• Title/Summary/Keyword: Aggregate particle size

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The Examination Fire Resistance of Mortar According to Particle Size Distrivution as Oyster Shell Fine Aggregate (굴 패각의 잔골재 입도분포 변화에 따른 모르타르의 내화성 검토)

  • Choi, In-Kwon;Jung, Ui-In;Kim, Bong-Joo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2017.05a
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    • pp.71-72
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    • 2017
  • The oyster shell is lightweight and exhibits strength characteristics similar to sand. In this study, mortar specimens were fabricated by crushing them and processed to 5mm or less of the fine aggregate standard, and examined the fire resistance of the mortar according to changes in particle size distribution. In this experiment, seven particle size distribution conditions were tested. In addition, the mixing ratio was fixed at 1: 3, and the experiment was conducted in terms of the volume ratio because the densities of sand and oyster shells were different.

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Gradation Curve of Coarse Aggregate by Digital Image Analysis (디지털 이미지 처리 기법을 이용한 굵은골재의 입도분포곡선)

  • Lee, Kwan-Ho;Kim, Young-Jin;Hwang, Tak-Jin;Cho, Jae-Yoon
    • Land and Housing Review
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    • v.2 no.1
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    • pp.69-78
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    • 2011
  • The purpose of this research is particle shape evaluation of aggregate using Digital Image Process(DIP). DIP is very useful to measure the roughness and particle shape of aggregates. Couple of aggregates, like standard sand, two different crushed stones, and two different marine aggregates, have been employed. Shape factors of two different marine aggregates are ranged 0.35 to 0.54. Crushed stone I is 0.74 which is highly flat, but standard sand is elongated shape. Especially, two marine aggregate showed a big difference of width and length which meaned a long shape. There is any significant difference of elongation ratio and flatness for each aggregate with different measuring system, like direct measurement of vernier calipers and DIP method. Shape conversion coefficient and equivalent diameter for changing 2D image to 3D image by the Digital Image Process(DIP) have been suggested and modified particle size distribution curve has been showed. The measured flatness ratios of each aggregate were 0.30, 0.36, 0.47 and 0.83, respectively. Also, the conversion shape coefficients of each aggregate were determinded as 0.77, 0.78, 0.84 and 0.92. The size of aggregate has been modified by multiplying the shape conversion coefficient and the aggregate size from DIP. The modified gradation curve with modified volume and weight of aggregate has been suggested. Within the limited test results, DIP is one of useful to get the particle shape of aggregate with limitation of measuring errors and to apply the particle distribution curve.

Gradation Curve of Aggregate using Digital Image Process (디지털 이미지 처리 기법을 이용한 골재의 입도분포곡선)

  • Hwang, Tak-Jin;Cho, Jae-Yoon;Lee, Kwan-Ho
    • Journal of the Korean Society of Hazard Mitigation
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    • v.10 no.2
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    • pp.31-37
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    • 2010
  • Shape conversion coefficient and equivalent diameter for changing 2D image to 3D image by the Digital Image Process(DIP) have been suggested and modified particle size distribution curve has been showed. Couple of aggregates, like two different marine aggregates and two different crushed stones, have been employed. The measured flatness ratios of each aggregate were 0.30, 0.36, 0.47 and 0.83, respectively. Also, the conversion shape coefficients of each aggregate were determinded as 0.77, 0.78, 0.84 and 0.92. The size of aggregate has been modified by multiplying the shape conversion coefficient and the aggregate size from DIP. The modified gradation curve with modified volume and weight of aggregate has been suggested. Within the limited test results, DIP is one of useful to get the particle shape of aggregate with limitation of measuring errors and to apply the particle distribution curve.

The Quality Status of Aggregate for Domestic Ready-mixed Concrete and the Effect of Aggregate Quality in Concrete

  • Kim, Yong-Ro;Lee, Jae-Hyun;Min, Choong-Siek;Park, Jong-Ho
    • Journal of the Korea Institute of Building Construction
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    • v.14 no.1
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    • pp.11-20
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    • 2014
  • This research examined the effect of the quality of aggregate on concrete workability and compressive strength through an investigation into regional aggregate used in domestic ready mixed concrete plants. Through the research, it was found that aggregate for ready mixed concrete shows poor quality overall. The main factor of deterioration in the quality of the concrete is the particle size of fine aggregate and fine particle content in coarse aggregate. The quality of aggregate significantly influences concrete's workability, which is defined based on 0.08mm passage related with powder and absorption. In addition, poor aggregate quality leads to increased water content in concrete to secure workability, which is related with a decline in the compressive strength and durability of concrete.

Rigorous Model for Spherical Cell-support Aggregate

  • Moon, Seung-Hyeon;Lee, Ki-Beom;Satish J. Paruekar
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.6 no.1
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    • pp.42-50
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    • 2001
  • The activity of immobilized cell-support particle aggregates is influenced by physical and biochemical elements, mass transfer, and physiology. Accordingly, the mathematical model discussed in this study is capable of predicting the steady state and transient concentration profiles of the cell mass and substrate, plus the effects of the substrate and product inhibition in an immobilized cell-support aggregate. The overall mathematical model is comprised of material balance equations for the cell mass, major carbon source, dissolved oxygen, and non-biomass products in a bulk suspension along with a single particle model. A smaller bead size and higher substrate concentration at the surface of the particle, resulted in a higher supply of the substrate into the aggregate and consequently a higher biocatalyst activity.

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Compressive Strength Properties of Small Diameter Core Concrete with Coarse Aggregate Particle Distribution (굵은 골재 입도분포에 따른 소구경 코어 콘크리트의 압축강도 특성)

  • Lee, Jin-Won;Lee, Sang-Soo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2023.11a
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    • pp.145-146
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    • 2023
  • One of the causes of recent construction site collapses was that the compressive strength of concrete was less than half of the allowable design standard strength range. In the safety diagnosis of structures, the compressive strength of concrete is a factor that determines the durability of a building. Therefore, in this study, we aim to examine the characteristics of compressive strength according to the particle size distribution of coarse aggregate among the compressive strength factors using small-diameter cores. To avoid problems when collecting cores, core specimens with diameters of 100×200, 50×100, and 25×50 (mm) were manufactured directly. As a result of measuring the compressive strength of concrete for each diameter, the larger the core diameter, the higher the compressive strength. has increased.

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Development of a Pretreatment Process for Coal Gasification Slag to Convert High-quality Aggregates. (고품질 골재 전환을 위한 석탄 가스화 용융슬래그의 전처리 공정 개발)

  • Hu, Yun-Yao;Han, Soo-Hwan;Lim, Gun-Su;Han, Jun-Hui;Kim, Jong;Han, Min-Cheol
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2021.11a
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    • pp.122-123
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    • 2021
  • This study examines the performance of pretreatment process system as the initial construction stage of the pretreatment process system to use CGS, a by-product generated in IGCC, as a concrete fine aggregate of construction materials. The process undergoes a grinding process capable of grinding to a predetermined particle size during primary grinding and a sorting plant through sieve grading of 2.5 mm or less for particle size correction. Afterwards, it is hoped that the use of coal gasification slag of Korean IGCC as a fine aggregate for concrete will be distributed and expanded by producing quality-improved CGS fine aggregate using water as a medium for removing impurities and particulates.

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Analysis of Characterization on Ancient Ink Stick (고대 먹의 특성 분석)

  • Nam, Tae-Gwang;Shin, Soo-Jeong;Park, Won-Kyu;Kim, Byung-Ro
    • Journal of Conservation Science
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    • v.28 no.2
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    • pp.165-173
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    • 2012
  • In this work, scientific and systematic analysis was conducted for finding out the methods and techniques of ancient ink stick making. Analysis the ancient ink stick on ancient documents and wooden writing as letter or painting, we concluded as followings. From the analysis of ancient wood by dendrochronology, wood was cut at 1899, which provided the information on the year of ink stick's made on writing on ancient wood. Single particle size for soot of ancient ink stick was 107 nm for ink on the roof-filling timber in Sinsunwonjeon of Changdeok Palace, compared to 38 to 86 nm on the letter on ancient 12 paper document. Aggregate particle size was 370 nm for ink on the roof-filling timber in Sinsunwonjeon of Changdeok Palace, but 206 to 318 nm for aggregate particle size on 12 paper documents. There was similar pattern between single particle size and aggregate particle size of soot, which might provide the information of raw material for ancient ink. From infra-red and Raman spectroscopic analysis of sheet of writing on paper or wood, there was severe interference from background material (paper or wood). From Raman spectroscopic analysis of ancient ink carefully separated from ancient wood, spectrum pattern was closer to ink stick made by the soot from pine burning.

Recycling Plan for Waste Concrete Fine Aggregate as Materials of Anti-Frost Layer and Sub-Base Layer (도로의 동상방지층 및 보조기층재로서 폐콘크리트 잔골재의 재활용 방안)

  • Lee, Dong-Wook;Yun, Jung-Mann
    • Journal of the Korean Geosynthetics Society
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    • v.11 no.3
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    • pp.19-25
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    • 2012
  • In this study, a recycling plan for waste concrete fine aggregate as fill material was researched by investigating environmental engineering properties. It is noted that the environmental influence of waste concrete fine aggregate is little since chemical level is satisfied the waste management standard. Waste concrete fine aggregate is not suitable for materials of anti-frost layer and sub-base layer since the particle-size distribution and engineering properties are not partially satisfied the quality standard. However, waste concrete fine aggregate can be recycled as materials of anti-frost layer and sub-base layer if we improve the engineering properties by mixing bigger aggregates than maximum particle size (5 mm) more than 25 percent of total weight.

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.