• Journal of the Korea Concrete Institute
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• v.12 no.5
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• pp.59-68
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• 2000

A series of experiments were performed to investigate the strength characteristics of concrete which contain air cooled blast-furnace slag as coarse aggregate. The slag is a by product of GISC. The experimental conditions are varied with three different W/C(45%, 50%, 55%) and the weight of water and S/a are constant. The strength properties of the concrete at 7days, 28days, 90days are examined. Also the same strength properties are examined for the normal concrete which contain river gravel and crushed stone respectively as coarse aggregate. As the comparison results of the strength properties, it was found that the compressive strength development of concrete containing blast-furnace slag is better than that of concrete using river gravel at early age, however this is adversely at long-term age, and the tensile and flexural strength of the concrete were not nearly affected by water-cement ratio.

• Journal of the Korean earth science society
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• v.27 no.7
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• pp.757-767
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• 2006

Alluvial-plain deposits in the southeastern part of the Eumsung Basin (Cretaceous) are characterized by coarse-grained channel fills encased in purple siltstone beds. It represents distinct channel geometry, infill organization, and variations in facies distribution. The directions of paleocurrent, sedimentary facies changes, and channel-fill geometry can be used to reconstruct a channel network in the alluvial system developed along the southeastern margin of the basin. The channel-fill facies represent downstream changes: 1) down-sizing and well-sorting in clast and martix of channel fills and 2) internal organization of scour fill or gravel lag and overlying cross-stratified, planar-stratified beds. These findings suggest multiple stages of channel-filling processes according to flooding and subsequent stream flows. In the small-scale pull-apart Eumsung Basin (${\sim}7{\times}33km^2$ in area), vertical-stacked alluvial architecture of the coarse-grained channel fills encased in purple siltstone is expected to result from episodic channel shifting under a rapidly subsiding setting.

• Geomechanics and Engineering
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• v.32 no.4
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• pp.445-452
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• 2023

Temperature is one of the important factors affecting the permeability of water in the soil. In the present study, the impact of water temperature on hydraulic conductivity (k) with and without coarse aggregations by considering six types of soils was analyzed. Moreover, the effect of sand and gravel presence in the soil was investigated through the infiltration based on constant and inconstant water head experiments. Results indicated that by increasing the water temperature, adding gravel to sandy soil caused the hydraulic conductivity to raise. It is supposed that the gravel decreased the contact surface between the water and the soil aggregates. It is deduced that due to decreasing kinetic energy, k tends to have lower values. Furthermore, adding the sand to sandy silt-clay soil showed that the sand did not have a marginal effect on the variation of k since the added sand cannot increase the contact surface like gravel. Finally, increasing the main diameter of the soil will increase the effect of the water temperature on hydraulic conductivity.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.3
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• pp.122-129
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• 2016

In this study, we developed a pressing device which can reproduce the pressure of concrete inside the conveying pipe as a part of the basic study to development of high fluidity concrete under high pressure pumping. Using this pressing device, we evaluated a absorption properties of aggregate that are crushed coarse aggregate, river gravel and lightweight coarse aggregate according to pressure of coarse aggregate and aggregate inside a high fluidity concrete, focused on the reduction of unit water quantity by pressure. In addition, it was evaluated the compressive strength of high fluidity concrete about before and after of pressive. Test a result, case of condition under the high pressure of 250 bar, absorption ratio of crushed coarse aggregate and river gravel were not increased above the surface absorption, absorption ratio of lightweight coarse aggregate was increased than the surface absorption.

• Advances in concrete construction
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• v.7 no.2
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• pp.97-105
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• 2019

In this paper, the workability and static stability were evaluated using a proposed test method. Workability and static stability represent a key property of self-compacting concrete (SCC) in fresh state. A number of standardized test methods were developed to assess these properties. However, no accelerated test method reliably predicts both workability and static stability of SCC. In the present work, a modified K-slump test method was developed to evaluate workability and static stability of SCC. In order to take implicit mixture variations of SCC constituents that can affect fresh SCC properties, a central composite design was adopted to highlight the effect of gravel to sand ratio (G/S), gravel 3/8 to gravel 8/15 ratio (G1/G2), water to cement ratio (W/C), marble powder to cement ratio (MP/C) and superplasticizer content (SP) on workability measured with slump and flow time (T50) tests and static stability measured with sieve stability test (Pi), segregation test index (SSI), Penetration test (Pd) and the proposed K-slump test (Km). The obtained results show that G/S ratio close to 1 and G1/G2 ratio close to 60% can be considered as optimal values to achieve a good workability while ensuring a sufficient static stability of SCC. Acceptable relationships were obtained between Slump flow, Pi, Pd and Km. Results show that the proposed K-slump test allow to assess both workability and static stability of fresh SCC mixtures.

• Asian Journal of Turfgrass Science
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• v.13 no.4
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• pp.181-190
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• 1999

This study was carried out to survey green system, area, green slope, green turfgrass variety, green section, and particle size of green construction materials, and to investigate and evaluate the characteristics of Design and Construction in Korean golf course green for improving the quality of Korean golf course into that of the international golf course held international tournament. The results were as follows. 1. The greens of 129 Korean golf courses consisted of 2(two) green system and 1(one) green system. 2(two) green system was 50.8%, 1(one) green system was 40.7%, and 1+2 green system was 8.5% of them. 2. In 48 Korean golf courses, the green area of 2(two) green system was mostly 400~$600\m^2$(56.5%) and the green area of 1(one) green system was mostly 600~$800\m^2$(47.8%). In 48 Korean golf courses, 1.5~3% green slope appeared the highest frequency(50.0%) and the next was 3~5%(29.4%). 3. Penncross variety was the highest frequency(71.2%). The next was mixed variety (Penncross+Crenshaw, Penn A-1, Pennlinks, or Penneagle/SR 1020+SR 1019) and the frequency of mixed variety was 7.6%. 4. In 48 Korean golf courses, 70~80cm total thickness of green appeared the highest frequency(36.1%), 10~20cm thickness of green mixed sandy layer appeared the highest frequency(43.6%), and 10~20cm thickness of green coarse sandy layer appeared the highest frequency(55.6%). 0~10cm thickness of green gravel layer appeared the highest frequency(67.6%), 20~30cm thickness of green drain layer appeared the highest frequency(52.8%), and 20~30cm width of green drain layer appeared the highest frequency(44.4%). Below 1mm sand diameter used in green mixed sandy layer appeared the highest frequency(46.2%), below 2mm or over 2mm sand diameter used in green coarse sandy layer appeared the highest frequency(31.4%). 20~40mm coarse gravel diameter used in green gravel layer appeared the highest frequency(43.2%) and 0~20mm fine gravel diameter used in green gravel layer appeared the highest frequency(65.8%). 20~40mm gravel diameter used in green drain layer appeared the highest frequency(64.1%).

• Journal of The Geomorphological Association of Korea
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• v.21 no.4
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• pp.109-120
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• 2014

This study is an analysis on gravel and sand of sand-gravel bar that stretches variously in the Duchon stream basin, which is one of Hong-Cheon River(a well-developed sand-gravel bar in upstream river)'s upper stream basin. The purpose of this study was to understand the characteristic of the stream's topographic development that variously occur in the small basin by comparing the differences between the aspects of development and the sediment of sand-gravel bar in each section and by examining the transition of sediments moving from upstream to downstream. Through the analysis on the roundness and flatness of gravel, we observed an irregular trend following the increase in supply of granite gravel and gneiss gravel as we traveled downstream. As for the aspect of change in sand's grain size, the overall ratio of medium-coarse sand was very high, but the results showed no big difference in the change following the inflow of stream from the main stream section to the gneiss and granite zone.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.1C
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• pp.39-51
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• 2011

A large number of small particles may surround large gravels which are non-contact and dispersed within the ground. The strength of such soil may be influenced by the mechanical properties of a few coarse gravels. A specimen or gravel size can impact the shear characteristics of sand with dispersed gravels. In this study, the size of gravel and specimen varies and its effect on shear characteristics of a granular soil was evaluated. Five sizes of gravels with 7, 12, 15, 18, and 22 mm were used repeatedly and inserted in the middle of each compacted layer. A specimen consists of five or ten equal layers depending on gravel size, which is 5 cm or 10 cm in diameter and 10 cm or 20 cm in height. An embedded gravel ratio by weight is 3% and constant for all cases with gravel. After consolidation, a series of undrained triaxial compression tests under three confining pressures was performed on sand with dispersed gravels. The maximum deviator stress of a specimen with 10 cm in diameter was at average 30% higher than that with 5 cm in diameter and increased up to 90% for a specimen with gravel. When a gravel size of 7 and 12 mm used, the maximum deviator stress of a specimen with 10 cm in diameter was higher than that of one without gravel, whereas the maximum deviator stress of a specimen with 5 cm was higher or lower than that without gravel. The gravel size and specimen diameter influenced the undrained behavior of sand. The maximum deviator stress of a specimen with gravel either increased or decreased compared to that without gravel, depending on the ratio of gravel size to specimen diameter, 1/5.

• Magazine of the Korean Society of Agricultural Engineers
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• v.33 no.4
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• pp.84-95
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• 1991

The compaction ratio of the field dry density to the maximum dry density is generally adopted as the index of quality control for embankment of earthfill structures such as Earth Dam, Sea Dike, River Bank and Road. In case of coarse materials are included in the earth material, the compaction ratio will be varied in wide range since the dry density is influenced by quantity of coarse material in the soil. The treatment for the coarse material should be controlled carefully in testing. In this study, the compaction characteristics of the soil contained the coarse materials were researched and calibration of the suitability of field quality control methods were carried out. 28 Samples were made of clay(CL) and sandy soil (SM) mixed with gravel whose content were 0, 4, 6, 8, 10, 12, 15, 20, 25, 30, 35, 40, 45, and 60% in Weight. The compaction characteristics depending on the coarse material content were analysed through 4 types of compaction tests which are A-1, B-i, C-i and D-1. The adjusting coefficients for density and moisture content namely a and ${\beta}$ respectively were proposed in order to consider the effects depending on content of the coarse materials. The test methods to control reasonably and promptly the quality of earthfill were proposed after analysing the ranges of possible errors on the relative compaction ratio between laboratory compaction methods and field density testing methods.

• Journal of the Korean earth science society
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• v.33 no.4
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• pp.350-359
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• 2012

The Korean terms of sediment grain size demonstrated in the 30 textbooks of elementary, middle, and high schools and university levels are compared and reviewed, and the problems of its use and alternative terms are proposed. The Korean terms of sediment grain size shown in the most textbooks are the translated terms of the Udden-Wentworth grade scale, and the different terms have been used in these textbooks. In the case of gravels, granule, cobble, and boulder have commonly been translated as wangmorae (king sand), janjagal (fine gravel), wangjagal (king gravel), and pyoryeog (drift gravel) or georyeog (large gravel), respectively. However, it is regarded to be reasonable that they are termed as janjagal, jungjagal (medium gravel), keunjagal (large gravel), and wangjagal, respectively. Adjectives such as 'maeu goun' (very fine), 'goun' (fine), 'junggan' (medium), 'gulgeun' (coarse), and 'maeu gulgeun' (very coarse), attached with each sediment name seem to be suitable to terms for sediments smaller than gravels. Silt has been commonly termed as misa (fine sand) in many textbooks, but it may be appropriate that silt is expressed as silt. Finally, mud, which is a mixture of silt and clay, should be named ito (mud) as shown in several textbooks including Dictionary of Korean Earth Science, though mud has been frequently termed as jinheug (slush or watery soil) in the most of textbooks for elementary and middle school students, and some high school and university textbooks.