• 전기의세계
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• v.24 no.5
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• pp.57-60
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• 1975

오늘날 컴퓨터는 일반 사무분야 및 과학기술분야에 널리 이용되어 계산의 신속, 정확 및 사무의 간편화를 가져왔음은 물론 여러가지 Simulation을 단시간내에 처리하여 우리에게 유익한 판단자료를 제공해 주기도 한다. 이러한 역할외에 제조공정에서 공정중의 일부분 또는 전부를 제어하여 공정의 안정 및 품질의 향상등을 기하는 역할을 수행케하는 데도 컴퓨터는 이용된다. 여기에서는 시멘트 제조공정제어에서 일반적으로 컴퓨터가 어떠한 역할을 하고 있는가에 대하여 당사의 계획을 중심으로 하여 약술코져 한다. 시멘트제조공정은 다입력, 다출력계로서 제어가 복잡한 관계로 종래 경험과 숙련에 의한 제어만으로는 만족한 공정의 안정을 얻을 수 없던 것을 공정제어에 컴퓨터를 도입하여 최적 공정제어를 기할 수 있게 되었으며 미국에서는 약 15년전부터 서독과 일본에서는 약 10년전부터 공정의 전부 또는 일부를 컴퓨터화시켰던 것이다. 당사에서는 여러가지 여건으로 공정에의 컴퓨터도입을 지연시켜 오다가 2-3년 후의 완전 설치, 운용을 목표로 추진하고 있다.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.321-322
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• 2009

when the polluted soil with heavy metal ions was solidified using magnesia-phosphate cement, heavy metal ions were rarely eluted. Furthermore, the results cf SEM-EDS analysis showed that heavy metal ions in polluted soil turns into insoluble solid solution by magnesia-phosphate cement, it come to have the effect to stabilize heavy metals.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.3
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• pp.105-110
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• 2011

Recently, a deep mixture method as a soil improvement method of marine soft ground, which causes less noise and vibration than other methods, are widely used. In this study, for DCM(Deep Cement Mixing) method, one of the deep mixture method, optimum mixing ratio of clay-cement was suggested using uniaxial compression tests on specimens with various mixing ratio of claycement. In addition, the stability of a caisson on tangent circle-type and wall-type DCM treated ground was evaluated using centrifuge tests. As a result, optimum mixing ratio of clay-cement was 28.5% and the stability of the caisson on DCM treated ground was confirmed. However, the lateral displacement of the caisson on the wall-type DCM treated ground was 7% less and the settlement of that was 39% less than the case of the tangent-circle-type DCM method.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.8
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• pp.909-914
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• 2007

Fluorine compounds are the essential chemicals for wet processes of semiconductor and LCD production line. Problems of conventional treatments for fluoride wastewater are their high operation costs and low fluoride removal capacity. In this study, cement paste containing various Ca-bearing hydrates such as portlandite, calcium silicate hydrate(CSH), and ettringite was investigated for fluoride removal. The objectives of this study are to assess the feasibility of using cement paste cured mixture of cement and water as an alternative agent for treatment of fluoride wastewater and to investigate fluoride removal capacity of the cement paste. The performance of cement paste was comparable to that of lime in the kinetic test. In column experiment where the effluent fluoride concentrations were below 0.5 mg/L. Then the leached calcium reached the maximum level of 800 mg/L. The nitrate reduced to the level of less than 10 mg/L. Nitrate in the wastewater was exchanged with interlayer sulfate of these cement hydrate LDHs. Phosphate concentration could be reduced to 10 mg/L by forming calcium phosphate. These results indicate that the cement paste generally has advantageous characteristics as an economical and viable substitute for lime to remove fluoride.

• Journal of the Korean Geotechnical Society
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• v.19 no.5
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• pp.189-197
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• 2003

The treatment and hauling of surplus soils which occur from construction activity are costly and have been demanding a reasonable recycling method. This study presents laboratory test results regarding the mechanistic properties of asphalt stabilized soils. The foamed asphalt equipment which generates the asphalt bubble was used to mix the soil. The marshall stability, indirect tensile test, resilient modulus, creep test and triaxial test(UU) were conducted to find out the performance of the asphalt stabilized soil. The test results were compared with the samples that fabricated in different conditions(the samples without asphalt and the reinforced samples using 2% cement). The inclusion of the asphalt in the soil has improved the marshall stability, resilient modulus and moisture susceptibility, and the addition of the 2% cement has even more increased these properties. The amount of the fines and the optimum moisture contents for mixing affects the mechanistic properties and important parameters for mix design.

• Journal of the Korean GEO-environmental Society
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• v.20 no.5
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• pp.39-46
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• 2019

Most of the soil used for reclamation is marine clay generated from dredging construction.The soft ground made of dredged clay has high water content and high compressibility, so the bearing capacity of the ground is very weak and it is difficult to enter the ground improvement equipment. Therefore, surface hardening treatment method is used to enter equipment prior to full-scale civil engineering work, and stabilizer is mainly used for cement series. Cement-based stabilizers have the advantage of improving the ground in a short period of time and have excellent economic efficiency, but they are disadvantageous in that they cause environmental problems due to leaching of heavy metals such as hexavalent chromium. In this study, environmental effects evaluation of dredged clay mixed with normal portland cement and environmentally friendly stabilizer was evaluated, and uniaxial compressive strength test and indoor model test were conducted to confirm the bearing capacity characteristics of the solidified layer.

• Journal of Conservation Science
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• v.27 no.3
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• pp.313-322
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• 2011

The floral wall of Lee Sang-beom's House and Atelier, which is No. 171 of the Registrated Cultural Heritage was conserved. In addition, materials characteristics and manufacturing technique have revealed through the scientific analysis. As a result of the analysis, samples were divided into three sections; the support layer that is made from block bricks, the paint layer and the cement mortar layer on the paint layer for the reinforcement of the construction. The higher layer lies, the finer grains it has. Furthermore, a little it was generated a small quantity of pores and calcium carbonates ($CaCO_3$) generated due to aeration of cement mortar. The patterns of letters, animals and plants pattern were expressed in the paint layer by relief and openwork. The results of qualitative analysis of the pigments of the paint layer were detected components of carbon black (C), Fe oxide ($Fe_2O_3$) and oyster shell white ($CaCO_3$, or quicklime). On the other hands, as the conservation of the floral wall, stainless frames were set up for the structural stability, the cement mortar were removed from the surface and the partly damaged and cracked areas were filled with KSE Filler A, B.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05c
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• pp.485-490
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• 1996

가연성 폐기물의 소각후 발생되는 소각재는 처분 안전성을 높이기 위해 고화/안정화되어야한다. 본 연구에서는 유해폐기물 소각재를 대상으로 기본유리 구성물질을 첨가하여 고온용융에 의한 유리고화체를 제조하고 특성을 분석하여 유해 및 방사성 폐기물 소각재의 유리고화처리 가능성을 알아보았다. 실험결과 소각재를 유리고화할 경우 시멘트류의 저온 고화매질에 의한 처리방법에 비해 내용출특성 및 감용률이 상당히 향상되었으며 안정된 유리고화체가 형성되었음을 확인 할 수 있었다.

• Korean Journal of Environmental Agriculture
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• v.29 no.1
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• pp.47-53
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• 2010

The purpose of this study was to investigate the effectiveness of a stabilization treatment for As contaminated soil. A combination of hydrated lime, Portland cement, $FeCl_3{\cdot}6H_2O$, and NaOH were used as stabilizing agents. The effectiveness of stabilization treatment was evaluated by the Korean Standard Test (KST) method (1N HCl extraction). Sequential extractions were performed to investigate the As distribution after treatment. Following the application of the treatment, curing periods of up to 7 and 28days were investigated. The experimental results showed that a combination of hydrated lime/Portland cement was more effective than treatments of hydrated lime or Portland cement at immobilizing As in the contaminated soil. The treatment of 25wt% hydrated lime and 5wt% Portland cement was effective in reducing As leachability less than the Korean warning standard of 20 mg/kg. However, the treatments of hydrated lime and Portland cement failed to meet the Korean warning standard even when up to 30 wt% was used. The treatment utilizing hydrated lime and $FeCl_3{\cdot}6H_2O$ was not effective in properly reducing As leachability. The addition of $FeCl_3{\cdot}6H_2O$ was negative in terms of pH condition. Moreover, the treatment with hydrated lime/NaOH was effective in reducing As leachability but not as much as hydrated lime/Portland cement. The sequential extraction results indicated that the residual phase was greatly increased upon the treatment of hydrated lime/Portland cement. It was concluded that the hydrated lime/Portland cement treatment was the best among the other combinations studied at achieving trace As concentrations.

• Journal of the Korean Geotechnical Society
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• v.27 no.5
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• pp.5-15
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• 2011

Recent increase of large scale construction near costal area has also increased the application of soft ground treatment. As a result, solidification with cement and lime which increases stability and durability of soils, is frequently used for surface layer stabilization in soft ground site. While stabilization of very soft clay with high plasticity and compressibility has widely been studied, studies on silty clay with low plasticity and compressibility are relatively rare. In this study, after stabilizing low plasticity silty clay of Songdo area with cement and lime under various water contents, mixing ratio, and curing time, uniaxial compression test and plate load test were performed. Strength properties from both tests were considerably consistent. And trackability of construction equipment on the treated surface layer of dredged land was estimated. Finally, optimum mixing condition for Songdo silty clay was proposed.