scholarly journals Key parameters of volcanic tuffs used as building stone: a statistical approach

2021 ◽  
Vol 81 (1) ◽  
Author(s):  
Christopher Pötzl ◽  
Siegfried Siegesmund ◽  
Rubén López-Doncel ◽  
Reiner Dohrmann
Keyword(s):  
Regression Analysis ◽  
Statistical Approach ◽  
Wide Spectrum ◽  
High Sensitivity ◽  
Building Stone ◽  
Material Behavior ◽  
Rock Properties ◽  
Salt Crystallization ◽  
Petrophysical Properties ◽  
Building Stones

AbstractVolcanic tuffs naturally show a strong heterogeneity in their petrography and petrophysical properties. The arrangement of the components in tuffs can create a very wide spectrum of porosities and fabrics, which in turn can lead to a highly differential weathering behavior. Considerable amounts of clay minerals and zeolites are common and can contribute to a high sensitivity to expansional processes and salt crystallization. Understanding the influence of the rock properties on material behavior and durability can help to make predictions on future material behavior and evaluate the suitability of the material for construction purposes. This study presents the petrographic and petrophysical data of 15 selected tuffs and 513 tuffs from the literature used as building stones. Regression analysis show if parameters are comparable and if key parameters can be identified. Key parameters can potentially be used for the estimation of the material behavior, without the use of expensive analytics or weathering simulations.

scholarly journals The building stone of the Roman city of Lixus (NW Morocco): provenance, petrography and petrophysical characterization

2020 ◽  
Vol 18 ◽  
pp. 1-16
Author(s):  
T. Ajanaf ◽  
D. Gómez Grás ◽  
A. Navarro ◽  
J.D. Martín-Martín ◽  
J.R. Rosell ◽  
...  
Keyword(s):  
Building Materials ◽  
Visual Analysis ◽  
Building Stone ◽  
Salt Crystallization ◽  
Favourable Effect ◽  
High Porosity ◽  
Porous System ◽  
Building Stones ◽  
Low Degree ◽  
Porosity And Permeability

The characterization of building materials is a key tool to assess deterioration processes and improve potential restoration works of archaeological sites. The aim of this paper is to identify and characterize the most important building stones used in the construction of the Roman city of Lixus (Larache, Morocco) by means of petrographic and petrophysical techniques. Based on the visual analysis of the monuments, three major building stones (i.e. lithotypes) have been identified: i) Oligocene sandstones, ii) Quaternary sandstones and iii) Quaternary conglomerates. Based on the analysis of the regional geology and exploitation marks, these three lithotypes have been recognised to crop out in the surroundings of Lixus and the quarries, presumably Roman in origin, recognized. The Oligocene sandstone is the primary building stone in Lixus as it forms and crops out extensively in the Tchemmis hill, at the top of which the city is settled. The Quaternary sandstones and conglomerates, which represent nearshore deposits and eolianites, crop out along the Atlantic coast where they form part of the cliffs next to Larache. Petrographic results indicate that lithotypes differ notably in grain size, ratio of detrital to allochemical components, and the configuration of their porous system. Mechanical analysis shows that the Oligocene sandstones are more resistant to compression than the Quaternary sandstones and conglomerates, the latter exhibiting relatively low compressive strength. The Oligocene sandstones, which display scarce porosity and permeability, show a hydric behaviour characterized by a very low degree of absorption and desorption water, likely resulting from a poor connectivity of the pore network. Contrary to the latter lithotype, the Quaternary sandstones, which exhibit very high porosity and permeability, display a hydric behaviour characterized by high degree of both absorption and desorption of water. This is attributed to the low degree of cementation compared to porosity of this lithotype and the excellent connectivity of the porous network. Finally, Oligocene and Quaternary sandstones do not show a significant weight loss after the accelerated artificial aging test, indicating that both are slightly affected by salt crystallization and presumably ice formation. Results indicate that the relatively fine state of conservation of the building rocks of Lixus is linked to intrinsic factors such as mineralogy and petrophysical characteristics together with the favourable effect of the climatic condition of the study area.

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.

Understanding the decay of stone-built cultural heritage

2008 ◽  
Vol 32 (4) ◽  
pp. 439-461 ◽  
Author(s):  
B.J. Smith ◽  
M. Gomez-Heras ◽  
S. McCabe
Keyword(s):  
Climate Change ◽  
Natural Environment ◽  
Management Strategies ◽  
Building Stone ◽  
Stone Decay ◽  
Building Stones ◽  
The Public ◽  
The Past ◽  
Built Heritage ◽  
Common Misconceptions

The problem of the decay and conservation of stone-built heritage is a complex one, requiring input across many disciplines to identify appropriate remedial steps and management strategies. Over the past few decades, earth scientists have brought a unique perspective to this challenging area, drawing on traditions and knowledge obtained from research into landscape development and the natural environment. This paper reviews the crucial themes that have arisen particularly, although not exclusively, from the work of physical geographers — themes that have sought to correct common misconceptions held by the public, as well as those directly engaged in construction and conservation, regarding the nature, causes and controls of building stone decay. It also looks to the future, suggesting how the behaviour of building stones (and hence the work of stone decay scientists) might alter in response to the looming challenge of climate change.

Machine Learning for Multiple Petrophysical Properties Regression Based on Core Images and Well Logs in a Heterogenous Reservoir

2021 ◽  
Author(s):  
Tao Lin ◽  
Mokhles Mezghani ◽  
Chicheng Xu ◽  
Weichang Li
Keyword(s):  
Machine Learning ◽  
Model Building ◽  
Image Features ◽  
Well Logs ◽  
Model Complexity ◽  
Rock Properties ◽  
Core Analysis ◽  
Petrophysical Properties ◽  
Blind Test ◽  
Porosity And Permeability

Abstract Reservoir characterization requires accurate prediction of multiple petrophysical properties such as bulk density (or acoustic impedance), porosity, and permeability. However, it remains a big challenge in heterogeneous reservoirs due to significant diagenetic impacts including dissolution, dolomitization, cementation, and fracturing. Most well logs lack the resolution to obtain rock properties in detail in a heterogenous formation. Therefore, it is pertinent to integrate core images into the prediction workflow. This study presents a new approach to solve the problem of obtaining the high-resolution multiple petrophysical properties, by combining machine learning (ML) algorithms and computer vision (CV) techniques. The methodology can be used to automate the process of core data analysis with a minimum number of plugs, thus reducing human effort and cost and improving accuracy. The workflow consists of conditioning and extracting features from core images, correlating well logs and core analysis with those features to build ML models, and applying the models on new cores for petrophysical properties predictions. The core images are preprocessed and analyzed using color models and texture recognition, to extract image characteristics and core textures. The image features are then aggregated into a profile in depth, resampled and aligned with well logs and core analysis. The ML regression models, including classification and regression trees (CART) and deep neural network (DNN), are trained and validated from the filtered training samples of relevant features and target petrophysical properties. The models are then tested on a blind test dataset to evaluate the prediction performance, to predict target petrophysical properties of grain density, porosity and permeability. The profile of histograms of each target property are computed to analyze the data distribution. The feature vectors are extracted from CV analysis of core images and gamma ray logs. The importance of each feature is generated by CART model to individual target, which may be used to reduce model complexity of future model building. The model performances are evaluated and compared on each target. We achieved reasonably good correlation and accuracy on the models, for example, porosity R2=49.7% and RMSE=2.4 p.u., and logarithmic permeability R2=57.8% and RMSE=0.53. The field case demonstrates that inclusion of core image attributes can improve petrophysical regression in heterogenous reservoirs. It can be extended to a multi-well setting to generate vertical distribution of petrophysical properties which can be integrated into reservoir modeling and characterization. Machine leaning algorithms can help automate the workflow and be flexible to be adjusted to take various inputs for prediction.

scholarly journals Oxygen and sulfur mass-independent isotopic signatures in black crusts: the complementary negative Δ<sup>33</sup>S reservoir of sulfate aerosols?

2020 ◽  
Vol 20 (7) ◽  
pp. 4255-4273 ◽  
Author(s):  
Isabelle Genot ◽  
David Au Yang ◽  
Erwan Martin ◽  
Pierre Cartigny ◽  
Erwann Legendre ◽  
...  
Keyword(s):  
Building Stone ◽  
Black Crust ◽  
Sulfur Source ◽  
Building Stones ◽  
Sulfate Aerosols ◽  
Magnetic Isotope Effect ◽  
So2 Oxidation ◽  
Isotopic Signatures ◽  
Black Crusts ◽  
Atmospheric Sulfates

Abstract. To better understand the formation and the oxidation pathways leading to gypsum-forming “black crusts” and investigate their bearing on the whole atmospheric SO2 cycle, we measured the oxygen (δ17O, δ18O, and Δ17O) and sulfur (δ33S, δ34S, δ36S, Δ33S, and Δ36S) isotopic compositions of black crust sulfates sampled on carbonate building stones along a NW–SE cross section in the Parisian basin. The δ18O and δ34S values, ranging between 7.5 ‰ and 16.7±0.5 ‰ (n=27, 2σ) and between −2.66 ‰ and 13.99±0.20 ‰, respectively, show anthropogenic SO2 as the main sulfur source (from ∼2 % to 81 %, average ∼30 %) with host-rock sulfates making the complement. This is supported by Δ17O values (up to 2.6 ‰, on average ∼0.86 ‰), requiring > 60 % of atmospheric sulfates in black crusts. Negative Δ33S and Δ36S values between −0.34 ‰ and 0.00±0.01 ‰ and between −0.76 ‰ and -0.22±0.20 ‰, respectively, were measured in black crust sulfates, which is typical of a magnetic isotope effect that would occur during the SO2 oxidation on the building stone, leading to 33S depletion in black crust sulfates and subsequent 33S enrichment in residual SO2. Except for a few samples, sulfate aerosols mostly have Δ33S values > 0 ‰, and no processes can yet explain this enrichment, resulting in an inconsistent S budget: black crust sulfates could well represent the complementary negative Δ33S reservoir of the sulfate aerosols, thus solving the atmospheric SO2 budget.

scholarly journals The problem of mechanical compatibility of natural building stones in the restoration of monuments. Part II: Specimens with modified boundaries

2011 ◽  
Vol 20 (1-3) ◽  
pp. 55-65
Author(s):  
Nikolaos L. Ninis ◽  
Stavros K. Kourkoulis
Keyword(s):  
Peak Stress ◽  
Building Stone ◽  
Building Stones ◽  
Deformation Control ◽  
Numerical Studies ◽  
Natural Building Stones ◽  
Natural Building ◽  
Indeterminate Structures ◽  
Ancient Monuments

AbstractIt was pointed out in Part I of this short two-paper series, that the mechanical incompatibility between the authentic building stone of ancient monuments and the stones used as substitute ones during restoration projects, may be the reason of violation of basic restoration principles concerning the protection of the ancient material. In this context certain geometrical configurations of the boundaries of the specimens are examined in this Part II as a possible means of modifying the mechanical behaviour of the substitute stones, in order to make them as compatible as possible with the authentic material. Modifications of both the contact surfaces (in order to change the friction conditions) of the specimens as well as of the free ones (in order to quantify the influence of transforming the smooth cylindrical surface to a fluted one) are examined experimentally. This approach is based on existing observations and numerical studies indicating that the behaviour of a stone specimen in the post-peak region is affected by the geometrical configuration of its boundaries. Taking advantage of the experimental results an alternative compatibility criterion is introduced for situations where the “required” quality of the building stone is its ability to withstand deformation without failing structurally, a characteristic pertinent to statically indeterminate structures, whose design is based on deformation control. This criterion combines both peak stress and maximum failure strain providing a better insight into the problem of mechanical incompatibility of natural building stones.

Damaging effect of salt crystallization on highly porous limestone from Hungary

2020 ◽  
Author(s):  
Nikoletta Rozgonyi-Boissinot ◽  
Mohammad Ali Khodabandeh
Keyword(s):  
Tensile Strength ◽  
Sea Water ◽  
Water Saturation ◽  
Salt Content ◽  
Physical And Mechanical Properties ◽  
Optical Microscope ◽  
Sodium Sulphate ◽  
Capital City ◽  
Salt Crystallization ◽  
Petrophysical Properties

&lt;p&gt;One of the most important weathering processes on stone-built monuments is the crystallization of salts. Since the transport material of these substances is water, the porous rock types are particularly affected. In Hungary many monuments and historic buildings have been constructed from oolithic Miocene limestone. So in this study, the effect of salt crystallization on the physical and mechanical properties of high porous limestone has been investigated. Samples were obtained from S&amp;#243;sk&amp;#250;t (near to Budapest, the capital city of Hungary).&lt;/p&gt;&lt;p&gt;At first the petrophysical properties of the stone were determined. The porosity of the investigated stone type was 26-34 V/V%, the uniaxial compressive strength (4-5 MPa) and the Brazilian tensile strength (0,4-0,5 MPa) were very low. A special proper of this rock type is the large-pore system (2-3mm) between the ooid fragments.&lt;/p&gt;&lt;p&gt;Sodium chloride (NaCl) and sodium sulphate (Na&lt;sub&gt;2&lt;/sub&gt;SO&lt;sub&gt;4&lt;/sub&gt;) were used to investigate the effect of salt crystallization. Cylindrical rock samples were exposed to salt solutions of 14 m/m% Na&lt;sub&gt;2&lt;/sub&gt;SO&lt;sub&gt;4&lt;/sub&gt; (MSZ EN 12370) and 5% NaCl solution (sea water salt content). After 15 salted water saturation- drying cycles the changes of mineralogical and petrophysical properties and indirect tensile strength of the samples were investigated. The damages on the pore walls were determined with scanning electron microscope (SEM) and the building of scaling layers on the stone surfaces were investigated with optical microscope.&lt;/p&gt;

Petrophysical properties of selected Quaternary building stones in western Austria

2010 ◽  
Vol 333 (1) ◽  
pp. 143-152 ◽  
Author(s):  
Michael Unterwurzacher ◽  
Ulrich Obojes ◽  
Roland Hofer ◽  
Peter W. Mirwald
Keyword(s):  
Petrophysical Properties ◽  
Building Stones

scholarly journals Mechanical Rock Properties Estimation for Carbonate Reservoir Using Laboratory Measurement: A Case Study from Jeribe, Khasib and Mishrif Formations in Fauqi Oil Field

2021 ◽  
Vol 54 (1E) ◽  
pp. 88-102
Author(s):  
Qahtan Abdul Aziz ◽  
Hassan Abdul Hussein
Keyword(s):  
Mechanical Properties ◽  
Bulk Density ◽  
Depositional Environments ◽  
Carbonate Reservoir ◽  
Oil Field ◽  
Well Logs ◽  
Rock Properties ◽  
Petrophysical Properties ◽  
Empirical Correlations ◽  
Rock Mechanical Properties

Estimation of mechanical and physical rock properties is an essential issue in applications related to reservoir geomechanics. Carbonate rocks have complex depositional environments and digenetic processes which alter the rock mechanical properties to varying degrees even at a small distance. This study has been conducted on seventeen core plug samples that have been taken from different formations of carbonate reservoirs in the Fauqi oil field (Jeribe, Khasib, and Mishrif formations). While the rock mechanical and petrophysical properties have been measured in the laboratory including the unconfined compressive strength, Young's modulus, bulk density, porosity, compressional and shear -waves, well logs have been used to do a comparison between the lab results and well logs measurements. The results of this study revealed that petrophysical properties are consistent indexes to determine the rock mechanical properties with high performance capacity. Different empirical correlations have been developed in this study to determine the rock mechanical properties using the multiple regression analysis. These correlations are UCS-porosity, UCS-bulk density, UCS-Vs, UCs-Vp Es-Vs, Es-Vp, and Vs-Vp. (*). For example, the UCS-Vs correlation gives a good determination coefficient (R2= 0.77) for limestone and (R2=0.94) for dolomite. A comparison of the developed correlations with literature was also checked. This study presents a set of empirical correlations that can be used to determine and calibrate the rock mechanical properties when core samples are missing or incomplete.

Sign in / Sign up

Export Citation Format

Share Document