreases its quality and durability (Sousa 2013 ). Fig.…”
Section: Classification System For Natural Stone Heterogeneities and ...mentioning
Portugal has a relevant role in natural stone production and trading. The national sector has been trying to follow the requirements of the Fourth Industrial Era, where automation of stone processing operations is necessary to increase productivity, balance the decreasing workforce and reduce stone waste. The identification of defects or defective areas in stone slabs is a time-consuming operation: not only highly subjective, dependent on the operator experience, but also disconnected from geological knowledge. Despite recent advances in automatic pattern recognition of stone products’ surface, stone selection lacks a geological foundation. Thus, this paper aims to discuss the terminology of stone defects and singularities applied to stone materials and in the stone selection process. A classification system of natural stone heterogeneities and discontinuities is developed to be used by stone operators and to be applied in future image analysis research. The system, based on three main classifiers (colour heterogeneities, textural and structural heterogeneities, and discontinuities) is validated by seventeen different Portuguese stone varieties and appears to be a suitable qualitative descriptor of stone slabs and tiles, showing flexibility in its use.
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