• Title, Summary, Keyword: 인공경량골재

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Water absorption characteristics of artificial lightweight aggregates preparedby pre-wetting (프리웨팅된 인공경량골재의 흡수 특성)

  • Kim, Yoo-Taek;Jang, Chang-Sub;Ryu, Yug-Wang
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.21 no.2
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    • pp.82-86
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    • 2011
  • Lightweight aggregate which is composed of sintered polycrystalline materials usually has a certain portion of pores inside of it. Because of such a structural characteristics, it tends to that movement of water in aggregate shows an abnormal behavior against the change of outside environment. In general, water movement behavior is controlled by porosity, distribution of pore size; however, dense surface layer will also affect water movement behavior in case of artificially sintered aggregates. Factors affecting water movement behavior in the aggregate are pore distribution, pore shape, pre-wetting method, etc. In this study, absorption characteristics of aggregate under the pressure and absorption rate according to water dipping time are analyzed for the basis of pressure pumping of lightweight concrete. Two kinds of aggregates were used for the test: one is made by 'L' company in Germany and the other is of our own made at the pilot plant in Kyonggi University. Absorption rate of aggregate is measured according to water dipping time, vacuum pressure, and quenching condition. Absorption rate of aggregate with $300^{\circ}C$ quenching is higher than that of aggregate with 24 hr water dipping. Generally the more vacuum the higher water absorption rate. Water absorption rate of 'L' aggregate under -300 mmHg is 54 % higher than that of aggregate with 24 hr water dipping; however, only 2 % increase in water absorption was measured for the K622 and K73 which were of our own.

Application of Powdered Waste Glasses and Calcium Carbonate for Improving the Properties of Artificial Lightweight Aggregate Made of Recycled Basalt Powder Sludge (현무암 석분 슬러지를 재활용한 인공경량골재의 물성개선을 위한 폐유리분말과 탄산칼슘의 활용)

  • Park, Soo-Je;Lee, Sung-Eun;Choi, Heebok
    • Journal of the Korea Institute of Building Construction
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    • v.14 no.3
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    • pp.230-236
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    • 2014
  • This study was carried out to investigate the manufacturability of artificial lightweight aggregate as a way to recycle basalt powder sludge, which is a waste produced during the manufacturing process of basalt in Jeju. Powdered waste glasses and calcium carbonate are used to improve the characteristics of manufactured artificial lightweight aggregate. Especially, considering the complex factors of basalt powder sludge, powdered waste glasses, and sintering method, the amount of calcium carbonate is appropriate at the 9 wt.% in order to improve the intumescent of lightweight aggregate. Also, the amount of powdered waste glasses is effective with using less than 50 wt.% and applying the direct sintering method at the same time on decreasing the absorption of lightweight aggregate. Furthermore, in order to manufacture artificial lightweight aggregate of high quality with a low specific gravity and low water absorption, it is considered to be more effective to apply the direct sintering method after the surface of artificial lightweight aggregate is covered with powdered waste glasses.

Study on the Physical Properties of the Artificial Lightweight Aggregate Recycled from the Dyestuff Sludge Treated Chemically With Ti and Fe Salt (Ti염 및 Fe염으로 화학처리된 염색공단 슬러지를 재활용한 인공경량골재의 물리적 특성에 관한 연구)

  • Choi, Jong-Oh;Jung, Yong-Wook
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.3 no.1
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    • pp.34-42
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    • 2015
  • The paper investigates environmental hazards and characteristics of the artificial lightweight aggregate manufactured by using dyestuff sludge from dyeing industrial complex. The dyestuff sludge used in this study is chemically treated with Ti and Fe salt for the purpose of recycling. The artificial lightweight aggregate is manufactured through 3 step; 1) Selecting the optimum moisture content by evaluating plasticity from the mixing ratio of the clay and sludge, 2) shaping round type based on the optimum mixing ratio, 3) drying and Sintering process. Based on KS F 2534 "Lightweight Aggregate for Structural concrete", the particle size, fineness modulus, the density, absorption, unit volume weight, stability and environmental hazards of the manufactured lightweight aggregate are evaluated. Experimental results show that the particle size and fineness modulus is out of the range. However, it is observed that other physical properties are within criteria. In addition, it is confirmed that the problem of the particle size and fineness modulus could be solved in the manufacturing process.

An Experimental Study for the Strength Variations of High-strength Lightweight Concrete According to Grain-size of Artificial Lightweight Aggregate (인공경량골재의 입도에 따른 고강도 경량콘크리트의 강도변화에 대한 실험적 연구)

  • Kim, Sung Chil;Park, Ki Chan;Choi, Hyoung Wook
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.15 no.5
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    • pp.209-217
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    • 2011
  • In recent days, while taller and more massive structures such as huge bridges and super skyscrapers have been welcomed, the structural stabilization in design and construction have been gradually limited due to the major weakness of current concrete which is relatively heavier when compared with its strength. To improve the weakness of the current concrete, The lightweight concrete with light weight and high strength should be used; however, not many researchers in Korea have studied on the lightweight concrete. Generally, artificial lightweight aggregate produced through high-temperature-plasticization has a possibility of its body-expansion with many bubbles. Therefore, depending on the size of aggregate, the effects of bubbles on the specific weight and strength of the lightweight concrete should be studied. In this study, considering grain-size, the mix design of the artificial lightweight aggregate produced through the high-temperature-plasticization and the body-expansion of waste and clay from the fire power plant in Korea was conducted. The experiment to analyze the variation in specific weight and strength of the lightweight concrete was followed. From these experiments, the optimized grain-size ratio of the artificial lightweight aggregate for the enhancement of high-strength from the lightweight concrete was revealed.

Manufacturing of Artificial Lightweight Aggregate using Stone-Dust and Bottom Ash (석분토와 바텀애쉬를 이용한 인공경량골재 제조)

  • Yoon, Seob;Kim, Jung-Bin;Jeong, Yong;Kim, Yang-Bea
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.381-384
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    • 2008
  • The artificial lightweight aggregate was manufactured using stone-dust(SD) and bottom ash(BA) from crushed aggregate manufacture process and thermoelectric power plant respectively. The properties of artificial lightweight aggregate according to mixing ratio of SD and BA was that the density was decreased and the absorption was increased with increasing BA content, because bottom ash was contained many unburned carbon and $Fe_2O_3$ which generates gas by oxidation during a sintering process. The appropriate mixing ratio of SD and BA was estimated at about 5:5. The properties of artificial lightweight aggregate according to addition flux admixture was that it had lower density with increasing of $Na_2SO_4$ content. In this study, we could developed the artificial lightweight aggregate as the bulk density was $1.52g/cm^3$ and water absorption 7.3% under the condition that mixing ratio of SD:BA was 5:5, $Na_2SO_4$, $Fe_2O_3$ 1%, sintering temperature $1,150^{\circ}C$ and sintering time 15mins.

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광미를 이용한 인공경량골재의 제조와 물리화학적 특성

  • 이종석;이현구;박영훈;김상중
    • Proceedings of the KSEEG Conference
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    • pp.169-171
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    • 2003
  • 최근 환경문제가 대두됨에 따라 산업폐기물의 처리문제에 많은 관심과 연구가 진행되고 있다. 또한 현대의 콘크리트 구조물은 거대화, 고층화되어 그 중량이 계속 커지고 있으므로 구조물을 경량화 하려는 노력과 개발이 계속 진행되어 왔다. 구조물의 주재료로 사용되고 있는 콘크리트는 강도 및 내구성에 비해 비중이 크다는 결점을 가지고 있으므로 강하고 가벼운 고강도의 경량골재 콘크리트 개발이 행해져 왔다. (중략)

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The Study on the Physical and Strength Properties of Lightweight Concrete by Replacement Ratio of Artificial Lightweight Aggregate (인공경량골재 혼합비율에 따른 경량 콘크리트의 물성 및 강도특성에 관한 연구)

  • Choi, Se-Jin;Kim, Do-Bin;Lee, Kyung-Su;Kim, Young-Uk
    • Journal of the Korea Institute of Building Construction
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    • v.19 no.4
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    • pp.313-322
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    • 2019
  • This study is to compare and analyze the physical and strength properties of lightweight concrete using domestic lightweight aggregate by replacement ratio of artificial lightweight fine and coarse aggregate after considering low cement mixture and pre-wetting time. The slump, unit weight, compressive strength and split tensile strength of lightweight concrete with domestic lightweight aggregate were measured. As test results, the slump of lightweight concrete by replacement ratio of lightweight fine aggregate increased as the replacement ratio of lightweight fine aggregate increased. The unit weight of lightweight concrete using 100% of lightweight fine aggregate was about 10.4% lower than that of the lightweight concrete with natural sand. In addition, the unit weight of lightweight concrete by replacement ratio of lightweight coarse aggregate increased with the increase of the ratio of LWG10(5~10mm). The compressive strength of lightweight concrete with lightweight fine and coarse aggregate increased as the replacement ratio of lightweight fine aggregate increased. The compressive strength of lightweight concrete with natural sand and LWG10 was 30 to 31MPa regardless of the replacement ratio of the lightweight coarse aggregate after 7 days.

Manufacturing of Sintered Lightweight Aggregate using Paper Mill Sludge Ash (제지 슬러지 소각재를 이용한 소성 경량골재의 제조)

  • 문경주;김재신;소양섭
    • Journal of the Korea Concrete Institute
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    • v.13 no.2
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    • pp.114-122
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    • 2001
  • The purpose of this study was to manufacture sintered lightweight aggregate using paper sludge ash and to evaluate the qualities of the aggregate according to various mix proportions, conditions of pelletization and sintering. The paper sludge ash alone, due to its mineral and chemical compositions could not gain suitable expansion and strength. Hence, it was essential to add mineral additives such as clay, fly ash etc. The optimum muting ratio range determined in this study is as follows , paper sludge ash 30∼50 %, clay 30∼50 %, fay ash 0∼40 %, Paper sludge 0∼10% and hematite 2∼3 %(for manufacturing lightweight aggregate both for non-structural and structural concrete). It was possible to manufacture various lightweight aggregate whose dry specific gravity ranged about from 0.6 to 1.4 by using this optimum mixing ratio. From the test results of the qualities of aggregate, it showed that the 10% granules crushing value test and water absorption percentage ranged about 5∼10 ton and 10∼20%. Thus, it was favorably comparable to those of the imported aggregate. The manufactured lightweight aggregate could be used for structural concrete and non-structural concrete.

Bloating mechanism of artificial lightweight aggregate with reject ash (잔사회를 이용한 인공경량골재의 발포기구)

  • Lee, Ki-Gang
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.22 no.3
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    • pp.158-163
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    • 2012
  • The purpose of this study is to improve recycling rate of the coal reject ash by investigating bloating mechanism for artificial lightweight aggregate of reject ash. In this study, we use reject ash (R/A) and dredged soil (D/S) as raw materials. The artificial lightweight aggregates were formed by plastic forming (${\phi}$ = 10 mm) and sintered by temperature raising method at different temperatures (between 1200 and $1275^{\circ}C$). The physical properties of the aggregates such as bulk specific gravity, adsorption and microstructure of surface and cross-section are investigated with the sintering temperature and rate of R/A-D/S contents. As the result of the bulk specific gravity graphs, we can found out the inflection point at content of R/A 80 wt.%. From the microstructure images, we considered the artificial lightweight aggregates content of R/A over 80 wt.% are distributed numerous uniform micro-pores by vitrification without Black Core and the artificial lightweight aggregates of R/A below 80wt.% are distributed macro-pores with Black Core.