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1.
One of the most important quality and design parameters of natural rock materials is uniaxial compressive strength (UCS). UCS value of a building stone determines its application area such as cladding, roofing, facing, and coverings. In rock mechanics and engineering practice determination of UCS values of rock materials is suggested on core specimens whereas in construction and building stone sector, cubic specimens are suggested. In this experimental study, the effect of cubic specimen size on UCS values of some carbonate rocks which are being used as dimension stones are investigated. A total of 299 cubic specimens at five different edge sizes (3, 5, 7, 9, and 11 cm) from limestone, marble, and travertine are prepared. Chemical, petrographic analyses and physical properties of specimens are determined and after that UCS tests are carried out. It is observed that as the specimen sizes increase from 3 to 11 cm, average UCS values decrease about 7% for the tested carbonate rocks. In the light of this finding, results of UCS tests could be interpreted considering cubic specimen sizes for the same rock types in various fields.  相似文献   

2.
Carbonate rocks have been extensively used as building stones because of their availability, workability, and attractiveness. Unfortunately, however, some stones suffer from chemical attack or freeze-thaw activity. The environmental affects, especially those due to pollution of the atmosphere, are discussed in terms of weathering processes, salt crystallization, and acid deposition. A review of some recent research in relation to deterioration of stone in urban environments is given and carbonate rocks are classified in relation to position within a building, geographical location, and degree of pollution. Some comments on stone preservation are provided, especially in terms of the properties a preservative should possess.  相似文献   

3.
The results of the geological characterization of an old stone building in southern Italy, are presented here. The Mondragone marble is a slightly metamorphosed carbonate rock, which was widely employed as monumental stone in the 18th century Royal Palaces of Naples and Caserta. In this paper, for the first time, this rock has been investigated with a thorough laboratory testing program, aimed at defining its mineralogical, physical and mechanical parameters. The two most important varieties of Mondragone marble were separately tested: the yellow and grey marbles (hereafter, YM and GM, respectively). The results obtained from physical tests (open porosity, dry density, specific gravity, water absorption coefficients, ultrasonic velocity) did not show marked differences between the two materials; in contrast, the mechanical strength tests (uniaxial compressive strength, point load strength, flexural strength) showed better behaviour of YM than for GM. After a tentative comparison with other well known carbonate rocks from Italy, some considerations on the response of Mondragone marble to local weathering were conducted. In particular, the weathering typologies were related to the particular texture of the brecciated marble and the different strength resistances displayed by the various constituents of the rock.  相似文献   

4.
This study aims to understand the effect of salt and frost crystallisation on the petrophysical and durability properties of representative types of travertine and carbonate tufas. Results demonstrate that the studied travertines and tufas exhibit a very high durability against salt and ice crystallisation cycles, compared to carbonates rocks with similar porosity values. The variation of the loss of mass, effective porosity, capillary absorption coefficient, ultrasonic wave velocity and attenuation, and compressive strength was scarce during weathering tests. The evolution of petrophysical properties was slightly more intense after 30 cycles of salt crystallisation than 100 cycles of freeze–thaw. Petrophysical and durability properties of the travertines and carbonate tufas depend on porosity fraction and on the manner in which the vuggy porosity is connected. In the travertine facies, vuggy macropores show little connection and can be considered as separate-vug porosity. Their addition to interparticle porosity increases effective porosity and reduces their mechanical strength but does not significantly increase capillary transport and the effectiveness of salt and ice action over the stone. On the contrary, in the carbonate tufas, vugs act as touching-vug pores, as capillary imbibition coefficients reveal. However, scanning electron microscopy displays that they underwent microcracking processes related mainly to both thermal stresses and/or ice and salt pressures. These microcracks present little connection, and they do not enhance noticeably the water flow or decrease the mechanical properties. These results are finally discussed in terms of a nonlinear decay pattern, which with long periods of apparent stability might be followed by rapid and catastrophic decay.  相似文献   

5.
Owing to its long building history, different types of building stones comprised the construction of the Cologne Cathedral. Severe damage is observed on the different stones, e.g., sandstones, carbonate, and volcanic rocks, especially when the different stone materials neighbor the medieval “Drachenfels trachyte” from the “Siebengebirge”. The question arises, “Is the insufficient compatibility of the implemented building materials causatively related to the strong decay of the Drachenfels trachyte?” The present investigations focus on the petrography and mineralogical composition of eight different stones from the Cologne Cathedral. Petrophysical data, i.e., phase content, moisture and thermal characteristics as well as strength properties are determined and discussed in correlation to each other, showing that not only in terms of lithology great differences exist, but also the petrophysical properties strongly diverge. The ascertained parameters are discussed in view of the deterioration behavior and decay mechanisms of the different stones. To evaluate the compatibility of original, replacement and modern building materials, the properties of the investigated stones are compared to those of Drachenfels trachyte by means of constraints given in the literature. Besides optical properties, petrophysical criteria are also defined as well as strength values. It could be shown that primarily moisture properties, i.e., capillary and sorptive water uptake, water saturation, drying processes and moisture dilatation can be addressed to the deterioration processes.  相似文献   

6.
The aim of the present article is to identify the influence of the pore morphology on the physical behaviour and durability of natural stone. Fifteen sedimentary rocks commonly used in the cultural and architectural heritage of Aragon (Spain) were characterized. The petrography, porous structure, fluid transport properties and durability of these rocks were analysed. They were classified into two different groups according to the results of the different tests. For each of these groups the physical behaviour was established. A principal components analysis was used in order to examine the correlation between pore structure, hydric properties and durability. The results show that the percentage of pore throats <0.1 μm control the fluid transport properties, have an important influence on stone durability, and can be used to predict resistance to salt decay while the average pore size does not. Stones with a high percentage of pore throats <0.1 μm are less susceptible to salt decay than stones with higher pore size if their pore network is characterized by high tortuosity and low connectivity.  相似文献   

7.
Three cities in the center of Mexico, declared as cultural heritage, were erected mainly of volcanic tuffs as main construction element. Many of the historic buildings of these cities show significant damage and deterioration. One of the causes of these damages can be attributed to a phenomenon poorly studied in volcanic tuffs, the thermal expansion. To understand the response of volcanic tuffs to thermal expansion, as well as to know their thermal expansion coefficient, thermal expansion test was performed on 12 representative tuffs of these localities. In the same way and to know which of their petrographic, petrophysical, mineralogical, and geochemical properties influence this phenomenon, several laboratory studies were carried out to determine which of these plays an important role in the expansion. The results of our tests showed that volcanic tuffs rocks have very varied thermal expansion values, ranging from 0.7 mm/m at their maximum expansion to even contraction in the order of ??0.5 mm/m. Equally varied were the thermal expansion coefficient values ranging from 10.1 to ??7.2 10?6/K. The most dominant behavior type is the “anisotropic no residual strain behavior”. In general, the behavior of the tuffs in practically all the tests carried out showed a very important heterogeneity in the rocks; however, in spite of the non-homogeneous behavior of the tuffs, three main factors could be identified that play an important role in the thermal expansion of the studied rocks, the chemical composition, e.g., acid volcanic tuff rocks (rhyolitic composition) had greater expansions, while the more basic rocks (basaltic composition) expanded less, the textural and fabrics homogeneity, e.g., the most homogeneous rocks texturally have higher expansion values and the degree of crystallinity, and, e.g., the tuff rocks with the largest amount of glass showed smaller thermal expansions than the tuffs composed of microcrystals.  相似文献   

8.
Investigation of the weathering and weatherability of three types of igneous rocks (granite, nepheline syenite and lamprophyric-minette dyke) was carried out by means of laboratory tests.For this purpose an experimental device was developed to obtain hot conditions alternating with room temperature and also with wet conditions, by immersion in two types of liquids (distilled water and a solution simulating “seawater”).Beyond qualitative effects emphasized in the text and in a photographic documentary, some quantitative determinations were made (weight loss and chemical decay of main cations of rock-minerals), which enable the authors to present an attempt at an alterability index for classification of the rocks. The research-program outlined on quantitative determinations is suitable for application in problems of engineering geology such as in determining suitability of rocks for use as breakwater stone or riprap for dams or in the stone deterioration measurements of the deterioration of stone used for buildings and ornamental facing stones.  相似文献   

9.
蓟县地区雾迷山组风暴硅质岩沉积序列   总被引：2，自引：0，他引：2  
从岩石学和沉积学方面对蓟县雾迷山组硅质岩沉积序列的研究表明,蓟县雾迷山组硅质岩沉积为典型的风暴沉积.蓟县雾迷山组广泛发育风暴沉积,在硅质条带状白云岩中发育的硅质砾屑具奇特的菊花状构造,这种构造形成于成岩作用后期,在岩石尚未完全固结成坚硬的岩石时期,遭遇风暴破坏,将原有的水平层理打碎,继而被风暴流搅起,风暴流的涡动使得岩石碎片或直立,或呈发散状,后经成岩作用保留了这种构造形态,与上下岩层形成典型的风暴沉积序列.通过野外与镜下观察并结合有机地球化学分析得出,蓟县地区雾迷山组硅质岩来源于海底热水活动.风暴硅质岩有两种沉积环境,对于异地搬运再沉积的风暴硅质岩,其沉积环境为潮上坪低能环境,即开阔台地中的泛溢沉积;而对于原地型的风暴硅质岩,其沉积环境应该是潮间带,因此推测其沉积环境为碳酸盐岩台地前缘斜坡.  相似文献   

10.
 I˙stanbul, the capital of the east Roman, Byzantine and Ottoman Empires embraces two continents, one arm reaching out to Asia, the other to Europe. It is therefore, a rich city in terms of monuments and historical cites. Shell limestones of Upper Miocene age are used as building stone in the majority of the monuments in I˙stanbul because of their attractiveness, availability and workability. The durability characteristics of the limestones are examined, and those factors that are responsible for atmospheric weathering are discussed, in a humid and marine environment with important problems of urban pollution, specifically due to traffic. In the present study weathering of the building stones were first examined in situ by macroscopic observations. The weathering that developed as a result of environmental effects since this limestone was first used in historical monuments has been affected 0.1–1.5 cm deep from the surface. The weathered facing stone of Şehzade Mehmed Mosque in I˙stanbul is undergoing a program of progressive replacement. During this study, samples were taken from this monument where the shell limestone was used. The stone surface was principally examined by means of Scanning Electron Microscopy (SEM). Petrographical and mineralogical analyses were made by using optical microscopy and X-ray diffraction method. The physico-chemical properties of these rocks control their weathering behaviour and reactivity. Major and trace element analyses and the effect of deterioration on the physical properties of the limestones (unit weight, porosity and water absorption) have also been investigated. Studies on the samples implies that weathering on the stone surface caused important variations on the physical characteristics of the rock. Received: 11 February 1998 · Accepted: 18 August 1998  相似文献   

11.
This work consists in estimating the role of climatic conditions in the degradation of two French limestones, tuffeau and Richemont stone, used in the construction and the restoration of the Castle of Chambord, the largest castle in the Loire Valley, France. Meteorological data, air temperature, air relative humidity and rainfall were statistically analysed in combination with stone data from thermal–humidity sensors inserted into the walls. The climatic conditions of the surrounding area were described to assess their role in enhancing the degradation of the stones through three weathering processes: thermal stress, condensation and freezing–thawing. The damage risks due to the weathering processes were taken into account not only through the bulk effects on the stone surfaces, but also their effects were extended to investigate the damage that occurs within the porous structure of the stone. Field observations showed that the main patterns of degradation affecting the stones of the castle are biological colonization and stone detachment in the form of stone spalling and exfoliation. The results of the analysis show that there is no risk of damage to the stones due to thermal stress. Moreover, the two stones experience similar overall trends against freezing–thawing processes. Finally, this study clearly highlights the important role of condensation in the degradation of the stones of the castle.  相似文献   

12.
Stone substitution is a conventional operation during heritage buildings’ restoration, but becomes problematic for architects and restorers when the quarry is mined out. The compatibility of the substitution stones with the original ones has been for long mainly based on the aesthetical aspect, this resulting too often in a patchwork of original and substitution stones with different patina after several years because of differences of properties. In this study, the objective is to show how substitution stones can be selected by combining aesthetic criteria and stones properties that are relevant for analyzing their compatibility. A couple of French limestones with their potential substitution stones were selected for the study. Our results showed that potential substitution stones selected on their aesthetic criteria require to be rejected because of their differences of physical properties. On the other hand, our results showed also the possibility to select substitution stones with satisfactory aesthetic aspect and properties that enable to expect a satisfactory compatibility with the original stone.  相似文献   

13.
Over 500 previously unidentified, symmetric pointed stones of similar size, shape, color, and texture have been found on the barrier beach of Mantoloking, New Jersey, since 1940. Petrographic, stereo, and scanning electron microscopy analysis reveals that the stones are made of either a biomicritic packstone composed of 50% siliceous microfossil remains ( including sponge spicules and radiolaria) embedded in a micrite matrix or a limestone with abundant angular quartz grains (50–150 μm wide) surrounded by a calcite matrix. The distinctive shape of the Mantoloking stones is most similar to whetstones used for sharpening scythes. We conducted a worldwide search and discovered one producer of carbonate whetstones: a company in the town of Pradalunga in Northern Italy. Microscope analysis reveals that the Pradalunga source rocks are exact matches for the spicule‐rich limestone and angular quartz‐rich limestone found in the Mantoloking collection. The whetstones are most likely lost cargo from a wreck offshore of Mantoloking, but the exact source may never be known. © 2006 Wiley Periodicals, Inc.  相似文献   

14.
The stone traditionally used to build cities contributes to their personality and attests to the geological substrate on which they stand. While stone decay in the built heritage can be attributed to a number of causes, anthropic activity has a particularly significant impact. The geomonumental routes project is one of the initiatives proposed in recent years for urban routes that convey geological fundamentals by observing the rocks present in heritage structures. Its innovative approach addresses traditional stone properties, original quarrying sites and mechanisms of decay. Madrid’s Royal Palace is a fine example of the use of traditional building stone in the centre of the Iberian Peninsula. In the geomonumental route proposed, the building doubles as an in situ laboratory that affords an overview of the main petrological properties of the two traditional stones most commonly used in the city’s built heritage, the forms of decay they are subject and the factors underlying such alterations. This route constitutes a tool for showing the main petrological features and decay forms in traditional building stones found in urban heritage façades, with a special focus on anthropic impact, primarily air pollution and the use of conservation treatments that time has proven to be unsuitable.  相似文献   

15.
The composition, structure, and properties of different genetic types of serpentinites developed after ultrabasic rocks are studied. The rocks were sampled from massifs located along the Main Uralian Fault, in a Paleozoic subduction zone. We consider specific features of serpentinites developed after chromite-bearing ultrabasic rocks, in metamorphic zones of carbonate rocks, and within the zone of weathering of ultrabasic rocks. A comparative study of the microstructure and chemical and phase compositions of serpentinites is carried out by IR spectroscopy, scanning electron microscopy, and thermal, X-ray diffraction, and microprobe analyses. The petrophysical properties and acoustic emission of the rocks are examined. Several genetic and structural groups of serpentinites developed after different protoliths (mantle and crustal) in different geologic conditions are recognized.© 2014, V.S. Sobolev IGM, Siberian Branch of the RAS. Published by Elsevier B.V. All rights reserved.  相似文献   

16.
Natural building stones are commonly used for a broad variety of purposes in the construction of many different types of buildings. Knowledge of the permeability of natural building stones, which are widely used in interiors, exteriors, flooring, veneering, landscaping, and walkway laying, is important for correctly determining their lifetime as well as their areas of use. The current study proposes a new test method to determine the air permeability of natural building stones, based on a previously developed method used to assess the permeability values of concrete samples. In this context, the air permeability index values of 96 natural building stone samples, belonging to 16 different types of natural stones classified into five groups, were determined using a new air permeability testing apparatus. The obtained permeability values were compared with the water absorption, open porosity, and apparent density properties of the natural building stones. Strong correlations were identified between the air permeability values of natural building stones and the open porosity and water absorption values. In contrast to other types of tests, the designed apparatus allowed information to be obtained concerning the porosity of natural building stones within a time period as short as 6 h. Based on the obtained results, the air permeability values of the natural building stones were classified into three groups as permeable, semi-permeable, and non-permeable. The study results indicated that the air permeability index can be effectively used to measure the air permeability of natural building stones within a short a period of time and by using a simple test apparatus.  相似文献   

17.
Effect of Rapid Thermal Cooling on Mechanical Rock Properties   总被引：1，自引：1，他引：0  
Laboratory tests have been conducted to investigate the effects of rapid thermal cooling on various rock specimens including igneous, sedimentary, and metamorphic rocks. At first, various types of thermal loading were conducted: heating up to 100, 200, and 300 °C, followed by rapid cooling with a fan. In addition, multiple cyclic thermal cooling (10, 15 and 20 cycles) with a maximum temperature of only 100 °C was conducted. Experiments included edge notched disc (END) tests to determine the Mode I fracture toughness, Brazilian disc tests to determine tensile strength, seismic tests to determine P-wave velocity, and porosity tests leading to meaningful results. Even though only small changes of temperature (rapid cooling from 100 °C to room temperature) were applied, the results showed that crack growth occurred in some rock types (granite, diabase with ore veins, and KVS) while crack healing occurred in other rock types (diabase without ore veins, quartzite, and skarn). To better understand the results, 3D transient thermo-mechanical analysis was conducted using the ANSYS program. The results indicated that there was a thin region near the outside of the specimen where large tensile stresses occur and microcracking would be expected, and that there was a large area in the middle of the specimen where lower magnitude compressive stresses occur and crack closure would be expected. It was found that the more heterogeneous and more coarse-grained rock types are more likely to exhibit crack growth, while less heterogeneous and more fine-grained rocks are more likely to exhibit crack healing.  相似文献   

18.
The prediction of production rate in ornamental stones sawing is very important in cost estimation and process planning of the rock sawing plants. The main aim of this paper is finding a mathematical correlation between production rate and rock brittleness indexes. The utilized data have been collected from several stone factories in Iran. Seventeen different granite and carbonate rocks have been experienced sawing conditions with large-diameter circular saws. The laboratory tests such as uniaxial compressive strength and tensile strength, were carried out on the rock samples which were collected from these factories. The ratio of compressive strength to tensile strength (B 1), the ratio of compressive strength minus tensile strength to compressive strength plus tensile strength (B 2), and the area under the line of compressive strength and the line of tensile strength (B 3) were used as brittleness indexes in this study. Then, the relationships between these brittleness indexes and production rate were investigated by using a regression analysis. The results show that, there is not a good relationship between the production rate and B 1 and B 2. However, the production rate correlates with B 3 very well. Therefore, there is a reliable prediction for ornamental stones production based on B 3 as a brittleness indexes.  相似文献   

19.
朱志铎  刘义怀 《岩土力学》2006,27(7):1153-1157
挤密碎石桩的材料是粒径较大的碎石,粒间粘结很小,其力学特性和其密度与侧压力有关,以往研究多作为弹性材料看待。利用大型三轴试验研究了碎石的变形特点,并根据试验结果总结了碎石的变形规律。在工程上常遇到的应变范围内,碎石三轴剪切试验的应力-应变关系可用双曲线拟合,体变曲线则接近于抛物线;单向压缩试验的轴向应力-应变符合幂函数曲线。徐－宿高速公路挤密碎石桩地基处理现场试验结果表明,经过碎石桩处理后的液化地基的液化势得到消除,该试验研究工作对类似工程有参考价值。  相似文献   

20.
Performance prediction of diamond wire saws is important in the cost estimation and the planning of the stone quarries. An accurate estimation of sawability helps to make the planning of the rock cutting projects more efficient. In this paper, the performance prediction of diamond wire saws in cutting carbonate rocks was studied on 14 different carbonate rocks in stone quarries located in Iran. Rock samples were collected from the quarries for laboratory tests. Uniaxial compressive strength, Brazilian tensile strength, Schmidt hammer value, and Los Angeles abrasion were determined in the laboratory. Performance prediction was evaluated using simple and multiple regression analyses. Finally, a new model was proposed for predicting the production rate of diamond wire saw. It was concluded that the production rate of carbonate rock using diamond wire saw can reliably be estimated using the developed model.  相似文献   

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