• Title/Summary/Keyword: fine sand

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Diffusivity of Chloride Ion of Composite Slag Aggregate Replacement Concrete (복합슬래그 골재 치환 콘크리트 염소이온 확산 특성)

  • Park, Dong-Cheon;Lee, Jun-Hae;Kim, Yong-Ro;Song, Yong-Chan
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2019.11a
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    • pp.147-148
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    • 2019
  • Lack of fine aggregate is adversely affecting the quality of concrete. Due to lack of land sand, EZZ sea sand has been used. However, the use of sea sand is also difficult because of the opposition of fishermen. The purpose of this study was to analysis the effect of slag fine aggregate to durability and compressive strength of concrete. The concrete compressive strength and durability were assessed to derive a proper mix ratio of fine aggregate.

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The Influence of the Properties of Crushed Stone Sand on the Mixing Factor and Compressive Strength of Concrete (부순모래의 품질특성이 콘크리트의 배합인자 및 압축강도에 미치는 영향)

  • Hong Ji Hoon;Yum Jun Haun;Choi Jin Man;Jeong Yang;Lee Seong Yeun;Yeo Byung Chul
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.11a
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    • pp.623-626
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    • 2005
  • This study is aimed for investigating the influence of the properties of crushed stone sand on the mixing factor and compressive strength of concrete. The results of this study are as follows; The influence of Particle Shape and Very Fine Sand(VFS) of crushed stone sand on the mixing factor was higher than Fineness Modulus. The demand water of concrete with crushed stone sand was decreased about $12\~18kg/m^3$with increasing $4\%$ of Particle Shape and increased $8\~15kg/m^3$ with increasing $3\%$ of ratio of Very Fine Sand(VFS).

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Study on the Decision of Saturated Surface Dry of Crushed Stone Sand with Very Fine Sand (잔입자함유랑에 따른 부순모래의 표건 상태 판정에 관한 연구)

  • 이성복;최진만;이도헌;전용수;김병환;이현희;지남용
    • Proceedings of the Korea Concrete Institute Conference
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    • 1996.10a
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    • pp.10-16
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    • 1996
  • This study is aimed for investigating a decision of the saturated surface dry of crushed stone sand and measuring the moisture with increasing percentage of VFS(Very Fine Sand) replacement each crushed stone sand. The results indicated that moisture of crushed stone sand is generally increased with increasing percentage of VFS replacement and the rate of increase of moisture is about 30% every time that VFS replacement increases 3.5%. Also the saturated surface dry for crushed stone sane is proposed as a point of time where shape of flow-cone first slumps in this paper.

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Technique of grouting in silty-fine sand with abundant water: Practice in Beijing

  • Liu, Jun;Zhang, Liang;Xue, Hongsong;You, Tian;Wu, Yuqian
    • Geomechanics and Engineering
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    • v.29 no.4
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    • pp.463-470
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    • 2022
  • In NATM tunnels, water inrush and tunnel collapse are often encountered in silty-fine sand with abundant water during excavation. Because of the special engineering properties of this stratum, grouting effect is difficult to achieve as expected, and it is a major problem in the field of civil engineering. Taking Beijing Metro Line 10 as a case, we applied PFC3D to simulate the process of grouting in this stratum. By analyzing the law of grout diffusing and porosity change under different grouting pressures, the study found that grouting was a process of splitting, and grouting pressure played an important role. The numerical results were verified by theoretical calculation analysis, and the grouting parameters were determined under the various grouting pressures for practice. After the excavation of this tunnel, the concretions in silty-fine sand are similar to the results of PFC3D simulation, which indicates that the grouting mechanism is confirmed by field observation further.

Preperties of Mortar Using Ceramic Wastes (도자기 폐기물을 사용한 시멘트 모르터의 특성)

  • 김기형;최재진;최연왕;신화철
    • Proceedings of the Korea Concrete Institute Conference
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    • 1999.10a
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    • pp.103-106
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    • 1999
  • In this study, the properties of mortar using ceramic wastes as admixtures and fine aggregates are considered experimentally. The main chemical of ceramic wastes is SiO2 and micro structure of ceramic wastes is porous. Absorption of ceramic wastes is higher than that of river sand and specific gravity is lower than that of river sand. Flow value of mortar using ceramic waste admixture and fine aggregates is increased more or less and the strength of mortar using ceramic wastes as fine aggregates is increased.

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Assessment of concrete properties with iron slag as a fine aggregate replacement

  • Noufal, E. Rahmathulla;Kasthurba, A.K.;Sudhakumar, J.;Manju, Unnikrishnan
    • Advances in concrete construction
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    • v.9 no.6
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    • pp.589-596
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    • 2020
  • In an effort to find alternate, environment friendly and sustainable building materials, the scope of possible utilization of iron slag (I-sand), generated as a by-product in iron and steel industries, as fine aggregates in reinforced cement concrete (RCC) made with manufactured sand (M-sand) is examined in this manuscript. Systematic investigations of the physical, mechanical, microstructural and durability properties of I-sand in comparison with RCC made with M-sand have been carried out on various mix designs prepared by the partial/full replacement of I-sand in M-sand. The experimental results clearly indicate the possibility of utilizing iron slag for preparing RCC in constructions without compromising on the property of concrete, durability and performance. This provides an alternate possibility for the effective utilization of industrial waste, which is normally disposed by delivering to landfills, in building materials which can reduce the adverse environmental effects caused by indiscriminate sand mining being carried out to meet the growing demands from construction industry and also provide an economically viable alternative by reducing the cost of concrete production.

Influence of plastic viscosity of mix on Self-Compacting Concrete with river and crushed sand

  • Rama, J.S. Kalyana;Sivakumar, M.V.N.;Kubair, K. Sai;Vasan, A.
    • Computers and Concrete
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    • v.23 no.1
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    • pp.37-47
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    • 2019
  • In view of the increasing utility of concrete as a construction material, the major challenge is to improve the quality of construction. Nowadays the common problem faced by many of the concrete plants is the shortage of river sand as fine aggregate material. This led to the utilization of locally available materials from quarries as fine aggregate. With the percentage of fines present in Crushed Rock Fines (CRF)or crushed sand is more compared to river sand, it shows a better performance in terms of fresh properties. The present study deals with the formulation of SCC mix design based on the chosen plastic viscosity of the mix and the measured plastic viscosity of cement pastes incorporating supplementary cementitious materials with CRF and river sand as a fine aggregate. Four different combinations including two binary and one ternary mix are adopted for the current study. Influence of plastic viscosity of the mix on the fresh and hardened properties are investigated for SCC mixes with varying water to cement ratios. It is observed that for an increasing plastic viscosity of the mix, slump flow, T500 and J-ring spread increased but V-funnel and L-box decreased. Compressive, split tensile and flexural strengths decreased with the increase in plastic viscosity.

Undrained Shear Behavior of Sandy Soil Mixtures (사질혼합토의 비배수 전단거동 특성)

  • Kim, Ukgie;Ahn, Taebong
    • Journal of the Korean GEO-environmental Society
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    • v.12 no.8
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    • pp.13-24
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    • 2011
  • In the part of geotechnical engineering, soils are classified as either the coarse grained soil or the fine-grained soil following the fine content($F_c$=50%) according to the granularity, and appropriate design codes are used respectively to represent their mechanical behaviour. However, sand-clay mixtures, which are typically referred to as intermediate soils, cannot be easily categorized as either sand or clay. In this study, several monotonic undrained shear tests were carried out on Silica sand fine mixtures with various proportions, and a wide range of soil structures, ranging from one with sand dominating the soil structure to one with fines controlling the behaviour, were prepared using compaction method or pre-consoldation methods in prescribed energy. The shear strength of mixtures below the threshold fines content is observed that as the fines content increases, maximum deviator stress ratio decrease for dense samples while an increase is noted for loose samples. Then, by using the concept of fines content and granular void ratio, the monotonic shear strength of the mixtures was estimated. It was found that the shear behavior of mixtures is greatly dependent on the skeleton structure of sand particles.

Correlation Analysis between Sediment Particle Size and Number of Macromia daimoji (Endangered Species II) Nymphs in Naeseong Stream, Korea (내성천 퇴적물 입도와 노란잔산잠자리(멸종위기야생생물 II급) 약충 개체수와의 상관관계 분석)

  • Park, Jinyoung;Kwon, Hyeok Yeong;Jang, Myeong Seong;Cha, Jin Yeol;Lee, Jong Eun
    • Korean journal of applied entomology
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    • v.59 no.4
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    • pp.325-331
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    • 2020
  • Macromia daimoji nymphs (Endangered Species II) are known to inhabit the Naeseong Stream in Korea. In March 2019, we performed a correlation analysis between sediment particle size and the M. daimoji population using data collected from a 0.2-㎡ area at 37 sites in Naeseong riverbed. Particle size analysis showed different ratios of sediments in the riverbed: Coarse Sand (500-1,000 ㎛) 52.5%; Very Coarse Sand (1,000-2,000 ㎛) 25.6%; Medium Sand (250-500 ㎛) 17.2%; Fine Sand (125-250 ㎛) 3.1%; Very Fine Sand (63-125 ㎛) 1.0%; and Silt (less than 63 ㎛) 0.7%. The number of M. daimoji nymphs showed a positive correlation with Very Fine Sand and Fine Sand and a negative correlation with Coarse Sand, indicating that M. daimoji nymphs inhabit fine sand. These results can be used to monitor changes in the riverbed environment of Naeseong Stream to ensure the conservation of M. daimoji habitat.

Shear Strength of Intermediate Soils with Different Types of Fines and Sands

  • Kim, Ukgie;Ahn, Taebong
    • Journal of the Korean GEO-environmental Society
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    • v.14 no.1
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    • pp.33-42
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    • 2013
  • In this paper, a series of monotonic undrained shear tests were carried out on four kinds of sand-fine mixtures with various fines content. Two kinds of sands (Silica sand V3, V6) and fines (Iwakuni natural clay, Tottori silt) were mixed together in various proportions, while paying attention to the void ratio expressed in terms of sand structure $(F_c{\leq}F_{cth})$. The undrained shear strength of mixtures below the threshold fines content was observed so that as the plastic fines content increases, maximum deviator stress ratio decrease for dense samples while an increase is noted for loose samples. For non-plastic fines, the increase in the amount of fines leads to an increase in density of the soil, which results in an increase in strength. Then, the monotonic shear strength of the mixtures was estimated using the concept of granular void ratio. It was found that the shear strength of mixtures is greatly dependent on the skeleton structure of sand particles.