PURPOSES : The aim of this study is to review freeze-and-thaw testing apparatuses, develop a freeze-and-thaw testing setup with a test protocol, test the freeze-and-thaw properties of soils collected from different parts of South Korea, and suggest an index for frost susceptibility criteria for soils found in South Korea. METHODS : Based on a literature review, a new freeze-thaw testing setup was developed. In addition, a test protocol was developed for freeze-thaw testing. Soils collected from different parts of South Korea and bedding sand used for block pavements were tested to determine whether the measurements from the newly developed test setup could capture important freeze-thaw characteristics of the soils. Finally, to develop local frost susceptibility criteria, a parameter including both the vertical deformation and thermal conductivity characteristics of the soils was suggested. RESULTS : The results from the laboratory experiments indicate that the newly developed freeze-and-thaw setup captures the required parameters to quantify the responses of soils subjected to cyclic freeze-and-thaw testing. In addition, a vertical deformation of up to 2.437 mm is measured. Moreover, seven soils out of the nine tested soils are classified as having a medium frost susceptibility, whereas the remaining two show low frost susceptibility. The bedding sand experiment also shows that there is a possibility of having a frost susceptible condition based on the moisture content. When submerged, the bedding sand is classified as having a medium frost susceptibility. CONCLUSIONS : The "HEART" freeze-thaw testing setup was able to capture the parameters required for evaluating the frost susceptibility of soils. This setup and testing procedure could be further used to test and prepare criteria for classifying the frost susceptibility of soils found in South Korea.

PURPOSES: This study proposes a cohesive shrinkage particle model that can be used to simulate a variety of dynamic behaviors and phase changes of construction materials, including road subsidence and debris flow, and phase change curing, via discrete element method (DEM). METHODS : From the perspective of DEM modeling, the water-content-dependent characteristics of soil particles and related modeling techniques are reviewed from literature. The static friction, cohesion, and particle size change are considered as the major parameters that should be reflected in DEM modeling for a more realistic simulation. The relationships of water content with cohesive force and particle radius, as determined from experimental test results in the relevant study, are utilized to develop the cohesive shrinkage model. For each water content value, the snapshot in simulation is compared to that in the experimental study. RESULTS: The numerical simulation shows very good agreement with the experimental test in terms of overall sample radius and thickness change due to drying. However, the local curling of soil sample in the DEM simulation does not perfectly match that in the experimental test. CONCLUSIONS : The cohesive shrinking particle model seems to be good enough for simulating the volumetric and phase changes of soil samples due to drying. However, it seems necessary to consider both bonding and cohesive contact models in DEM modeling because the only cohesive contact model exhibited limitations in the simulation of curling and crack development.

PURPOSES: This study intends to develop an inorganic soil pavement material using industrial by-products and to evaluate its applicability as a road pavement material. METHODS: In this study, a compressive strength experiment was conducted based on the NaOH solution molarity and water glass content to understand the strength properties of the soil pavement material according to the mixing ratio of alkali activator. In addition, the strength characteristic of the inorganic soil pavement material was analyzed based on the binder content. The performance of the soil pavement was evaluated by conducing an accelerated pavement test and a falling weight deflectometer (FWD) test. RESULTS: As a result of the soil pavement material test based on the mixture ratio of alkali activator, it was identified that the activator that mixed a 10 M NaOH solution to water glass in a 5:5 ratio is appropriate. As a result of the inorganic soil pavement materials test based on the binder content, the strength development increased sharply when the amount of added binder was over 300 kg; this level of binder content satisfied 28 days of 18 MPa of compression strength, which is the standard for existing soil pavement design. According to the measured results of the FWD test, the dynamic k-value did not show a significant difference before or after the accelerated pavement testing. Furthermore, the effective modulus decreased by approximately 50%, compared with the initial effective modulus for pedestrian pavement. CONCLUSIONS: Based on these results, inorganic soil pavement can be applied by changing the mixture proportions according to the use of the pavement, and can be utilized as road pavement from light load roads to access roads.

In this study, using soil brick with combined effective microorganisms and emergent plants was identified which it can increase the effect of conservation and improvement of water. Lab-test was consist of four kind of reactors and each of reactors were A(rawwater), B(soil brick), C(emergent plant) and D(soil brick+emergent plant). Iris pseudoacorus, Phargmites australis, Typha angustifolia and Zizania latifolia were used for emergent plant. Evaluation of application on various environment were performed on agricultural waterway and pond. The pH measurement test of soil brick was performed due to evaluate whether a strong alkaline water flows out of the soil brick. Result of lab-test, removal efficiency of D was better than removal efficiency of A presenting 20.9%, 27.9% 21.5%, 33.8% and 58.4% for CODCr, BOD5, TN, TP and TSS respectively. Removal efficiency of soil brick on agricultural waterway was revealed to be 49.5%, 45.0%, 43.7%, 37.3% and 28.6% for CODCr, BOD5, TN, TP and TSS respectively. And removal efficiency of soil brick on the pond was revealed to be 12.7%, 10.5%, 9.32%, 10.4% and 36.3% for CODCr, BOD5, TN, TP and TSS respectively. Result of pH measurement test of soil brick was neutral which was about 6 to 8.

PURPOSES : The purpose of this study is to determine the optimum addition rate of SBR latex through the evaluation of durability and strength of SBR latex applied soil pavement. Formerly used materials such as fly ash and cement in soil pavement had resulted in decreased durability due to micro crack by heat of hydration and shrinkage crack in winter. However, that agglutinated polymers help adhesion to aggregate increased comes up with preventing the crack opening when the number of capillary tubes of SBR latex get decreased in the hydration process of cement. Therefore, in this study, it is suggested that the evaluation of the field applicability of soil pavement be conducted through the performance lab test in terms of strength increment, adhesion improvement, and crack resistance based on SBR latex addition rate. METHODS: In order to evaluate the field applicability of soil pavement, SBR latex was added 0 to 3% by 1% increment, with fixed cement contents of 3% and 5%. The resistance of shear failure and crack of soil pavement were evaluated by performing the uniaxial compressive strength test and indirect tensile strength test at -20 and 20℃, respectively. RESULTSCONCLUSIONS: It was found out that from both tests, resistance of shear failure and crack were improved with increment of curing time, and especially more than 2% of SBR latex addition rate and 5% cement content gave better results.

최근 흙포장은 친환경 재료로 알려지기 시작하면서 시공이 점차 늘어나고 있는 추세이다. 그러나 기존 흙 포장은 자연상태의 흙에 시멘트와 경화제를 혼합하여 포설되고 있으며, 강도 발현은 시멘트의 첨가량(일반 적으로 15~20wt%)에 의존하고 있다. 시멘트는 소성과정에서 1400℃이상의 막대한 에너지가 소비되며, 온 실가스의 주요인인 이산화탄소를 다량으로 배출하고 있으며, 이는 전세계 온실가스의 7%에 달한다. 따라서 국내외 콘크리트 제조업체들은 시멘트 제조시 발생되는 이산화탄소의 감축을 위한 기술개발을 위해 노력을 하고 있다. 본 연구에서는 기존 흙포장 재료에서 시멘트를 대체하기 위하여 산업부산물(고로슬래그 미분말, 플라이애쉬)을 이용한 무시멘트 무기계 습식 흙포장 재료의 배합비에 따른 강도실험을 수행하였다.

본 연구에서는 사질토와 점성토의 인발저항의 관계를 파악하고, 나무말뚝의 직경 근입깊이, 직경과 근입깊이에 따른 근입비의 변화에 따라 인발저항력의 상관관계를 연구하고자한다. 그리하여 간척지 지반 특성인 점성토 지반 위 적당한 나무말뚝의 직경과 근입깊이, 근입비를 통하여 최적의 나무말뚝의 제원을 결정하고자 한다. SM과 ML로 이루어진 두 지반조건의 다짐률을 70 %로 동일하게 하여 말뚝의 인발저항력을 측정하였다. 직경과 근입깊이를 동일하게 하였을 때 ML 지반의 값이 더욱 크게 나오는 것을 보아 인발저항력은 점착력의 영향을 크게 받는다는 것을 알 수 있다. 또한 각 지반에 대해서 동일한 직경에 대한 근잎깊이 를 달리하여 말뚝의 인발저항을 측정하였을 때, 근입깊이가 깊을 수로 인발저항력의 크기가 비례하였다. 말뚝의 인발저항력은 주면면적이 클수록 증가하는 것으로 나타났다. 말뚝의 직경을 일정하고 근입깊이를 달리한 경우에는 근입깊이가 증가함에 따라 인발저항력은 증가하는 것으로 나타났다. 그러나, 직경이 일정하지 않은 경우 근입비 만을 고려하였을 때, 인발저항력과의 관계는 불규칙한 것으로 나타났다.

W. B. 예이츠에 대해서는 “쇠퇴”라는 비평적 주제는 『보일러』(1938)라는 책자에서 다루어지는, 계시적 지지에 이르는 그의 마지막 단계의 우생학에 집중된다. 이 글은 예이츠의 초기를 다루는데, 최초의 성공작 『유신의 방랑』(1889)의 영웅적 신화의 전개를 다룬다. 예이츠는 제국적 남성의 코드나 그 반대의 식민적 아일란드적 야만성을 반복하지 않고, 데카당스와 쇠퇴의 두려움에 대항해서 남성의 힘과 신화적 영웅의 미덕을 시로 표현하려한다. 필자는 아일랜드의 모더니즘의 주요 수사법인 나태하고 무력한 남성상으로 이 문제를 극복한다고 본다.

Pits and mounds created by windthrow have significant impacts on forest ecosystem. In order to establish initial data base, 80 pits and mounds were sampled and surveyed in 5 fir forests in Nae-Sorak Mountain. Characteristics and forms were surveyed and fr

Background : Plants cultivation is hindered by root rot, a major disease caused by the soil-born fungi. The ginseng-cultivated soil is one of the nutritious habitats for soil-borne microorganisms. Bacteria from ginseng-cultivated soil can increase plant growth by supplying nutrients and hormones as well as protecting against pathogenic fungal infections and induced systematic resistance. Methods and Results : The novel species DCY115T was isolated from ginseng-cultivated soil in Gochang province, Republic of Korea. The isolate was assigned to the genus Paraburkholderia due to its 16S rRNA gene sequence closely proximity to P. xenovorans LB400T (98.8%). Strain DCY115T is gram-negative, facultative aerobic, rod-shaped, non-flagellated, oxidase and catalase positive. The predominant isoprenoid quinone is ubiquinone Q-8. The genomic DNA G + C content is 61.3 mol%. Phenotypic tests and chemotaxonomic analysis place strain DCY115T in the genus Paraburkholderia. DNA-DNA hybridization values between strain DCY115T and closely related reference strains were lower than 51%. The DNA relatedness data in combination with phylogenetic and biochemical tests showed that strain DCY115T could not be assigned to any recognized species. Finally, strain DCY115T showed the plant growth promoting activities of siderophores production, phosphate solubilization, and antagonistic activity against root rot fungal pathogen Fusarium solani (KACC 44891T) and Cylindrocarpon destructans (KACC 44660T). Conclusion : The results support the novel strain DCY115T as a potential biocontrol agent against root rot fungal pathogen within the genus Paraburkholderia for which the name Paraburkholderia panacihumi is proposed. The type strain is DCY115T (= KCTC52952T = JCM32099T).

This study was conducted to improve the economy, quality, and load of Soil paving concrete by using waste materials such as Oystery and Dolomitic to solve strength reduction and durability reduction caused by hardening agents in Korea. According to the results of the study, for the curing expenses, the Fine part agreement (FC) and the Furnace slag power lower (BS) are 5:5, It was possible to verify that the best results were obtained in terms of the quality of cement mortar when the natural organic lime and dolomitic lime were mixed at a ratio of 5:5.

In this study, the correlation between the durometer and the proctor penetration resistance tester, which is considered to be efficient in determining the setting time in a simple portability for soil and concrete utilizing organic lime (H) and Goto lime (G), is used. The results of the study show a high correlation between the portable hardness meter, the durometer and the proctor penetration resistance test period. Therefore, it is expected that the durometer will be useful for the measurement of setting time and the time limit.

An experiment to understand how natural fiber reinforcement would influence rammed earth P-δ curves was conducted. The experiment results showed that the natural fiber reinforcement had generally increased loads of specimens and that the longer the fibers and the higher the mixing ratios, the lpad degradation after failures tend to be slowly appeared.

Geosynthetics have been widely applied in waste landfill site for reinforcement, filtration, drainage, protection, and separation. Geosynthetics inevitably contact soil particle directly, composing a geosynthetic-soil interface corresponding to external conditions. In this study, particularly, the effects of chemical aggressors on the geosynthetic-soil interface were investigated under cyclic shear loading, based on the experimental approach. The Multi-purpose Interface Apparatus (M-PIA) was newly manufactured and modified for better performance. The Disturbed State Concept (DSC) and disturbance function were introduced and employed to estimate shear stress degradation based on the experimental study, quantitatively. New disturbance functions and parameters were mathematically evaluated. Microscopic observation by Focused Ion Beam (FIB) was utilized to clarify the reason of the variation of interface damage subjected to the chemical conditions. As a result, the variation of the cyclic shear behavior at the geosynthetic-soil interface was due to the different damage patterns of the soil particle surface. Furthermore, the numerical back-prediction based on the DSC parametric study of the cyclic shear stress-strain behavior was performed and verified the accuracy and applicability of the DSC parameters. Consequently, a general methodology to estimate the cyclic shear stress degradation of geosynthetic-soil interface considering chemical effects has been established and verified.

In this study, an experimental research is conducted to determine the influence of field conditions on the soil dielectric constant in order to evaluate the feasibility of using TDR method as a cavity exploration. Dielectric constant of the ground considering field conditions(e.g. casing and ground disturbance) was measured using TDR method. The results conclude that the dielectric constant of ground tended to decrease with the increase in the water contents and density.

The purpose of this study was to develope the environmentally favorable method of roller compacted soil concrete pavement using industrial waste red mud. Red mud was the major solid waste produced in the process of alumina extraction from bauxite(Bayer process). For recycling purpose, red mud was treated and applied to use as concrete admixtures. To this end, laboratory test such as compressive strength of soil concrete, and field test such as construction characteristics of soil concrete pavement, had been conducted. From the study results, the compressive strength of soil concrete was strongly related to its matrix proportion and compaction energy. The optimum mix proportion was comprised of cement 300 kg/m3, water 110 kg/m3, fine aggregate 600 kg/m3, course aggregate 1400 kg/m3, red mud admixture 50 kg/m3 and compaction energy above 2.86 cm-kgf/cm3. The 7th-day and 28th-day mean compressive strength of soil concrete were 43.8 MPa and 53.3 MPa each under the optimum condition. Pavement application of soil concrete using red mud admixture indicated that the proposed method was simple in case of construction and showed a good surface texture.

자유로운 흙놀이란 유아들이 유치원 주변에 있는 흙과 자연물 등을 이용해 자유스러운 분위기에서 놀이를 선택하고 즐기는 것이며, 감각을 이용하여 흙을 탐색하고 놀이하면서 흙을 자유롭게 느끼는 경험을 말한다. 본 연구는 유아들이 자연 놀잇감인 흙과 자유롭게 놀이하는 과정에서 나타나는 흙에 대한 태도와 유아들 간에 이루어지는 놀이행위에 대한 상호작용을 심층적으로 알아보고자하였다. 전라북도 J시에 소재한 공립 하늘유치원 푸름반 만 5세 유아 26명을 대상으로 2010년 5월 19일(수)부터 7월 14일(수)까지 9주 동안 매주 2회씩 18회의 흙놀이를 참여관찰 하였다. 유아들은 유치원 주변에 있는 흙을 탐색하는 감각경험과 흥미와 선택에 의해 이루어지는 자유로운 흙놀이를 경험하였다. 지속적으로 이루어진 흙과의 만남은 유아들로 하여금 흙이 주는 느낌을 감각적으로 즐기면서 흙이 주는 자유로움, 즐거움, 부정적인 감정 등을 경험하는 등 흙을 친근하게 느끼는 태도를 보였다. 유아들은 흙놀이 중 또래와의 다양한 상호 작용경험을 통해 흙을 친근하게 생각하고 있었으며, 또래와 함께 흙놀이 주제를 선택하고, 생각을 공유하고, 놀이에 참여하면서 이루어지는 상호작용을 통해 흙에 가까이 다가가는 방법과 흙이 주는 자유로움 속에서 협력의 즐거움을 경험하였다.