Types Of Marble Research Articles

Research on the selection of biocides for the ‘disinfection’ of statues and masonry at the National Trust (UK)

In order to refresh guidance on garden statuary maintenance conservation, 16 biocides available on the British and European markets were selected for testing in situ at 11 properties of the National Trust (NT) located in England and Wales. For the testing, a range of decorative items, statues and architectural features were chosen, made of various types of stone, including limestone, sandstone, marble, slate and granite, as well as cast concrete, terracotta and brick. Tests were preceded by evaluation of the local microclimate and visual examination of the condition of the objects, including assessment of the presence of any micro-organisms and salt efflorescence. The history of previous conservation works and their materials was also reviewed. Microbiological analysis was carried out in many cases, which identified various algae, lichens and mosses. The effectiveness of the biocides and any potential side effects were evaluated periodically for 24 months after application. Three of the most effective biocides were selected for further assessment. An adenosine triphosphate (ATP) luminometer was used to measure whether biological growth had recurred on the stone at 7 and 12 months after application. Observed side effects included an occasional brown discolouration of Carrara marble after application of three of the biocides tested. An important outcome of the project was not only to recommend which biocides to use where treatment was necessary but also to determine when their use would not be advisable.

A Study of Various Types of Natural Marble Towards Their Use in Cultural Applications

Marble has been used as decorative or building material since ancient times. Various archaeological marble materials of cultural heritage (e.g., statues) are frequently encountered in excavation sites amongst other finds. The scope of the present work is to investigate whether natural marble could be used for dosimetric purposes in cultural applications, such as dating or authenticity test of ancient marble objects, through an integrated experimental approach. For this purpose, the chemical composition, structure/morphology, and luminescence properties of 11 different types of natural marble of different origin (from various geographical regions) were examined by means of micro-x-ray fluorescence spectroscopy, stereoscopic microscopy, thermoluminescence (TL), and optically stimulated luminescence (OSL), respectively. Results indicate that though TL and OSL could be used for the identification of the marble type (origin), the use of natural marble for dosimetric purposes using these methods requires the a-priori knowledge of its type along with some of the main luminescence properties.

Determination of the wear performance of diamond saw blades using inductively coupled plasma

Saw blades are one of the most used cutting tools. They compose the expensive parts of a cutting machine. Therefore, saw-blade wear is an important parameter governing the economy of the cutting process. Significant savings could be made when it is controlled effectively. In this study, a new methodology is employed for the determination of the saw-blade wear in the cutting of two types of marble. Wear of segments is determined by high-precision inductively coupled plasma method. Two types of marbles were used to investigate the wear performance of diamond-impregnated segments of circular saw-blade matrix. Taguchi mixed design L16 (43 21) is used as an experimental design and the results are evaluated statistically with Minitab. The results reveal that the specific wear rate (SWR) of Beige marble increases with the increase of the peripheral speed, traverse speed, depth of cut and down-cut mode operation. Additionally, it is demonstrated that the traverse speed and peripheral speed are the dominant cutting parameters affecting the SWR. It is also seen that similar trends are observed for Onyx marble (excluding peripheral speed). Finally, it is concluded that the proposed models can be effectively used for the estimation of the SWR.

One-step and low-temperature deposited Ag nanowires/TiOx hybrid transparent conductive thin film and its application in antistatic coating

Transparent conductive thin films play an important role in antistatic coating. In this work, highly robust Ag nanowires/TiOx hybrid transparent conductive thin film was deposited by a one-step and low-temperature method. Firstly, 4.2 g of silver nanowires and 1.0 liter of TiOx sol-gel solution were synthesized. The Ag nanowire dispersion and TiOx sol-gel solution were mixed and sprayed onto many types of substrates, including glass, wood and marble. Highly robust Ag nanowires/TiOx hybrid thin film with a sheet resistance of 7–102*/□ and transmission of 63%–84% can be obtained by a low-temperature sintering process or by UV/ozone irradiation at room temperature. Our results indicated that low-cost and robust Ag nanowires/TiOx hybrid thin films have a high potential in antistatic coating.

Investigation of gamma-ray shielding effectiveness of natural marble used for external wall cladding of buildings in Riyadh, Saudi Arabia

Gamma-ray shielding effectiveness of different types of natural marble tiles commonly used for cladding the exterior walls of residential and non-residential buildings in Riyadh, Saudi Arabia has been investigated in the energy range 59.5–1332.5keV. To this end, linear attenuation coefficients (μℓ) have been obtained by applying narrow-beam technique. Mass attenuation coefficient (μm), transmission factor (TF) and half-value layer (HVL) have been employed to study the shielding performance of marbles and also compared with those of calcite. The experimental findings revealed that HVL parameter correctly determined the shielding effectiveness of the dissimilar types of marble. Compared with other marbles, Carrara marble (Italy) showed preferable shielding effectiveness. Moreover, a formula, μm=aE−b, was proposed to evaluate and compare the shielding properties of the marble tiles over a broad energy range. In this formula, a and b were determined empirically. In conclusion, natural marble proves to be more reliable in reducing gamma radiation when used for external building cladding than ordinary concrete, and it could be a good alternative to lead shield against high gamma energy because it is 24% heavier than lead.

Biofouling of marbles by oxygenic photosynthetic microorganisms.

Phototrophic microorganisms disfigure the surfaces of different types of stone. Stone structure is damaged by the activity of photoautotrophic and other microorganisms. However, to date few, investigations have been undertaken into the relationship between microorganisms and the properties of different types of marble. In this study, biological activity of photoautotrophic microorganisms on three types of marble (Yatagan White, Giallo Anticato and Afyon White) was investigated under laboratory conditions over a short period of time. The three types of marble supported the growth of phototrophic microbial communities on their outer and inner layers, turning their original colour from white to a yellowish green colour. The porosity of the marble types facilitated filamentous microbial growth in the presence of water. Scanning electron microscope analysis revealed the accumulation of aggregates such as small spherical, fibrillar, calcified globular bodies on the inner surfaces of the marbles. This suggests that the microscopic characteristics of particular marble types may stimulate the growth of certain types of microorganisms.

Safety analysis of slipping barefoot on marble covered wet areas

This study was conducted in order to determine the suitable surface processing techniques which will increase the safety of pedestrians, reducing the risk of slipping on wet floor coverings on which they walk barefoot. In the scope of the study, slip angle of surface-processed marbles in three different dimensions is determined by using DIN 51097 Standard “The determination of the characteristics that reduce slipping on wet, barefoot surfaces”. Slip angles were calculated with the help of an inclined plane method and by using three different surface processing techniques (polishing, honing and tumbling techniques) for five different types of marble. It was found that the parameters which affected slip angle values of the marbles were surface roughness, plate sizes, grain size of the abrasives used for surface processing, physical and mechanical properties. Statistical analysis was used to determine the relationship between these parameters. The marbles were then grouped according to safe utilization places depending on slip angle and surface roughness, according to the statistical results.

Los mármoles de La Vega (Balazote, Albacete). Tipos y morfología

Las excavaciones en La Vega de Balazote (Albacete), proporcionaron, a finales de la década de los ochenta, uno de los conjuntos marmóreos más importantes del panorama rural hispano de finales del Imperio. En este trabajo presentamos los diferentes tipos aparecidos y su posible adscripción cronológica y espacial dentro del grupo de edificaciones halladas en el yacimiento, pertenecientes en su mayoría a opera sectilia parietales y pavimentales.

Geology and geochemistry of paleoproterozoic magnesite deposits (∼1.8Ga), State of Ceará, Northeastern Brazil

Five important magnesite mines and small occurrences in the state of Ceará form a sequence of lenses that extend, discontinuously, for over 140km. The magnesite rocks are hosted by metadolomites with lutecite, sulphate nodules pseudomorphosed by fiber-radiated quartz, scapolite and dissolution breccias. This metacarbonate sequence is more voluminous and more calcic in the southwestern extremity of the belt, but less voluminous and more magnesian towards the northeastern portion of the belt, the highest Mg contents being observed in the Alencar-Orós region. Magnesite deposits pass gradually into metadolomites and then to almost pure calcitic marbles westward the belt. This group is hosted in a greenschists to amphibolite-facies metavolcanic-sedimentary sequence crosscut by basic sills and granitic intrusions of variable size, form, composition and age (middle to late Proterozoic ∼550Ma). Two types of magnesite marble may be distinguished: (1) medium-grained (1 to 9mm) and (2) sparry-magnesite marble (1 to 15cm). The latter displays wide textural variation (porphyric, rosette, layered and palisadic types) and exhibits remnants of the original sedimentary features. The sparry crystals, in spite of their deformation, are hypidiomorphic and pinolitic. The colors vary from white to light or dark gray, or even red. The dark banded term presents traces of microfossils and stromatolites structures. The medium-grained magnesite marble, on the other hand, shows more homogeneous texture and color and anhedral crystals are more abundant. The sparry-magnesite marble is less enriched in SiO2, Fe2O3, Al2O3 and CaO and richer in MgO than the medium-grained ones. The magnesitic marbles display positive Ce, and negative Eu anomalies. This suggests a shallow marine platform environment with continental, reduced influence (lagunar). These magnesitic marbles also show positive Ce and Eu anomalies in relation to the present seawater, suggesting compositional differences, materialized mainly by an enrichement of these elements in the past seawater. Fluid inclusions in the medium-grained magnesites of the Riacho Fundo deposit are aqueous inclusions, while in the sparry magnesite deposits, particularly in Cabeça de Negro, aquo-carbonic inclusions dominate. Hydrocarbons, however, are found in both cases. The calcitic marble, deposited on open-marine environment, displays positive13C (+0.5 to 2.1 ‰ PDB), while dolomitic to dolostone marbles, deposited on less open marine environment, display negative shift (0.7 to −3.2‰ PDB). This13C fluctuation is within the range for carbonates deposited around 1.8Ga. The depositional environment of these carbonates is close to a paralic system, lagoon, with strong evaporitic conditions. The depressions were of variable depth and lengths and could be isolated, in particular by stromatolitic barriers, dried and flooded by seawater with continental inflows. The largest and deepest ones correspond to the sparry magnesite deposits. These magnesites are located in a lateral way to almost pure calcitic marbles, through dolomitic marbles. This points to a process of chemical differentiation within a paralic system, from open sea to landwards, more calcic in the first to more magnesian in the confined environment, in which lagoon waters are progressively purified from Ca through preferential precipitation of calcic carbonates and secondly of gypsum/anhydrite, which increases the Mg/Ca ratio, and lead carbonate deposits towards the magnesite pole. These metacarbonates also reveal a fractionation of the light REE, starting from the calcitic, through the dolomitic to magnesitic marbles. In the calcitic marbles, REE are in association with the clay fraction, while in magnesitic marbles, they seem to be in association with organic and/or soluble complexes. The magnesitic marbles are of sedimentary origin and underwent important diagenetic evolution before being metamorphosed during the Brasiliano orogenic cycle.

Flexural strength and notch sensitivity in natural building stones: Carrara and Dionysos marble

A study of the behaviour of marble beams under four-point bending tests is presented. Two types of marble are considered: Carrara and Dionysos, which were in the past widely used in buildings in Italy and Greece and are still in use to replace failed or damaged parts of historic buildings. It is shown that the nominal strength and the global response of a given geometry and load configuration depend on the specimen sizes. The materials considered did not show a significant notch sensitivity. The presence of a notch is of help in using a crack mouth opening displacement (CMOD) control. Thus, it is possible to have stable control over the test and to determine the overall structural response. The achieved nominal strength is compared with the direct tensile strength values and with some theoretical formulae.

Round Two—Confined Compression: Young's Modulus, Poisson's Ratio, and Ultimate Strength

Abstract The Institute for Standards Research interlaboratory study of rock properties has provided precision statements for two additional ASTM rock-property test methods, D 5407 (Young's modulus and Poisson's ratio) and D 2664 (ultimate strength), both in confined compression. Three types of intact rock, Barre Granite, Berea Sandstone, and Tennessee Marble, were used in this study. Data were collected for both test methods at confining pressures of 10, 25, and 40 MPa, with four replications per rock type. The rock testing was preceded by pilot testing for Young's modulus and Poisson's ratio on aluminum alloy 2024 T351, with three replications. Young's modulus and Poisson's ratio were evaluated, for both aluminum and rock, from stress-strain data for the intervals from 25–50% and 40–60% of the maximum differential stress. Seven laboratories produced pilot data, and six of these laboratories produced data on rock for this report. Both the aluminum and rock specimens were prepared at central locations and were furnished ready for testing to the participating laboratories. For both elastic moduli, the overall normalized repeatability limit (“within laboratory”) for rock is about twice that for aluminum; the overall normalized reproducibility limit (“between laboratory”) for rock is about the same as that for aluminum.

Deposition of atmospheric pollutants to monuments, statues, and buildings

The impact of atmospheric pollutants on ∼ 100-year old marble monuments was measured at Gettysburg National Military Park, Pennsylvania, USA, from 1986–1988. Dry deposition of pollutants, at increased spatial scale and surface complexity, was studied at the Merchants Exchange Building in Philadelphia from 1988 through 1994. At Gettysburg, runoff from small, well-defined catchment areas was collected from two Carrara marble statues, a Carrara marble obelisk and a Pennsylvania Blue marble obelisk. The catchment areas were chosen to be surfaces that were washed almost entirely by direct precipitation, to minimize the long-term accumulation of gypsum crust. Chemical differences between incident rain and monument runoff were observed for individual rain storms. Concurrent meteorological and air quality data were collected so that estimates of dry deposition of particulate sulfate and nitrate, and gaseous sulfur dioxide and nitric acid could be computed for between-rain intervals. Thus, both the wet and dry deposition of atmospheric pollutants could be examined. The data indicate that marble loss from complex, sculptural marble surfaces is several times greater than from flat, vertical surfaces of comparable petrography and exposure history. Weathering rates based on simple geometries must be adjusted when applied to monuments and statues with more complex surface geometry. The Merchants Exchange was built of Pennsylvania Blue marble and Carrara marble in central Philadelphia in 1835–1839. After 150 years of exposure to an urban environment, deterioration, in the form of surface erosion, discoloration, gypsum crust development and cracking, varies with location around the building for both types of marble. From 1988 through 1994, stone surface wetness cycles and airborne pollutant concentrations at two locations on the buildings' exterior were monitored to determine the potential variation of dry deposition rate with exposure orientation. Near-surface relative humidity, air temperature, wind speed and solar radiation, as well as the surface wetness and temperature of the marble were continuously measured. An air sampling system, controlled by measured surface wetness, collected separate pollutant samples for conditions of wet and dry marble surface. The measured microclimate parameters, dry deposition rates derived from the Gettysburg data and measured pollutant concentrations were used to estimate sulfur deposition to the marble building exterior. These estimates of deposition were compared with relative measurements of soluble surface deposits sampled by deionized water washdowns. The concentration of Ca++, SO4= and NO3− in these surface samples agreed closely with the calculated deposition regime and the observed condition of the surface.

Dynamic Load Transfer in Virgin and Damaged Granular Rock Media

An experimental investigation is conducted to study dynamic load transfer in granular rock media. The granular rock media is modeled as a one-dimensional chain of disks fabricated from four different types of white Vermont marble. The study focuses on the effect of microstructure on transient pulse propagation. The transient pulse is generated by exploding a small amount of lead azide charge on top of the rock disk assembly. During wave propagation dynamic contact strains are recorded using electrical resistance strain gages. The location of the strain gages is chosen such that the averaging effects are minimized. This information is used to calculate wave velocity and attenuation as a function of the cumulative damage in the disk assembly. The results indicate a considerable influence of the microstructure and prior loading history on the wave propagation process. A correlation exists between the stress wave velocity and the microstructure of the rock material. Also the wave velocity increases initially and then decreases with repeated explosive loading.