• Title/Summary/Keyword: recycling cement

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A Study on the Development of Recycling Cement Using the Waste Concrete Powder (폐콘크리트 미분말을 이용한 재생 시멘트 개발에 관한 기초적 연구)

  • 조민철;박태성;추유선;황혜주
    • Proceedings of the Korea Concrete Institute Conference
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    • 2002.05a
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    • pp.137-142
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    • 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.

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Recycling of the Waste Rock and Tailings from Yangyang Iron Mine (양양철광산 선광 부산물의 순환자원화)

  • Jung, Moon Young;An, Yong Hyeon;Kim, Young Hun
    • Resources Recycling
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    • v.25 no.4
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    • pp.23-31
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    • 2016
  • It was found that there was no problem in recycling by-products (waste rock and tailings) from Yangyang iron mine themselves through matter conversion because they are not hazardous according to results of KSLT method. In case of using tailings as sub-materials of cement, it recommended the use of less than 3% tailings dosage not to exceed 0.6% of total alkali ($R_2O$) content based on standard quality of portland cement (KS L 5201). Non sintered eco-brick corresponding to class 1 quality of recycled clay brick (KS I 3013) can replace 15% of cement with tailings and 100% of general fine aggregate with waste rock from iron mine. As mentioned above, recycling the by-products (waste rock and tailings) as sub-materials of cement and non sintered eco-brick could gain both environmental and economic benefits, that is, reduction of scale and maintenance cost of tailing ponds, decrease of energy use and $CO_2$ emission.

Recycling Technology of Cementitious Powder for Completely Recycling of Concrete Waste (폐콘크리트의 순환이용을 위한 폐미분말의 재활용 기술)

  • Park, Cha-Won;Kang, Byeung-Hee
    • Journal of the Korea Institute of Building Construction
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    • v.5 no.3 s.17
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    • pp.109-116
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    • 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.

A Study on Pretreated Paper Sludge Ash for Cement Admixture (시멘트 혼합재로의 전처리 제지애쉬 적용가능성 연구)

  • Jung, Jae-Hyun;Seo, Seong-Kwan;Chu, Yong-Sik
    • Resources Recycling
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    • v.25 no.6
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    • pp.58-64
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    • 2016
  • Paper industry discharges many by-products and quantity of PSA (Paper sludge ash) has been increased. In this study, hydration water was added to PSA for use as cement admixture. PSA with added water was mixed with anhydrite and this mixture was used as cement substitute. Physical properties of PSA cement were changed by contents of PSA, but PSA cement containing PSA less than 10% had similar properties to those of OPC. Compressive strength of PSA cement mortar had a certain relationship with $Ca(OH)_2$ content. Compressive strength at 3 days increased, as $Ca(OH)_2$ content increased. However, the strength at 28 days increased, as $Ca(OH)_2$ content decreased.

A Study on the Reusability of Incinerated Paper Mill Sludge Ash as Cement Additive (시멘트 혼화재로서 제지슬러지 소각재의 재활용 특성)

  • 주소영;연익준;이민희;박준규;김광렬
    • Journal of environmental and Sanitary engineering
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    • v.18 no.2
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    • pp.34-41
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    • 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.

The Cement Industry in Ethiopia

  • Mulatu, Dure;Habte, Lulit;Ahn, Ji Whan
    • Journal of Energy Engineering
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    • v.27 no.3
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    • pp.68-73
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    • 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.

The Study Concrete Brick Material of Recycle Cement Using (재생시멘트를 이용한 콘크리트벽돌의 물성 연구)

  • Seo Kyung-Ho;Park Cha-Won;Ahn Jae-Cheol;Hee Byeung
    • Proceedings of the Korean Institute of Building Construction Conference
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    • v.y2004m10
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    • pp.87-90
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    • 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.

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Recovering Hydration Performance of Cementitious Powder by Concret Waste according to Burning Temperature (폐콘크리트계 미분말의 소성조건에따른 수화성 회복)

  • 강태훈;정민수;안재철;강병희
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2003.05a
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    • pp.81-87
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    • 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.

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Properties of Lightweight Foamed Concrete with Waste Styrofoam and Crude Steel Cement (폐스티로폼과 조강시멘트를 혼입한 경량기포콘크리트의 특성)

  • Park, Chae-Wool;Lee, Sang-Soo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2020.06a
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    • pp.77-78
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    • 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.

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