• 한국지반공학회논문집
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• 제23권10호
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• pp.65-72
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• 2007

본 연구에서는 효율의 관점에서 흙 자체의 전단강도 및 흙/토목섬유 상호간의 접촉면 마찰특성을 조사하기 위하여 대형직접전단시험을 수행하였다. 모래와 쇄석, 3종류의 지오텍스타일(즉, 2종류의 부직포와 1종류의 직포)을 시험에 사용하였다. 접촉면에서의 전단강도를 산정하는데 고려한 접촉면은 모래/모래, 쇄석/쇄석, 모래/직포, 쇄석/직포, 쇄석/부직포-A 그리고 쇄석/부직포-B 등이다. 연구결과, 모래/직포의 접촉면에서는 모래자체의 전단강도(즉, 모래/모래 접촉면)와 비교하여 84%의 효율을 얻었다. 쇄석/부직포-A, 쇄석/부직포-B, 쇄석/직포의 접촉면에서는 쇄석자체의 전단강도(즉, 쇄석/쇄석 접촉면)와 비교하여 각각 74%, 83%, 72%의 효율을 얻었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2003년도 봄 학술발표회 논문집
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• pp.717-724
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• 2003

Although sand compaction pile is applied considerably for increase of hearing capacity in domestic, it is getting more necessary to develope the alternative materials because of exhaustion and increase of unit cost of sand. In this study, stress concentration ratio between crushed-stone pile and soft ground was measured and, a displacement ratio 30, 40 and 50%, variation of stress concentration ratio was analyzed. As an increase displacement ratio, the stress concentration effect of crushed-stone compaction pile doesn't increase proportionally and effect of ground improvement in case of ground was good at displacement ratio 30% or 40%. The stress concentration ratio of crushed-stone compaction pile in group piles is 1.5 times that of crushed-stone compaction pile in single pile.

• 한국지반신소재학회논문집
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• 제5권1호
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• pp.33-38
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• 2006

쇄석의 전단강도와 쇄석과 부직포사이의 접촉면 전단강도를 산정하기 위해서 본 연구에서는 대형직접전단시험기를 사용하였다. 두 개의 서로 다른 쇄석의 단위중량을 한 종류의 직포와 두 종류의 부직포인 총 3가지 형태의 토목섬유에 고려하였다. 본 연구에서는 총 15번의 시험을 수행하였다. 그 결과는 쇄석의 단위중량이 각각 $1.4t/m^3$과 $1.5t/m^3$일 때 $47^{\circ}$와 $57^{\circ}$의 내부마찰각을 나타내었다. 부직포와 쇄석의 접촉면 마찰각은 쇄석의 내부마찰각에 비하여 A타입에서 $39^{\circ}$로 83%의 효율을 보였으며 B타입은 $42^{\circ}$로 89%의 효율을 나타내었다. 이와 비슷하게 직포와 쇄석의 접촉면 마찰각은 $39^{\circ}$로 83%의 효율을 나타내어 비교적 거칠기가 작은 A타입 부직포와 거의 동일한 결과를 보였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.213-216
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• 2004

Aggregate occupies about 70 to 80 percent by volume in concrete as skeleton of concrete, but recently, it has been insufficient in quantity to collect good natural aggregate because of exhaustion of aggregate resources. In case of Korea, in 2002, the using ratio of crushed stone occupies about $97\%$ of whole coarse aggregate, and ratio of crushed sand occupies about $18.3\%$ of whole fine aggregate. This is an experimental study to compare and analyze the properties of concrete according to the grading of crushed stone to improve quality and mix design of concrete using crushed stone. According to results, it was found that grading level of crushed stone in the range of G42 to G60 was better than any other grading level in terms of fluidity and compressive strength. And it is considered to be in the range of 6.52 to 6.85 in terms of FM.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.263-266
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• 1999

This study aims to make high performance concrete for normal strength using crushed stone fines to control high strength of the high performance concrete. According to the experimental results, when crushed stone fines are increased every 10%, 15% of compressive strength is decreased, and 5% of drying shrinkage is increased, compared to normal high performance concrete. Also, high performance concrete has been evaluated to have good durability factor more than 100% in the 480cycle of freezing and thawing test, without regard to using AE and crushed stone fines.

• 한국건축시공학회지
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• 제6권1호
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• pp.101-107
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• 2006

While a Study with regard to the measurement on Concrete Strength and the Change of Drying Shrinkage in accordace with Content Ratio of Crushed Stone Powder, it is being analyzed as the result that the strength according to Content Ratio of crushed Stone Powder is somewhat lowering. Accordingly, it is the real situation that the Concrete mixed with Crushed Stone Powder is utilized for non-structural material, not for the structural material. Therefore, this Research willing to furnish the suitable utilizing scheme for construction site as well as practical life by means of conduct the experiment on both Concrete Pressure Strength according to mixture with Crushed Stone Powder and Elastic Modulus, it also presumes the optimum Elastic Modulus Equation after analysis of comparison with common concrete strength. As the result of the experiment, in case of the Content Ratio of Crushed Stone Powder is less than 5%, it did not display a big difference in its both strength and matter-property compare with common concrete. In case of Elastic Modulus, when the Pressure Strength is 50% and 40% respectively, the Elastic Modulus Equation accords very well with the provided condition of Quadratic function, and as the result of the Presumption on Elastic Modulus according to Content of Crushed Stone Powder, in case the Pressure Strength is 50%, Elastic Modulus Equation showed that Error Ratio of Cubic function is at degree of 0.0005%, in case the Pressure Strength is 40%, Elastic Modulus Equation was accorded well with the value of the experimental data likely as the Error Ratio of Cubic function is at the degree around 0.0034%, respectively.

• 한국농공학회논문집
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• 제54권1호
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• pp.39-45
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• 2012

In this study, field test on utilization of recycled aggregates and crushed stone as horizontal drains to use an alternative material of sand in soft ground is practiced. The settlement with time showed similarly ranged from 28.4-30.3 cm in the all horizontal materials. The excess pore water pressure of the recycled aggregates and crushed stone showed smaller than sand. The small the excess pore water pressure becomes faster the consolidation period and it can reduces the amount of residual settlement. Therefore, it was verified as having enough to an alternative materials that the field applicability is excellent. The distribution of earth pressure with time showed similarly in the all horizontal materials. The recycled aggregates and crushed stone was very applicable to practice because there is no mat resistance in the horizontal drains layer. The penetration rate in the SCP and PVD improvement sections did not show large differences as the grain size and the horizontal drainage height increases.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1996년도 가을 학술발표회 논문집
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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.

• Geomechanics and Engineering
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• 제10권4호
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• pp.455-470
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• 2016

In ballasted railway tracks, ballast fouling due to finer material intrusion has been identified as a challenging issue in track maintenance works. In this research, deformation characteristics of crushed stone-sand mixtures, simulating fresh and fouled ballasts were studied from laboratory and a 3-D discrete element method (DEM) triaxial compression tests. The DEM simulation was performed using a recently developed DEM approach, named, Yet Another Dynamic Engine (YADE). First, void ratio characteristics of crushed stone-sand mixtures were studied. Then, triaxial compression tests were conducted on specimens with 80 and 50% of relative densities simulating dense and loose states respectively. Initial DEM simulations were conducted using sphere particles. As stress-strain behaviour of crushed stone-sand mixtures evaluated by sphere particles were different from laboratory specimens, in next DEM simulations, the particles were modeled by a clump particle. The clump shape was selected using shape indexes of the actual particles evaluated by an image analysis. It was observed that the packing behaviour of laboratory crushed stone-sand mixtures were matched well with the DEM simulation with clump particles. The results also showed that the strength properties of crushed stone deteriorate when they are mixed by 30% or more of sand, specially under dense state. The results also showed that clump particles give closer stress-strain behaviour to laboratory specimens than sphere particles.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2004년도 춘계학술발표회
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• pp.90-99
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• 2004

Stone column is one of the soft ground improvement method, which enhances ground conditions through ground water draining, settlement reducing and bearing capacity increasing complexly by using crushed stone instead of sand in general vertical drain methods. In recent, general construction material, sand is in short of supply, because of the unbalance of demand and supply. Also, the bearing capacity improving effect of stone column method is needed in many cases so the bearing capacity estimation is considered as important point. Nevertheless, adequate estimation methods to predict bearing capacity of stone column considering stone column and improving ground behavior reciprocally is not yet prepared. To contribute this situation, bearing capacity behavior of stone column were simulated as numerically on various property cases of crushed stone and surrounded ground. Through the numerical analysis of simulation results, bearing capacity behavior prediction formula was suggested. This formula was verified by comparing the prediction result with in situ test.