• Title, Summary, Keyword: Fine aggregate modulus

Search Result 105, Processing Time 0.047 seconds

The Effect on the Properties of Concrete by Fine Aggregate Fineness Modulus and Grain Shape of Coarse Aggregate (잔골재 조립율 및 굵은골재 입형이 콘크리트의 특성에 미치는 영향)

  • 정용욱;윤용호;이승한
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • /
    • pp.102-105
    • /
    • 2003
  • The purpose of this study is to examine the influence of the flowability and the compressive strength of concrete after the improving of grain shape of the coarse aggregate and fine aggregate fineness modulus. According to the experimental results, the coarse aggregate after improvement of grain shape it lead to be down by 6% fine aggregate ratio, from 47% to 41%. The 0.5% increase of fine aggregate fineness modulus lead to 3% increase of concrete slump, and 1% reduction of concrete air content. While compressive strength on fine aggregate fineness modulus, it was increased until fineness modulus 3.0, but after it reached by 3.5 it was decreased. The compressive strength of the coarse aggregate after improving the grain shape was decreased by 6% due to loss of the adhesion of cement paste.

  • PDF

Mechanical behavior of recycled fine aggregate concrete after high temperature

  • Liang, Jiong-Feng;Wang, En;He, Chun-Feng;Hu, Peng
    • Structural Engineering and Mechanics
    • /
    • v.65 no.3
    • /
    • pp.343-348
    • /
    • 2018
  • This paper reports mechanical behavior of recycled fine aggregate concretes after high temperatures. It is found that compressive strength of recycled fine aggregate concretes decline significantly as the temperature rises. The elastic modulus of recycled fine aggregate concretes decreases with the increase in temperature, and the decrease is much quicker than the decrease in compressive strength. The split tensile strength of recycled fine aggregate concrete decrease as the temperature rises. Through the regression analysis, the relationship of the mechanical behavior with temperature are proposed, including the compressive behavior, elastic modulus and split tensile strength, which are fitting the test data.

Influence of high temperature on mechanical properties of concrete containing recycled fine aggregate

  • Liang, Jiong-Feng;Wang, En;Zhou, Xu;Le, Qiao-Li
    • Computers and Concrete
    • /
    • v.21 no.1
    • /
    • pp.87-94
    • /
    • 2018
  • This paper presents the results of an experimental study to investigate the influences of high temperatures on the mechanical properties of concrete containing recycled fine aggregate. A total of 150 concrete prisms ($100{\times}100{\times}300mm$) and 150 concrete cubes ($100{\times}100{\times}100mm$) are cast and heated under five different temperatures ($20^{\circ}C$, $200^{\circ}C$, $400^{\circ}C$, $600^{\circ}C$, $800^{\circ}C$) for test. The results show that the mass loss, compressive strength, elastic modulus, splitting tensile strength of concrete specimens containing recycled fine aggregate decline significantly as the temperature rise. At the same temperature, the compressive strength, splitting tensile strength, elastic modulus of concrete specimens containing recycled coarse aggregate and recycled fine aggregate (RHC) is lower than that of concrete specimens containing natural coarse aggregate and recycled fine aggregate (RFC). The shape of stress-strain curves of concrete specimens at different temperatures is different, and the shape of that become flatter as the temperature rises. Normal concrete has better energy absorption capacity than concrete containing recycled fine aggregate.

The Effect of Fine Aggregate Fineness modulus on Properties High Performance Concrete (잔골재 조립율이 고성능콘크리트의 특성에 미치는 영향)

  • Lee Seung-Han;Jung Yong-Wook;Park Tae-Hyun
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • /
    • pp.388-391
    • /
    • 2004
  • This research investigates how the fineness modulus of fine aggregates and the grain shape of coarse aggregates affects flow characteristics, packing characteristics and compressive strength characteristic. The experimental results, show that increase of the fine aggregate's fineness modulus improved concrete flow, but filling ability was high at over KS regulation extent due to segregation phenomena. It is considered that the improvement of 0.1 spherical rate was effective to concrete fluidity elevation by reducing about $6\%$ of fine aggregate ratio displays which the smallest gap rate of aggregate. Compressive strength was increased to about 0.6MPa everytime F.M. 0.1 of fine aggregate fineness is increased. However, it was decreased to about 9MPa at F.M. 3.5 compared to F.M. 3.0.

  • PDF

The Influence of Fineness Modulus of Pine Aggregate and Grain Shape of Coarse Aggregate on the Properties of High Flowing Concrete (잔골재 조립률 및 굵은골재 입형이 초유동 콘크리트의 특성에 미치는 영향)

  • Jung Yong-Wook;Lee Seung-han;Yun Yong-Ho
    • Journal of the Korea Concrete Institute
    • /
    • v.17 no.5
    • /
    • pp.785-792
    • /
    • 2005
  • This study is to examine the influence of defective grain shape of coarse aggregate and lowered fineness modulus of fine aggregate on the characteristics of high flowing concrete. The flow ability and compact ability of high flowing concrete was examined using fine aggregate, varying its fineness modulus to 2.0, 2.5, 3.0, and 3.5, and coarse aggregate with before and after grain shape improvement. Also the influence of fineness modulus of fine aggregate and grain shape of coarse aggregate on dispersion distance of particles of aggregate was examined by relatively comparing the dispersion distance between particles of aggregate. According to the experimental result, minimum porosity when mixing fine aggregate and coarse aggregate was shown in order of fineness modulus of fine aggregate, 3.0, 2.5, 2.0, 3.5, regardless of the improvement of grain shape. So when the fineness modulus is bigger or smaller than KS Standard $2.3\~3.1$, the porosity increased. When the spherical rate of the grain shape of coarse aggregate unproved from 0.69, a disk shape to 0.78 sphere shape, the rate of fine aggregate, which represents minimum porosity, decreased $6\%$ from $47\%\;to\;41\%$. The 28 days compressive strength according to fineness modulus of fine aggregate increased about 3 ma as the fineness modulus increased from 2.0 to 2,5, and 3.0. However, the 28 days compressive strength decreased about 9 ma at 3.5 fineness modulus as compared with 3.0 fineness modulus. The improvement of grain shape in coarse aggregate and increase of fineness modulus in fine aggregate made the flow ability, compact ability, and V-rod flowing time improve. Also the fineness modulus of fine aggregate increased the paste volume ratio when a higher value was used within the scope of KS Standard $2.3\~3.1$.

Mechanical properties of recycled fine glass aggregate concrete under uniaxial loading

  • Liang, Jiong-Feng;Yang, Ze-Ping;Yi, Ping-Hua;Wang, Jian-Bao
    • Computers and Concrete
    • /
    • v.16 no.2
    • /
    • pp.275-285
    • /
    • 2015
  • This paper reports the results of an experimental study on the compressive strength and the stress-strain curve (SSC) of recycled fine glass aggregate concrete with different replacement percentages of recycled fine glass aggregate. The results show that the recycled fine glass aggregate contents have significant impact on the workability, compressive strength, the elastic modulus, the peak and the ultimate strains of recycled fine glass aggregate concrete. Analytical expressions for the stress-strain relationship of recycled fine glass aggregate concrete are given, which can satisfactorily describe the effect of the recycled fine glass aggregate on the SSC.

A Study on the Properties of Mortar with Recycled Fine Aggregate (순환잔골재를 사용한 모르타르의 제물성에 관한 실험적 연구)

  • Moon, Dae-Joong;Choi, Jae Jin
    • Journal of the Korean Recycled Construction Resources Institute
    • /
    • v.4 no.1
    • /
    • pp.96-100
    • /
    • 2009
  • The properties of recycled fine aggregates which had different source concrete were examined by mortar test. With higher strength of source concrete, specific gravity of recycled fine aggregate was higher and absorption of recycled fine aggregate was lower due to reduction of the volume of adhered cement paste. The compressive strength and flexible strength of mortar with recycled fine aggregate were affected by the interface boundary of new mortar and the strength of adhered mortar. Strength development of mortar with recycled fine aggregate reduced because recycled fine aggregate become a porous material with the smaller strength of source concrete. The drying shrinkage of mortar was about$800{\sim}2000{\mu}m/m$. It was about 1.5 times than that of mortar with natural fine aggregate. Relative dynamic modulus of elasticity was a similar level with that of mortar with natural fine aggregate.

  • PDF

The Effects of Horizontal Vibration on the Concrete Compressive Strength under Fine Aggregate Modulus Variation (잔골재율을 변화시킨 콘크리트의 압축강도에 수평진동이 미치는 영향)

  • 정병훈;김종훈;장희석;김종수;김명식
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • /
    • pp.304-312
    • /
    • 2001
  • The objective of this study is to find out effects of horizontal vibration on the compressive strength for 7days and 28 days cured concrete specimens according to the variation of fine aggregate modului, vibration velocities, and times began to vibrate. Four kinds of fine aggregate modului(40, 42, 45, 47%), three of vibration velocities(0.25, 0.5 0.1kine(cm/sec)), and four of times(0, 3, 6, 9hrs after concrete casting) were chosen as the experimental parameters in this study, the vibrations were applied for 30 minutes in each case. From this study, it could be seen that the most increase of compressive strengths were obtained in case of 47% fine aggregate modulus, and 0.25kine of vibration velocity, but the strength was decreased when vibrated after 9hrs from concrete casting.

  • PDF

A Study on the Mix Design and Quality Factors of the Combined High Flowing Concrete Using High Belite Cement

  • Kwon, Yeong-Ho
    • KCI Concrete Journal
    • /
    • v.14 no.3
    • /
    • pp.121-129
    • /
    • 2002
  • This study investigates experimentally into the design factors and quality variations having an effect on the properties of the combined high flowing concrete to be poured in the slurry wall of Inchon LNG in-ground receiving terminal. Especially, high belite cement and lime stone powder as cementitious materials and viscosity agent in order to improve self-compaction and hydration heat are used in this study. Water-cement ratio(W/C), fine aggregate volume ratio(Sr) and coarse aggregate volume ratio(Gv) as design factors of the combined high flowing concrete are applied to determine the optimum mix design proportion. Also quality variations for sensitivity test are selected items as followings. (1)Surface moisture(5cases) and (2)Fineness modulus of fine aggregate(5cases), (3)Concrete temperature(3cases), (4)Specific surface(3cases) and particle size of lime stone powder. As experimental results, water-cement ratio, fine and coarse aggregate volume ratio are shown as the optimum range 51%, 43% and 53% separately considering site condition of slurry wall. Also quality factors by sensitivity test should be controlled in the following ranges. (1) Surface moisture :to.67% and (2)Fineness modulus 2.6$\pm$0.2 of fine aggregate, (3)Concrete temperature l0-20t, (4) Specific surface 6,000$\textrm{cm}^2$/g and particle size 9.7$\pm$1.0${\mu}{\textrm}{m}$ of lime stone powder. Based on the results of this study, the optimum mix design proportion of the combined high flowing concrete are selected and poured successfully in the slurry wall of LNG in-ground tank.

  • PDF

Application of Waste Foundry Sand for Concrete-Based Products of Low Water Ratio (낮은 물비를 갖수용성 합성 절삭유의 재사용을 위한 한외여과 연구는 콘크리트 제품에 대한 폐주물사의 적용)

  • Kim, Jin-Man;Cho, Sung-Hyun;Kwak, Eun-Goo
    • Clean Technology
    • /
    • v.8 no.3
    • /
    • pp.129-139
    • /
    • 2002
  • This is the study for recycling waste foundry sand. Authors studied about main subject of grading of aggregate and three experimental items such as physical properties of waste foundry sand, optimum grading for concrete products of low water ratio, and quality variations of concrete products according to substitution proportion of fine aggregate as waste foundry sand. We were convinced of following results by experimental study. The first was that waste foundry sand was not fit as the aggregate for concrete because of bad qualities such as grading, unit weight, solid volume and passing 0.08 mm seive, so it is proper to composition using with other fine aggregetes. The second was that optimum grading is fineness modulus of 2.77 to 3.28 And the last is that optimum condition about substitution proportion as waste foundry sand is 10% fine aggregate.

  • PDF