• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.267-267
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• 2008

시멘트를 이용한 지반개량 및 시멘트계 건설폐기물을 (예, 폐콘크리트, 및 시멘트 개량토 등) 성토재로 재활용하는 경우 지반 환경에 미칠 수 있는 영향으로는 (1) 시멘트에 함유된 6가 크롬($Cr^{6+}$) 및 (2) 강알칼리 물질의 용출이 있을 수 있다. 특히 $Cr^{6+}$의 경우 인체에 치명적인 발암성물질로 알려져 있어 이에 따른 주의가 필요하다. 최근 일본에서는 시멘트의 $Cr^{6+}$에 의한 지반오염이 우려됨에 따라 2000년 시멘트계 고화재를 지반에 사용하는 경우와 개량된 토양을 재이용하는 경우에는 토양환경기준을 만족하도록 규제하고 있다. $Cr^{6+}$외의 시멘트계 물질에 의한 환경오염으로는 강알칼리 물질의 유출이 있을 수 있다. 시멘트 개량토나 폐콘크리트 등의 건설폐기물을 성토재로 재활용하는 경우, 강우의 유입에 따라 구성물질인 수산화칼슘이 용해되어 높은 pH의 유출수가 발생한다. 강알칼리 유출수가 주변 하천 등으로 유입되는 경우 심각한 환경문제를 유발할 수 있으므로 이에 대한 기술적 검토가 필요하다. 본 발표에서는 시멘트계 물질에 의한 일본의 지반환경오염 사례 및 대책을 소개하였다.

• International Journal of Highway Engineering
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• v.12 no.3
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• pp.113-119
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• 2010

This study presents experimental findings on the performance of cement concrete pavement incorporating mineral admixtures such as ground granulated blastfurnace slag and silica fume. Flexural strength, compressive strength, charge passed, diffusion coefficient of chloride ions and initial surface absorption of cement concrete pavement incorporating mineral admixtures were periodically measured and the corresponding results were compared to those of plain concrete pavement. As a result, strength behaviors of concrete pavement were dependent on the types of mineral admixtures. However, it was true that incorporation of silica fume had a beneficial effect on compressive strength development. Furthermore, the application of mineral admixtures led to a lower diffusion coefficient of chloride ions compared to plain concrete pavement. Based on the experimental results, the present study would be helpful to design high-performance cement concrete pavement.

• Cement Symposium
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• no.32
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• pp.192-197
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• 2005

• 월간산업보건
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• s.340
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• pp.33-46
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• 2016

본 연구 결과, 한국의 대표적 시멘트 5개 회사에서 10년 이상 근무한 근로자 1,083명(94명 제외)들의 흉부엑스선 판독결과 진폐증이나 진폐증의증자들은 발견되지 않았다. 이들이 근무한 부서의 과거 총분진 평균 농도는 $1mg/m^3$ 미만으로 진폐 발생 분진농도에 휠씬 미치지 않는 것으로 조사되었으며, 시멘트 분진내 진폐발생물질인 결정형 실리카는 1% 미만으로 국내 시멘트 공장 근무자들은 포틀랜드시멘트 분진노출에 의한 진폐증 발병가능성은 매우 낮은 것으로 사료된다. 그럼에도 불구하고 2009년부터 지속되고 있는 시멘트분진과 COPD 및 진폐증 관련성 주장은 언론 보도는 물론이고 일부 학자들에서 조차 시멘트분진 구성성분에 진폐증이나 폐암발생 물질인 실리카(결정형 실리카)가 다량(20%)으로 포함되어 있다고 잘못 인식한 큰 이유로 생각된다.

• Cement
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• s.124
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• pp.15-18
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• 1991

• KSCE Journal of Civil and Environmental Engineering Research
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• v.44 no.4
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• pp.433-441
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• 2024

This study aims to prevent freezing of existing domestic buildings by developing an energy storage mortar with increased energy efficiency that can reduce the increase in carbon emissions and maintenance costs due to external energy use due to heat wires in civil engineering and buildings with embedded heat wires. I suggest. Research has focused on incorporating phase change materials (PCMs) into common cement composites to provide latent heat performance. However, concrete mixed with phase change materials shows problems such as leakage of phase change materials, decreased strength, and insufficient thermal performance. To overcome this problem, we encapsulate phase change materials using microcapsules and mix them into cement composites to minimize strength loss and leakage, and use multi-walled carbon nanotubes and silica fume to minimize the strength reduction of concrete. A heat storage cement composite was developed. When high-efficiency heat storage cement was used as a replacement for ordinary cement composite in an environment where heat wires were buried, the effect was shown to reduce energy by about 42 %, and compared to a cement composite containing only PCM, the compressive strength and bending strength were 18 % and 23 %, respectively. was improved and its effectiveness was proven.

• Cement
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• s.108
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• pp.57-60
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• 1987

이 논문에서는 통상의 포졸란 대신에 제올라이트 물질 즉, 화산 응회암을 적절히 분쇄한 후 혼합해서 만든 시멘트의 특성 변화에 대해 논하였다. 이러한 치환이 알칼리-골재 팽창 반응을 최소화시키고 장기강도를 향상시키는 장점이 있다는 사실도 밝혀냈다. 특히 제올라이트를 미리 열처리해서 첨가했을 때 이러한 팽창감소 효과가 현저하다는 것도 발견하였다. 강도증진 효과는 포졸란 유리상의 활성도에 비해 제올라이트 광물의 활성도가 높기 때문으로 해석되며 팽창의 감소는 비정질 수화 규산염이 먼저 알칼리와 반응을 하는 성질이 있기 때문으로 판단된다.

• Resources Recycling
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• v.29 no.5
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• pp.64-72
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• 2020

When the multi-stage combustion process is applied to the cement kiln to reduce nitrogen oxide emissions in the cement industry, oxidation/reduction section that can increase combustion efficiency by reducing NO_x to NO and completely burning unburned materials is essential In this study, when applied the oxidation/reduction system of the cement kiln preheater and calciner, the optimal oxidation/reduction calcination crisis that can secure the quality stability of the final product, cement clinker, was to be observed macroscopically, and the mass change of raw materials according to the burning conditions, decarbonation rate, and calcination rate were investigated. The results showed that the thermal decomposition of raw materials tends to be promoted in the oxidation condition rather than in the reduction condition, and that the thermal decomposition of limestone, which has a relatively high CaO content, is carried out later than that of cement raw meal, which is thought to be caused by the CO₂ fractionation in the kiln. The thermal decomposition properties of raw materials according to oxidation/reducing burning condition showed a relatively large difference in temperature range lower than normal limestone themal decomposition temperature, which is thought to be expected to improve the thermal efficiency of raw materials according to the formation of oxidation condition in the section 750℃ of burning temperature. However, for this study, lab scale. Because there is a difference from the field process as a scale study, it is deemed necessary to verify the actual test results of the pilot scale.

• Cement Symposium
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• no.12
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• pp.48-62
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• 1984

• Journal of the Korea Concrete Institute
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• v.28 no.6
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• pp.665-672
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• 2016

This study is conducted to investigate the effect of phase change materials (PCM) on hydration heat and strength characteristics of cement mortar. Two types of Barium and Strontium-based PCMs were used in this study and the addition ratio of each PCM to the cement mortar ranged from 1% to 5% by cement weight. Flow test, semi-adiabatic temperature rise test, compressive strength and flexural strength test were carried out to examine the PCM effect on heat and mechanical properties of cement mortar. Test results indicated that PCMs used in this study were effective to control hydration heat of cement mortar, and Barium-based PCM slightly reduce flow value. The compressive and flexural strength of cement mortar with PCM decreased with increasing the adding mount of PCM. The prediction model for compressive strength of cement mortar with different addition levels of PCMs are suggested in this study.