• Journal of the Korean Geotechnical Society
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• v.18 no.5
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• pp.179-193
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• 2002

Waste foundry sands were tested to determine their leaching characteristics when used as reactive media in permeable reactive barriers (PRBs). Water leach tests and column leach tests were performed on twelve foundry sands and three reference materials such as Peerless iron, a local fill material, and torpedo sand. The latter three materials were tested to compare concentrations of heavy metals and anions found in other materials commonly placed below the groundwater table with those from the foundry sands. Results of water leach tests md total elemental analyses showed that all of the laundry sands are Category 2 materials per Section NR 538 of the Wisconsin Administrator Code. However, tests on Peerless iron, torpedo sand, and a typical fill material indicate that these materials, which are commonly placed below the groundwater table, also are Category 2 materials. Thus, using foundry sand as a PR3 medium should pose no greater risk than that imposed using conventional construction materials.

• Journal of the Korean Geotechnical Society
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• v.22 no.4
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• pp.85-94
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• 2006

Triaxial tests at isotropic confining pressure of 200 kPa were carried out to show the undrained shear behavior of artificially cemented sands, which were cemented by gypsum, and the influences of relative density and DOC (degree of cementation) were investigated from the results. The yield strength, the elastic secant modulus at yield point and the peak frictional angle of cemented sands increased abruptly compared to uncemented sands, and it was checked that cementation exerts more influence on the behavior of sand than the relative density. But after breakage of the cementation bonds, the relative density was more important factor on the behavior of sand than the cementation. Because the compressibility md the excess pore pressure of cemented sands were reduced due to the cementation bonds, the effective stress path of cemented sands was going toward to the total stress path of uncemented sands. The cementation of sand restricted the dialtion of sand at the pre-yield condition, but induced more dilation in the post-yield condition.

• International Journal of High-Rise Buildings
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• v.8 no.1
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• pp.19-27
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• 2019

This presentation traces the evolution of the SkyPark across multiple building types in different cities, climates and contexts from urban, architectural and social perspectives.

• Applied Chemistry for Engineering
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• v.24 no.1
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• pp.10-17
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• 2013

Heavy oil residue upgrading process was being used in conventional refinery process. Recently, as the importance of non conventional energy development is growing up, the commercial projects of heavy oil upgrading are getting more active than before. For having competitive business model in the resource competition, non conventional energy development should be considered as an important business strategy. In developing oil sands, extra heavy oil, and shale gas, canadian oil sands and extra heavy oil have great importance in substitution of conventional oil consumption. In oil sands development, the bitumen, which is extracted from oil sands, has great value after upgrading or refining process. Similar process is being used current conventional refinery process. The bitumen is highly viscous hydrocarbon. This bitumen includes impurities which can not be treated in conventional refinery process. As this reason, specified process is needed in bitumen or extra heavy oil upgrading process. Moreover, there will be additional specified facilities in the process of production, transportation and marketing. In oil sands, there are various kinds of commercial upgrading process. Extraction, dilution, coking and cracking method were being used commercially.

• Geomechanics and Engineering
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• v.10 no.1
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• pp.77-94
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• 2016

Cyclic triaxial and resonant column tests were conducted to understand the beneficial effects of various grouted sands on liquefaction resistance and dynamic properties. The test procedures were performed on a variety of grouted sands, such as silicate-grouted sand, silicate-cement grouted sand and cement-grouted sand. For each type of grout, sand specimen was mixed with a 3.5% and 5% grout by volume. The specimens were tested at a curing age of 3, 7, 28 and 91 days, and the results of the cyclic stress ratio, the maximum shear modulus and the damping ratio were obtained during the testing program. The influence of important parameters, including the type of grout, grout content, shear strain, confining pressure, and curing age, were investigated. Results indicated that sodium silicate grout does not improve the liquefaction resistance and shear modulus; however, silicate-cement and cement grout remarkably increased the liquefaction resistance and shear modulus. Shear modulus decreased and damping ratio increased with an increase in the amplitude of shear strain. The effect of confining pressure on clean sand and sodium silicate grouted sand was found to be insignificant. Furthermore, a nonlinear regression analysis was used to prove the agreement of the shear modulus-shear strain relation presented by the hyperbolic law for different grouted sands, and the coefficients of determination, $R^2$, were nearly greater than 0.984.

• Journal of the Korean Geotechnical Society
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• v.15 no.5
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• pp.205-215
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• 1999

Crushable sandy soil grounds are widely found along the coast throughout the world. The ground composed of lime sand, which is characterized by the material with high compressibility due to particle crushing contains carbonate calcium. In this study, in order to clarify the characteristics of the particle crushing as related to the strength and deformation properties of sands, isotropic compression test was carried out on three different types of carbonate sands and a silica sand. A crushability index, K, is proposed in connection with the yielding and particle crushing stress of sands at various relative densities under isotropic compression. It is concluded that the representative crushability index, K, associated with the soil particle strength, can be a key factor in preliminary parameters in evaluating soil crushability.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1159-1166
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• 2005

In the present study, a series of laboratory tests with sands of different silt contents, are conducted and methods to assess non-linear behaviors based on in-situ test results are proposed. Modified hyperbolic stress-strain model is used to analyze non-linearity of silty sands in terms of non-linear degradation parameters f and g as a function of silt contents and relative density $D_R$. Stress-strain relationship results were obtained from a series of triaxial tests on sands containing different amounts of silt. Initial shear modulus which was applied to normalize modulus degradation of silty sands were determined based on the resonant column test results. From the laboratory test results, it was observed that, as the relative density increases, values of f decrease and those of g increase. Cone resistance $q_c$ for silty soil condition used in the triaxial tests were estimated based on the cavity expansion analysis. A suggestion to make an estimation of degradation parameters f and g as a function of fine contents is addressed in terms of cone resistance $q_c$ .

• Journal of the Korean Geotechnical Society
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• v.19 no.2
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• pp.57-64
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• 2003

The liquefaction potential of saturated sands under seismic loading conditions has been carefully considered by many investigations. Typical of these investigations is the laboratory determination of cyclic strength of sands by means of cyclic triaxial tests. This study was conducted to investigate the effects of the method of sample preparation on the liquefaction characteristics of remolded samples of saturated uniform sands. Cyclic triaxial tests were performed on saturated uniform sand compacted to the same density by 3 different procedures of pluvial compaction through air, pluvial compaction through water and vibratory compaction. It was validated that the cyclic stress ratio of remolded saturated uniform sands by different compaction procedures at the same density was very different.

• Geomechanics and Engineering
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• v.22 no.5
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• pp.441-448
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• 2020

This paper presents a study on the undrained shear strength (s_u) of various sands treated with a biopolymer by employing an extensive series of laboratory fall-cone penetration values covered a range of about 15 mm to 25 mm. In the tests, two sizes (0.15 mm-0.30 mm, and 1.0 mm-2.0 mm) and shapes (rounded, angular) of sand grains, Xanthan gum (XG), and distilled water were used. The XG biopolymer in 0.0%, 1.0%, 2.0%, and 3.0% by dry weight were mixed separately with four different sands, and water. The tests results obtained at the same water content revealed an increase in the su values at different levels with an increase in the XG content. Treating the sands with the XG biopolymer addition was concluded to have a greater efficacy on finer and more angular grains than coarser and more rounded grains in the samples. Overall, the present study indicates that different amount of the XG biopolymer has an important potential to be utilized for increasing the s_u values of samples with various size/shape of sand grains and water content.

• Geosciences Journal
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• v.22 no.6
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• pp.955-973
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• 2018

Twenty-eight beach sand samples from the shorelines of Aegean islands adjacent to the plutonic rocks of the Atticocycladic zone were analyzed for major and rare earth element (REE) contents. Results are compared with the adjacent plutonic rocks, in order to determine relative enrichments or depletions and assess the potential for REE exploitation. Among the samples, several are significantly enriched in REE, being deposits of heavy minerals and their concentrations are controlled by the sea waves and local winds. These samples contain Th, U and REE rich minerals such as zircon, xenotime and allanite. The available geochemical characteristics were also used to confirm the parent rocks of the beach sands. The heavy fractions (total, total magnetic and total non-magnetic) of the beach sands are very well correlated with the Heavy REE (HREE) concentrations. Among the minerals of the heavy magnetic fraction, allanite seems to control the REE content in the heavy mineral-enriched samples, while from the heavy non-magnetic fraction, zircon controls mainly the HREE fraction. One site from Mykonos and 3 from Naxos could have potential for REE exploitation as they present the highest ${\Sigma}REE$ and HREE contents than other beach sand placers measured in Greece (Kavala, Sithonia, Maronia, Samothraki, NE Chalkidiki).