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The cavernous features are considered one of the geological hazards that are dominant in the carbonate rocks as a results of dissolution effect of groundwater. The dissolution process extends for many years at the subsurface layers and causes catastrophic collapse if migrated to the surface layers. The problem become crucial in the urbanization areas where there are wide varieties of construction activities. Beside the natural weathering process, the human interventions, representing in the wastewater, can accelerate the weathering process of the prevailing cracks. Al Kharj governorate is one of the promising areas close to Riyadh, the capital of Saudi Arabia, that attracts wide aspects of urbanization, agriculture and industrial activities. The study area is located inside an urban neighborhood at the western part of Al Kharj city. The site is surrounded by buildings extensions from three sides and the fourth side was excluded from urbanization activities due to existence of surface cracks along the area especially at the northern direction. Excavations and boring tests reveal that the exposed cracks are extended downward and may be connected to subsurface karstic features in the limestone rocks. Two surface geophysical measurements have been planned to provide clear information about the locations, horizontal and vertical extensions of the cavernous features along the study site. The Time Domain Electromagnetic (TEM) and Electrical Resistivity Tomography (ERT) methods were applied for investigating the subsurface characteristics up to 40m depth with different resolutions. The data have been acquired along profiles path across most of the surface fractured features. In spite of the inverted TEM data representing the subsurface resistivity variations in 1D mode, the dense TEM stations and the direct comparing the results with the available borehole lithology, enabled to trace the subsurface cavernous features laterally and vertically with reasonable resolution. Moreover, the 2D ERT processed data have been compared with the TEM results along some localities for guiding the data interpretation to locate the subsurface cavernous features. The two methods are analyzing the subsurface in two different resolutions, the TEM can explore the deeper parts and the layer successions, whereas the ERT methods can provide the lateral extension tracing of cavernous features. Based on the results 3D fence diagrams, most of the cavernous features that are located along the northern part of the study area related to fractured limestone zones extend vertically to more than 20m in some localities. Data interpretation has been flowed by excavation process for confirming the interpreted anomalies and resulted in discovery of huge cavity system extended laterally and vertically at deeper massive limestone layer. [ABSTRACT FROM AUTHOR]

The presence and distribution of pores in natural stones affect their durability and aesthetic value, especially when exposed to weathering agents like salt crystallization and freeze–thaw cycles. In this study, a multi-analytical approach was used to analyse the pore structure of twelve carbonate rocks, including different types of limestone and the Carrara marble. Mercury intrusion porosimetry, digital imaging analysis on backscattered electron images taken at the scanning electron microscope, and micro-computed tomography were used to overcome the limitations of each technique and create a more accurate reconstruction of the pore structure. This approach can aid in predicting the deterioration processes stones in heritage structures. [ABSTRACT FROM AUTHOR]

The investigation of karst channels is an important work to ensure the safety of underground construction and mining engineering. At present, the combination of the geophysical method and drilling method is the primary and most commonly used approach in karst detection work. However, sometimes limited by conditions, it is difficult to carry out drilling work. In coastal limestone mines, karst is usually developed, so it is crucial and significant to carry out the exploration work on karst channels. Taking a coastal limestone mine in Guangxi Zhuang Autonomous Region of China as a case study, electrical resistivity tomography (ERT) and transient electromagnetic method (TEM) were adopted to investigate the subsurface low-resistivity anomalies. According to the results, the distribution area of karst channels was preliminarily determined by the low-resistivity responses. Then, a sluicing test was carried out to analyze the primary direction of underground karst channels in this area, and several main leakage and outflow points were identified, which could serve as evidence for the channel paths. Besides, the ERT method was used for repeated exploration in the detection area not submerged by seawater after the sluicing test, and the results showed that the low-resistivity responses were consistent before and after the sluicing test. Combining the results of the electrical exploration and the sluicing test, the direction and main pathway of underground runoff were determined, and the distribution of underground karst channels in the study area could be obtained. [ABSTRACT FROM AUTHOR]

In the study of subsurface reservoirs, permeability is a key parameter whose evaluation and extrapolation at the desired scale, such as that of the numerical model mesh, are both a necessity and a difficult task. Relating permeability measurements to the geological characteristics of the rock, at intermediate scales seldom characterized, can help understanding the heterogeneity of the medium and correctly determining the permeability at the desired scale. This concern is particularly important in karst reservoirs, which exhibit highly variable permeability at different scales of observation and from one location to another. Here, we study the petrophysical and geological properties of carbonate facies from the centimeter to the meter scale. Several boreholes a few meters apart were cored and exhaustively described. Petrophysical measurements were made on rock samples, while inter-packer injection tests were undertaken to investigate some meter intervals of the medium surrounding the wells. The results show that the investigated medium is a complex multi-medium with a multi-scale heterogeneity. The detailed geological description allowed explaining the differences between the permeability values at different scales and from one interval to another. Relationships were quantified between the texture of the limestone matrix, the density and aperture of the discontinuities, the permeability of the matrix, and the permeability contrast related to the dual medium at the meter scale. A strong correlation between this permeability contrast and the aperture of the discontinuities, itself more correlated to the texture of the rock than to the facies, is highlighted. [ABSTRACT FROM AUTHOR]

Specialist ecosystems have developed on small areas (< 1 ha) of alkaline (pH 7–10) soil-free disturbed substrates in semiarid areas of southern New Zealand, where rare endemic plants are being outcompeted by adventive species as soil develops. We have conducted a pilot study for soil and weed removal at seven sites to increasing habitat availability for the rare plants. Six sites are on impermeable clay-altered schist where evaporation of marine aerosols in rain has formed localised NaCl-rich encrustations. These bare substrates host endemic salt-tolerant plants (halophytes), especially where electrical conductivity (EC) exceeds 1 mS/cm and excludes most weeds. One site is on limestone and associated erosional residues, where endemic calciflora have evolved on substrates that have pH of 7–8 and variable EC. Soil and weeds were removed to a depth of ~ 0.5 m, and the study plots were monitored for changes in substrate salinity, pH and plant colonisation for up to 1.5 years. The most successful saline plot, an abandoned mining area, had initial halophyte colonisation after 4 months, and after a year, the halophytes had achieved > 50% substrate coverage. The other saline plots also had lesser halophyte colonisation and more weed incursion. Bare limestone talus that had weeds allowed successful calciphyte germination. Parts of the limestone site where weeds and soil were removed had no calciphyte colonisation but significant weed development after 6 months. Our results suggest that soil removal is a viable management option for enhancing ecosystems that require bare substrates, preferably with deeper (~ 1 m) excavation. [ABSTRACT FROM AUTHOR]

As a building material, limestone is affected salt and acid solutions resulting from intense weather conditions over time. In the present study, variations in capillary water absorption, porosity, physical changes, and internal rock decomposition mechanisms caused by salt crystallization and air pollutants (SOx and NOx) in sedimentary limestone from the Antalya region were explored. The mineralogical–petrographical and geochemical properties of the limestones were determined using polarizing light microscopy, scanning electron microscopy (SEM), and X-ray fluorescence methods. The variations in the capillary water absorption coefficient, weight, and pore distribution and size were also determined by mercury porosimetry (MIP). An increase in weight was observed in the salt and SA (150 ± 10 mL deionized water and 500 ± 10 mL H2SO3 acid) weathering tests, but a reduction in weight was found under the action of NA (150 ± 10 mL deionized water and 500 ± 10 mL HNO3 acid). The reaction of SA with the limestones influenced the presence of calcium sulphite hemihydrate and gypsum on the rock surface, which affected weight gain. A decrease was observed in the weights of the limestones under the action of NA, and the porous structure seen in the microscale examination from SEM analysis supported a loss of material. The values for capillary water absorption increased in the limestones exposed to salt, SA, and NA. According to MIP analysis, the pore size distribution curves became multimodal, and the pore sizes varied in the studied limestones exposed to salt, SA, and NA. The findings of our study serve as an important guide for the use of limestone as a natural stone in regions with severe weather conditions. [ABSTRACT FROM AUTHOR]

Abrasion resistance is the most important parameter that determines the usage areas and service life of natural stones. Especially, in cold climates where freezing–thawing (F–T) is effective, it is crucial to determine the abrasion resistance of stones after F–T before using them in engineering projects. It is well known that abrasion resistance and freeze–thaw tests are time-consuming and laborious experiments. This study seeks to develop a new empirical equation for predicting the abrasion resistance before and after F–T test of limestones using the initial material properties without performing abrasion resistance and F–T tests. Böhme abrasion (BA) test which is the most widely used method was performed to determine the abrasion resistance of the limestones. For this purpose, the relationships between BA values before and after F–T and several most common material properties (density, ρ; unit weight, γ; water absorption, Wa; effective porosity, n; P-wave velocity, Vp; point load strength index, Is50; uniaxial compressive strength, UCS; indirect (Brazilian) tensile strength, BTS; Schmidt hardness, SH; Böhme abrasion, BA) of limestones showing seven different types outcropped in Manisa, Turkey were investigated by simple and multiple regression analyses. Consequently, two equations have been developed to predict the abrasion resistance before and after F–T test of the limestones based on the routinely measured material properties. Some error metrics, such as root-mean-square error (RMSE), variance account for (VAF), and standard error of estimate (SEE), were used to check the estimation accuracy of the developed equation. This study has shown that the developed equations are reliable and have a good prediction performance only considering the routinely measured properties of the limestones without requiring BA and F–T tests. [ABSTRACT FROM AUTHOR]

The aim of this study is to evaluate the potential weathering of three different varieties of Algerian limestones. Standard durability tests such as salt crystallization, thermal shock or freeze–thaw are usually employed to compared stone behaviors. However, salt crystallization tests do not consider the thermal effect on the samples, and freeze–thaw tests, the non-pure water solution in real conditions. In this study, standard tests were compared to adapted tests, to efficiently separate the real damage agent for each situation, and to develop durability tests close to real environments. The evaluation was carried out by non-destructive measurements such as porosity variations, water capillary uptake and P-wave velocity. The residual deformation in fresh samples and those subjected to the different tests was also quantified using strain gauges. The results showed that limestones with the same porosity and different microstructure behave differently. The combined effect of thermal shock, salt crystallization, and freeze–thaw tests modify the stone's porous network by opening and creating new fractures. The variation of the residual strain is considered as the main parameter that conditions the final deterioration of the stone, especially on the surface. In the travertine stone, the exposition to high temperature in the standardized salt crystallization tests is more damaging than the salt crystallization itself. At low temperature, freeze–thaw cycles with salt solutions show slightly less deformation than the ones carried out with pure water and a stabilization after 20 cycles. [ABSTRACT FROM AUTHOR]

This paper presents the petrographic and textural characterization of some ornamental limestones widely used in UNESCO World Heritage Sites in northeastern Italy, and the assessment of the main decay factors present in the environment where they are employed. Eleven carbonate building materials have been here considered, all commonly present in the built environment of northeastern Italy: two different varieties of Vicenza Stone (Nanto and Costozza), of Verona Stone (Red and Brown Verona), of Asiago Stone (Pink and White Asiago), and of Chiampo Stone (Ondagata and Paglierino), the Istria Stone (Orsera), the Aurisina Stone, and the Botticino Stone. The Carrara marble is also considered, and used as a reference material for the determination of the grain-size distribution. Stone durability was measured by accelerated aging tests which reproduced freeze–thaw and salt crystallization cycles, among the main causes of deterioration in the region. Petrographic and textural features of these carbonate rocks as well as their porosity resulted to strongly influence their deterioration rate, and their knowledge is, therefore, essential when trying to predict stone decay as a function of the local environmental forcings. [ABSTRACT FROM AUTHOR]

The dovecote is one of the last two witnesses of the medieval history of the city of Créteil (11 km SE of Paris). Classified as a historical monument by the French Ministry of Culture in 1972, it was moved away from its original location the same year and restored between 1980 and 1987. Fifty years after its displacement, the dovecote still shows salt efflorescence on the inner and outer wall surface. The aim of this study is to determine the composition and the ancient or modern source of these salts and whether their presence is harmful to the preservation of the dovecote. A combination of low- to non-invasive methods associating microclimatic measurements, mineralogical, petrophysical, chemical and isotopic analyses on micro-samples with historical documentation are used to find the causes of salt enrichment and migration throughout and after the service life of this monument. [ABSTRACT FROM AUTHOR]

Air pollution is one of the most complex atmospheric conditions and causes the deterioration of the natural stone. Air pollutants are effective on the deterioration process of natural stones, and this process varies in wet and dry environmental conditions. In this study, the ageing resistance to H2SO3 (SSA) and HNO3 (NSA) solutions in the presence of moisture of four limestone samples from the Elmalı region were analyzed based on standard procedures. The mineralogical-petrographic features and pore size distribution were also determined using a polarized light microscope (PLM), scanning electron microscope (SEM–EDX), and high-pressure mercury porosimetry (MIP). Physical and morphological (weight, roughness, color and microtextural properties) variations were also observed in the studied samples after SSA and NSA treatments. Secondary gypsum with different crystal morphology was observed on the surfaces of calcite crystals under the influence of SSA. The NSA treatment caused the emergence of secondary pores. The weight, whiteness and roughness increased with the effect of SSA in the presence of moisture. The weight and whiteness decreased and the roughness increased after NSA exposure. [ABSTRACT FROM AUTHOR]

The relationship between the deterioration type (DT) of ancient limestone steles and deterioration degree (DD) and the relationship between the carved age and DD were investigated and studied. Data on the DT, DD and carved age were collected and analysed from 191 ancient limestone steles in the Guihai Forest of Steles, Guangxi Zhuang Autonomous Region, southern China. A distribution map of deterioration on each stele was drawn, and six DTs were identified, including biological colonization, missing parts, exfoliation, erosion, encrustation and graffiti. The DDs were visually assessed on a generalized 4-point scale: intact, slight, serious and extremely serious. The carved ages of steles, which ranged from 894 to 1940 A.D., were verified. The relationship between the DT and DD was analysed using partial correlation analytical methods. The correspondence between the carved age of the limestone stele and the DD was established and analysed. The results show that (1) the DD was strongly correlated with erosion, which was mainly caused by seepage water and rainwater, and the DD was weakly or not correlated with the other five DTs; (2) the DD was related to the carved age, but the relationships were weak. The results provide a scientific reference for the conservation and restoration of these caves. [ABSTRACT FROM AUTHOR]

There are historic subsurface dimension stones in the capital of Hungary (Budapest) that were excavated in porous limestone. The stability of these subsurface openings is important, since most of them are located in urban areas, where existing buildings or new structures are planned to be built. The paper presents a detailed study considering the geometry of the system and the mechanical parameters of the limestone. The geometry of the cellar system was obtained using terrestrial laser scanning (TLS). The cover beds are few meters in thickness, and the width of the pillar is between 2.50 and 3.98 m, according to the measurements. The rock mass parameters which were used in the calculations were obtained from laboratory tests. A finite element (FEM) software Rocscience (RS2) were applied to model the stability of the galleries. Calculations were made for various geometries taking into account the thickness of cover beds and the width of pillars. Altogether 70 models were made. A surface load of 150 kN/m2 was also applied to model the buildings. New relationships between cover bed thickness, pillar width and displacements are outlined to compare these results to previous works. The strength reduction factor was also calculated for all geometries, indicating the changes in the stability of these underground quarries and pointing out the importance of cellar geometries. [ABSTRACT FROM AUTHOR]

Travertine is a sedimentary rock with generally layered structure, mainly comprising carbonate. They are used for different purposes in interior and exterior spaces by cutting parallel or perpendicular to the bedding according to use. Travertine may contain several facies linked to variations in conditions during formation. With these features, travertine is one of the rocks with anisotropy most commonly observed. In this study, the anisotropic structure due to facies and bedding in travertine was investigated considering geological and engineering properties. The Sarıhıdır travertine quarry face was divided into four different zones with different features. Chemical, mineralogic, physical, index and mechanical properties of the samples taken from these zones were determined. During determination of engineering parameters, samples were prepared parallel and perpendicular to bedding. The source of the travertine is a mixture of limestone, dolomite, evaporite and ultramafic rocks and they have epigean character, though they were affected by the hypogean environment. It appeared there were textural differences between the zones, rather than differences in chemical and mineralogic composition. When travertine was cut parallel to bedding, all zones were suitable for decoration and facing. Only T-4 zone samples cut parallel were useable for flooring and load-bearing elements. In terms of compression and abrasion resistance, T-4 zone was better than the other zones. The cut direction of the travertine samples is an important factor for physical and mechanical behavior. Samples cut parallel to bedding were observed to provide better results. According to the results, it is recommended to use products from the same travertine zone side-by-side in structures and to consider the cutting direction for long life of the building and to prevent economic losses. [ABSTRACT FROM AUTHOR]

The size, slenderness ratio h/d (h = height, d = diameter), the shape of a rock specimen, but also the lithological type of the rock are the most significant factors affecting results of uniaxial compressive strength (UCS) tests. The proposed experimental pilot study shows the variable impact of these parameters on UCS values by implementing four lithological types widely used in Slovakia. The research results of studied selected rock samples can be used for in different regions of Western Carpathians and in other regions with similar lithological formations. Standard tests were performed on four lithological types: granodiorite, limestone, sandstone and andesite. Cylindric and cube-shaped test specimens of different sizes were prepared from each rock. Cylindric specimens with diameters of 20 mm, 35 mm, 50 mm and 70 mm, as well as cubic and prismatic specimens with a base edge of 50 mm were tested. Applied h/d ratio was 1:1 and 2:1. Performed UCS tests confirmed a high variability of results within the same lithological type. They represent a further contribution to the already wide diversity of opinions how the size and shape of specimens influence the measured strength of rocks. UCS increases in the sequence limestone < granodiorite < sandstone < andesite. The study revealed the impossibility of conclusive correlations between the UCS and the size and shape of specimens to be generally applicable for all lithological types. But the aspect of the specimen slenderness ratio was the best pronounced one regarding all studied rocks: higher slenderness ratio gave mostly lower UCS. [ABSTRACT FROM AUTHOR]

The studied limestone is a well known Portuguese natural stone that occurs in Valverde—Alcanede region, located in the Maciço Calcário Estremenho (center of Portugal). This stone is used in several exterior and interior applications such as paving, cladding, masonry and decorations. Slabs made of the studied limestone were installed in ventilated facade with a "kerf" anchoring system in a building located in Valencia (Spain). After approximately five years, signs of degradation were detected on the facades through changes in color, enhancment of cracks and fissures that caused instability and collapse on several slabs. Limestone slabs comprise irregular patterns due to rock cutting across stylolites. These features represent ideal paths for fluid circulation through the slab and can be identified as vulnerability zones for exterior applications. Experimental procedure included several laboratory analyses to study clays and the iron oxide contents. Microscopic petrography, XRD and SEM observations were important to identify the interaction of the clay material in stylolites and fossil contours. Results show the importance of establishing standard methods for selecting stone on cladding applications. From the results, it is possible to understand that clay minerals have a strong influence on the mechanical performance of this stone. Among other important remarks, results show the importance of the development of standard procedures that acknowledge the structure and mineral composition before setting these natural products as construction materials. Proper stone selection was found important to avoid facade degradation, and hence contribute to prevent accidents and promote user safety as well as economic impacts. [ABSTRACT FROM AUTHOR]

This research paper is concerned with studying and evaluating the geoengineering characteristics and potential risks of the area under study with a view to safe urban expansion using GIS techniques. Different geotechnical laboratory tests such Atterberg limits, free swelling test, swell potential and pressure tests, chemical analysis, unconfined compressive strength (UCS) and rock quality designation (RQD) were performed on 28 boreholes (95 samples). Furthermore, X-ray diffraction was used to examine clay minerals. The results indicate that the UCS values range from 47 to 72.2 kg/cm2 and RQD from 21 to 45%. The free swell ratio ranges from 110 to 120%, and the plasticity index from 34 to 37%. In addition, GIS techniques have been utilized to produce the distribution layers of different geotechnical characteristics, then integrated to produce a geospatial urban model for delineating and defining safe and dangerous urban zones. This model is classified into four classes: low, moderate, high and very high hazard. Low and moderate hazards were detected in the major portion of the survey area. These portions are suitable for foundations at shallow depths. However, high to very high hazards were detected in the southeast portion of the study area. The reason for these areas is caused by the existence of heavily fractured limestone and highly swelling clay layers. This model would aid in the creation and discovery of the best areas of shallow base in the region under consideration. [ABSTRACT FROM AUTHOR]

The chief objective of the article is to learn the spatial characteristics of stress distribution around a shallow buried spherical Karst cave containing fill materials in limestone strata. First, considering the effect of external load, stress field in the Earth's crust, internal filling and Karst geomorphology characteristics in China, a spatial axisymmetrical model was established. Concurrently, combing available work and the concept of elasticity, the boundary conditions are determined. Subsequently, the Love displacement method was introduced, and stress component expressions were obtained. The diagram characteristics of each stress component are summarized, which are affected by various influencing factors. Finally, to prove the rationality of the general solution, a numerical simulation was carried out based on practical engineering, and the maximum error is less than 5%. Thus, the analytical solution could represent the spatial characteristics of stress distribution around a shallow buried spherical karst cave containing fill materials in limestone strata. [ABSTRACT FROM AUTHOR]

In present paper, we consider the impact of blast-induced vibrations on constructions by analyzing the blasting results at limestone quarry Hardovac near Doboj (Bosnia & Herzegovina) recorded in period 2012–2015. Analysis is conducted using the multiple linear regression (MLR) and artificial neural networks (ANN) for establishing the correlation between the peak particle velocity, vibration frequency and several controlling factors (number of boreholes and their average depth, distances between the boreholes, between the arrays of boreholes and between the blasting and recording point, total and immediately detonated amount of explosive). As a result, we formulate explicit nonlinear models for estimation of safe distance between blasting points and different neighboring structures, including the construction of safe distance isolines. Suggested approach provides results which are comparable to the commonly used techniques but indicate the important effect of the examined controlling factors on safe distance, which is usually underestimated in common practice. [ABSTRACT FROM AUTHOR]

As a successive alkalinity-producing system pond for purifying mine drainage is operated, sediment accumulates in the limestone layer of the pond, and as the amount of accumulated sediment increases, the water permeability and treatment efficiency of the pond decrease. Hence, a flushing system is required, comprising of a network of perforated pipes installed in the limestone layers, to periodically discharge sediment and mine drainage to the outside. The performance of a flushing system depends on four distinct characteristics of the system: the characteristics of the limestone layer, the sediment, the flow, and the flushing device. However, existing studies have evaluated the performance of the entire system without considering these conditions. In this study, a new experimental method for designing a flushing system is proposed. This method is based on an experiment to evaluate the influence radius of orifice, which is the radius of the spherical volume around an orifice that can suck sludge by flushing. The results showed that the flow rate of water through the orifice in the glass bead layer matched well with the Blake–Kozeny formula, and that the greater the diameter of the orifice is, the greater the influence radius of orifice. The influence radius of orifice according to the diameter and spacing of the orifice was evaluated, which provides a key criterion for designing a flushing system. [ABSTRACT FROM AUTHOR]

Limestones are of wide variety, namely with differences in the process of formation, mineralogical composition, grain size and texture. Such variability leads to differences in weathering characteristics and behaviour under different environmental conditions and applications. Therefore, detailed studies are mandatory to assess the main factors controlling the physical–mechanical properties and durability to propose the best applications for limestones. This study presents the petrographic and petrophysical data of 11 selected Portuguese limestones. Texture, mineralogy and porosity were identified as key parameters for the durability of limestones. Two main groups were identified regarding the texture/petrography and weathering resistance: the compact micritic limestones and with the sparitic grainstones. For the first time an outstanding bowing behaviour was identified in a limestone, probably related with clay swelling minerals and iron oxides present in the micrite groundmass around or in the stylolitic planes. [ABSTRACT FROM AUTHOR]

This study investigated the effect of environmental physical factors on the relative abundance of bacteria and the consequential landscape evolution in karst topography, focusing mainly on the effects of ureolytic microbial CaCO3 precipitation. The narrow-sky located in the upper part of Tangshan is a small gulch of Pleistocene coralline limestone formation in southern Taiwan. A 16S-metagenomic approach was used to determine the relationship of microbial community structures on the landscapes in various habitats. Our results showed that the biomass of habitats in the opening of the gulch was two times higher than the inside where light penetration was lower. We also found that speleothems only occurred at the inner wall inside the gulch, where the environment exhibited water drips running through the surface of speleothems and less light penetration. The sequence reads of operational taxonomic units relative to urease-producing bacteria and weathering-associated bacteria from each habitat were determined by NCBI database. Our data revealed that the 16S-metagenomics of the inner wall and water samples exhibited more sequences that were similar to those of urease-producing bacteria, whereas the outer wall showed more sequences that were similar to those of weathering-associated bacteria, suggesting that bacteria facilitated the formation of limestone weathering and calcite precipitation for various habitats. The semi-quantitative PCR for determining bacterial urease gene (ureC) levels confirmed that the inner limestone habitat had higher ureC gene levels than the outer limestone habitat. This study revealed the pivotal role of microorganisms in governing the geological evolution in the lightless limestone landscape. [ABSTRACT FROM AUTHOR]

Due to high water pressure on deeply buried coal-seam stope floors, the primary voids in the rock mass can easily expand and connect under the actions of water pressure and mining. This can form a vertical water passage that increases the risk of water inrush accidents at the stope floor. At present, many coal mines in eastern China adopt advanced regional ground grouting to transform aquifer floors or reinforce aquicludes to control confined water. However, there are some problems such as the low filling rate of primary micro-voids and ineffective grout diffusion along the vertical macro-fractures of the stratum, which seriously reduce the grouting effect. Given the above problems, we combined macroscopic and mesoscopic sacle characteristics of pore development in the top stratum of the Middle Ordovician limestone (MOL), which is the target stratum of coal-seam floor advanced grouting in the Hanxing mining area. Macroscopically, based on drilling fluid consumption and field outcrop development of the MOL, the macro-scale vertical porosity development characteristics of the MOL stratum were analyzed. At the micro-level, micro-computed tomography was used to scan rock samples from the top of the MOL to quantify the development characteristics and geometric parameters of the voids. The results show that, macroscopically, the Fengfeng Formation at the top of the MOL in the Hanxing mining area has good water yield, but the horizontal and vertical distributions are not uniform and the water yield increases or decreases with burial depth. Microscopically, the locally developed part of the rock samples showed good vertical connectivity, and the plane porosity of the rock samples was concentrated within ranges of 0.40–5.12% and 6.8–15.28%. Most pores had equivalent diameters of less than 200 μm and the volume proportion was more than 2000 μm. In the fractures, closed fractures and micro-open fractures were most common, with stable average widths of 120 μm and 420 μm, respectively. Medium-tension and wide-tension fractures accounted for a relatively small proportion of the fractures in the rock samples, which had good ductility. [ABSTRACT FROM AUTHOR]

This study investigated the mineralogical, chemical, physical, mechanical, durability–hygrothermal, thermal shock properties, and economic aspects of the Kandira stone, one of the well-known natural building stones, commonly used in many historical structures in the Marmara and Thrace regions. Especially, it has been preferred to Malta stone in historical structures in Istanbul due to economic reasons at the beginning of the 1900s. A similar appearance and lithology with Malta stone and closeness of the Kandıra stone to İstanbul made it attractive to be used as natural building stone in historical monuments and new structures. The mean physico-mechanical properties of Kandira stone yielded 2.24 g/cm3 apparent density, 2.72 specific gravity, 19.21% total porosity, 5.8% water absorption by weight, 48 MPa compressive strength, 11.4 MPa bending strength. In terms of durability properties, Kandira stone has high resistance to aging by CaCl salt mist and no or low resistance to SO2 aging in a humid environment. Also, the freeze–thaw test of Kandira stone yielded an exceptionally low mass loss (0.11%) indicating that the stone is resistant to freeze–thaw effect. Thermal shock tests indicated that Kandira stone is mainly resistant to thermal shock cycles. Economically, the calculated probable reserve of Kandira stone resulted in 40.8 × 106 tons of material and the potential economic value based on the probable reserve is calculated around 54.672 × 109 TL (approximately €7.2B). In conclusion, this study defined the petrographic, geomechanical, durability–hygrothermal and thermal shock properties essential for the use of Kandira stone as building stone and restoration material. [ABSTRACT FROM AUTHOR]

Malta is known for its limestone megalithic temples of which many are inscribed on the UNESCO World Heritage List. A variation of this limestone was historically, and until very few years ago, a primary building material in Malta. The temples are subject to various environmental influences which until recently have led to several collapses due in part to serious stone surface and infill loss. As a protection measure, open-sided shelters have been built over three of these temples. This work assesses the degrading influence of air pollution (nitrogen dioxide, ozone, particle matter, sulfur dioxide, and acidity in rain) on the temples, in combination and comparison with the influence of other environmental factors (relative humidity, temperature, precipitation, moisture, sea salt, wind) and in this respect evaluates the potential protective effect of the shelters. The variation in air pollution weathering of limestone exposed outdoor in Malta was calculated by exposure–response functions from the ICP-materials programme and compared with measured values, and its contribution to the deterioration of the temples was evaluated. The difference between urban and rural locations in Malta, in the first year of atmospheric chemical weathering of limestone due to air pollution, was found to be about one micrometer loss of stone surface. This is probably less than the annual variations due to the influence of natural climatic factors, and small compared to the present annual variations in continental Europe. The deposition of sea salt and presence of salts on and in the limestone megaliths and changes in salt-crystallization events due to relative humidity fluctuations, inside and outside the shelters, will account for more of the variations in the first year of weathering of Globigerina limestone than variations in air pollution. The deterioration will also be related to temperature (including condensation events), wind parameters and rainfall, as well as ground water replenished from areas beyond the shelter. [ABSTRACT FROM AUTHOR]

The extra siliceous limestone sample of the Lower Eocene from the abandoned cement quarry part of the limestone deposit from the area of Bizerte (Extreme North East of Tunisia) has been investigated for its suitability for cement making. Petrological as well as X-ray diffraction pattern studies indicated that the limestone sample was crystalline and dominantly composed of calcite and quartz. They have variable silica and lime contents. Geochemical analysis results of 25 samples indicated that the limestone from the Bizerte deposit shows a wide range of variation in LOI (33–39 wt%), SiO2 (7–6 wt%), CaO (4–49 wt%) Al2O3 (2–4 wt%), and Fe2O3 (0.74–1.45 wt%). MgO, K2O, Na2O, and TiO2 are present in traces. CaO shows a strong positive correlation with LOI, whereas CaO and SiO2 show a negative correlation. The chemical composition of limestone confirms the mineralogical composition. The aim of this paper is to show the influence of high siliceous limestone component from Bizerte deposit on clinker parameters (silica modulus and lime saturation factor) in order to highlight their effect for the cement process making. In addition, to establish a predictionnal geochemical model in order to integrate and optimize this raw material estimated at 81,78,000 tons in cement manufacturing. The geochemical analysis by XRF of the limestone samples taken at different levels from the quarry proves their affluence in carbonate with a lime content of 46 wt% and the abundance of silica with a content of 12 wt%. Mineralogical analysis shows the predominance of calcite and quartz at the XRD diffraction patterns. The obtained results are used subsequently to establish geochemical maps of lime and silica allowing the orientation of the operational plan according to the geochemical quarry composition. The geochemical as well as mineralogical analyses show that the integration of the extra siliceous limestone in the raw powder composition permits the filling in of the defect of silica in limestone exploitation by preserving the quality of the produced cement in accordance with the Tunisian and European standard requirements. This study explains then the importance of geochemical assessment of limestone for cement manufacturing. [ABSTRACT FROM AUTHOR]

Alpine grasslands of the Neotropical Andes have high soil organic carbon (SOC) stocks and provide crucial ecosystem services. However, stability of the SOC in these grasslands is not well-studied. Having insights into SOC stability contributes to a better understanding of ecosystem vulnerability and maintaining of ecosystem services. The objectives were to get a first insight into organic matter (OM) stabilization in soils from different bedrocks of Andean alpine grasslands near Cajamarca, Peru (7° 11″ S, 78° 35″ W) and how this controls SOC stocks. Samples were collected from soils formed on limestone and acid igneous rocks. Stabilization mechanisms of OM were investigated using selective extraction methods separating active Fe, Al and Ca fractions and determined SOC stocks. In both soil types, the results showed important contributions of complexation with and/or adsorption on Fe and Al (oxides) to OM stabilization. Exclusively in the limestone soils, Ca induced OM stabilization by promoting the formation of Ca2+ bridges between OM and mineral surfaces. Furthermore, no evidence showed that OM stabilization was controlled by crystalline Fe oxides, clay contents, allophones, Al toxicity or aggregate stability. Limestone soils had significantly higher SOC stocks (405 ± 42 Mg ha−1) compared to the acid igneous rock soils (226 ± 6 Mg ha−1), which is likely explained by OM stabilization related to Ca2+ bridges in addition to the stabilization related to Fe and Al (oxides) in the limestone soils. Our results suggest a shift from OM stabilization dominated by Fe and Al (oxides) to that with the presence of Ca-related cation bridges, with increasing pH values driven by lithology. [ABSTRACT FROM AUTHOR]

Groundwater trace element geochemistry was evaluated in the Narji Limestone which possesses a range of substituted trace elements in the mineral matrix. The data indicate three interrelated processes control water-rock interactions and elemental concentrations in this aquifer. Dissolution influenced by pH-Eh, recharge processes and residence time controls Ca, Mg, Mn, Al, Cd, Ba, Sr, Co, Li, Rb, V, Fe, Pb, As, Si and Cu concentrations, while the weathering of quartzites and shales releases minute quantities of Na, K, Cl, Si and F into groundwater. A significant amount of Na, K, Cl, NO , SO , Al, Fe, Cd, As, Pb, Ni, Zn, Mn, Sr, Cl, Br, Sb, Ag, Mo, Co and Cu has leached into groundwater from the use of fertilizers/manures and decayed organic matter in cultivated areas. High evapotranspiration has concentrated the chemicals by about 84%. Urbanization, land-use changes, mining and local industries have significantly increased Cd, Se, Ni, Zn, V, Fe, Cd, Sb, Ag and Cr concentrations in groundwater. The composition of groundwater is also affected by sewage, waste disposal and industrial and commercial activities. The chemical properties of about 18% of groundwater samples suggest the role of dissolution/weathering, 46% of samples have been influenced by the effects of evaporation and agricultural activities while 29% of the samples have been affected by natural hydrogeochemical processes and the effects of agricultural and industrial contamination. The quality of groundwater in the area generally conforms to the WHO recommended limits for drinking. Increasing anthropogenic interactions are likely to degrade the groundwater as karst is highly prone to contamination. This demands further investigations to ensure that the groundwater remains suitable for its intended uses in the future. [ABSTRACT FROM AUTHOR]

This study examines the natural radioactivity in cements and raw materials used in cement production industry with the aim to assess the population exposure to the radiation due to their use in dwellings. The results show that the limestone is the principal contributor for the presence of Ra activity concentration in cements. The contribution of aluminosilicate materials, mainly for the presence of K and Th, shows high variability mainly due to the possibility of use of different types of raw materials. The activity concentration is found to be higher in Portland cements relative to Portland-limestone cements with values varying from 12.0 to 16.1 Bq kg for Ra, 46.2-51.2 Bq kg for Th and 133.7-168.8 Bq kg for K. The activity concentration index (ACI), recommended by the Council Directive 2013/59/EURATOM and recently amended in the Albanian legislation, was adopted as a screening tool to assess the radiological hazard due to the use of cements as building materials. The ACI varies from 0.26 to 0.31, which allows us to conclude that potentially these building materials do not pose any significant risk to humans due to their use in dwellings. This conclusion is confirmed by calculating the annual effective dose rate, varying from 0.33 to 0.38 mSv y. [ABSTRACT FROM AUTHOR]

Rock water interactions play an important role in the flow of groundwater. Groundwater samples were collected from deep production wells with depths ranging from 120 to 230 m. Complete chemical analysis of 40 groundwater samples was collected from the fractured limestone aquifer including major cations (Na, K, Ca, Mg) and major anions (Cl, SO , HCO , CO ). A geochemical modeling (NETPATH Software) was applied for environmental simulate net geochemical mass-balance reactions between initial and final waters along a hydrologic flow path. This program simulates selected evolutionary waters for every possible combination of the plausible phases that account for the composition of a selected set of chemical constraints in the system. The groundwater of the Eocene aquifer mainly belongs to fairly fresh water with salinity contents ranging from 228 to 3595 ppm. The measured groundwater levels range between 8 and 25 m near the river Nile to the limestone plateau (eastwards). Consequently, groundwater flows from east to westward toward the river Nile. Groundwater aquifer in the study area is mainly composed of fractured limestone; the saturated states of the PCO, calcite, aragonite, dolomite, siderite, gypsum, anhydrite, hematite, and goethite in addition to H gas were estimated. The undersaturated state of carbon dioxide reflects closed conditions and very low probability of recent recharge, and it reveals also the high tendency of water to precipitates carbonate species. Undersaturation by carbonate minerals is only restricted to some pockets distributed on the different places of the aquifer in the study area. The majority of groundwater samples of Eocene aquifer in the study area indicated that groundwater is not suitable for irrigation with treatment and requires good drainage. [ABSTRACT FROM AUTHOR]

The Taiyuan group is one of the coal-bearing formations in Shanxi Province, in which coal resource is extremely abundant. No.15 coal seam is the main minable coal seam in Taiyuan group, and it develops with thick-hard limestone roof which is a threat to safe and efficient mining because of the roof failure. Aiming at the geological setting of No.15 coal seam and its surrounding rock, we conduct an experimental study on physical and mechanical properties of No.15 coal seam and its floor as well as roof, and we also have an underground measurement on roof fracture width and floor loose range of headgate. Based on experimental results and fracture mechanics theory, we established a thick-hard limestone roof cracking model and discussed the factors that affect roof fracture initiation and extension. The research results demonstrate that roof fracture height is affected by the horizontal stress, surrounding rock deformation, roof mechanical strength and roof span. The deformation of wall and floor will induce the roof fracture extension. The roof fracture extension is high in stress concentration area under the upper coal face residual coal pillar. The fracture height can be effectively controlled by reducing surrounding rock loose range and improving mechanical strength of walls. [ABSTRACT FROM AUTHOR]

The study of the degradation mechanisms of materials constituting historical buildings is very relevant in the context of cultural heritage preservation. In this work, a limestone sample collected from the masonry blocks of the entrance gate of historic Castello Svevo, Bari, Italy, was subjected to depth profile elemental analysis of the ablated black crust and the underlying limestone by double pulse laser-induced breakdown spectroscopy. The specific elemental components were identified and their concentrations along the sample profile analyzed, so allowing to identify the boundary between the weathered and unaltered rock. The laser-induced plasma stability, i.e., the absence of parameter changes during ablation, was verified to be constant and not to affect the elemental peak sizes during the entire depth analysis process when the plasma is confined in the ablation crater. [ABSTRACT FROM AUTHOR]

Four ready-mix commercial available repair mortars-that are used for porous limestone repair-were studied under different laboratory conditions. To have better compatibility with porous limestone, not only pure mortars but also mortars with 50 wt% of limestone aggregate was tested. The reason why limestone aggregate was added to mortar was to modify the strength and porosity. Samples kept under climate control, dry and humid conditions were tested to understand the influence of environmental conditions. The bulk density and uniaxial compressive strength of cubic specimens were measured 3, 7, 14, 28 and 90 days after casting. The microscopic analyses revealed that tested repair mortars contain Portland cement and also non-hydrated cement particles even after curing. The strength of mortars in time does not show similar changes; however, specimens kept under dry conditions show the lowest strength 90 days after casting. High humidity leads to lower strength than normal humidity for tested mortars, but there is one mortar with added limestone aggregate, which has higher strength under humid conditions. In general, adding 50% of porous limestone aggregate reduced the strength and increased the density of repair mortars kept in climate chamber. Limestone aggregate that has larger pores causes a shift in effective pore radii toward smaller pores of 50% limestone aggregate mortar mixtures compared to pure mortars, with one exception. Tests results indicate that these commercially available repair mortars, even though they are suggested to be used for porous limestone, behave very differently under different environmental conditions and that adding limestone aggregate do not shift properties of the mortars toward appropriate compatibility. [ABSTRACT FROM AUTHOR]

To clarify mechanical and permeability characteristics of fractured limestone in complete stress-strain process, the hydromechanical coupling tests with various differential water pressures and confining pressures were performed. The mechanical characteristics of fractured limestone specimens are sensitive to confining pressure, differential water pressure, and effective stress. The increasing differential water pressure weakens the rock strength and deformation modulus by activating the lateral deformation of fractured limestone, which is attributed to the decrease in the effective minimum principal stress. The experimental results verify the validity of Mohr-Coulomb yield criterion considering the effective stress effect under hydromechanical coupling condition. The permeability values display four stages of decrease-gradual increase-rapid increase-small drop in complete stress-strain process, which roughly correspond to volumetric compression stage, elastic deformation stage, yield, and post-peak stage, as well as residual strength stage, respectively. At a low differential water pressure in the range of 2-5 MPa, the corresponding relationship mentioned above is obvious. However, at high differential water pressures up to 8-14 MPa, there is a deviation from the correspondence above, i.e., permeability reduction stage is shorter than the stage of volumetric compression. A cubic polynomial is used to describe the relationship between permeability and volumetric strain at volumetric compression stage. However, it is difficult to describe the relationship between the permeability and volumetric strain by a uniform fitting equation at the dilatancy stage. [ABSTRACT FROM AUTHOR]

Expansive soils are considered as a potential natural hazard if they are not adequately treated. Expansive soils have high potential for shrinking and swelling under changing moisture conditions and cause extensive damages to engineering infrastructures. This study is concerned with the suitability of natural ornamental limestone dust to reduce the swelling characteristics of high expansive soils. The results are revealed that the swelling pressure and percent of heave are greatly decreased with increasing the inserted core diameters and mixing percentages of limestone dust. The average reduction percent values of swelling pressure and percent of heave are increased from 2.21% to 43.09% and from 2.56% to 45.64%, respectively, for treated soil samples with increase in limestone dust core diameters from 5 mm to 20 mm (1% to 16% of total soil area). The average reduction percent values of swelling pressure and heave percent are increased from 10.29% to 70.73% and from 22.29% to 82.90%, respectively, for treated soil samples with increase in limestone dust mixing percentages from 10% to 30%. The results are revealed that the enhancement in swelling characteristics of high expansive soils that are treated by ornamental limestone dust is mostly attributed to the replacement of high expansive fine clay particles by non-expansive and non-plastic coarse limestone dust particles, and to the presence of a considerable amount of free lime in limestone dust (4.97% as [Ca(OH)]) that is responsible for converting the high expansive soils to less expansive soils by pozzolanic reaction. The mixing treatment method is more suitable for surficial and shallow foundation high expansive soil beds, while the compacted limestone dust piles 'inserted limestone dust core method' are more suitable for deep foundation high expansive soil beds. [ABSTRACT FROM AUTHOR]

Compressional Vp and shear Vs velocities measurements were taken out on fluid-saturated shale and limestone obtained from the Ewekoro quarry of Southern Nigeria sedimentary basin at constant differential pressure of 50 MPa with porosities ranging from 0.32 to 0.53% and 0.01 to 0.35 for limestone and shale, respectively, while the volume of clay content C ranges from 0 to 60% and 0 to 40% for limestone and shale, respectively. Correlation coefficient for the velocities of both clean samples and those with clay minerals ranged from 0.972 to 1.000 and 0.971 to 1.000, respectively, with limestone having the lesser for both. A very small amount of clay, about 0.21 and 0.23, reduced the elastic modulus of limestone and shale, respectively. For water-saturated shaly samples, Vs was more sensitive to porosity and clay content than Vp. Consequently, velocity ratios Vp/Vs also showed a reasonable degree of correlations with clay content and porosity. For both limestone and shale studied, the presence of porosity is the most important parameter in reducing velocities followed by clay content due to the softening of its matrix. This study established that wave velocities are functions of porosity and clay content of porous shale and limestone of Ewekoro formations. [ABSTRACT FROM AUTHOR]

Vast amounts of carbide lime waste generated as a by-product of acetylene gas production require urgent utilization to avert handling and disposal difficulties. The carbide lime waste is often rich in calcium hydroxide (Ca(OH)), rendering it an alternative potential precursor for precipitated calcium carbonate (PCC) production. The study demonstrated that suspension of carbide lime can be utilized to synthesize PCC at favorable conditions. The characteristics and crystal morphology of the lime and as-synthesized PCC were determined using X-ray fluorescence and scanning electron microscope. The influencing reaction parameters based on temperature, flow rate, total dissolved solid and carbide lime concentration were investigated. Under specific reaction conditions of 2 M carbide lime concentration, final pH of 6.98, 90 min, and 452.30 mL/min CO flowrate, high purity of 99 % PCC was attained. The produced PCC from carbide lime meets end user requirement on a par with conventional PCC products. [ABSTRACT FROM AUTHOR]

A crushed rock layer is often reveted on a cold-region embankment side slope to keep the underlying permafrost layer cool. However, its cooling effect is strongly affected by the solar absorption of this layer. This study proposes a procedure for measuring the albedo of a heterogeneous surface like a crushed rock layer. The albedo of crushed rock layers with different aggregate sizes is measured. It is found that the albedo of the crushed rock layer decreases with the aggregate size and that the albedo of the crushed rock layer is 0.1–0.2 lower than the albedo of the fresh flat rock. This is because the multiple reflections in the inter-aggregate cavity increase the solar absorption of the layer. Painting the crushed rock layer with high-reflective pigments can increase the albedo of the layer about 0.10–0.20, with the greater increase for the layer with the larger aggregate size. [ABSTRACT FROM AUTHOR]

Atmospheric pollutants are changing due to policies aiming at attenuating climate change. Some of the results of these measures are the current inversion on the SO/NO proportion and the pH increase of acid rains to 5 in some areas. The aim of this study was to have a better understanding of the relation between the microstructural and chemical characteristics of carbonated stones and their response to acid rain effects. This work also compared the response of natural stones as opposed to an artificial stone used in their replacement in the Orval Abbey (Belgium). Three natural and one reconstituted stones were selected. Nitric and sulphuric acidic solutions at pH = 5 were tested. For each solution, two tests of 'passive immersion' and 'active immersion' were conducted. Variations in weight, porosity, dissolved concentrations, colour and surface topography were measured. Stone SEM observations were additionally performed. The results indicate that active immersion is more effective than the passive one. The pore connectivity plays a key role in the stone dissolution and entails a difference between passive and active conditions. The different effect of nitric and sulphuric acids is related to the stone type. In spite of the initial presence of sulphur, the artificial stone appears less sensitive than the natural stone it replaces, due to its low pore connectivity and the concentrated distribution of iron oxides. [ABSTRACT FROM AUTHOR]

The Hasankeyf Antique City located in southeastern Anatolia (Turkey) includes several historical heritages and man-made caves. It is mainly located in dolomitic limestone. The city will be partly under water after reservoir impounding of the Ilısu dam, and the limestone will be subjected to cyclic processes such as wetting-drying and freezing-thawing. Although a new town is formed and part of the city is transported to a nearby area, this cannot be done for many existing historical and cultural values at the site. The behavior of the limestone under cyclic processes is not known. In this study, deterioration mechanisms of the limestone were investigated with field and laboratory studies. It is found that the rock is not durable. Very thin surficial deterioration zone exists on the rock surface. Discontinuity-controlled block failures associated with collapse of man-made caves occur at the site before reservoir impounding. Further discontinuity-controlled block failures are expected to occur after reservoir impounding by aggravated deterioration and surface erosion of the rock within the fluctuation zone of the reservoir. [ABSTRACT FROM AUTHOR]

To study the effect of high temperature on the microstructure and velocity of primary wave (P-wave) propagation in rocks, scanning electron microscope (SEM) experiments, mercury injection experiments and P-wave velocity tests were conducted on limestone samples which had been heated at high temperature (from 25 to 900 °C), and then the variations of P-wave velocity and microstructure were analyzed. Consequently, a P-wave velocity-based damage model was established to evaluate the damage level of limestone. The experimental results showed that: (1) the internal defects of limestone started to develop at 300 °C, and the range of 300-600 °C was the main development stage; (2) the porosity increased slowly with the rising of temperature below 200 °C, and rapidly increased above 300 °C; and (3) the P-wave velocity grew a little below 100 °C and decreased tardily in 100-300 °C, and then sharply decreased in 300-600 °C. The P-wave velocity damage model also shows that damage of the samples occurred above 300 °C. This study suggests that 300 °C should be the damage threshold temperature of limestone, and in 300-600 °C, significant damage of limestone would occur. [ABSTRACT FROM AUTHOR]

The frost weathering of three French limestones [Lens (LS), Migné (MI) and Savonnières (SA)], with different physico-mechanical properties, during the freeze-thaw cycles was studied. The weathering evolution in stone samples undergoing the freeze-thaw cycles was monitored by measurement of following properties: total porosity, P-wave velocity, static elastic moduli, uniaxial compressive strength and toughness. The thermo-mechanical behaviour of stones was also studied by measurement of the strain and temperature (in surface and centre of sample) during one freeze-thaw cycle. These results, mainly the weathering observed for SA(73) with a degree of saturation of 73 % and a lack of weathering for LS with a degree of saturation of 90 %, show that it is impossible to define a unique critical degree of saturation for different stones and this varies from stone to stone. The shrinkage and (or) the expansion of samples during the crystallization phase were determined. The shrinkage is related to the migration of water away from tiny pores towards larger cavities where ice has already formed. The expansion is attributed on the one hand to the rise in pressure that comes from the water which flows towards the ice front and on the other hand to the relatively important quantity of ice formed when thermal contraction and the contraction due to migration dominate. The elastic moduli (static moduli and dynamic moduli) was found to be affected the most by frost weathering and is a real sensor of first micro-crack initiation, whereas the uniaxial compressive strength and the porosity were found to be affected the least. [ABSTRACT FROM AUTHOR]

Tournai stone has been extensively used in Western European historical architecture and is subjected to severe deterioration mechanisms, which were investigated in two Romanesque portals of the cathedral of Tournai city. The stone material was studied with thin-section petrography and SEM-EDX and its hygric, hydric and thermal properties were measured. The porosity is very low and the pore size distribution can be related to either typical pores associated with the clay fraction or with micro-cracks. The formation and propagation of cracks are related to anisotropy of the stone (clay presence in laminae with a preferred direction) and the influence of different external climatic factors. As expected, the effect of liquid water has the highest damage potential while the clay fraction imparts a pronounced hygroscopic behaviour to the stone. The identified clay mineral was illite. Although its non-swelling properties exclude interlayer swelling as a cause of damage, interparticular osmotic pressure is recognized as the most plausible damage cause at the micro-scale. Gypsum crusts occur in two morphologies: films and thick deposits, both showing a comparable layered structure, but significantly differing in the proceeding process and shapes and features. Due to the nature of the stone and of the damage processes, feasible measures for preventive conservation on the long term are to be found in the direction of decreasing the climatic influence by means of sheltering. [ABSTRACT FROM AUTHOR]

The general form of degradation of tuffeau is the progressive spalling of the surface of the stone. Over time, thick plates (1- to 3-cm thick) form gradually on the surface of the stone. Once the plate drops, the resulting stone surface turns into powder. At the Castle of Chambord, mineralogical analysis of the degraded stone, throughout its depth, shows the presence of gypsum (CaSO·2HO) located mainly within a crack network parallel to the surface. The objective of this research is to study different hypotheses of gypsum formation to improve the understanding of the damaging process of spalling. Fresh stones were subjected to artificial ageing in the laboratory through imbibition/drying tests, to study the resulting distribution of gypsum as a function of several parameters: the source of gypsum, initial stone cracking, drying conditions, and analysis after different measurement sequences. Tested samples were analysed at different stages of ageing by using X-ray diffraction and ion chromatography to localise and quantify the amount of gypsum throughout the depth. Results indicate that gaseous SO can lead to a distribution of gypsum very similar to that observed in stones subjected to spalling in situ at the Castle of Chambord. [ABSTRACT FROM AUTHOR]

Rocky slope landscapes are widely distributed on arid land mountains, where there are many restoration and forestation project sites. This study has surveyed the role of deep crevices and stone layers for supplying water to establish trees and shrubs on arid lands rocky slopes. The research was concentrated on the layers of Limestone, Granite and Andesite in central Iran. Thirty Transects, each 25 m long, were randomly laid out throughout the studied lithologic units. Correlation of vegetation cover percentage and abundance of trees were studied along with crack dimensions including width, depth, and length categorized into three classes; large, medium, and low sizes. Along those transects, the amount of EC, pH, organic materials, CaSO, CaCO, soil texture, N, P, K and soil moisture content in the cracks were also measured. The results showed significant differences ( p < 0/05) among crack properties, vegetation cover and life forms in the study units. Also the vegetation cover and life forms have positive significant relationships with increase of crevice width as well as length and depth of each lithologic unit. The findings demonstrated that the inherent potential of limestone rocky slopes with deep layers is higher than other rocky units for restoration and afforestation in this arid region. [ABSTRACT FROM AUTHOR]

Diagnosing the weathering of stones used in built heritage is essential for their preservation. Samples taken from the surface and the core stones of Al-Ziggurat walls in the archaeological city of Al-Nimrud (North Iraq) were characterized. Stone samples from a quarry believed to be the origin of the stones used in the construction of Al-Nimrud were also characterized. Physical properties, pore space system, mineralogical and chemical compositions and microstructural properties of historic, fresh and weathered stones were determined by various complementary techniques at the microscopic level. Results show that the main damage observed on the stone surface of Al-Ziggurat walls is due to salt weathering. Gypsum is the predominant salt and probably originated from the soil in contact with the stones during burial of the walls. Results also indicate that the characteristics of samples of the core of historic stone are quite similar to those of the fresh stone extracted from the quarry, demonstrating that the core of the historic stone is unweathered and that this quarry was probably the source of the construction material for Al-Ziggurat. This means that these fresh stones could be used in future restoration work. [ABSTRACT FROM AUTHOR]

One third of Turkey's surface is underlain by carbonate rocks that have been subdivided into four karst regions. The carbonate rock units are about 200 km wide along the Taurus Mountains that attain elevations of 2500 m. Karst features of western Turkey bordering the Aegean and Mediterranean seas demonstrate the tectonic, lithological and climatic controls on the occurrence, movement, and chemical characteristics of groundwater. In Turkey all karstic feature, such as lapies, caves, sinkholes, uvalas, poljes, ground river valleys developed in all karstic areas. Karstification is related not only to the thickness and to purity of limestone, climate and height but also to tectonic movements. Water resources of karst terrains of Turkey are relatively rich and as such are very important for the economic development of the country. High mountain chains, very often associated with the karst terrains, are responsible for some important and beneficial characteristics of these water resources. Four karst regions are: (1) Taurus karst region, (2) southeast Anatolia karst region, (3) central Anatolia karst region, and (4) northwest Anatolia and Thrace karst regions. [ABSTRACT FROM AUTHOR]

The geochemical and isotope analysis of groundwaters from the Murunkan basin in north western Sri Lanka was carried out to examine their evolution and recharge sources in order to shed light to enhance the current knowledge of the hydro-geochemical processes in a karst geological setting. A total of 40 water samples from ground and surface water bodies were collected from the Miocene limestone terrain, nearby metamorphic and from unconsolidated Quaternary terrains for major anions, cations and environmental isotopes ratios (δO and δH). Distinct geochemical differences were noted between waters from limestone terrain and nearby metamorphic terrain indicating the modification of groundwater flow paths. Bicarbonate-chloride rich water is dominated in the limestone terrain in which water flows through a less mineralized aquifer system and is modified by the sea water intrusion. Groundwater in the metamorphic terrain is modified by dissolving of Ca-Mg rich mineral phases and subsequent ion exchange processes. The environmental isotopes of groundwater from both limestone and metamorphic terrains vary from −0.38 to −6.68 ‰ and −2.41 to −42.3 ‰ for δO and δH, respectively. However, slightly enriched isotope signatures and low d-excess values from limestone terrain indicate an excessive evaporation compared to that of the metamorphic terrain where rapid infiltration occurs through the overlying highly permeable grumusols soil layers. [ABSTRACT FROM AUTHOR]

The Karstic thrust edge, a pronounced geomorphologic step, which is a result of the tectonostratigraphic evolution of the active Adria-Dinarides thrust zone, represents a major obstacle for the planned new railway route Divača-Koper. Thus, the geotechnical and structural properties as well as the geometry of the thrust-fault planes in this area are of great importance. Since geological mapping cannot give insight into the subsurface to reveal a complex 3D structure, and the numerous boreholes needed to investigate the area would be too expensive and time consuming, the application of a geophysical method such as ground penetrating radar (GPR) is needed. To test the method for determining near surface features and detecting low-angle inclined thrusts, a low frequency GPR system with 50 MHz rough terrain antenna was used to record 13 GPR profiles along all three floors of the Črnotiče quarry, where the spatial position of the Socerb thrust fault that separates limestones above and flysch layers below is relatively well documented. The profiles were positioned across selected existing boreholes. The GPR results were correlated with borehole data as well as geological mapping results. The GPR provided not only precise information on the geometry of the Socerb thrust fault, but was also very useful for establishing the position of some known as well as several potential cavities, both air- and sediment-filled. In areas further from the thrust-fault zone, where the limestone is less tectonically damaged, it was also possible to determine apparent dip angles of the strata, which after reconstruction matched the true dips gathered from geological mapping. [ABSTRACT FROM AUTHOR]