The Experts below are selected from a list of 246 Experts worldwide ranked by ideXlab platform
Sandeep Shrivastava - One of the best experts on this subject based on the ideXlab platform.
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effective utilisation of quartz Sandstone mining wastes a technical note on its thermal resistance
Journal of Cleaner Production, 2017Co-Authors: Sanjeev Kumar, Ramesh Chandra Gupta, Sandeep ShrivastavaAbstract:Sandstones are a sedimentary type of rock which is composed of quartz, feldspar and other minerals. Since quartz and feldspar are the most common minerals in the Earth's crust, they are found in most of the Sandstones irrespective of the region they occur. The formation of Sandstone results by sedimentation through air or wind followed by the compacting pressure of overlying deposits and cementation by precipitation of minerals. Rajasthan, being the largest state by area in India, is the major Sandstone producing region. Although Sandstones from the area are extensively used as roofing, flooring and paving material, the process of mining them generates an enormous amount of Sandstone wastes. These Sandstone wastes with quartz-dominated elemental framework were utilised in an M30 grade concrete with water to cement ratio of 0.35 to overcome the landfilling problems and to reduce the use of depleting conventional coarse aggregates in the Vindhyan regions of Northern India. The concrete samples were investigated by scanning electron microscopy and thermogravimetry. The microscopic study revealed the presence of increased void fractions in the concrete samples containing quartz Sandstone aggregates. These void fractions were found to enhance the thermal resistance of concrete based on the reduced weight loss upon heating them and also assumed to improve insulation properties by hindering the heat transfer in the material. The efficient utilisation of these quartz Sandstone wastes in concrete can reduce the substantial amount of landfill that is used for dumping them and also provide a valuable source of supplementary aggregate used in the production of cement concrete contributing to the overall sustainability.
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strength abrasion and permeability studies on cement concrete containing quartz Sandstone coarse aggregates
Construction and Building Materials, 2016Co-Authors: Sanjeev Kumar, Ramesh Chandra Gupta, Sandeep ShrivastavaAbstract:Abstract Sandstones being a sedimentary type of rock are composed of sand-sized mineral grains, rock fragments and pieces of fossils which are held together by mineral cement. They differ from other igneous rocks in possessing a framework of grains that touches each other but not in continuous contact. Quartz being a mineral which is highly resistant to both physical and chemical weathering are also found in Sandstones. Being found in Sandstones, they can be used as partial replacement of aggregate in cement concrete without a substantial decrease in strength properties. In countries like India, Sandstone waste generation is very high and it is estimated that Rajasthan alone produces 900 million tonnes of Sandstone waste thus leading to a large dumping of these materials without any essential utilisation. To overcome this massive dumping of Sandstone wastes and to lessen the use of natural aggregates, a study was carried to find out the effective use of these Sandstone wastes in concrete. M30 grade of concrete was designed as per IS 10262: 2010, with water cement ratio of 0.4. However to find the scattering of strength plots, water cement ratios of 0.35 and 0.45 were also adopted for the study. Control mix consists of 0% quartz Sandstone and substitution of coarse aggregates was done for 0–100%, in the multiples of 20%. Tests were done to determine the compressive strength, flexural strength, abrasion resistance, permeability and sorptivity in concrete samples. It was observed that the quartz Sandstones might be utilised as a partial replacement of coarse aggregates up to 40% without considerable decrease in its preferred strength.
Xu Feng - One of the best experts on this subject based on the ideXlab platform.
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diagenetic heterogeneity pore throats characteristic and their effects on reservoir quality of the upper triassic tight Sandstones of yanchang formation in ordos basin china
Marine and Petroleum Geology, 2018Co-Authors: Kangjun Wu, Zhengjian Xu, Xu FengAbstract:Abstract Upper Triassic tight Sandstones in Ordos Basin are typical tight oil reservoirs in China. Using a combination of thin sections, SEM, BSE, EDS and mercury injection, 48 Sandstone core samples from 17 wells in the study area were collected to investigate the diagenetic heterogeneity, pore-throat characteristics and their correlations with reservoir quality. Five diagenetic types were identified according to their specific diagenetic evolution pathways. Type A Sandstones are characterized by abundant authigenic chlorite rims, rare quartz cement and high porosity. Type B Sandstones underwent moderate compaction, moderate dissolution and moderate cementation. Samples from Type C are characterized by intense dissolution and large amounts of carbonate cements, they can be subdivided into two categories according to if pore throats in larger size were still reserved (Type C2) or not (Type C1) after late-stage cementation. Type D Sandstones underwent intense compaction, moderate dissolution and minor carbonate cementation. Type E Sandstones are characterized by the most intense compaction. Depending on the pore-throat size distributions from MICP analysis, three Sandstone types with their own specific pore-throat characteristics were identified. Type Ⅰ Sandstones generally contain a certain amount of mesopores (including a few macropores) and pore spaces are dominant intergranular pores, intragranular pores and even oversized pores. These Sandstones generally correspond to Type A, B, C2 and D Sandstones and thus represent good-quality reservoir. Type Ⅱ Sandstones usually contain dominant transitional pores (77% in average) and their pore systems mianly consist of clay intercrystal microporosity and a few isolated intergranular or intragranular pores. Type Ⅲ Sandstones are representative by relatively abundant micropores (17.7% in average) and pore spaces are dominant clay intercrystal microporosity. Type Ⅱ and Type Ⅲ pore structures generally correspond to Type C1 and E and thus represent poor-quality reservoir. This study gives insights into the link between different diagenetic features, pore structures and their impact on reservoir quality and this will be helpful for reservoir prediction.
Sanjeev Kumar - One of the best experts on this subject based on the ideXlab platform.
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effective utilisation of quartz Sandstone mining wastes a technical note on its thermal resistance
Journal of Cleaner Production, 2017Co-Authors: Sanjeev Kumar, Ramesh Chandra Gupta, Sandeep ShrivastavaAbstract:Sandstones are a sedimentary type of rock which is composed of quartz, feldspar and other minerals. Since quartz and feldspar are the most common minerals in the Earth's crust, they are found in most of the Sandstones irrespective of the region they occur. The formation of Sandstone results by sedimentation through air or wind followed by the compacting pressure of overlying deposits and cementation by precipitation of minerals. Rajasthan, being the largest state by area in India, is the major Sandstone producing region. Although Sandstones from the area are extensively used as roofing, flooring and paving material, the process of mining them generates an enormous amount of Sandstone wastes. These Sandstone wastes with quartz-dominated elemental framework were utilised in an M30 grade concrete with water to cement ratio of 0.35 to overcome the landfilling problems and to reduce the use of depleting conventional coarse aggregates in the Vindhyan regions of Northern India. The concrete samples were investigated by scanning electron microscopy and thermogravimetry. The microscopic study revealed the presence of increased void fractions in the concrete samples containing quartz Sandstone aggregates. These void fractions were found to enhance the thermal resistance of concrete based on the reduced weight loss upon heating them and also assumed to improve insulation properties by hindering the heat transfer in the material. The efficient utilisation of these quartz Sandstone wastes in concrete can reduce the substantial amount of landfill that is used for dumping them and also provide a valuable source of supplementary aggregate used in the production of cement concrete contributing to the overall sustainability.
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strength abrasion and permeability studies on cement concrete containing quartz Sandstone coarse aggregates
Construction and Building Materials, 2016Co-Authors: Sanjeev Kumar, Ramesh Chandra Gupta, Sandeep ShrivastavaAbstract:Abstract Sandstones being a sedimentary type of rock are composed of sand-sized mineral grains, rock fragments and pieces of fossils which are held together by mineral cement. They differ from other igneous rocks in possessing a framework of grains that touches each other but not in continuous contact. Quartz being a mineral which is highly resistant to both physical and chemical weathering are also found in Sandstones. Being found in Sandstones, they can be used as partial replacement of aggregate in cement concrete without a substantial decrease in strength properties. In countries like India, Sandstone waste generation is very high and it is estimated that Rajasthan alone produces 900 million tonnes of Sandstone waste thus leading to a large dumping of these materials without any essential utilisation. To overcome this massive dumping of Sandstone wastes and to lessen the use of natural aggregates, a study was carried to find out the effective use of these Sandstone wastes in concrete. M30 grade of concrete was designed as per IS 10262: 2010, with water cement ratio of 0.4. However to find the scattering of strength plots, water cement ratios of 0.35 and 0.45 were also adopted for the study. Control mix consists of 0% quartz Sandstone and substitution of coarse aggregates was done for 0–100%, in the multiples of 20%. Tests were done to determine the compressive strength, flexural strength, abrasion resistance, permeability and sorptivity in concrete samples. It was observed that the quartz Sandstones might be utilised as a partial replacement of coarse aggregates up to 40% without considerable decrease in its preferred strength.
Markus Lenz - One of the best experts on this subject based on the ideXlab platform.
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deterioration of Sandstones insights from experimental weathering in acidic neutral and biotic solutions with acidithiobacillus thiooxidans
Construction and Building Materials, 2020Co-Authors: Anna Potysz, Wojciech Bartz, Katarzyna Zboinska, Felix Schmidt, Markus LenzAbstract:Abstract The susceptibility of Sandstones to deteriorative factors when used for construction requires detailed experimental evaluation. This study investigated the (bio)weathering behaviour of Lower-Silesian Cretaceous Sandstones (quartz arenites) to quantify the deteriorative effect of bacterium Acidithiobacillus thiooxidans. For controls, ultrapure water (in undersaturated conditions) and sterile acidic medium (in abiotic acidic conditions pH 2.5) were used. Sandstone exposure to A. thiooxidans mimicked the extremely acidic conditions (pH up to 0.9) that may develop under long-term weathering, which promote microbial activity and acidic metabolite production. Element release was assessed using triple quadrupole inductively coupled plasma mass spectrometry (QQQ-ICP-MS) and identifying potential element donor minerals through scanning electron microscopy, coupled with energy dispersive spectrometer (SEM-EDS). The results demonstrated that Sandstones were relatively susceptible to weathering, especially when exposed to aggressive acidic conditions, where the presence of bacteria apparently acts as an accelerating factor in deterioration. Based on Si release, Sandstone degradation under biotic conditions was 0.27% within 86 days, whereas the dissolution achieved in ultrapure water did not exceed 0.02%. A highly pronounced weathering feature observed on Sandstones was the dissolution of goethite and/or kaolinite cement, whereas quartz was less susceptible to weathering under the conditions studied. Bioweathering investigations may help solve deterioration issues in Sandstone building materials.
Jinhong Wang - One of the best experts on this subject based on the ideXlab platform.
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tight gas Sandstone reservoirs in china characteristics and recognition criteria
Journal of Petroleum Science and Engineering, 2012Co-Authors: Ling Su, Xiangxiang Zhang, Xuejian Yuan, Jinhong WangAbstract:Abstract Tight gas Sandstone (tight gas) reservoirs have been widely discovered in a number of basins in China including the Sichuan, Ordos, Turpan-Hami (Tuha), Songliao, Junggar, Tarim, Chuxiong and East China Sea basins. Genetically they are of either primary or secondary accumulations. The tight gas accumulations are mostly associated with coal strata. The reservoir rocks are mainly lithic arkosic Sandstones and feldspathic lithic arenite. They are characterized by low compositional maturities, low cement contents and moderate petrological textural maturities. The diagenetic evolution of the reservoirs is generally at a high level, reaching the mid-late diagenesis stages. Reservoir porosities are dominated by secondary intragranular dissolution porosity and intergranular dissolution porosity with subordinate primary residual intergranular porosity. The pore throats are sheet like or bending-flake like in geometry and generally have poor connectivity. The tight gas reservoirs have poor petrophysical properties and show strong heterogeneities. Locally, some moderately porous and low permeable or low porous and moderately permeable Sandstone reservoirs are present. Compaction and cementation appear to be key factors contributing to the formation of the tight gas Sandstone reservoirs. Based on the synthesis of a vast data set obtained from some known tight Sandstone gas accumulations from (1) the upper Palaeozoic Sandstones in the Ordos Basin, (2) the Triassic Xujiahe Formation in the Sichuan Basin, (3) the Jurassic Sandstones from the foothill belt in the Tuha Basin and (4) the Cretaceous deep reservoirs in the Songliao Basin, the criteria for recognizing tight gas Sandstone reservoirs in China can be established as an in situ permeability of less than or equal to 0.1 mD and with no natural commercial production.
