• Title/Summary/Keyword: normal weight aggregate

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Properties of Thermal Expansion Strain of Light Weight Aggregate Concrete with Loading Conditions (하중조건에 따른 경량골재 콘크리트의 열팽창변형 특성)

  • Yoon, Min-Ho;Kim, Gyu-Yong;Lee, Tae-Gyu;Nam, Jeong-Soo;Shin, Kyoung-Su;Lee, Sang-Soo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2012.05a
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    • pp.255-256
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    • 2012
  • In this study, strain properties of high strength concrete using light weight aggregate which is widely used in recent years are evaluated. For these purpose, thermal strain, transient creep were measured in prestressed condition as 0, 20, 40% of specimen strength at target temperature with 60MPa specimens which was using normal and light weight aggregate. As a result, light weight aggregate is more advantageous for the control of strain than normal aggregate because of its low thermal expansion.

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Evaluation on Mechanical Properties of High Strength Concrete according to the Aggregate Type and after Heating Cooling Conditions (가열 후 냉각조건에 따른 골재 종류별 고강도 콘크리트의 역학적 특성 평가)

  • Yun, Jong-Il;Kim, Gyu-Yong;Nam, Jeong-Soo;Choe, Gyeong-Cheol;Yoon, Min-Ho;Ham, Eun-Young
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2012.11a
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    • pp.99-100
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    • 2012
  • Aggregate thermal properties and cooling methods are most important to evaluate the residual mechanical properties of concrete. In this study, we evaluate the residual mechanical properties of concrete according to the aggregate type and cooling method. We use the normal weight aggregate and light weight aggregate which have different thermal properties. After heating to the target temperature, we evaluate the mechanical properties according to the slow and fast cooling condition. As a result, normal weight aggregate concrete has higher effectiveness of cooling conditions than light weight aggregate concrete.

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Uniaxial bond stress-slip behavior of reinforcing bars embedded in lightweight aggregate concrete

  • Tang, Chao-Wei
    • Structural Engineering and Mechanics
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    • v.62 no.5
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    • pp.651-661
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    • 2017
  • This paper presents an experimental study of bond-slip behavior of reinforced lightweight aggregate concrete (LC) and normal weight concrete (NC) with embedded steel bar. Tests were conducted on tension-pull specimens that had cross-sectional dimension with a reinforcing bar embedded in the center section. The experimental variables include concrete strength (20, 40, and 60 MPa) and coarse aggregate type (normal-weight aggregate and reservoir sludge lightweight aggregate). The test results show that as concrete compressive strength increased, the magnitudes of the slip of the LC specimens were greater than those of the NC specimens. Moreover, the bond strength and stiffness approaches zero at the loaded end, or close to the central anchored point of the specimen. In addition, the proposed bond stress-slip equation can effectively estimate the behavior of bond stress and steel bar slipping.

A Study on Chloride Attack Resistibility in Light Weight Aggregate Concrete and Normal Weight Aggregate Concrete (보통 콘크리트와 인공경량골재 콘크리트의 염해 저항성에 관한 실험적 연구)

  • Lee, Chang-Soo;Nam, Chang-Sik;Yoo, Bo-Sun
    • Proceedings of the Korea Concrete Institute Conference
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    • 2010.05a
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    • pp.197-198
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    • 2010
  • The purpose of this study is to compare chloride attack resistibility of light weight aggregate concrete to chloride attack resistibility of normal concrete and confirm the utility. As a result, light weight aggregate concrete's chloride attack resistibility is lower than normal concrete's chloride attack resistibility.

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Ultrasonic Pulse Velocity of Normal Aggregate Concrete and Lightweight Aggregate Concrete at Early age According to Elapsed Time (초기재령에서 보통골재 및 경량골재 콘크리트의 시간경과에 따른 초음파 속도 변화)

  • Kim, Won Chang;Choi, Hyeong Gil;Nam, Jeong Soo;Kim, Gyu Young;Lee, Tae Gyu
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2021.11a
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    • pp.61-62
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    • 2021
  • Because of the problem of increasing self-weight due to the enlargement and high-rise of buildings using normal aggregate concrete, the need for structural lightweight aggregate concrete increases. However, early strength prediction is required when placing structural lightweight aggregate concrete, but research is insufficient. In this study, the ultrasonic pulse velocity of normal aggregate concrete and lightweight aggregate concrete was measured at early age. As a result, the ultrasonic pulse velocity of lightweight aggregate concrete was lower than normal aggregate concrete according to elapsed time at early age.

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A Study on the Development of the Artigicial Eco Light-Weight Aggregate using EAF-Dust and Application of the Concrete (전기로제강 분진의 복합안정화 처리를 통한 에코이공경량골재의 개발 및 콘크리트 적용 연구)

  • Lee, Jin-Woo;Kim, Kyung-Min;Jung, Chul-Hee;Bae, Yeoun-Ki;Lee, Jae-Sam
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.05b
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    • pp.149-152
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    • 2005
  • To make artificial light-weight aggregate with EAF-dust and estimate ability to apply to concrete, characteristics of the aggregate were considered in density, weight of unit volume, fineness modulus and so on. And then it was executed to experiments of the concrete mixed with the light-weight aggregate. As it was results that artificial light-weight aggregate with EAF-dust was heavier and more watertight than with only clay, concrete weight of unit volume was heavier than with expended clay aggregate. But it was regarded that concrete with EAF-dust artificial aggregate was able to field application as light-weight concrete because concrete of the weight of unit volume was lighter and compress strength and workability were similar to normal concrete.

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Local bond stress-slip behavior of reinforcing bars embedded in lightweight aggregate concrete

  • Tang, Chao-Wei
    • Computers and Concrete
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    • v.16 no.3
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    • pp.449-466
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    • 2015
  • This paper aims to study the local bond stress-slip behavior of reinforcing bars embedded in lightweight aggregate concrete (LWAC). The experimental variables of the local bond stress-slip tests include concrete strength (20, 40 and 60 MPa), deformed steel bar size (#4, #6 and #8) and coarse aggregate (normal weight aggregate, reservoir sludge lightweight aggregate and waterworks sludge lightweight aggregate). The test results show that the ultimate bond strength increased with the increase of concrete compressive strength. Moreover, the larger the rib height to the diameter ratio ($h/d_b$) of the deformed steel bars is, the greater the ultimate bond stress is. In addition, the suggestion value of the CEB-FIP Model Code to the LWAC specimen's ultimate bond stress is more conservative than that of the normal weight concrete.

Relation Between Water Content Ratio and Fire Performance of Class 1 Structural Light Weight Aggregate Concrete (1종 경량골재콘크리트의 함수율과 내화특성)

  • Song, Hun
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.2 no.4
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    • pp.321-327
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    • 2014
  • Structural light weight aggregate concrete are made with both coarse and fine light weight aggregates, but it is common with the high strength concrete to replace all or part with normal weight sand be called class 1 structural light weight aggregate concrete. Fire resistance of structural light weight aggregate concrete are determined by properties of high water content ratio and explosive spalling. Especially, structural light weight aggregate concrete is occurred serious fire performance deterioration by explosive spalling stem from thermal stress and water vapor pressure. This study is concerned with experimentally investigating fire resistance of class 1 structural light weight concrete. From the test result, class 1 structural light weight concrete is happened explosive spalling. The decrease of cross section caused by explosive spalling made sharp increasing gradient of inner temperature.

Failure of lightweight aggregate concrete-filled steel tubular columns

  • Ghannam, Shehdeh;Jawad, Yahia Abdel;Hunaiti, Yasser
    • Steel and Composite Structures
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    • v.4 no.1
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    • pp.1-8
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    • 2004
  • Tests on steel tubular columns of square, rectangular and circular section filled with normal and lightweight aggregate concrete were conducted to investigate the failure modes of such composite columns. Thirty-six full scale columns filled with lightweight and normal weight aggregate concrete, eighteen specimens for each, were tested under axial loads. Nine hollow steel sections of similar specimens were also tested and results were compared to those of filled sections. The test results were illustrated by a number of load-deflection and axial deformation curves. The results showed that both types of filled columns failed due to overall buckling, while hollow steel columns failed due to bulging at their ends (local buckling). According to the above-mentioned results, and due to low specific gravity and thermal conductivity of the lightweight concrete the further interest should be concentrated in replacing the normal concrete by the lightweight aggregate concrete.

Engineering Properties of Lightweight Aggregate Concrete Using Dry Bottom Ash as Coarse Aggregate (건식 바텀애시 굵은골재를 사용한 경량골재 콘크리트의 공학적 특성)

  • Sung, JongHyun;Sun, JungSoo;Choi, SunMi;Bok, YoungJae;Kim, JinMan
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2013.11a
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    • pp.166-167
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    • 2013
  • Bottom ash, which is discharged through a wet process in a thermal power plant, contains much unburned coal due to quenching and much salt due to seawater. However, dry bottom ash discharged through a dry process contains low unburned coal and salt, and has light -weight due to many pores. Therefore, it is expected that it can be used as lightweight aggregate. This study deals with the basic properties of concrete used dry bottom ash as coarse aggregate. As a results, the concrete having high content of dry bottom ash aggregate showed high slump by using water reducing agent and its air content was within 5±1.5% as designed value, similarly to normal weight concrete. It also showed a lower compressive strength than 100% of crushed stone.

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