• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.793-808
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• 2009

This paper presents procedure and prediction method of internal and external stabilities when designing D.C.M, with main factors to be considered, such as chemical reaction of additive, physical properties of stabilized body and mixing strength. Results show that through case studies, a design unconfined compressive strength of stabilized body (hereafter referred to as 'compressive strength') directly depends on the quantity of cement, which is decided by laboratory test, and the compressive strength enormously affects internal and external stabilities. So laboratory mixing test to obtain the compressive strength for design allowable stress should be given careful considerations.

• Journal of the Korean Society of Safety
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• v.18 no.1
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• pp.76-80
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• 2003

There will be a big problem in disposing of waste tie coming from the cars. Because many of these have been thrown away to the field and environmentally polluted. New, We need to find out how to dispose or recycle these waste material. It is thought that recycling this material especially mixing with concrete will be a good idea. This study is focused how each material do its behavior due to the size of waste type particle and its amount into concrete material. 0.4mm-10mm range of particle has been applied to the material : Also, 1.0%, 1.5%, 2.0% range of tyre particle proportion has been applied to make cylinder molds. The concrete mold with waste-tyre particle has vibration-absorbing ability. It is found that 0.4 -0.6mm particle mixing concrete has been more solid organized. And this waste tyre material could be applied to the general concrete, it is found.

• Journal of The Korean Society of Agricultural Engineers
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• v.47 no.3
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• pp.49-56
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• 2005

This study was conducted by the tests of materials engineering and soil mechanics to see the strength characteristics of the ‘Cement-Mixed Soil'. To sum up my experiments, I would like to present the results which are the theoretical base and fundamental data to establish the standard design including the design of mixing proportions of the soil as a construction material. In conclusion, in this study the optimum cement mixing ratio is $9\%$ and in this ratio the optimum moisture content of compaction work is $19.3\%$ from the analysis of the strength characteristics, as well as in consideration of the economic profits and nature familiar facts.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.513-516
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• 2006

Waste concrete powder(WCP) is a secondary by-product generated while processing waste concrete manufactured to coarse and fine aggregates for concrete. In order to assess the possibility of using WCP as admixture for self-compacting concrete, self-compactability, compressive strength and durability of self-compacting concrete containing waste concrete powder were investigated. Experimental results of this study appeared that in case of SCC mixed with WCP only, self-compactability and compressive strength decreased with increasing mixing ratio of WCP. When Blast-furnace slag(BFS) was added to SCC, self-compactability and compressive strength for a unit amount of cement increased. Also, SCC containing 15% BFS and 15%, 30% and 45% WCP, the dry shrinkage and carbonation depth appeared a tendency to decrease with increasing mixing ratio.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.461-464
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• 2006

An experimental study is conducted to charaterize the mechanical properties of a fiber-reinforced, lightweight concrete (FRLAC) that is produced without an autoclave process. The FRLAC enhances the strength of lightweight cellular concrete by adding polypropylene fibers. A series of compressive strength tests on cylindrical specimens are carried out to characterize the compressive strength and the modulus of elasticity of the FRLAC. Specifically, various mixing rates of a foam agent are applied in casting of the specimens to investigate the influence of the mixing rate of the foam agent on the performance of the FRLAC and to determine the optimal mixing rate of the foam agent.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.11a
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• pp.38-39
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• 2013

In this study, in regard to fiber reinforced mortar mixing steel fiber and 4types of organic fiber, impact test was carried out. Because to predict fracture reduction performance with flexural, tensile strength when types of fiber were different as impact reduction performance of concrete is closely related with toughness such as flexural strength, tensile strength and fracture energy etc. As a result, enhancement of toughness by fiber reinforcement controls the spall of rear. On the other hand in case of steel fiber relatively turned up high toughness in appropriate load compared with organic fiber but in same mixing rate, impact reduction performance by projectile showed low performance due to few number of an individual of mixing.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.30-31
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• 2021

This study aims to build a deep learning model that can predict the value of concrete mixing properties according to a given concrete strength value. A model was created for a total of 1,291 concrete data, including 8 characteristics related to concrete mixing elements and environment, and the compressive strength of concrete. As the deep learning model, DNN-3L-256N, which showed the best performance on the prior study, was used. The average value for each characteristic of the data set was used as the initial input value. In results, in the case of 'curing temperature', which had a narrow range of values in the existing data set, showed the lowest error rate with less than 1% error based on MAE. The highest error rate with an error of 12 to 14% for fly and bfs.

• Structural Engineering and Mechanics
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• v.84 no.4
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• pp.465-477
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• 2022

The formation of biopolymer-soil matrices mainly depends on biopolymer type and concentration, soil type, pore fluid and phase transfer to influence its strengthening efficiency. In this study, the physical and mechanical properties of sodium alginate (SA) treated kaolinite are investigated through compaction test, thread rolling teat, fall cone test and unconfined compression test with considering biopolymer concentration, curing time, initial water content, mixing method. The results show that the liquid limit slightly decreases from 69.9% to 68.3% at 0.2% SA and then gradually increases to 98.3% at 5% SA. At hydrated condition, the unconfined compressive strength (UCS) of SA treated clay at 0.5%, 1%, 2% and 3% concentrations is 2.57, 4.5, 7.1 and 5.48 times of untreated clay (15.7 kPa) at the same initial water content. In addition, the optimum biopolymer concentration, curing time, mixing method and initial water content can be regarded as 2%, 28 days, room temperature water-dry mixing (RD), 50%-55% to achieve the maximum unconfined compressive strength, which corresponds to the UCS increment of 593%, compared to the maximum UCS of untreated clay (780 kPa).

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.189-190
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• 2023

In this study, the compressive strength and hydration heat of cement paste mixed with cellulose nanocrystal(CNC) and graphene oxide (GO) were evaluated. The difference was compared by mixing 0.1 vol.% ~0.4 vol.% of CNC and 0.05 wt.% ~ 0.1 wt.% of GO in a cement paste with a water cement ratio of 0.3. As a result, it was confirmed that the compressive strength increased as CNC and GO were mixed respectively, and then the compressive strength decreased when the appropriate mixing rate was exceeded. In the hydration heat measurement, there was no significant difference when only CNC was mixed, but it was confirmed that the hydration heat decreased as the amount of CNC mixing increased when used in combination with GO.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.815-826
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• 2009

The paper presents a case study addressing the design and construction aspects for DCM(Deep Cement Mixing) method employed as the foundation of a caisson type breakwater with heavy weight(10,700 ton/EA) and a high design wave height($H_{1/3}$=8.7m). The DCM was designed for the project(Ulsan New Port North Breakwater Phase 1) by optimizing the pattern of DCM columns with a combination of short and long columns (i.e., block type(upper 3m)+wall type(lower)) and considering overlapped section between columns as a critical section against shear force where the coefficient of effective width of treated column($\alpha$) was estimated with caution. It was shown that the value can be 0.9 under the condition with the overlapped width of 30cm. In addition to that, a field trial test was performed after improving conventional DCM equipment (e.g., mixing blades, cement paste supplying pipes, multi auger motor, etc.) to establish a standardized DCM construction cycle (withdrawal rate of mixing blades) which can provide the prescribed strength. The result of the field strength test for cored DCM specimens shows that the averaged strength is larger than the target strength and the distribution of the strength(with a defect rate of 7%) also satisfies with the quality control normal distribution curve which allows defect rate of 15.9%.