• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2002년도 봄 학술발표회 논문집
• /
• pp.137-142
• /
• 2002

The purpose of this study is to develop of recycling cement using the waste concrete powder. For presentation possible of practical use as cement powder, we activated waste-powder at temperatures between 600 and 100$0^{\circ}C$. And we made recycling cement hardening as being added Ca(OH)$_2$ and the others in recycling cement. The result of this study are as follow; 1)According to compressive strength result, it is found setting and hardened. 2)Active waste powder is positive to the pozzolan reaction and is enable to be used as cement.

• 자원리싸이클링
• /
• 제25권4호
• /
• pp.23-31
• /
• 2016

양양철광산 선광 부산물(폐석, 광미)의 폐기물공정시험기준에 의한 중금속용출량은 환경기준값 보다 낮아 유해성이 없으므로 그 자체를 물질전환법에 의해 순환자원화 하는 데는 문제가 없다. 선광 광미를 시멘트 부원료로 사용할 경우에는 시멘트 품질안정성 차원에서 전 알카리($R_2O$)함량이 포틀랜드 시멘트(KS L 5201) 품질 기준치인 0.6%를 초과하지 않도록 광미 첨가량을 3%이하로 사용하는 것이 좋다고 판단된다. 재활용 점토벽돌(KS I 3013) 1종 규격에 부합되는 비소성 에코벽돌은 무기결합제의 15%를 광미로 그리고 일반잔골재의 100%를 철광산 폐석으로 대체하여 제조 가능하였다. 이처럼 선광 부산물을 시멘트 부원료 및 비소성 에코벽돌로 순환자원화함으로서 광미 적치장의 축소 및 유지관리비용 절감 그리고 에너지 사용 및 $CO_2$ 발생 절감으로 환경적 효과 및 경제적 효과를 동시에 얻을 수 있을 것이다.

• 한국건축시공학회지
• /
• 제5권3호
• /
• pp.109-116
• /
• 2005

Recently, there have been many studies seeking towards the utilization of cementitious powder from concrete waste as recycled cement. However, most of the studies actually have been researches about the reuse of mortar or paste, not concrete waste. In fact, either mortar or paste is quite different from a real concrete waste in terms of age and mixture. Thus the purpose of this study is to examine basic physical properties of recycled cement, manufactured with cementitious powder from concrete waste, and analyze differences in chemical and hydraulic properties of the cement and its tested model. As a result of the chemical analysis, recycle cement is composed mainly of CaO and $SiO_2$, and that it is even lower in the content of CaO than Portland cement, which is also supported by previous studies. But, Differently from previous studies, calcining temperature of 650 was found an optimal condition under which cementitious powder from concrete waste could restore its hydraulic properties.

• 자원리싸이클링
• /
• 제25권6호
• /
• pp.58-64
• /
• 2016

제지산업은 다량의 산업부산물을 배출하고 있으며, 제지애쉬 발생량도 증가하고 있다. 본 연구에서는 제지애쉬를 시멘트 혼합재로 사용하기 위해서 수화수를 사용하여 전처리 하였다. 전처리 제지애쉬와 석고를 혼합하여 혼합재를 제조하였으며, 이후 시멘트를 대체하여 사용하였다. 제지애쉬 혼합시멘트는 제지애쉬 함량에 따라 물성이 변화하였으나, 10% 이하 사용시에는 기존 OPC와 동등 물성이 발현되었다. 이때 압축강도는 수화물 중 $Ca(OH)_2$의 생성량과도 일정 상관성을 나타내었으며, 3일 강도는 $Ca(OH)_2$ 함량이 증가할수록, 28일 강도는 감소할수록 압축강도가 증가하였다.

• 환경위생공학
• /
• 제18권2호
• /
• pp.34-41
• /
• 2003

The purpose of this study is to examine the effect of stabilization disposal and recycling on incinerated paper mill sludge ash as cement additives. It was investigated chemical(pH, ICP, TGA XRD) and physical(PDA, SEM) characteristics of the incineration ash. And the pozzolanic characteristics of incineration ash was applied to cement as additive to increase the compressive strength. The results were that the pH characteristic of incineration ash was strong alkalinity, the content of silica and alumina as a pozzolanic material was 50.97%, and the average particle size was $5.03{\mu}m$ respectively. When the ash contents as cement additive were varied in 0~15%(wt) of cement weight to explore the effect of the compressive strength on the solidified cement mortar, the proper amount of the incineration ash substituted was about 5~l0%(wt). Therefore we found that using the incineration ash as cement additive obtains the recycling of waste material, the stabilization disposal, the reduction of waste disposal expense, and the protection of environmental problem, too.

• 에너지공학
• /
• 제27권3호
• /
• pp.68-73
• /
• 2018

The cement industry is one of the rapidly growing industry in Ethiopia. The average per capita cement consumption of the country has increased from 39kg to 62kg. However, this is still way below than the global average per capita consumption of 500kg. The Ethiopian government is planning to expand its cement industry by upgrading the current cement plants and also opening of new cement plants in order to meet the future demand of the country. Currently, the number of cement plants in Ethiopia has reached to 20. By the year 2025, per capita cement consumption is expected to increase to 179kg. Recently, Ethiopia has become one of Africa's largest market for the cement industry. In addition, Ethiopia has become the major exporter of cement in the Sub-Saharan African region. The Ethiopian cement industry is highly dependent on the use of imported energy sources for its production. This situation has a significant amount of impact on the high production costs of the industry. This paper will try to review the history, production, available resources, the technologies and energy use of the Ethiopian cement industry.

• 자원리싸이클링
• /
• 제6권4호
• /
• pp.17-23
• /
• 1997

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2004년도 학술대회지
• /
• pp.87-90
• /
• 2004

Serious problems of the environment protection and resource exhaustion are exhibited. due to the increase of the construction materials and activation of the remodeling, recently. Especially, most of the advanced countries. recycling plan for the waste concrete is vigorously progressing. The purpose of this study is making advances in the recycling of waste concrete material for use as recycled aggregate to make secondary concrete product. Using recycled aggregates form demolished concrete, we manufactured cement bricks to experiment overall performance in Korean Standard and feasible performances. On the recycled cement, in the case of cement : aggregate is 1 : 7 is satisfied with KS F 4004 : dimensions, water absorption, compressive strength of quality of a standard. So we concluded that it has great feasibility to apply these products to construction industry.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2003년도 학술.기술논문발표회
• /
• pp.81-87
• /
• 2003

The purpose of this study is the development of a recycling process to recover the hydrated ability of cement hydrate which accounts for a large proportion of cementitious powder by concrete waste in order to recycle cementitious powder by concrete waste as recycle cement. Therefore, after having theoretical consideration based on the properties of high-heated concrete, we consider the properties of hydration of cementitious powder in hardened mortar under various temperature conditions. As a result of experiment, it is revealed that an effective development of recycling cement is possible since the cementitious powder by concrete waste recovers a hydraulic property during burning at $600^{\circ}C$ or $700^{\circ}C$. And it is shown that the fluidity of mortar decreases rapidly as the burning temperature of recycle cement increases. however, the improved effect of fluidity is predominant if adding the additive such as fly-ash or blast furnace slag.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2020년도 봄 학술논문 발표대회
• /
• pp.77-78
• /
• 2020

In Korea, more than 30,000 tons of waste Styrofoam are produced every year. Styrofoam is spent more than 500 years decomposing during the reclamation process, so it needs to be recycled. The recycling rate of waste styrofoam continues to be the third highest in the world, but it is lower than that of Germany and Japan. Therefore, measures are needed to increase the recycling rate of waste Styropol. Another problem is that cement is mainly used in existing lightweight foam concrete. However, large amounts of CO2 from cement-producing processes cause environmental pollution. Currently, Korea is increasing its greenhouse gas reduction targets to cope with energy depletion and climate change, and accelerating efforts to identify and implement reduction measures for each sector. In 2013 alone, about 600 million tons of carbon dioxide was generated in the cement industry. Therefore, this study replaces CO2 generation cement with furnace slag fine powder, uses crude steel cement for initial strength development of bubble concrete, and manufactures hardening materials to study its properties using waste styrofoam. As a result of the experiment, the hardening agent replaced by micro powder of furnace slag was less intense and more prone to absorption than cement using ordinary cement. Further experiments on the segmentation and strength replenishment of furnace slag are believed to contribute to the manufacture of environmentally friendly lightweight foam concrete.