• 한국세라믹학회지
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• 제55권3호
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• pp.224-229
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• 2018

OPC production requires high calorific value and emits a large amount of $CO_2$ through decarbonation of limestone, accounting for about 7% of $CO_2$ emissions. To reduce $CO_2$ emissions during the Ordinary Portland Cement (OPC) production process, there is a method of reducing the consumption of cement or lower temperature calcination for OPC product. In this study, for energy consumption reduction, we prepared Hauyne-belite cement by calcination at a low temperature compared to that used for OPC and studied the early hydration properties of the synthesized Hauyne-belite cement. We set the ratios of Hauyne and belite to 8 : 2, 5 : 5 and 3 : 7. For the hydration properties of the synthesized Hauyne-belite cement, we tested heat of hydration of paste and the compressive strength of mortar, using XRD and SEM for analysis of hydrates. As for our results, the temperature for optimum synthesis of Hauyne-belite is $1,250^{\circ}C$. Compressive strength of synthesized Hauyne-belite cement is lower than that of OPC, but it is confirmed that compressive strength of synthesized Hauyne-belite cement with mixing in of some other materials can be similar to that of OPC.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2020년도 봄 학술논문 발표대회
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• pp.144-145
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• 2020

Recently, the cement industry has been using various wastes as raw materials and fuel for cement as an eco-friendly business. However, most of these waste resources contain large amounts of chloride and alkali, which are concentrated in manufacturing facilities and adversely affect cement production products. Accordingly, in the cement production process, the chlorine ion contained in cement is managed by introducing the Chlorine Bypass System (CBS) into the manufacturing facility and releasing the dust. However, the processing volume of CBS-Dust has been limited due to the shortage of domestic processing companies, and the cost has also been raised, requiring measures to be taken in dealing with CBS-Dust. In this study, rheological properties of CBS-Dust incorporated paste are tested. With the increase of CBS-Dust, flow was decreased due to enhanced viscosity.

• 한국자원리싸이클링학회:학술대회논문집
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• 한국자원리싸이클링학회 2004년도 춘계임시총회 및 제23회 학술대회
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• pp.109-113
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• 2004

본 연구에서는 현재 농촌 지역에서 광범위하게 사용되고 있으나 거의 재활용이 안 되어 방치상태에 있는 농업용 폐비닐을 이용하여 시멘트 제조를 위한 고형 연료를 제작할 수 있는 이동식 장치를 개발하려 하였다. 이를 위해 재생연료의 연소 특성 및 2차 오염 발생여부에 대해 조사했으며, 1cm 이하 알갱이 형태의 고형 연료를 제조 가능한 이동식 장치를 개발하였다. 또한 기존의 시멘트 예열탑에서의 투입 방식에서 벗어나, main burner에 적용기술 개발을 통해, NOx 및 O2 발생량의 감소가 나타났고, 0.5ton/hour 투입 시, 0.2-0.3ton/hour 정도 Coal량이 감소하는 연료 단가 절감 효과를 얻을 수 있었다.

• Advances in concrete construction
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• 제2권1호
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• pp.29-37
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• 2014

Increasing emphasis on energy conservation and environmental protection has led to the investigation of the alternatives to customary building materials. Some of the significant goals behind understaking such investigations are to reduce the greenhouse gasemissions and minimize the energy required formaterial production.The usage of concrete around the world is second only to water. Ordinary Portland Cement (OPC) is conventionally used as the primary binder to produce concrete. The cement production is a significant industrial activity in terms of its volume and contribution to greenhouse gas emission. Globally, the production of cement contributes at least 5 to 7 % of $CO_2$. Another major problem of the environment is to dispose off the fly ash, a hazardous waste material, which is produced by thermal power plant by combustion of coal in power generation processes. The geopolymer concrete aims at utilizing the maximum amount of fly ash and reduce $CO_2$ emission in atmosphere by avoiding use of cement to making concrete. This paper reports an experimental work conducted to investigate the effect of curing conditions on the compressive strength of geopolymer concrete prepared by using fly ash as base material and combination of sodium hydroxide and sodium silicate as alkaline activator.

• 대한화학회지
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• 제55권3호
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• pp.490-494
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• 2011

이산화탄소 방출을 줄이기 위해 포트랜드 시멘트 성분 일부를 시멘트 보충재를 혼합해준 시멘트의 제조에 대해 연구하였다. 이산화탄소를 0.18 kg $CO_2$/kg 정도 줄이기 위해 포트랜드 시멘트에 보충재를 20 wt% 정도 혼합하였다. 이 혼합시멘트의 압축 강도는 포트랜드 시멘트 ASTM C-150의 표준치를 초과하며, 28일간의 굳는 과정중에 37 MPa의 압축 강도를 가졌다. 혼합시멘트의 미세구조는 포트랜드 시멘트와 유사하였다.

• 한국세라믹학회지
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• 제44권11호
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• pp.633-638
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• 2007

The setting time of alkali activated slag cement tends to be much faster than ordinary Portland cement, and its compressive strength had been higher from the 1 day but became lower than that of the cement on the 28 days. According to the results of the surface observation, weight loss, compressed strength, and erosion depth tests on the sulphuric acid solution. It has been drawn that alkali activated slag cement has a higher sulphate resistance than ordinary Portland cement, and in particular, the alkali activated slag cement added 5 wt% alumina cement has little deterioration on the sulphuric acid solution. The reason why the alkali activated slag cement has higher sulphate resistance than other hardened cement pastes is that it has no $Ca(OH)_2$ reactive to sulphate ion, and there is little $CaSO_4{\cdot}2H_2O$ production causing volume expansion, unlike other pastes. And it is supposed that $Al(OH)_3$ hydrates with high sulphate resistance, which is produced by adding the alumina cement increases the sulfate resistance.

• Computers and Concrete
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• 제14권3호
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• pp.247-262
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• 2014

Partial replacement of Portland cement by slag can reduce the energy consumption and $CO_2$ emission therefore is beneficial to circular economy and sustainable development. Compressive strength is the most important engineering property of concrete. This paper presents a numerical procedure to predict the development of compressive strength of slag blended concrete. This numerical procedure starts with a kinetic hydration model for cement-slag blends by considering the production of calcium hydroxide in cement hydration and its consumption in slag reactions. Reaction degrees of cement slag are obtained as accompanied results from the hydration model. Gel-space ratio of hardening slag blended concrete is determined using reaction degrees of cement and slag, mixing proportions of concrete, and volume stoichiometries of cement hydration and slag reaction. Furthermore, the development of compressive strength is evaluated through Powers' gel-space ratio theory considering the contributions of cement hydration and slag reaction. The proposed model is verified through experimental data on concrete with different water-to-binder ratios and slag substitution ratios.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 춘계 학술논문 발표대회
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• pp.265-266
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• 2018

In recent years, active loess cement has been used instead of cement in order to reduce the amount of cement and industrial byproducts that are the main cause of environmental pollution. We also used polysilicon sludge as a by-product to reduce the amount of cement used and to improve the environmental pollution due to the reduction of carbon dioxide. Polysilicon is a raw material used in the production of panels for solar power generation. When producing 1 ton of polysilicon, 2 tons of sludge is generated. It is an experiment to reduce sludge treatment and cement usage. This study analyzed basic characteristics of polysilicon sludge and active loess cement according to replacment ratio.

• 한국재료학회지
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• 제23권10호
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• pp.599-605
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• 2013

CSA, a cement mineral compound that is mainly composed of $3CaO{\cdot}3Al_2O_3{\cdot}CaSO_4$, generates ettringite as a hydration product after a reaction with glass (lime), gypsum and water to speed up the hardening process and enhance the strength and degree of expansion. When used as a cement admixture, there is increased production of ettringite, which can improve the initial strength in the first three days and ameliorate the reduction in the initial strength caused by the use of fly ash in particular. In this study, a hydrate analysis was performed using XRD and SEM after substitution with fly ash (30%) and CSA (8%) with the goal of observing the effect of CSA on the initial strength of a cement mixture containing fly ash. The results of the analysis showed that an addition of CSA promoted the production of ettringite and improved the initial strength, resulting in the generation of hydrates, which can effectively enhance the long-term strength of these materials.

• Computers and Concrete
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• 제24권5호
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• pp.453-458
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• 2019

Today, concrete remains the most important, durable, and reliable material that has been used in the construction sector, making it the most commonly used material after water. However, cement continues to exert many negative effects on the environment, including the production of carbon dioxide (CO2), which pollutes the atmosphere. Cement production is costly, and it also consumes energy and natural non- renewable resources, which are critical for sustainability. These factors represent the motivation for researchers to examine the various alternatives that can reduce the effects on the environment, natural resources, and energy consumption and enhance the mechanical properties of concrete. Geopolymer is one alternative that has been investigated; this can be produced using aluminosilicate materials such as low calcium (class F) FA, Ultra-Fine GGBS, and high calcium FA (class C, which are available worldwide as industrial, agricultural byproducts.). It has a high percentage of silica and alumina, which react with alkaline solution (activators). Aluminosilicate gel, which forms as a result of this reaction, is an effective binding material for the concrete. This paper presents an up-to-date review regarding the important engineering properties of geopolymer formed by FA and slag binders; the findings demonstrate that this type of geopolymer could be an adequate alternative to ordinary Portland cement (OPC). Due to the significant positive mechanical properties of slag-FA geopolymer cements and their positive effects on the environment, it represents a material that could potentially be used in the construction industry.