• Title, Summary, Keyword: artificial aggregates

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Properties of artificial aggregates of coal bottom ash-dredged soil system added with waste glass (폐유리가 첨가된 석탄바닥재-준설토 계 인공골재의 특성)

  • Jo, Sinae;Kang, Seunggu
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.23 no.3
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    • pp.146-151
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    • 2013
  • In this study, the effect of addition of waste glassy slag produced from recycling of spent catalyst (denoted as waste glass hereafter) on the physical properties of artificial aggregates made of coal bottom ash and dredged soil (7 : 3 by weight base) was evaluated. Especially, the bloating behavior of artificial aggregates was analyzed by performing the relation study between the apparent density, water absorption and microstructure. The apparent density of artificial aggregates increased slightly with sintering temperature at $1050{\sim}1150^{\circ}C$, but decreased above $1150^{\circ}C$ showing bloating phenomenon. The bloating behavior of artificial aggregates was decreased so the apparent density increased with amount of waste glass added. Also, the water absorption of artificial aggregates decreased with sintering temperature. Above $1200^{\circ}C$, big fissure and much liquid were formed at the surface of artificial aggregates and these phenomena could be suppressed by increasing amount of waste glass added. The artificial aggregates fabricated in this study had an apparent density of 1.1~1.6 and water absorption of 8~22 % which meet KS requirements for the artificial lightweight aggregates.

Effect of different binders on cold-bonded artificial lightweight aggregate properties

  • Vali, Kolimi Shaiksha;Murugan, S. Bala
    • Advances in concrete construction
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    • v.9 no.2
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    • pp.183-193
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    • 2020
  • The present investigation is to identify an optimum mix combination amongst 28 different types of artificial lightweight aggregates by pelletization method with aggregate properties. Artificial aggregates with different combinations were manufactured from fly ash, cement, hydrated lime, ground granulated blast furnace slag (GGBFS), silica fume, metakaolin, sodium bentonite and calcium bentonite, at a standard 17 minutes pelletization time, with 28% of water content on a weight basis. Further, the artificial aggregates were air-dried for 24 hours, followed by hardening through the cold-bonding (water curing) process for 28 days and then testing with different physical and mechanical properties. The results found the lowest impact strength value of 16.5% with a cement-hydrated lime (FCH) mix combination. Moreover, the lowest water absorption of 16.5% and highest individual pellet crushing strength of 36.7 MPa for 12 mm aggregate with a hydrated lime-GGBFS (FHG) mix combination. The results, attained from different binder materials, could be helpful for manufacturing high strength artificial aggregates.

Characterization of Artificial Aggregates Fabricated by Using Various Forming Methods (다양한 성형법으로 제조된 인공 골재의 특성)

  • Kang, Seung-Gu
    • Journal of the Korean Ceramic Society
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    • v.46 no.1
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    • pp.94-101
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    • 2009
  • The physical properties of artificial aggregates made from clay and inorganic wastes with poor plasticity depends largely on forming method. The artificial aggregates composing of coal fly ash, stone sludge and clay were fabricated using 4 different forming methods and those physical properties were comparatively analyzed. The surface of aggregates made through the extrusion forming process was dense and smooth but was rough for the aggregates obtained by crushing a tile-shaped green body. The aggregates made by pelletizing process had a weak green strength and bumpy surface. The shell generated at surface during a high temperature sintering process induced the most aggregates to be bloated due to a dense shell. But the aggregates made through pelletizing process with dense surface layer showed no significant change in bulk density with sintering temperatures. The water absorption of aggregates decreased with sintering temperature, and that of pelletized specimen was standing $1.8{\sim}2.2$ times higher than that of made by other forming methods. It is concluded that the aggregates having various properties could be fabricated from one batch by using different forming methods.

Properties of artificial lightweight aggregates made from waste sludge

  • Chiou, I.J.;Chen, C.H.
    • Computers and Concrete
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    • v.8 no.6
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    • pp.617-629
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    • 2011
  • In this investigation, reservoir sediment and municipal sewage sludge were sintered to form the artificial lightweight aggregates. The sintered aggregates were compared with the commercialized lightweight aggregates to in terms of potential alkali-silica reactivity and chemical stability based on analyses of their physical and chemical properties, leaching of heavy metal, alkali-silica reactivity, crystal phase species and microstructure. Experimental results demonstrated that the degree of sintering of an aggregate affected the chemical resistance more strongly than did its chemical composition. According to ASTM C289-94, all potential alkali-silica reactivity of artificial lightweight aggregates were in the harmless zone, while the potential reactivity of artificial lightweight aggregates made from reservoir sediment and municipal sewage sludge were much lower than those of traditional lightweight aggregates.

Effect of Shell Structure of Artificial Lightweight Aggregates on the Emission Rate of Absorbed Water (인공경량골재의 표피층 구조가 흡수된 물의 방출속도에 미치는 영향)

  • Kang, Seung-Gu
    • Journal of the Korean Ceramic Society
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    • v.45 no.11
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    • pp.750-754
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    • 2008
  • The artificial aggregates with dense surface layer (shell) was fabricated and the dependence of water emission rate upon the shell structures was studied. The EAF dust containing many flux components and waste white clay with ignition loss of above 48% were used as for liquid phase and gas forming agents during a sintering process respectively. In addition, the shell structure was modified with various processes and the modification effect on water emission rate was analyzed. The pores under $10{\mu}m$ were found in the sintered artificial light aggregates and disappeared by incorporating to a bigger pore during re-sintering. The water emission rate in an initial step depended on a void content of aggregates filled in a bottle rather than a shell structure. But, after 7 days where the water emission of the aggregate with a shell is above 40%, the shell of aggregates suppressed the water emission. The core of aggregates was exposed and most shell was lost when crushed to smaller size so, the ability for suppressing water emission of the crushed aggregates decreased. The activation energy for the water emission was $3.46{\pm}0.25{\times}10^{-1}$J/mol for the most specimens showing that the activation energy is irrelevant to the pore size distribution and shell structure.

The Quality Characteristics of Artificial Aggregates Using Bottom ash from Industrial Waste Incinerator (산업쓰레기 소각재를 이용한 인공골재의 품질특성)

  • 김재신;고대형;문경주;백명종;소양섭
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.257-262
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    • 2000
  • The purpose of this study is grasping quality aggregate using Bottom Ash of Industrial Waste Incinerator, and is evaluating possibility of application as construction materials. Cement and Fly ash is used with binder of aggregates using bottom ash. It is tested for basic property and strength of artificial aggregates, and the results are compared with crushed stone and elution tests is done for environmental safety. In the results of tests, it is confirmed that basic property and strength are lowe than crushed stone but the aggregates have possibility of application as artificial lightweight aggregates. When it is manufactured with aggregates, it is sage environmentally because of protecting elution of harmful heavy metals.

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Fresh and hardened properties of concrete containing cold bonded aggregates

  • Thomas, Job;B., Harilal
    • Advances in concrete construction
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    • v.2 no.2
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    • pp.77-89
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    • 2014
  • The properties of fresh and hardened concrete made using three types of artificial cold bonded aggregates are determined. The properties, namely, slump, water absorption, compressive strength and splitting tensile strength of concrete containing artificial aggregate are reported. The variables considered are aggregate type and water-to-cement ratio. Three types of cold bonded aggregates are prepared using fly ash and quarry dust. The water-to-cement ratio of 0.35, 0.45, 0.55 and 0.65 is used. The test result indicates that artificial aggregates can be recommended for making the concrete up to a strength grade of 38 MPa. The use of quarry dust in the production of artificial aggregate mitigates environmental concerns on disposal problems of the dust. Hence, the alternate material proposed in this study is a green technology in concrete production.

The Applications of the Artificial Aggregate using the Municipal Waste Incineration Fly-Ash to Interlocking Block (도시 쓰레기 소각 비산재를 활용한 인공골재의 인터로킹 블록 적용)

  • 김대규;윤성진;문경주;소양섭
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.327-332
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    • 2003
  • The incinerated municipal waste can be classified into two general types of ash; fly ash and bottom ash. The fly ash is appointed as specified waste, because it contains harmful heavy metals, ie Pb , Cd, etc. more than permitted standard index. The purpose of this study is to manufacture the non-sintering artificial aggregates using municipal waste incineration fly-ash and to evaluate their applications as coarse aggregates in concrete interlocking block. The test results of water absorpsion, strengths of the concrete block using artificial aggregates showed that the artificial aggregates could be used in part of 10-20% as coarse aggregate in concrete block.

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Bloating Mechanism of Lightweight Aggregate with the Size

  • Lee, Ki Gang
    • Journal of the Korean Ceramic Society
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    • v.53 no.2
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    • pp.241-245
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    • 2016
  • The purpose of this study was to investigate the bloating mechanism of artificial lightweight aggregates with different sizes (ESA, effective surface area). Aggregates were produced using hard clay, stone sludge, and a bloating agent in order to observe the effect of the gradation of the artificial lightweight aggregates. Kerosene and amorphous carbon were used as bloating agent. The particle size of the produced aggregate ranged from 3 mm to 9 mm. With regard to the amount of bloating agent to be used, 2 ~ 6 parts by weight were used. The specific gravity, absorption rate, and the type of aggregates produced by rapid sintering at $1075{\sim}1200^{\circ}C$ were determined. Microstructures were observed. When ESA had a value of 1 or below, kerosene, which has a high burning rate, was found to be advantageous for use as a bloating agent. When ESA had a value of 1 or above, carbon, which has a relatively low burning rate was found to be an advantageous bloating agent. It is thought that kerosene is more advantageous, as ESA decreases, for the production of aggregates having low water absorption rate.

A study on the properties of artificial aggregates containing bottom ash from the power plant and waste catalyst slag (화력발전소 바닥재와 폐촉매 슬래그로 제조된 인공골재의 특성 연구)

  • Jo, Si-Nae;Kang, Seung-Gu
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.22 no.4
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    • pp.200-206
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    • 2012
  • The artificial aggregate composing of coal bottom ash and waste catalyst slag (7 : 3, wt%) were fabricated using direct sintering method and, the bloating properties of aggregates were investigated as a function of raw material particle size and sintering temperature. Most of the artificial aggregates sintered at over $1150^{\circ}C$ showed the bloating phenomenon regardless of particle size of the raw materials. Consequently, the specific gravity of the aggregates was drastically decreased to below 1.4. The aggregates containing waste catalyst slag of $90{\mu}m$ under among the W-series specimens, however, did not show the noticeable bloating phenomenon. For the aggregates sintered at lower temperature as $1050{\sim}1150^{\circ}C$, the specific gravity increased with particle size of raw materials. Also, the water absorption of all aggregates decreased with the sintering temperature. The aggregates fabricated in this study met the lightweight aggregate standard showing the specific gravity 1.7~1.4 and water absorption 8~19 % and, therefore, can be applicable for the various fields.