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1
Pivko, Daniel. "Litavský vápenec zo St. Margarethenu a Fertőrákosu a jeho využitie na Slovensku ako dekoračný kameň". Geologické práce Správy 138 (24 febbraio 2023): 95–118. http://dx.doi.org/10.56623/gps.138.4.
Abstract (sommario):
In Western Slovakia, especially in the Bratislava region and Trnava region, Leitha limestone of the Badenian (Langhian – early Serravalian) age from St. Margarethen in Austria was widely used for architectural articles and sculptures (200 realizations), alternatively a similar limestone from Fertőrákos in Hungary. 380 tombstones were identified only in Bratislava cemeteries. From the second half of the 17th century to the first half of the 20th century, the limestones were one of the most used in Slovakia due to their light dressing and relatively homogeneous appearance. The strongly porous coarse-grained to medium-grained the Leitha limestone has the appearance of sandstone and is composed of a predominance of red algae nodules over foraminifers, sea urchin, moss and shell fragments. The rhodoliths, pectenoids and oysters are scattered in the Leitha limestones up to a few cm size, which distinguish the limestone type from other the Leitha limestones and similar Sarmatian limestones. The limestone is dominated by rhodolithes in the St. Margarethen quarry and by bivalves and macroscopic quartz in Fertőrákos quarry. Porous limestones are exposed to weathering outdoors, leading to mass loss, flaking, sulphate efflorescence, black crusts from microscopic organisms and the colonization by lichens and mosses. The peak of limestone use for public buildings and sculptures was the years 1745 to 1780 (reign of Maria Theresa), and about 1880 to 1915, when there was relative prosperity and machine production began. The tombstones made of the Leitha limestones shifts to a peak between 1905 and 1925. In the 20th century, the Leitha limestones gave way to a competition from Czech decorative stones.
2
Hagen, Arnulf P., William D. Lee e Tisha M. Jones. "Asphalt-Aggregate Interactions Characterized by Zeta Potential and Retained Strength Measurements for Natural and Organosilane-Treated Aggregates". Transportation Research Record: Journal of the Transportation Research Board 1535, n. 1 (gennaio 1996): 111–16. http://dx.doi.org/10.1177/0361198196153500114.
Abstract (sommario):
Zeta potentials in water have been measured for a poorly performing, easily stripped hard limestone, a well-performing hard limestone, a sandstone, a rhyolite, soda lime glass beads, and for eight AC-20 asphalt binders. Four of the binders selected to represent a range of zeta potentials were combined with the sandstone, the limestones, and the glass beads according to Oklahoma Department of Transportation mix formulas and tested for retained strength. The good hard limestone was the best overall performer with retained strengths of 96 to 100 percent, the poor hard limestone was acceptable, overall the sandstone was unsatisfactory; and the glass beads did not survive the retained strength preconditioning procedure. The aggregates were then treated with organosilane derivatives to chemically modify their surfaces and to change the aggregate zeta potential. For example, the zeta potential of the poor hard limestone was made to be closer to that of the good hard limestone. The modified aggregates were then used in the same mix and the retained strengths measured. The good hard limestone mix exhibited no change in retained strength; however, the poor hard limestone, the sandstone, and the glass bead mixes gave excellent retained strengths.
3
Kramar, Sabina, Nina Žbona, Mojca Bedjanič, Ana Mladenović e Boštjan Rožič. "Drenov Grič black limestone: a heritage stone from Slovenia". Geological Society, London, Special Publications 486, n. 1 (16 luglio 2019): 149–62. http://dx.doi.org/10.1144/sp486-2017-188.
Abstract (sommario):
AbstractDrenov Grič black limestone is considered to be one of the most beautiful Slovenian natural stones due to its black colour interwoven with white veins. Over the centuries, it has been extracted from two major quarries located west of Ljubljana. One of these quarries has been declared a valuable natural feature of national importance and is protected as a natural monument. This well-stratified, Triassic (Carnian) micritic limestone occurs in 10–80 cm thick beds with thin marl interlayers. The limestone occasionally contains abundant fossil bivalves, gastropods and ostracods. It is relatively rich in carbonaceous and bituminous organic matter, which is responsible for the black colour of the stone. The stone has been widely used in Slovenian monuments. Many indoor and outdoor architectural elements have been constructed using this limestone, particularly during the Baroque period, which was known for its extensive use of black limestones in other European countries as well. The most significant use of this limestone has been recorded in sculpted portals and altars. Some important buildings, which were decorated utilizing this stone, have been declared cultural monuments of local or national importance. Use of this limestone was also documented in other European countries (Italy, Austria, Serbia) and worldwide (USA). When exposed to climatic influences, chromatic and salt weathering are recognized as the main deterioration phenomena for this limestone when used in monuments.
4
Mohammed, Syakirah Afiza, Abdul Ghapar Ahmad, Ragunathan Santiagoo, Vikneswaran Vijean, Wan Amiza Amneera Wan Ahmad, Razi Ahmad e Lim Shi Kai. "Optimum Binder Content of Asphaltic Concrete (ACW14) Mixture Incorporating Limestone". IOP Conference Series: Earth and Environmental Science 1216, n. 1 (1 luglio 2023): 012020. http://dx.doi.org/10.1088/1755-1315/1216/1/012020.
Abstract (sommario):
Abstract Due to the high demand for natural aggregates in pavement construction, researchers have been looking for alternative materials to replace natural aggregate. In this research, the optimum binder content of asphalt mixture incorporate limestones was investigated. The optimum binder content of asphalt mixture was tested according to Marshall method. About 20 % of limestone was used as aggregate replacement in asphaltic concrete mixture. To determine the stability, volumetric properties, and bitumen binder content, three percentage of asphalt binder content, namely 4.0%, 5.0% and 6.0% was prepared. From analysis, it indicated that stability and volumetric properties of asphalt mixture incorporate limestone meet the requirement set by JKR. From the result obtained, the optimum binder content of the control sample is 5.0% and optimum binder content of limestone mixture is 5.2%. The slightly different in optimum binder content value indicate that the optimum binder content of limestone mixture was comparable with control mixture.
5
Knezevic, Milan, e Olivera Kosanin. "Genesis and characteristics of the soil in A-R stage in forest ecosystems of NP 'Tara'". Bulletin of the Faculty of Forestry, n. 99 (2009): 75–89. http://dx.doi.org/10.2298/gsf0999075k.
Abstract (sommario):
Different types of soil in A-R stage formed on limestone and serpentinite in forest ecosystems in NP 'Tara' were researched. Based on the specific effect of limestone on the soil genesis and evolution, two types of calcareous limestone bedrocks were distinguished: dense limestones, and soft, marly limestones. Three subtypes of black earth were studied on dense limestones. They are: organogenic, organo-mineral and brownised soils. One soil type was researched on soft, marly limestones: rendzina, the leached variety. One soil type was researched on serpentinites, within the A-R stage: humus-siliceous soil (ranker), subtype eutric ranker. This paper also presents the evaluation of ecological and productive characteristics of the study soils. If the soil is observed separately, regardless of the tree species growing on it, the soils in A-R stage in NP 'Tara' cannot be evaluated as highly productive. However, in all plant communities on the soils in A-R stage on limestone, the values of average volume, current volume increment, and basal area were high. The unfavourable physical characteristics of the soil in the area of NP 'Tara' are compensated by the effect of humid climate. On the study eutric humus siliceous soils in the area of NP 'Tara', in the natural and artificially established stands of Scots pine and Austrian pine, the ecological and productive value is conditioned by numerous factors and it is mainly limited by unfavourable physical characteristics. Regardless of the unfavourable ecological and productive characteristics of the soil, the natural and artificially established stands of Scots pine and Austrian pine are in the coeno-ecological optimum.
6
Wang, Yige, Tao He, Guocheng Rong, Putao Song, Jingliang Xia e Faguang Leng. "Study on Crack Resistance of C35 Limestone Powder Concrete". Journal of Physics: Conference Series 2468, n. 1 (1 aprile 2023): 012025. http://dx.doi.org/10.1088/1742-6596/2468/1/012025.
Abstract (sommario):
Abstract C35 pier concrete was prepared with natural limestone powder and fly ash, and the effect of the proportion of limestone powder and fly ash on hydration heat of composite cementitious material system was studied At the same time, the effects of different proportions of natural limestone powder and fly ash on adiabatic temperature rise, early shrinkage, drying shrinkage and early cracking of concrete were studied. The results show that the hydration heat of composite cementitious material system can be reduced by adding natural limestone powder and fly ash, the early shrinkage and dry shrinkage of concrete can be reduced, and the cracking of concrete can be reduced. On the contrary, when natural limestone powder and fly ash replace cement by 20%, 10% mass ratio, C35 concrete has the best indexes and better crack resistance.
7
Lai, LanXin, Toshio Imai, Motohiro Umezu, Mamoru Ishii e Hironao Ogura. "Possibility of Calcium Oxide from Natural Limestone Including Impurities for Chemical Heat Pump". Energies 13, n. 4 (12 febbraio 2020): 803. http://dx.doi.org/10.3390/en13040803.
Abstract (sommario):
Improving energy recycle is an important way to save energy resources and preserve the global environment. Chemical heat pump (CHP) is a technology for saving energy, which utilizes chemical reactions to store thermal energy such as waste heat and solar heat, then release it to provide heat for heating/cooling/refrigeration. For a practical CHP, it is necessary to find cheaper and more stable supply materials. In order to evaluate the possibility of calcium oxide from natural Ofunato natural limestone including impurities, we compare Ofunato limestone with Kawara natural limestone and Garou natural limestone from Japan. These calcium oxides worked as a reactant for CaO/H2O/Ca(OH)2 CHP by repeated hydration/dehydration reaction cycle experiments in a thermogravimetric analyzer. As a result, Ofunato CaO exhibits a high hydration reaction rate after decarbonization at 1223 K for 5 h. The reactivity increased by the repeated hydration reaction although the first hydration rate was low. Furthermore, the sintering of impurities in Ofunato limestone occur easier than that in Kawara limestone with lower impurities. The impurities adhered to the surface of the CaO particle to make specific surface area of CaO particle smaller, which could inhibit hydration reaction of CaO particle. Even if Ofunato limestone contains some impurities, it can be utilized as a raw material for chemical heat pumps.
8
Hao, Xiu Hong, Ai Qin Zhang e Zhi Guo Liu. "Influence of Fine Aggregate on the Performance of Asphalt Concrete". Advanced Materials Research 598 (novembre 2012): 655–58. http://dx.doi.org/10.4028/www.scientific.net/amr.598.655.
Abstract (sommario):
The performance of asphalt concrete mixed with 3 types of fine aggregate respectively (i.e. natural sand, limestone, basalt) are compared. The results of Marshall test and rutting test show that the high temperature performance of asphalt mixture mixed with basalt is the best, that of asphalt mixture mixed with natural sand is the worst, and that of asphalt mixture mixed with limestone is between the above two. The result of immersion Marshall test show that the water stability of asphalt mixture mixed with basalt and that of asphalt mixture mixed with limestone are similar, but better than that of asphalt mixture mixed with natural sand. Therefore, it indicates that the machine-made aggregate (of basalt or limestone) have better pavement performance and environment benefit than the natural sand.
9
Kostohryz, K. P., V. A. Zhaivoronok, Yu I. Khvastukhin e S. M. Roman. "PRODUCTION OF LIME WITH HIGH REACTIVITY IN A FLUIDIZED BED APPARATUS OF AN INERT MATERIAL". Energy Technologies & Resource Saving, n. 1 (20 dicembre 2018): 31–37. http://dx.doi.org/10.33070/etars.1.2018.04.
Abstract (sommario):
In dry desulfurization, for example, of gaseous combustion products of thermal power plants and incineration plants, calcium oxide CaO, as a product of firing of natural carbonate rocks, mainly limestones (CaCO3), is widely used. Firing technology, depending on the limestone heat treatment regimes, form a product with certain physicochemical properties: porosity, specific surface, shrinkage value, chemical activity. The influence of heat treatment conditions on the properties of the product obtained is studied. The possibility of fast low temperature heat treatment of finely dispersed limestone in a fluidized bed of an inert material to produce CaO of the required quality is shown. Research facility, technique for carrying out experiments and processing experimental data are described. As a result of the research, the degree of calcination of 80 % of fine limestone in a device with fluidized bed of inert material was achieved and the residence time of the particles in the inert layer was determined. Bibl. 10, Fig. 2, Tab. 1.
10
La Verde, Giuseppe, Adelaide Raulo, Vittoria D’Avino, Giovanni Paternoster, Vincenzo Roca, Marco La Commara e Mariagabriella Pugliese. "Pietra Leccese and Other Natural Stones in Puglia Region: A New Category of Building Materials for Radiation Protection?" International Journal of Environmental Research and Public Health 18, n. 21 (26 ottobre 2021): 11213. http://dx.doi.org/10.3390/ijerph182111213.
Abstract (sommario):
In this paper, an in-depth and systematic study of the radiological characterization of three types of Puglia region natural limestones (Pietra Leccese, Pietra Mazzara and Carparo) was carried out. The investigation was performed by XRF spectroscopy for a chemical analysis, and gamma spectroscopy of the specific activity concentration of natural radionuclides 226Ra, 232Th, and 40K. Although the limestone does not fall within the category included by Italian Legislative Decree 101/2020, the gamma index was calculated using the results of the gamma spectroscopy measurements. For Pietra Mazzara and Carparo stones, the gamma index was found to be less than the reference value; conversely Pietra Leccese was found to be higher. To obtain a more complete evaluation of the external exposure, radium equivalent activity and external radiation hazard were calculated for all analyzed stones. The results suggest the need to broadly consider the radiological risk for these stones, and for limestone more generally, when used as a building material.
11
Vyšvařil, Martin, Tomáš Žižlavský, Štěpán Zimmermann e Patrik Bayer. "Effect of Aggregate Type on Properties of Natural Hydraulic Lime-Based Mortars". Materials Science Forum 908 (ottobre 2017): 35–39. http://dx.doi.org/10.4028/www.scientific.net/msf.908.35.
Abstract (sommario):
In the current restoration practice, the mortars based on aerial or hydraulic lime with siliceous aggregate are used on repair / reconstruction of historical plasters. The resulting properties of lime mortars do not depend only on the type of aggregate, but also on its contamination, origin and a degree of hardening. For this reason, it is needed to know a detailed characteristic of the aggregate and the results obtained for the particular aggregate cannot be generally applied for the similar type of aggregate. This work presents the applicability of Czech local crushed limestone aggregate and limestone fines as a filler to natural hydraulic lime-based mortars. The role of aggregate and limestone fines on the properties of mortars is examined by comparing the mechanical strengths, porosity and frost resistance of the mortars with pure quartz sand and limestone aggregate and its quantity in the mortar. It was found that the limestone aggregate has produced lower strengths, higher total porosity of natural hydraulic lime-based mortars. It has resulted in low frost resistance of the mortars.
12
Vzorodov, Sergey A., e Anton M. Klyushnikov. "Process features of neutralization of technical sulfuric acid with natural limestone". Butlerov Communications 58, n. 4 (30 aprile 2019): 110–18. http://dx.doi.org/10.37952/roi-jbc-01/19-58-4-110.
Abstract (sommario):
The work was devoted to the solution of the environmental problem associated with the disposal of sulfur dioxide emissions from metallurgical production at the Nadezhda Metallurgical Plant (Norilsk, Norilsk Nickel PJSC). For utilization of sulfur dioxide it is planned to build a sulfuric acid plant. Concentrated sulfuric acid produced at plant is planned to be neutralized with natural limestone. This work presents the results of the study on the neutralization of concentrated sulfuric acid with limestone pulp from the Mokulay deposit (Norilsk). The influence of the following parameters was investigated: limestone consumption, acid dosing rate, limestone pulp density. It is established that the process is limited by the internal diffusion of acid through the layer of gypsum. In order to eliminate internal diffusion process it is advisable to carry out neutralization in a periodic mode by introducing a strictly measured amount of acid into an excess amount of limestone pulp. This process allows one to speed up the process of neutralization in 3-3.5 times and achieve a higher value of the final pH of the pulp comparing with continuous process. Carrying out the process in the periodic way also makes it possible to achieve the complete absence of the release of acidic off-gas during neutralization. The optimal values of neutralization parameters were determined as the following: limestone pulp density was 11-12%, acid delivery time was 40 minutes, neutralization time was 20 minutes, and final pH value was at least 6.5, while the limestone feeding was an excessive by 22-28% from stoichiometry. It was shown that an increase in the limestone pulp density is impractical because it will lead to an increase in the duration of neutralization, as well as to a sharp increase in the viscosity of the gypsum pulp. That, in its turn, makes gypsum pulp difficult to flow from the neutralization apparatus. It was recommended to filter the resulting pulp in order to obtain a gypsum cake with a moisture content of about 55%. It was recommended to store cake on a special site. A flowsheet has been developed and process schedules have been implemented for the design of a neutralization plant with a capacity of up to 2 million tons technical sulfuric acid per year.
13
Dolák, Dušan, Karel Dvořák e Jaroslav Bureš. "Effect of Firing Temperature on Reactivity and Sedimentation Volume of Different Types of Limestones". Materials Science Forum 908 (ottobre 2017): 45–50. http://dx.doi.org/10.4028/www.scientific.net/msf.908.45.
Abstract (sommario):
Limestone as a natural rock tends to have various parameters. Variation in parameters, as well as firing temperature have significant impact on key properties of quicklime. Sedimentation volume and reactivity determine quality of quicklime in building industry. This paper is focused on monitoring the reactivity and sedimentation volume of quicklime prepared from various types of limestone at different temperatures. Selection of limestones with high purity collected from various quarries around the world were characterized by porosity, chemical and petrographic composition. To create quicklime, these samples were fired at 4 different temperatures. Reactivity measurements were made on quicklime with specific particle size. Sedimentation volume of hydrated slurry was determined. Obtained results suggest that there is tendency for slower reactivity and smaller sedimentation volume with increased firing temperature.
14
ARIK, Fetullah, Figen UYSAL e Yeşim ÖZEN. "Evaluation of the Usability of Miocene Aged Carbonate Rocks as Natural Building Stone in South of Konya". Afyon Kocatepe University Journal of Sciences and Engineering 22, n. 2 (30 aprile 2022): 405–16. http://dx.doi.org/10.35414/akufemubid.1066508.
Abstract (sommario):
The block material taken from the light brown, dirty yellow, beige and cream colored lacustrine limestones (Gödene stone) of the Upper Miocene Ulumuhsine formation, located between the villages of Hatip-Pamukçu-Dikmeli-Karagın-Çayırbağı in the southwest of Konya, is generally well-bedded and the layer thicknesses are between 10 cm and 2 cm. The layer surfaces are quite clean and smooth. Due to it was deposited in a shallow lake environment, it gained a porous and hollow structure as a result of decay. Ulumuhsine limestone, which was examined petrographically, is in demand in the market in terms of color, pattern and texture harmony. To determine the physical and mechanical properties of the lacustrine limestones of Ulumuhsine formation (Gödene taşı), in accordance with TS 699 standards, unit weight, porosity, void ratio, water absorption by weight and weight loss after frost, uniaxial compressive strength, bending strenght, impact strenght, Böhme abrasion resistance tests were carried out. As a result of the experiments carried out according to TS 699 and TS 11143 standards, it was concluded that the Miocene aged carbonate rocks in the south of Konya can be used as building and covering stones, but they should be preferred more in pavement due to the low impact strenght and Böhme abrasion resistance test values. Approximately 4.000.000 m3 of producible limestone reserves were calculated in the region.
15
Yofianti, D., e U. A. Latuconsina. "Application of the use of local natural materials as cement treated base materials". IOP Conference Series: Earth and Environmental Science 1267, n. 1 (1 dicembre 2023): 012103. http://dx.doi.org/10.1088/1755-1315/1267/1/012103.
Abstract (sommario):
Abstract The use of local natural materials as alternative materials in road construction could save construction costs, especially for Maluku Province. One of the local natural materials in Maluku Province is Limestone in Kelan Village and Kaliobar Village. Therefore, this study aims to see how far the use of limestone to be applied as a cement treated base material. Before being applied, the limestone is tested first in the laboratory. After the limestone was applied as a cement treated base (CTB) material, compaction and compressive strength tests were carried out. The number of CTB compressive strength test specimens was 26 samples from STA 4+100 to STA 8+900. The limestone on Larat Island is unique in that it contains the composition CaCO3 (Calcium Carbonate), which is the result of shallow sea sedimentation. The potential of limestone in the work location area has not been utilized optimally to improve the economic level of the community. The test results show that the compressive strength values obtained are still within the interval range, namely between 25 - 40 gr/cm2. Therefore, it can be concluded that the CTB mixture material at this location meets the requirements to be used as a foundation layer for road pavement using local natural materials.
16
Labus, Krzysztof. "Comparison of the Properties of Natural Sorbents for the Calcium Looping Process". Materials 14, n. 3 (24 gennaio 2021): 548. http://dx.doi.org/10.3390/ma14030548.
Abstract (sommario):
Capturing CO2 from industrial processes may be one of the main ways to control global temperature increases. One of the proposed methods is the calcium looping technology (CaL). The aim of this research was to assess the sequestration capacity of selected carbonate rocks, serpentinite, and basalt using a TGA-DSC analysis, thus simulating the CaL process. The highest degrees of conversion were obtained for limestones, lower degrees were obtained for magnesite and serpentinite, and the lowest were obtained for basalt. The decrease in the conversion rate, along with the subsequent CaL cycles, was most intense for the sorbents with the highest values. Thermally pretreated limestone samples demonstrated different degrees of conversion, which were the highest for the calcium-carbonate-rich limestones. The cumulative carbonation of the pretreated samples was more than twice as low as that of the raw ones. The thermal pretreatment was effective for the examined rocks.
17
Wang, Ya Li, Shi Jie Dong, Lin Lin Liu e Su Ping Cui. "Using Calcium Carbide Slag as One of Calcium-Containing Raw Materials to Produce Cement Clinker". Materials Science Forum 743-744 (gennaio 2013): 171–74. http://dx.doi.org/10.4028/www.scientific.net/msf.743-744.171.
Abstract (sommario):
Calcium carbide Slag is from CaC2 hydrolysis reaction and will do harm to land and make pollution. Calcium carbide slag can be a substitute for limestone to produce clinker with a high portion of CaO as an excellent calcium raw material. As a kind of industrial wastes, the properties of calcium carbide slag differentiate from that of natural limestone. In the present investigation, the modern analysis methods of XRF, XRD, DTA/TG, petrographic analysis were used to compare carbide slag and limestone, and the results showed that the main chemical compositions of the calcium carbide slag were basically the same with that of natural limestone. Comparing with limestone materials, calcium carbide slag had a higher content of CaO, and the main mineral phase constituent of limestone was CaCO3, whereas the main mineral of calcium carbide slag was Ca (OH)2 with a lower decomposition temperature. It has been found that under the same temperature the amount of C3S in the clinker of calcium carbide slag batching was slightly less than that of limestone batching.
18
Ahmad, Muhammad, Muhammad Sajjad, Irfan Khan, Amina Durrani, Ali Durrani, Saeed Gul e Asmat Ullah. "Sustainable production of blended cement in Pakistan through addition of natural pozzolana". Chemical Industry and Chemical Engineering Quarterly 22, n. 1 (2016): 41–45. http://dx.doi.org/10.2298/ciceq141012017a.
Abstract (sommario):
In this work pozzolana deposits of district Swabi, Pakistan were investigated for partial substitution of Portland cement along with limestone filler. The cement samples were mixed in different proportions and tested for compressive strength at 7 and 28 days. The strength activity index (SAI) for 10 % pozzolana, and 5% limestone blend at 7 and 28 days was 75.5% and 85.0% satisfying the minimum SAI limit of ASTM C618. Twenty two percents natural pozzolana and five percents limestone were interground with clinker and gypsum in a laboratory ball mill to compare the power consumption with ordinary Portland cement (OPC) (95% clinker and 5% gypsum). The ternary blended cement took less time to reach to the same fineness level as OPC due to soft pozzolana and high grade lime stone indicating that intergrinding may reduce overall power consumption. Blended cement production using natural pozzolana and limestone may reduce the energy consumption and green house gas emissions.
19
Prestes, Nelson Eduardo, Cassandro Vidal Talamini do Amarante, Cassiano Eduardo Pinto, Gabriel Prestes, Guilherme Doneda Zanini, Cauby Medeiros-Neto e André Fischer Sbrissia. "Forage production in a natural grassland with limestone and phosphorus dosages". Semina: Ciências Agrárias 37, n. 5 (26 ottobre 2016): 3265. http://dx.doi.org/10.5433/1679-0359.2016v37n5p3265.
Abstract (sommario):
The objective of this study was to assess forage production in a natural grassland by applying different doses of limestone and phosphorus, and the influence of these applications on soil profile. The treatments consisted of the application of limestone doses of 0.0, 7.2, and 14.4 t ha-1 and phosphorus doses of 0,35, 70, and 140 kg of P2O5 ha-1 on the soil surface. The experiment was conducted in a randomized complete block design with split-plots and three replications. The limestone doses were distributed in the main plot and applied only at the beginning of the experiment, whereas the phosphorus doses were distributed in the subplots with subsequent annual maintenance applications. Was used a ruler (cm) for monitoring the growth of pastures and, when grasses reached an average height of 20 cm, forage samples were collected in each subplot and botanical and morphological components were separated and dried until a constant weight was achieved. In the third and fourth assessment years, soil samples were collected in the 0-5, 5-10, 10-15, and 15-20-cm layers to evaluate the influence of treatments on the chemical properties of the soil. The variables analyzed were related to the production of several components, including fodder, native grasses, leguminous plants, unwanted plants, and dead material, in addition to soil properties such as pH, exchangeable aluminum concentration, and base saturation. There was no interaction between the limestone and phosphorus treatments. The effect of limestone doses on forage production was assessed in the third year, and, in the following year, the intermediate dose of limestone (7.2 t ha-1) produced the highest yield (2,316.1 kg of dry matter [DM] of forage ha-1). The increase in phosphorus doses increased forage production in the second year, and reached yields of up to 2,232 Kg DM ha-1 in the fourth year. In summary, the production of natural pastures was enhanced by the application of 25% of the recommended dose of limestone (7.2 t ha-1), and by the application of 50% of the recommended dose of phosphorus (70 kg P2O5 ha-1). The increase in limestone doses directly affected the chemical properties of the soil by decreasing acidity and exchangeable aluminum, and increasing base saturation, even in deeper layers (0-20 cm). The increase in phosphorus doses did not increase the mobility of this nutrient in the deeper layers of the soil (10-20 cm), and the effects were restricted to a depth of up to 10 cm.
20
Zhang, Xutao, Mingyang Ren, Zhaobo Meng, Baoliang Zhang e Jinglong Li. "Experimental Study on the Mechanical Behavior of Yunnan Limestone in Natural and Saturated States". Advances in Civil Engineering 2021 (28 febbraio 2021): 1–16. http://dx.doi.org/10.1155/2021/6614412.
Abstract (sommario):
Rock material is a kind of mineral assemblage with complex structural heterogeneity, whose mechanical behavior is strongly affected by water or moisture content. In this work, we carried out a series of laboratory tests to investigate the mechanical response (e.g., deformation, strength, and failure characteristics) of Yunnan limestone in natural and saturated states. Our test results show that (1) after saturation, the stiffness and strength of Yunnan limestone degenerate considerably. Compared with the natural condition, the elastic modulus, deformation modulus, and tensile modulus decrease by about 30% on average, and uniaxial compressive strength and tensile strength also decrease by about 15% and 20%, respectively. While Poisson’s ratio is less affected by water content, it can be regarded as a constant; (2) the elastic modulus and deformation modulus of Yunnan limestone are significantly affected by confining pressure, and the relationship between them and confining pressure satisfies the law of hyperbolic function; (3) the peak strength envelope of Yunnan limestone has significant nonlinear characteristics, which can be well described by generalized Hoek-Brown strength criterion. However, the generalized Hoek-Brown criterion does not apply to the residual strength, which shows a linearly increasing trend with the increasing confining pressure; (4) the failure modes of Yunnan limestone are significantly dependent on confining pressure but insensitive to water content. With the increasing confining pressure, the failure modes of Yunnan limestone transform from splitting failure, tension-shear mixed failure, single inclined plane shear failure to Y-shaped or X-shaped conjugated shear failure. The test results can provide important experimental data for the establishment of the constitutive model of Yunnan limestone, which will contribute to obtain more reliable results for stability assessment of Xianglu Mountain Tunnel.
21
Yusupov, A. R., V. K. Suleymanov, A. A. Alimagomedov, K. G. Alkhulaev e A. S. Mamaev. "NATURAL MONUMENTS OF THE REGION OF LIMESTONE DAGHESTAN". PROCEEDINGS OF INSTITUTE OF GEOLOGY DAGESTAN SCIENTIFIC CENTER OF RAS 76, n. 1 (2019): 8–12. http://dx.doi.org/10.33580/2541-9684-2019-63-1-8-12.
22
Semenov, V. S., I. V. Stepina, I. A. Kotlyarova e D. A. Ilushkin. "Assessment of reliability of natural limestone cladding material". IOP Conference Series: Materials Science and Engineering 918 (7 ottobre 2020): 012105. http://dx.doi.org/10.1088/1757-899x/918/1/012105.
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Doina-Cezara, Albu. "Use of Limestone Blocks in Constructions in the Republic of Moldova". Bulletin of the Polytechnic Institute of Iași. Construction. Architecture Section 67, n. 1 (1 marzo 2021): 47–56. http://dx.doi.org/10.2478/bipca-2021-0004.
Abstract (sommario):
Abstract One of the most important problems in modern society is the problem of using natural, ecological, harmless products for humans. In construction, this problem is solved by selecting, combining and using natural, traditional materials for some geographical areas. The most widespread in the world, starting from antiquity, is limestone. The limestone block, the so-called „cotileț”, is a construction material that has been used in masonry for over 60 years on the territory of the Republic of Moldova. In this research is considered dynamic extraction of limestone blocks, are analysed existing excavations and its location, the limestone reserves in Moldova. The technical characteristics of the „cotileț” are studied, such as dimensions, density, water absorption level, softening coefficient and earthquake resistance. At the same time, the existing buildings on the territory of the Republic of Moldova were examined and the characteristics of those built of limestone blocks were highlighted.
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Wahab, Majd I. Abdul, Awatif Soaded Alsaqqar e Sura Kareem Ali. "REMOVAL OF PHOSPHORUS FROM WASTEWATER BY ADSORPTION ONTO NATURAL IRAQI MATERIALS". Journal of Engineering 17, n. 02 (1 aprile 2011): 395–411. http://dx.doi.org/10.31026/j.eng.2011.02.15.
Abstract (sommario):
This study focused on treating wastewater to remove phosphorus by adsorption onto naturaland local materials. Burned kaolin, porcelinite, bauxite and limestone were selected to be testedas adsorption materials.The adsorption isotherms were evaluated by batch experiments, studyingthe effects of pH, temperature and initial phosphorus concentration. The results showed that at pH6, temperature 20°C and 300 mg/l initial phosphorus concentration; the sorption capacity was0.61, 9, 10 and 13 mg/g at 10 h contact time, for burned kaolin, porcelanite, limestone and bauxiterespectively. As the pH increased from 2 to 10 the removal efficiency for the materials differs inbehaviour. The removal efficiency increased from 40 to 90 % for limestone, and decreased from60 to 30 % for porcelinite. As for bauxite it increased from 60 to 90 % reaching pH 6 thendecreased to 30%. Burned kaolin showed the lowest adsorption capacities in these tests. Theadsorption isotherms showed that the Langmuir–Freundlich model significantly correlated theexperimental data for porcelinite and bauxite, whereby the Freundlich model was best forlimestone. The Freundlich and Langmuir–Freundlich models both fit for Burned kaolin. Theresults show that it is possible to adsorb phosphate from wastewater onto natural Iraqi materialand their ability could be ranged as limestone> bauxite> porcelanite> burned kaolin.
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Mutaz, Elamin, Muawia Dafalla, Ahmed M. Al-Mahbashi e Mehdi Serati. "Utilizing Crushed Limestone as a Sustainable Alternative in Shotcrete Applications". Materials 17, n. 7 (25 marzo 2024): 1486. http://dx.doi.org/10.3390/ma17071486.
Abstract (sommario):
Solving the challenges facing the mining industry is crucial for shaping the global attitude towards clean energy technologies associated with critical minerals extracted from depth. One of these challenges is the well-known explosion-like fractures (rockbursts) or spalling failures associated with the initiation of internal cracks. To prevent such catastrophic failure, shotcrete, as a cement grout, is widely used in tunnel support applications. In areas where the tunnels are constructed within the limestone strata using tunnel boring machines (TBM), drilling, and/or blasting, millions of cubic meters of crushed limestone (CL) in powder form are extracted and landfilled as waste. Given the fact that natural sand consumption as a raw material in the construction industry exceeds previous records, recycling of such excavation material is now becoming increasingly needed. From this perspective, this study aims to utilize crushed limestone as a potentially sustainable alternative to natural sand in shotcrete applications in deep tunnels. Accordingly, several strength characterization and crack initiation determinations through various stress–strain-based models were carried out on cylindrical samples containing different proportions of crushed limestone. By increasing the crushed limestone content in the shotcrete mix, the crack initiation stress (as a measure of the in situ spalling strength) increased as well. The results suggest that the crushed limestone has good potential to replace the natural sand in the shotcrete mixture used in tunnel support applications.
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Rokhman, Abdul, e Dhani Van Chairi. "Pemanfaatkan Subtitusi Fly Ash dan Bahan Kapur Alam untuk Peningkatan Mutu Paving Block". Jurnal Sipil Krisna 8, n. 2 (26 ottobre 2022): 57–67. http://dx.doi.org/10.61488/sipilkrisna.v8i2.168.
Abstract (sommario):
Utilization of waste materials as building materials is a solution to reduce waste materials that exist in nature.Fly ash as a waste product from coal combustion contains silica which can be used to increase the compressivestrength of concrete/mortar. Paving Block as a building material made of mortar composition can be increasedits compressive strength by substituting some cement material with fly ash. Fine aggregate material in the formof sand can also be substituted with natural limestone waste material. In this study, paving blocks were madeusing limestone as a substitute for fine aggregate and fly ash as a cement substitute. The ratio of materials formaking paving blocks is 1: 4. For variations of substitution materials, fly ash is used as a cement substitution.The variation of fly ash is 20% and while the limestone waste is used variations of 0%, 10%, 20%, 30% and 40%.The compressive strength test was carried out at the age of 7 days, 14 days, and 28 days. The results of the studyof compressive strength at the age of 7 days obtained a value of 12.24 MPa at a natural limestone substitutionconcentration of 20.7%. For the age of 14 days the compressive strength value is 15.27 MPa with an optimumconcentration of 20.1% at the concentration of natural limestone, while at the age of 28 days the compressivestrength value is 17.11 MPa, with the optimum concentration of natural limestone material being 20. .15%. Theincrease in compressive strength from the optimum mixture to the normal mixture was 28.93%. Based on SNI 03-0691-1996 the paving blocks produced in this study include Quality B.
27
Amaral, Pedro M., Rui S. Camposinhos e José C. Lello. "Natural Stone Testing Specification for a New Facade System". Key Engineering Materials 548 (aprile 2013): 295–303. http://dx.doi.org/10.4028/www.scientific.net/kem.548.295.
Abstract (sommario):
This paper discusses in detail the materials properties that should be evaluated for producing large prestressed natural stone cladding panels made of limestone, marble and granite. The work underlines the importance of having standard test procedures used to determine the stone properties employed in the design and dimensioning of prestressed panels. A case-study using 2 types of stones (granite and limestone) is presented to exemplify the application of the stone characterisation under the scope of the technical specification. When safety requirements consider the environmental aspects of the application, the design and dimensioning of the panels must consider the decay of the properties evaluated under the corresponding natural stone specification.
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Sutrisno, Sutrisno, e Azhari Azhari. "The Study of Socioeconomic and Environmental Aspects of Dolomite Limestone Mining in Tuban Regency". Journal of Socioeconomics and Development 3, n. 1 (22 aprile 2020): 63. http://dx.doi.org/10.31328/jsed.v3i1.896.
Abstract (sommario):
Limestone mining in Tuban District has serious problems due to unlicensed mining that does not comply with conservation rules and mining procedures standards. This review article aims to study the socioeconomic and environmental aspects of limestone mining in Tuban Regency. Limestone mining by the village community substantially meets the eligibility criteria. Most of them work as unlicensed or illegal miners, mining kumbung limestone as material for building bricks. They generally work for landowners or investors who have limestone management rights. Livelihoods as miners provide better welfare guarantees compared to working on agricultural land. Limestone mining activities have impacted the destruction of the natural landscape, leaving lakes, caves, or giant holes in the ex-mining limestone hills. Efforts to resolve the issue include licensing arrangements, partnerships to improve the status of illegal miners, reclamation work to control erosion, and the development of the limestone tourism business. JEL Classification: J21, L72, Q15
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Zakaria, Myrna Nurlatifah, Ida Rodiyah Siti Halimah, Atia Nurul Sidiqa, Ira Artilia e Arief Cahyanto. "Antimicrobial Activity of Calcium Hydroxide Synthesized from Indonesian Limestone against Enterococcus faecalis". Materials Science Forum 1044 (27 agosto 2021): 171–77. http://dx.doi.org/10.4028/www.scientific.net/msf.1044.171.
Abstract (sommario):
Recurrent endodontic infections of treated teeth are mainly linked to microbial persistency in the root canal system. Enterococcus faecalis is a bacterium that is often identified in these recurrent infections. Calcium hydroxide (Ca(OH)2) is a widely used root canal medicament and is now being developed to be produced from natural materials. Ca(OH)2, which is synthesized from natural limestone from Palimanan, Indonesia, has a structure similar to Ca(OH)2, which is often used as a root canal medicament. The purpose of this study was to determine the antimicrobial property of Ca(OH)2 paste synthesized from natural limestone compared to conventional Ca(OH)2 paste. This study is an in vitro experimental study consists of 3 groups (n=24, namely, conventional Ca(OH)2 paste, limestone synthesized Ca(OH)2 paste, and saline as the negative control, for 2 intervals of time and evaluated by Total Plate Counting (TPC) method. Samples were mandibular first premolar root canal prepared by root canal preparation and contaminated with E. faecalis (ATCC 29212). The infected root canals of each group were treated by the medicaments, and samples from the root canals were taken on day 7 (n=4) and 14 (n=4). Results showed that both Ca(OH)2 groups had antimicrobial activities against E. faecalis. The limestone Ca(OH)2 paste group had the least amount of bacterial colonies on the 7th day compared to other groups. In contrast, on the 14th day, the conventional Ca(OH)2 paste had the least bacterial colonies. It can be concluded that the Ca(OH)2 paste synthesized from natural limestone has an antimicrobial effect on E. faecalis, the antimicrobial effect was higher on the 7th day but decreases on the 14th day, whereas the conventional Ca(OH)2 had a higher antimicrobial effect on day 14 compared to day 7. Further studies are expected to improve the long-term antimicrobial effectiveness and sustainability of the natural limestone synthesized Ca(OH)2 paste.
30
Guilbert, Daphne, Tim De Kock, Steven Caluwaerts, Veerle Cnudde, Klaas Calle e Nathan Van Den Bossche. "The urban heat island effect on frost damage of natural building stones." MATEC Web of Conferences 282 (2019): 02086. http://dx.doi.org/10.1051/matecconf/201928202086.
Abstract (sommario):
Climate plays a major role in the weathering of building stones. This study specifically investigates the influence of the urban heat island (UHI) in Ghent, Belgium, on freeze-thaw (F-T) weathering of natural building stones and their hydrophobic equivalent. Climatic analysis of data of two places in and around Ghent indicates higher temperatures and lower wind speeds in the city center. This leads to a reduced number of F-T cycles and a lower wind-driven load. Hygrothermal modelling of a natural building stone, Savonnières limestone, is performed for the urban and rural climate of Ghent on the untreated limestone and on the treated limestone to assess the freeze-thaw risk inside these materials. Urban climate has a mitigating effect on the potential frost risk in natural building stones as a result of the urban heat island. Additionally, the application of a water repellent product reduces the potential frost risk even more, since the water density in the stone is reduced.
31
Elsen, Jan, Marie D. Jackson e Encarnación Ruiz-Agudo. "Historic Concrete Science: Opus Caementicium to “Natural Cements”". Elements 18, n. 5 (1 ottobre 2022): 301–7. http://dx.doi.org/10.2138/gselements.18.5.301.
Abstract (sommario):
The history of mineral components in cementitious materials begins with clays and bitumen in the most ancient mortars, followed by gypsum- and lime-based plasters, mortars, and concretes. Romans perfected the fabrication of extremely durable mortars that form the basis of audacious architectural monuments in Rome, massive harbor constructions, and water-proofed cisterns in the Mediterranean region. During the industrial revolution, “natural cements” were developed through the burning of impure limestone or Si- and Al-bearing materials blended with pure limestone. Delving into the past of concrete science and the composition, durability, and resilience of historic binders, mortars, and concretes can inspire the development of modern environmentally friendly cementitious materials.
32
Dias, Luís, Tânia Rosado, Ana Coelho, Pedro Barrulas, Luís Lopes, Patrícia Moita, António Candeias, José Mirão e Ana Teresa Caldeira. "Natural limestone discolouration triggered by microbial activity—a contribution". AIMS Microbiology 4, n. 4 (2018): 594–607. http://dx.doi.org/10.3934/microbiol.2018.4.594.
33
El-Sohby, M. A., e A. M. Elleboudy. "Instability of natural slope in interbedded limestone and shale". International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts 26, n. 2 (marzo 1989): 89. http://dx.doi.org/10.1016/0148-9062(89)90317-3.
34
Diwan, V., e S. K. Sar. "Limestone: A Natural, Low-Priced Adsorbent for U(VI)". Radiochemistry 65, n. 3 (giugno 2023): 354–62. http://dx.doi.org/10.1134/s1066362223030128.
35
Saleh, Shaif Mohammed Kasem, Radhwan Mohammed Saleh e Amal Hasen. "A STUDY ON THE DEFLUORIDATION FROM WATER BY USING LOCAL LIMESTONE". Electronic Journal of University of Aden for Basic and Applied Sciences 3, n. 4 (31 dicembre 2022): 276–83. http://dx.doi.org/10.47372/ejua-ba.2022.4.196.
Abstract (sommario):
Removal of excess fluoride [F-] from the water has been attempted by several authors by using different materials both natural and artificial. The main aim of this study was to the fluoride removal by using the local limestone adopting column method. The use of limestone obtained from the National Company of Cement (NCC) at Wadi Saim deposit and Wadi Nakhleen deposit, in Lahj Governorate, Yemen. X-ray spectroscopy analyses revealed that that limestone are classified as high and very high pure limestone, respectively. Local limestone has fluoride removal abilities by phosphoric acid (PA)- local crushed Limestone treatment (PACLT), with the treated water conforming to WHO guidelines for Fluoride in drinking water. Fluoride removal and pH of treated water attained stability within 3ℎ for defluoridation from 10 mg/L [F-], to 0.20 mg/L with 0.68 mM [PA]. The results may be useful for suitability of local limestone for fluoride removal from drinking water.
36
Chen, Xia, Jian Jun Yan e Hua Quan Yang. "Influence of Aggregates on Cracking Sensitivity of Concrete". Applied Mechanics and Materials 204-208 (ottobre 2012): 3299–302. http://dx.doi.org/10.4028/www.scientific.net/amm.204-208.3299.
Abstract (sommario):
Concrete cracking sensitivity made from different aggregates was compared with employment of advanced temperature and stress test machine by tracking thermal and stress development of concrete with age and elements distribution in interfacial transition zone of each concrete was explored by SEM and EDS. Test results indicated that compressive strength of concrete made from basalt and limestone was greater than diorite and natural aggregate and crack resistance of concrete based on cracking sensitivity comparison in terms of cracking temperature varying from minus 0.3°C to minus 2.5°C as diorite, basalt, limestone and natural aggregate. Elements Ca and Mg were apparently accumulated in vicinity of ITZ and some reaction between limestone and cement matrix might have taken place which blurred the boundary between aggregates and cement matrix.
37
Abdullahi, Shittu, Aznan Fazli Ismail e Supian Samat. "ASSESSMENT OF NATURALLY OCCURRING RADIONUCLIDES IN MALAYSIA’S BUILDING MATERIALS". Radiation Protection Dosimetry 186, n. 4 (29 aprile 2019): 520–23. http://dx.doi.org/10.1093/rpd/ncz125.
Abstract (sommario):
Abstract The activity concentrations of 226Ra, 232Th and 40K radionuclides from common building materials used by Malaysian people for construction purposes were studied using High-Purity Germanium (HPGe) detector. The measured activity concentrations of the aforementioned radionuclides range from 10 ± 1 Bq kg−1 (limestone) to 155 ± 61 Bq kg−1 (feldspar), 12 ± 3 Bq kg−1 (limestone) to 274 ± 8 Bq kg−1 (kaolin) and 62 ± 19 Bq kg−1 (limestone) to 1114 ± 20 Bq kg−1 (pottery stone) for 226Ra, 232Th and 40K, respectively. The measured activity concentrations of the natural radionuclides reported herein were found to be in accordance with other previous studies. In general, the activity concentration of the natural radionuclides revealed that all the determined values were below the recommended limit.
38
Chen, Hong Wei, Zheng Hui Zhao, Kumar Patchigolla e John Oakey. "The Agglomeration of CaO-Based Sorbent Used to Capture CO2 in Fluidized Bed". Advanced Materials Research 781-784 (settembre 2013): 2517–23. http://dx.doi.org/10.4028/www.scientific.net/amr.781-784.2517.
Abstract (sommario):
High temperature CO2 capture via a CaO-based sorbent was investigated in a fluidized bed. The sorbents tested included natural limestone, pellets made from powdered lime with a calcium aluminate cement binder, mixtures of natural limestone and alumina with a ratio of 1:1 and 2:1. Air-combustion flue gas with a composition of 15% CO2 + 6% H2O + 3% O2 + 76% N2 at 680°C and oxy-combustion flue gas with a composition of 80% CO2 + 16% H2O + 3% O2 + 1% N2 at 950°C were used as a carbonation and calcination atmosphere separately to simulate real CFB running conditions. Results showed that pellets have a lower carrying capacity (g CO2/g calcined limestone or pellets) than nature limestone for the first few cycles mainly due to the existence of calcium aluminate cement (CaAl2O4) binder, while pellets have better cyclic activity than natural limestone. Solids agglomeration was found to be a big problem in the application of using Ca-based sorbent to capture CO2. The solids was not powdery as original ones and tended to clump together after few cycles, making it difficult to fluidize and some dead areas form in the fluidized bed. Agglomeration became severer as cycle number increase and pellets had a much slighter agglomeration than nature limetone due to large particle size. The two mixtures were run in different conditions and H2O was speculated to accelerate agglomeration.
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Prestes, Nelson Eduardo, Cassandro Vidal Talamini do Amarante, Cassiano Eduardo Pinto, Gabriel Avila Prestes, Guilherme Doneda Zanini, Pablo Giliard Zanella e André Fischer Sbrissia. "Limestone and phosphorus application and forage production in natural pastures with sodseeding of cool-season species". Semina: Ciências Agrárias 38, n. 6 (23 novembre 2017): 3681. http://dx.doi.org/10.5433/1679-0359.2017v38n6p3681.
Abstract (sommario):
Natural pastures are important ecosystems that both contribute to biodiversity conservation and provide an important source of income, especially for cattle ranchers. While these pastures yield fairly low productivity, they can be improved by increasing soil fertility and introducing species with high productive potentials. In this sense, the purpose of this study was to evaluate the effects of applying limestone and phosphorus, as well as introducing cool-season species with a mixture of species dominated by Schizachyrium tenerum Nees, into a natural pasture in the Catarinense Plateau. The experiment was conducted from January 2010 to December 2013; the treatments consisted of superficial distribution of limestone in proportions of 3.6, 7.2, 11.0, and 14.4 t ha-1, as well as distribution of phosphorus in the form of triple superphosphate in proportions of 35, 70, 105, and 140 kg of P2O5 ha-1. In addition, cool-season species were overseeded. The experiment consisted of a randomized block design with subdivided plots and three replications. Limestone was applied to the main parcel, whereas phosphorus was applied to the subplots. There was no interaction between the levels of limestone and phosphorus. The application of 11.0 t ha-1 of limestone yielded the highest forage production, with 3,932.2 kg of dry matter (DM) ha-1 during the second year. Red clover was the species that best reacted to the additions, with levels of 7.2 and 11.0 t ha-1 over the 4 years. In addition, phosphorus provoked a positive response throughout the experiment. The highest forage production was observed during the second year, with an addition of 140 kg P2O5 ha-1 (4,419.4 kg DM ha-1). Only one-eighth of the recommended amount of limestone (3.6 t ha-1) allowed for the establishment and persistence of the legumes introduced into natural pastures. These additions, associated with increasing levels of phosphorus, yielded linear growth in the production of forage in natural pastures with a mixture of species dominated by Schizachyrium tenerum Nees.
40
Lamont, Kristine, Erica Pensini, Prasad Daguppati, Ramesh Rudra, John van de Vegte e Janice Levangie. "Natural reusable calcium-rich adsorbent for the removal of phosphorus from water: proof of concept of a circular economy". Canadian Journal of Civil Engineering 46, n. 5 (maggio 2019): 458–61. http://dx.doi.org/10.1139/cjce-2018-0512.
Abstract (sommario):
A calcium-rich rock (limestone) was used as adsorbent to remove phosphorus from water. Phosphorus could be subsequently desorbed from limestone at pH = 4, and potentially reused as fertilizer following pH neutralization. Sorption of phosphorus onto limestone was not affected by 100 mM KCl or by the nitrogen present in a commercial fertilizer, but it was hindered by 100 mM NaCl, urea and river water. The phosphorus removed was however never below ∼9 mg P/kg rock, and it increased with increasing phosphorus concentrations in water. Phosphorus removal increased with 100 mM CaCl2 at neutral pH, likely due to its precipitation. Mixing for 30 s enhanced phosphorus sorption. Desorption of phosphorus from limestone following sorption in deionized water was ∼50%, ∼22%, and ∼11% at pH = 4, pH = 7, and pH = 11, respectively. Phosphorus desorption was lower when sorption had occurred in river water than in deionized water or in 100 mM urea.
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Schmidt, M., K. Harr e R. Boeing. "Blended Cement According to ENV 197 and Experiences in Germany". Cement, Concrete, and Aggregates 15, n. 2 (1 gennaio 1993): 156–64. http://dx.doi.org/10.1520/cca10603j.
Abstract (sommario):
Abstract The European prestandard on common cements, ENV 197, Part 1 [1], differentiates 5 main types and 25 different varieties. Except for portland cement, all cements are composed of at least two or more main components: clinker, blastfurnace slag, natural or artificial pozzolans, fly ash, silica fume, burnt shale, and pulverized or interground limestone. The proportions differ from 5 to 95% (all percentages by mass) clinker. German experiences with high-quality portland-limestome cements and portland-fly ash-slag cements in concrete show some advantages in workability and the same favorable behavior in strength and durability.
42
Sutrisno, Sutrisno, Rudy Soenoko, Yudy Surya Irawan e Teguh Dwi Widodo. "Effect of coconut fiber treatment with limestone water media on the fiber surface, wettability, and interface shear strength". Eastern-European Journal of Enterprise Technologies 1, n. 6 (109) (10 febbraio 2021): 48–56. http://dx.doi.org/10.15587/1729-4061.2021.217730.
Abstract (sommario):
The development of technology has increased the need for composite materials, where the technology of composite materials with natural fiber reinforcement is growing. The existence of natural fiber is very abundant, and it has not been fully utilized. Until now, the use of coconut fiber was still limited to the furniture and household handicraft industries. Coconut coir fiber has the potential as a raw material for composite materials. The lack of strength of the bonds is due to the hydrophobic fiber, and the fiber surface is less rough, and dirty. This study evaluates the coir surface characteristic of the fiber and its bounding with the polyester matrix after being treated by limestone water. The scanning electron microscope was used for observing fiber surfaces and surface matrix. The wettability test to observe fiber surface energy was performed. Interface shear strength to evaluate the bonds between fibers and matrix was determined. Coconut coir fibers were immersed in limestone water, with a 5 % percentage of limestone and time variations of 0, 4, 8, 12, 16, and 20 hours. The scanning microscope electron observations of fibers show that the fiber surface tends to be clean, rough, and grooved. The highest surface energy was obtained at 40.74 mN/m during the limestone water immersion for 8 hours. The highest value of the interface shear strength between the fiber and the matrix is 3.80 MPa during 8-hour immersion, 0, 4, 12, 16, and 20-hour immersion, respectively, 3.02, 3.09, 3.52, 3.47, and 4.40 MPa. The results showed that coir fiber with limestone water immersion for 8 hours had a clean, rough, and grooved surface so that the bond between the fiber and matrix was better. This research shows that limestone water can be used as a fiber treatment medium which was natural
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Megawati, Megawati. "Synthesis Of Glycerol Carbonate From Glycerol And Urea Using Limestone As Catalyst Source". Jurnal Akta Kimia Indonesia (Indonesia Chimica Acta) 12, n. 2 (30 dicembre 2019): 91. http://dx.doi.org/10.20956/ica.v12i2.8096.
Abstract (sommario):
Synthesis of Glycerol carbonate from glycerol and urea using limestone as a catalyst has been conducted. This study aims to make glycerol carbonate from glycerol and urea by utilizing scattered natural limestone widespread in Southeast Sulawesi as a catalyst source. The catalyst was obtained from the calcination of natural limestone to decompose CaCO3 to CaO. This condition added to glycerol and urea to test the catalyst activity. Synthesis of glycerol carbonate was carried out through the carbamoylation reaction of glycerol with urea. The advantage of this method is the reaction carried out with free solvents and running in ambient pressure (1 atm). The stages of catalyst testing in the reaction of glycerol carbonate formation were carried out by reacting glycerol, urea, and calcined limestone with 1: 1 substrate mole ratio with a catalyst concentration of 5% mass over glycerol. Characterization used was Fourier Transform Infrared Spectroscopy (FTIR) and supported by Gas Chromatography (GC) data. Optimization catalysis reaction was obtained at a temperature of 140oC for 4 hours and using a catalyst mole ratio to 5% substrate
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Toyota, Hiroko, Daiki Ito, Shuya Suzuki, Ryohei Hara e Junxiang Wang. "Mapping vanished mountain shapes – The struggle between limestone mining and establishing a natural park at Mount Bukō –". Abstracts of the ICA 1 (15 luglio 2019): 1–2. http://dx.doi.org/10.5194/ica-abs-1-368-2019.
Abstract (sommario):
<p><strong>Abstract.</strong> This report searches for the Japanese view of beauty and nature through a study of the mapping of the transformation of a mountain’s shape. A normal map primarily intends to express existing shapes, but this report maps the vanished shape of a mountain from the limestone mining of its slopes. This is done to consider how its vanished shape has impacted the Japanese view of beauty and nature. The mountain studied is Mount Bukō located in Chichibu City and Yokozemachi in Saitama Prefecture. Mount Bukō is suitable for limestone mining, and during the Edō Period, limestone was mined on this mountain to obtain material for mortar and fertilizer. In the Meiji Period, cement was used in Japan to construct buildings and surface roads, and limestone (raw material for cement) was produced and consumed in large quantities. During the Taishō Period, corporations started to mine vast quantities of limestone. At Mount Bukō, the shape of the mountain was heavily transformed by limestone mining (Figure 1,2).</p><p>However, during the 1940s, Mount Bukō was mentioned as a candidate site for a national park. In 1957, the entire area &ndash; including the mining site &ndash; was designated the Saitama Prefectural Natural Park. Parks are designated in Japan in imitation of Europe and America, and their major purposes are to preserve beautiful scenery and serve as places for residents’ recreational activities. Thus, by the Meiji Period, national parks such as Nikko National Park (which includes the Tōshōgū Shrine) were already being designated. Considering the above historical background, the movement to designate Mount Bukō as a park can be understood as an effort to preserve its scenery and provide a place for residents’ activities. But limestone mining continues to transform the shape of the mountain as, for example, a total of roughly 6.99 million tons of limestone were mined on Mount Bukō in 2016. By analyzing the facts of this case, this study can portray the Japanese consciousness of the change of the shapes of mountains and clarify the nature of their view of beauty and nature in mountains.</p><p>This paper reports on the preparation of a stereoscopic map based on topographical maps and photos created since the start of the Meiji Period, Chichibu <i>fudasho</i> temple drawings from the Edō Period, and the chronological mapping of the shape of the mountain before and since its designation as a park. Mapping using diverse source materials to represent exposed rock and landslides caused by limestone mining permits a detailed study that would be impossible based on topographical maps lacking contour lines, photographs, or drawings from one direction, primarily from the northern side of the mountain (Figure 3,4). This study shows which parts of the disappearing Mount Bukō are important to people and which parts of the remaining mountain shape they value highly. It also portrays the Japanese view of beauty and nature from a cultural perspective to aesthetically evaluate artificially formed “nature” as seen in temple gardens or bonsai.</p>
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Kortnik, Jože. "Stability Assessment of the High Safety Pillars in Slovenian Natural Stone Mines / Ocena Stabilności Wysokich Filarów Bezpieczeństwa W Kopalniach Kamieni Naturalnych W Słowenii". Archives of Mining Sciences 60, n. 1 (1 marzo 2015): 403–17. http://dx.doi.org/10.1515/amsc-2015-0027.
Abstract (sommario):
Abstract For the first time in Slovenia, the underground excavation of natural stone blocks was introduced on a trial basis at the Hotavlje I colourful limestone quarry in 1993, in 2002 at the Lipica II limestone quarry, in 2008 at the Lipica I limestone quarry and in 2009 also at the Doline limestone quarry. This was primarily because of the geological structure of the site, the quarry’s condition, the potentially large amounts of the overburden in the event of an expansion of the surface part of the quarry, and the increasing needs for this raw material, i.e. natural stone. The underground excavation of natural stone in all locations are done using a modified room-and-pillar excavation method that is adjusted to each site’s characteristics, with regularly or irregularly distributed high safety pillars. Since the underground excavation of natural stone blocks is performed at a relatively shallow level under the surface, i.e., at a depth of only 10-40 m, the value of the primary vertical stress state is also relatively low (less than 1.0 MPa). This significantly increases the risk of wedge-shaped pieces or blocks falling out of the ceiling in open underground spaces. In previous years, special attention was paid to the installation of stress-strain systems for controlling the planned dimensions (width and height) of large, open, underground spaces (rooms) and the dimensions of the high safety pillars, along with continual monitoring and identification of the instability phenomena in the ceiling and sides of the large open spaces (rooms). The paper presents the methods and devices used for the optimization and the safety monitoring of high safety pillars for the underground excavation of natural stone blocks in Slovenian natural stone mines.
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SANG, JULIA, RUTH KIEW e CONNIE GERI. "Revision of Begonia (Begoniaceae) from the Melinau Limestone in Gunung Mulu National Park and Gunung Buda National Park, Sarawak, Borneo, including thirteen new species". Phytotaxa 99, n. 1 (9 maggio 2013): 1. http://dx.doi.org/10.11646/phytotaxa.99.1.1.
Abstract (sommario):
Besides Begonia conipila, 13 new species (Begonia apiensis, B. benaratensis, B. conniegeriae, B. divergens, B. lucychongiana, B. magentifolia, B. melinauensis, B. ramosissima, B. rhodoneura, B. umbratica, B. vulgare, B. yiii and B. xiphophylloides) and a putative natural hybrid between B. conipila and B. lucychongiana are described from the Melinau limestone. All these species are endemic in the Melinau limestone and 10 species are restricted to limestone habitats. The Melinau limestone includes the highest limestone hills in Malaysia with Gunung Api (1710 m) and Gunung Benarat (1615 m), which above 800 m are covered by montane forest. The vegetation types and habitats of each species are described. Conservation-wise, all are of Least Concern following IUCN criteria and categories, except for B. apiensis that is extremely local and threatened by tourist activities and is designated Rare following Malaysian criteria and categories.
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Korneeva, Elena, Muayad Sabri Sabri Mohanad, Anna Babanina, Egor Zaytsev e Sergey Poberezhskii. "Operational characteristics of limestone and methods to increase its strength". E3S Web of Conferences 91 (2019): 02028. http://dx.doi.org/10.1051/e3sconf/20199102028.
Abstract (sommario):
Since ancient times, limestone has been known as an inexpensive and reliable building material. The main problem of limestone materials in the construction of buildings is its reduced longevity due to various factors, such as wind and rain. These factors have a huge impact on the strength characteristics of the building material, so adherence to special recommendations is an important practical task. A review of literature on the problem of durability and the use of limestone is presented. With the help of experience, the strength of nummulite limestone is established. The analysis of the obtained data is made, as well as its comparison with the indices of other artificial and natural stones. The main methods of strengthening the structures made of limestone are considered at three different stages. Practical recommendations for minimizing the impact of negative factors on this material are given.
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Kotlyar, V. D. "The Calcite Crystallinity and the Age of Limestone Brick Mortars of Medieval Objects of the North of the Byzantine Oecumene". Materials Science Forum 974 (dicembre 2019): 83–89. http://dx.doi.org/10.4028/www.scientific.net/msf.974.83.
Abstract (sommario):
The paper describes the process of recrystallization of portlandite of limestone mortar in calcite. The degree of crystallinity of calcite in limestone mortar of some medieval objects of the north of the Byzantine oecumene is shown through the example of Abkhazia and calcite in natural limestone and marble. The work provides a comparative analysis of the calcite crystallinity and the estimated age of the building objects according to historical and architectural data. It is proven that the higher the calcite crystallinity is the elder the lime mortar and, accordingly, the architectural object is.
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You, Donghua, Jun Han, Wenxuan Hu, Yixiong Qian, Qianglu Chen, Binbin Xi e Hongqiang Ma. "Characteristics and formation mechanisms of silicified carbonate reservoirs in well SN4 of the Tarim Basin". Energy Exploration & Exploitation 36, n. 4 (19 febbraio 2018): 820–49. http://dx.doi.org/10.1177/0144598718757515.
Abstract (sommario):
High-yield natural gas was discovered in well SN4 in the Ordovician Yingshan Formation in the Tarim Basin. The gas is found in unusual, silicified, carbonate reservoirs. According to the degree of silicification, the silicified reservoirs can be divided into a lower section of silicified carbonates, a middle section of limestone, and an upper section of silicified carbonates. The silicified carbonates are mainly composed of quartz and calcite, in which the reservoir space mostly occurs as vugs, inter-crystalline pores of quartz, and partial fractures. Porosity varies widely, ranging from 3 to 20.5% with strong heterogeneity. The homogenization temperatures of fluid inclusions in quartz and calcite show that the silicification temperatures were 150–190°C, with characteristics of high temperature/low salinity and low temperature/high salinity. The 87Sr/86Sr ratios of secondary calcite are 0.709336–0.709732, which are significantly higher than that of concurrent seawater, indicating that the hydrothermal fluid originated from the deep clastic strata or the basement (sialic rock). The δ13C values of the secondary calcite are similar to that of the surrounding limestone, indicating that the carbon in the secondary calcite is derived from the limestone strata, and that the secondary calcite is the product of dissolution and re-precipitation resulting from interaction between the silica-bearing hydrothermal fluids and surrounding limestones. The silicification of silica-bearing hydrothermal fluid was significantly controlled by strike-slip faults. The fluids ascending along the fault zone and branch faults interacted with the surrounding limestone in the Yingshan Formation. As a result, a large amount of quartz and secondary calcite were formed together with various types of secondary pores, resulting in excellent reservoirs.
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Pastor, José Luis, Jinchun Chai e Isidro Sánchez. "Strength and Microstructure of a Clayey Soil Stabilized with Natural Stone Industry Waste and Lime or Cement". Applied Sciences 13, n. 4 (16 febbraio 2023): 2583. http://dx.doi.org/10.3390/app13042583.
Abstract (sommario):
Industrial waste generated by the natural stone industry when working with limestone and dolostone is mainly composed of calcium carbonate and calcium magnesium carbonate. This mineral composition makes soil stabilization a potential use of the natural stone industry waste. However, much research must be carried out to fully understand the aptitude of this waste for soil improvement. In this work, the strength and microstructure of a clayey soil stabilized using limestone powder waste and lime or cement were studied employing the following techniques: unconfined compressive strength tests, mercury intrusion porosimetry, thermogravimetric analysis, X-ray diffraction, and scanning electron microscopy. Moreover, the effects of an aggressive environment were simulated using a sodium sulfate solution. Its effects were investigated from 7 days to 6 months. The results obtained show an increase in the unconfined compressive strength and a more compact structure for the samples with the industrial waste. Therefore, limestone powder waste from the natural stone industry can be used as a ternary element with lime and cement in soil stabilization.