• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.141-144
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• 2006

In this study, evaluation of physical and chemical properties of crushed sand was performed to establish optimal mix proportion standard for concrete using crushed sand afterward. Most of properties of crushed sand were satisfied with KS F 2527. Especially, chemical stabilities such as alkali-aggregate reaction were fairly good. However, considerable attention would be required in using crushed sand from lime stone judging from the result that weight loss of it was more than 23.8%. There were some differences in the properties with production region, stone type and capacity of facility, therefore it is thought that quality should be controled by optimal regulations for corresponding items.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.10a
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• pp.84-88
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• 1995

The results of an experimental study on manufacture and mechanical properties of concrete utilizing crushed sand and fly ash for construction materials are presented in theis paper. As the results show, the workability, compressive strength and freezing-thaw resistance were improved by proper contents of fly ash, replaced crushed sand, and air entraining agent. And the drying shinkage was decreased by proper contents of those. Also, the suitable weight contents of replacing ratio of crushed sand and weight ratio fly ash in concrete using crushed sand were in range of 30% and 15% respectively.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.365-368
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• 2008

In recent, the crushed sand as a fine aggregate has increasingly used for concrete industry due to the shortage of natural sand from river and the growing demand for protection of natural environments. Aggregates may have a significant influence on the properties of self-compacting concrete (SCC) including self-compacting mortar (SCM). The rheological properties of SCC and SCM using crushed sand as a fine aggregate has been compared to that of SCC and SCM using natural sand and mixed sand of both. Test results indicate that the yield stress of SCM containing 50% of mixed sand present higher than those prepared with natural sand and crushed sand according to SP content. the slump values of SCC with natural sand have approximately 5-15% higher than those of SCC with crushed sand. Also the L-box test values ($H_2/H_1$) of SCC with natural sand have approximately 20-30 higher than those of SCC with crushed sand under same water/cement ratio and viscosity enhancing admixture.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.137-140
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• 2006

This study make an investigation into the quality of sand supplied with remicon manufacturing plant and examine concrete influenced by a source of supply of sand. As a result of the indoor test, the quality of crushed sand, EEZ sand and sand of north korea are worse than general sea sand. therefore, crushed sand, EEZ sand and sand of north sand lower quality of concrete.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.863-868
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• 2004

The use of oyster shells is proposed as a substitute construction material for geotechnical applications. To investigate recycling possibility as a substitute of sand compaction pile (SCP) for oyster shells, the geotechnical characteristics including permeability and shear strength of crushed oyster shell, sand and crushed oyster shell-sand mixted soil. Experimental results show that the crushed oyster shells are lighter than sand in weight, and have similar characteristics on permeability to sand. The results of direct shear test show that the measured value of friction angle ${\Phi}$ of crushed oyster shell was lager than that of sand. It would be expected that more angular particles (crushed oyster shells) would interlock more thoroughly than rounded particles (send).

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1290-1295
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• 2008

The relative density of soil indicate loose and dense state of sand. Because sand is low compressibility, initial relative density of sand is important effect factor of compression and shear behavior. To measure exactly relative density, the exactly maximum and minimum void ratio was determinated by laboratory tests. Generally, vibrating table method is adapted for minimum void ratio(KS F 2345). However KS F 2345 is not consider the particle break during the vibrating table test. In this study, The minimum void ratio is compared with a method of Pluviation and Vibrating table test results using the K-7(crushed sand). It is concluded that the K-7 sand particles were crushed during the vibrating table test and vibrating table test is not a suitable test for a crushed sand $e_{min}$.

• Geomechanics and Engineering
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• v.10 no.4
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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.

• 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).

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.533-536
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• 2003

The objective of in this study makes investigation into the characteristics of antiwashout underwater concrete as to mix proportion, casting and curing water through experimental researches. in this study, sea sand is blended with river sand, crushed sand is blended with river sand and sea sand as to investigate the quality change and characteristics of antiwashout underwater concrete with variation of blend ratio of sea sand and crushed sand(0, 20, 40, 60, 80, 100%). Higher compressive strength is measured following the order of river sand, sea sand, crushed sand regardless of age and casting condition. Except for case of using river sand, blended ratio of 40% is appeared on most compressive strength.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.417-422
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• 2001

The purpose of this study is to investigate experimentally the workability, compressive and flexural strength properties of rapid-set concrete with various mixture. The kinds of fine aggregate(river sand, sea sand, crushed sand), water-cement ratio(40%, 45%, 50%), sand-aggrega to ratio(33%, 36%, 39%) were chosen as the experimental parameters. Test variables are temperature of concrete, slump, air contents, compressive and flexural strength. The compressive and flexural strength for 3 hours and 6 hours were tested. As result, it was shown that temperature of concrete involved 45$^{\circ}C$, some time later decreased. The workability were decreasing in steps as the sand-aggregate ratio increased and crushed sand was the highest value. Higher compressive and flexural strength was shown following the order of river sand, sea sand, crushed sand regardless of sand-aggregate ratio. But the values of gap was just a little.