• Structural Engineering and Mechanics
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• v.88 no.2
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• pp.179-188
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• 2023

The mechanical behaviours of biopolymer-treated soil depend on the formation of soil-biopolymer matrices. In this study, various biopolymers(e.g., xanthan gum (XG), locust bean gum (LBG), sodium alginate (SA), agar gum (AG), gellan gum (GE) and carrageenan kappa gum (KG) are selected to treat three types of natural soil at different concentrations (e.g., 1%, 2% and 3%) and curing time (e.g., 4-365 days), and reveal the reinforcement effect on natural soil by using unconfined compression tests. The results show that biopolymer-treated soil obtains the maximum unconfined compressive strength (UCS) at curing 14-28 days. Although the UCS of biopolymer-treated soil has a 20-30% reduction after curing 1-year compared to the maximum value, it is still significantly larger than untreated soil. In addition, the UCS increment ratio of biopolymer-treated soil decreases with the increase of biopolymer concentration, and there exists the optimum concentration of 1%, 2-3%, 2%, 1% and 2% for XG, SA, LBG, KG and AG, respectively. Meanwhile, the optimum initial moisture content can form uniformly biopolymer-soil matrices to obtain better reinforcement efficiency. Furthermore, the best performance in increasing soil strength is XG following SAand LBG, which are significantly better than AG, KG and GE.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.689-696
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• 2003

In this study, ordinary portland cement, slag cement and micro cement which have been used in the construction fields were evaluated for the environmental effects and compression strength characteristics for curing solution. To find the leaching of C $r^{6+}$ characteristics in cement grouts, C $r^{6+}$ content tests were performed for the raw materials(cement powder). In addition, C $r^{6+}$ leaching tests were peformed for the homo-gel samples according to change of pH and each curing solution with the deionized water and leachate. Then, the unconfined compression strength tests were peformed with the homo-gel samples and the amount of changed C $r^{6+}$ was measured by curing solution.

• Geomechanics and Engineering
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• v.6 no.5
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• pp.437-453
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• 2014

This paper studies the swelling and strength characteristics of unimproved and improved expansive soils in terms of the swell potential, swelling pressure, rate of secondary swelling, unconfined compressive strength and California bearing ratio (CBR). The admixtures used in this study are locally available cement and fly ash. The soils used in this study were taken from the Mae Moh power plant, Lampang Province, in northern Thailand. A conventional consolidation test apparatus was used to determine the swelling of the soil specimen. The optimum admixture contents are determined to efficiently reduce the swelling of unimproved soil. The rate of secondary swelling for unimproved soil is within the range of highly plastic montmorillonite clay, whereas the specimens improved with optimum admixture contents can be classified as non-swelling kaolinite. A soil type affects the swelling pressure. Expansive soil improvement with fly ash alone can reduce swelling percentage but cannot enhance the unconfined compressive strength and CBR. The strength and swelling characteristics can be predicted well by the swelling percentage in this study.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.10a
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• pp.263-270
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• 1999

In country, for 2002 World-cup the peak is to construct soccer playground. the stabilizing method by additives is mainly applied of permanent improvement for bearing capacity of structure foundation and for strength, durability and transformation of road pavement layer except for construction machine's trafficability and bearing capacity. This study is on soft ground improvement of $\bigcirc$$\bigcirc$ world-cup stadium field. construction field constitutes of very various layers and after construction the lawn grass should be planted on the surface of the earth and in addition, chemical effects should be limited from improved ground layer. Mixing soft clay in field with three domestic representative additives, it evaluated the unconfined compression strength. In the results, after curing during 28 days the objective strength has been obtained on about 5% combination ratio.

• Earthquakes and Structures
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• v.18 no.3
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• pp.379-390
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• 2020

Four full-scaled partially confined and unconfined masonry panels were tested with monotonic lateral loads. To study the effects of vertical force and boundary columns, two specimens with no boundary columns were subjected to different vertical forces, while two wing-wall specimens had the column placed eccentrically and in the middle, respectively. The specimens with no boundary columns exhibited ductile rocking behavior, where the lateral strength increased with increasing vertical compression. The wing-wall specimens with columns behaved as strut-and-tie systems. The column-panel interaction resulted in greater strength, lower deformation capacity and differences in failure modes. A comparison with analytical models showed that rocking strength can be accurately estimated using vertical force and the panel aspect ratio for panels with no boundary columns. The estimation for lateral strength on the basis of a panel section area indicated scattered error for wing-wall specimens.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.326-330
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• 2009

In this study, coarse-grained geomaterials were mixed with cementing binder. To do that, typical soils from road construction sites were selected to assess the strength and stiffness characteristics of cemented geomaterials mixed with cement and recycled fly ash. Mechanistic evaluation on these samples was performed depending on the various binder contents. Increasing cementing content tend to increase the resilient modulus under repeated loadings and unconfined strength respectively. In addition, the toughness of cemented geomaterials was also estimated in order to check the ability to resisting fatigue failure.

• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.4
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• pp.123-128
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• 2002

This study was performed to use fiber mixed soil which has clayey soil or sandy soil with fibrillated fiber or monofilament fiber on purpose of construction materials, filling materials, and back filling materials. In addition, this study was conducted to analyze strength properties and fiber reinforcing effect with fiber mixed soil by direct-shear test. In case of fibrillated fiber mixed soil, the more quantity of fiber was in both cohesive soil and sandy soil, the larger shear stress was in respective step of normal load. The respective mixed soil at 0.5% and 0.1% mixing ratio of monofilament fiber mixed soil showed maximum shear stress. According to unconfined compression or direct-shear test, making specimen of the monofilament fiber mixed soil, it is required to be careful and stable mixing method, while it is expected that monofilament fiber mixed soil doesn't increase strength.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.529-534
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• 2009

This study had propose that a characteristic of recently developed Silicasol to make a close in this study, grouting material usually used portland cement and a characteristic is compared between Silicasol and sodium silicate in this study, examined strength and environmentally friendly for compare characteristics of sodium silicate and Silicasol through unconfined compressive strength, SEM analysis, Permeability test, Chemical Resistance test, leaching test etc. In the test, I gained that unconfined compressive strength of Silicasol three times promoted than sodium silicate Within 72 hours and I gined through analysis of SEM that Silicasol is more compactivetive than sodium silicate. In the result of test, it was found to be a environmentally friendly material as the toatal amount of eluviated elementary had small quantity.

• Journal of the Korean Geotechnical Society
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• v.22 no.10
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• pp.33-45
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• 2006

C.S.G is a material made by adding cement and water to rock-like material such as riverbed gravel or excavation muck that can be obtained easily near dam si. Recently, the use of C.S.G is gradually increasing as the construction material for dam, road, revement and so on. Commonly, the strength characteristics of C.S.G is affected by various influence factors such as grade, unit cement, age and water contents. In this study, a series of compaction test and unconfined compressive strength test were performed to investigate the relationship between a strength and influence factors such as three kinds of gradation, age, unit cement and water contents with riverbed gravel in Hwa Buk dam. The results show that strength Properties of C.S.G is variously affected by these influence factors. Especially, gradation and water contents are found to be very important factors fur determining the strength of C.S.G material. And, from the results of experimental study, the correlation equations between uncompressive strength and these factors are proposed.

• Magazine of the Korean Society of Agricultural Engineers
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• v.17 no.1
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• pp.3685-3701
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• 1975

This study was conducted to investigate the strength of soil cements for varied molding water content and cement content(3,6,9,12%) in four cementstabilized soils(KY: sand, MH: sad, SS: sandy loam, JJ: loam). The eoperimental results obtainedfrom unconfined compressive strength tests are asfollows: 1. The optimum moisture content increased in accordance with the increase of the cement while maximum dry density didn't change uniformly. 2. The moisture content for maximum strength was higher than the optimum moisture content in the higher cement content. Moisture-density curves showed a dull peak in the higher cement contents, on the other hand, a sharp peak in the lower cement contents. 3. In molding the specimen with the approximate optimum moisture content, the maximum strength showed at the wet side of the optimum moisture content. 4. SS and JJ maybe used as cement-stabilized base of road to require 300PSI of compressive strength cured seven days, but MH and KY may be not adequate. 5. In soil cement, the better the grain size distribution was, the stronger the compressive strength was itn general. 6. The relation between 28-day strengh and 7-day strength in the cementstabilized four soils may be expressed as follows: q28=1.55q7+1.5 in which q28:28-day strength. q7:7-day strength.