• Journal of the Korean GEO-environmental Society
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• v.7 no.6
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• pp.113-119
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• 2006

Recently, the ground injection method using water glasses as one of the main resources and the products of these constructions have basic problems in terms of the method of constructions for the permanent foundation reinforcement and stopping leakage of water because they have some serious problems such as durability, compressive strength, injectant eluviation and so forth even though they are still used to stop leakage of water in the temporary structures. The purpose of this study is to demonstrate the strength characteristic and environment friendliness of NDS method by unconfined compressive strenth test, permeability test, length change test, leaching test, and assessment of environmental impact in comparison water glass type material. The test results show that NDS method has significant improvement of strength, permeability, volume change, and leaching. An assessment of environmental impact also demonstrates that the NDS material is environmentally friendly.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.3
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• pp.182-189
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• 2018

Controlled low strength material(CLSM), known as flowable fill is used sewer. This paper evaluates flowability, segregation, early strength and excavatability of CLSM made using standard soils such as SM, ML, CL, CH. Also, various mix proportions of CLSM containing kaolinite, red soil, Joomun Jin standard soil were developed and the mixing ratio optimized. It was considered as the flowability and early strength were severly affected by W/B, S/B, and early strength and flowability depend on standard soils which means the satisfaction conditions of CLSM were variety of standard soil conditions. Finally, not only optimal mixing proportions were deducted according to standard soil condition but confirmed effectiveness of bleeding and excavatability.

• Journal of the Korean GEO-environmental Society
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• v.14 no.11
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• pp.65-71
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• 2013

Despite of the various merits of soil pavement, it has not been widely adapted because portland cement was conventionally used as soil stabilizer to improve the mechanical properties such strength parameters. Recently, natural soil stabilizer(NSS) were developed and virtually adopted to several case of soil pavement construction under control of heavy metal pollution compared to cement-used cases. However, the application of natural soil stabilizer is not settled yet, and empirical design have been widely adopted. In this study, therefore, the strength parameter of soil-NSS mixture was estimated by some triaxial compression tests, CU-test. From the tests, the relationship between curing period and strength parameter such as internal friction and effective cohesion was examined. As a result, effective cohesion of dredged clay and granite soil increased as curing time is increased. However, internal friction is almost same result in all soil type used in this study.

• The Journal of Engineering Geology
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• v.4 no.3
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• pp.269-281
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• 1994

Microscopic study and X-ray diffraction analysis were carried out to find out rock type, tock forming minerals; and weathering characteristics of rocks at the constructing site of the churyong Tunnel, Kyongju-Gun, Kyongbuk. Seismic velocity and compressional strength were measured to evaluate mechanical properties of rock. The rock of the study area is Jurassic tuff consisting of clay minerals, crystals of quartz and feldspar, fragments of volcanic rocks and shale. Fresh tuff has compressional strength of about $443kg/\textrm{cm}^2$ and seismic velocity of about 3680m/sec in average. It is classified as soft rock. Rock fragment within tuff is andesite and it has compressional strength of about $2500kg/\textrm{cm}^2$ and seismic velocity of about 4340m/sec in average. It is classified as hard rock. A good linear relationship is found between compressional streangth and seismic velocity in both laboratory sample and in-situ rocks. Laboratory samples has seismic velocities faster about 1.5km/sec than those in-situ rocks. It is interpreted that joints, fractures, and water content in the in-situ rocks result in decreas of seismic velocity. As Tuff has more than 50% of clay minerals in matrix and shale fragments, it absorbs water easily in atmospheric condition. Therefore, though the rock in the study area is medium hard rock before weathering, it is weathered very easily in the case of exposure to natural environment, comparing with other rock.

• Journal of the Korean Geosynthetics Society
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• v.15 no.2
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• pp.1-12
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• 2016

In this study, laboratory mixture design test and field test were performed to evaluate applicability of eco-friendly binder material (CMD-SOIL) using desulfurized dust in deep cement mixing method (DCM). As a result of laboratory mixture design test, the uniaxial compressive strength of CMD-SOIL was up to 1.136 times bigger than slag cement by changing the water content, mixing rate, and W/B. Also, it had shown the strength up to 1.222 times bigger in shell content and up to 1.363 times in mixing of floating soil. As a result of field test, field strength/laboratory design criterion strength ratio (${\lambda}$) is shown 0.77. And this result was similar to earlier studies. From this result, CMD-SOIL can show the same efficiency compared with existing binder.

• International Journal of Highway Engineering
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• v.12 no.3
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• pp.1-8
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• 2010

This study is performed to evaluate the physical and mechanical characteristics of an acryl polymer concrete that is developed as an overlay material for cement concrete slabs and pavements. Various laboratory tests including viscosity, flow, compressive strength, flexural strength, tensile strength, linear shrinkage, thermal expansion and thermal compatibility tests are performed. It is observed from the laboratory tests that the acryl polymer concrete developed in this study satisfies all the requirements suggested by ACI guideline. In addition to the laboratory tests, an accelerated performance testing (APT) is conducted to validate the performance of the acryl polymer concrete. During the APT, no significant distresses are observed until 15,903,939 cycles of equivalent single axle loading is applied. Finally, a 10mm thick overlay with the acryl polymer concrete is applied on top of an old deteriorated concrete pavement to evaluate field performance. Right after the field construction, skid resistance, noise and roughness are measured. The skid resistance and noise level have been significantly improved while the roughness is increased. Periodic investigation for the field study section will be conducted to evaluate the long-term performance.

• Journal of the Korean Geosynthetics Society
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• v.22 no.3
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• pp.61-69
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• 2023

As global trade and maritime port environments change, the need to respond to larger and faster ships is increasing. Accordingly, new ports are being built around metropolitan cities such as Busan and Ulsan. In general, a compaction method using sand or gravel is applied to the construction of a new port. However, due to the lack of sand or gravel and the difficulty in securing economic feasibility due to the increase in unit price, the deep mixing method has recently been used. Therefore, in this study, CMD-SOIL using circulating resources was applied to the Ulsan area, and the applicability was determined by analyzing the laboratory mixing test and boring results at in-situ. As a result of the test, it was analyzed that it showed more than the design mixing strength, and it was possible to secure the similar performance as blast furnace slag cement. In addition, it was analyzed that the design standard strength can be sufficiently secured as a result of in-situ boring. Therefore, considering the field applicability in the Ulsan, it is judged that the use of CMD-SOIL is possible.

• Journal of the Korean Geotechnical Society
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• v.24 no.5
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• pp.79-87
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• 2008

Recently, a new seismic probe, called "MudFork", has been developed and can be utilized for accurate and easy measurements of shear wave velocities of cohesive soils. To expand its use to estimate undrained shear strength and density, a preliminary investigation to correlate these properties with shear wave velocity was attempted. Cone penetration tests and a seismic test, using MudFork, were performed at a silty soil site near Incheon, Korea. Also, undisturbed samples were obtained using thin-wall tube samplers, and the shear wave velocities and undrained shear strengths of the samples were measured in the laboratory. A simple linear relationship between shear strength and shear wave velocity was obtained, and a tentative relationship between density and shear wave velocity was also defined.

• Journal of the Korea Concrete Institute
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• v.25 no.3
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• pp.295-304
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• 2013

Ultra-High Performance Concrete (UHPC) has recently been one of the most active research fields in Korea as well as in foreign countries, because it can contribute to a longer life and economic efficiency of structures. Although precast-type UHPC fabricated in a factory is preferable in terms of quality control and reduction of construction period, there exist, even in the precast structure, some parts that need to be cast in-place such as the joints between precast segments. In the cast-in-place UHPC, however, it is probable that an optimum curing condition can hardly be realized in contrast to the factory production. In this study, therefore, the trend of compressive strength development of UHPC was experimentally investigated by assuming various inferior curing conditions that may be anticipated at a construction site. Concrete specimens were fabricated and cured under different conditions with the variables such as curing temperature, delay time before the initiation of curing, duration of curing time and moisture condition. The strengths were compared with those of the specimens cured by standard high temperature steam. Through the analysis of the test results, some minimum requirements for curing have been proposed that are required when the UHPC is cast in-place. It is expected, through this study, that practical use of UHPC in construction sites can be increased.

• Journal of the Korean Geosynthetics Society
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• v.14 no.4
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• pp.147-158
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• 2015

In this study, sewer backfill material was developed to prevent sewer damage and ground subsidence. Laboratory test was performed in the field of CA replacement ratio, accelerator type and replacement ratio and W/M. The compression strength of backfill material was 0.55~0.64MPa below in W/M 70% and 0.20MPa over W/B 80%. Ice block was used to simulate the ground cavity and subsidence caused by sewer damage in application study. The existing sand compaction and the new backfill material was comparative estimated in field. The ground settlement of cross section was 23.4cm and that of longitudinal section was 27cm in sand compaction section, but the ground had not sunk in backfill material section.