• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.451-454
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• 2005

Recently, Trouble of sand supply is occurred according to exhaustion of natural sand resources. therefore, various measures are proposed for solution of trouble of sand supply and crushed sand among measures is used as one of most universal measures. but because crushed sand have poor particle shape and plenty of makes micro particle, the quality of concrete using crushed sand deteriorated. Therefore, this study evaluated engineering property of concrete with replacement ratio of crushed sand and applied evaluation result to fundamental data for quality control of concrete using crushed sand. The result of this study have shown that quality of concrete using crushed sand independently is poor against general concrete. but, the concrete mixing crushed sand with general sand can be similar in workability of concrete used general sand and increase compressive strength of concrete as against concrete using general sand.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.105-108
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• 2006

Recently, trouble of sand supplying is occurred according to exhaustion of natural sand resources. Therefore various measures are proposed for solution of trouble of sand supply and crushed sand among measures is used as one of most universal measures. But because crushed sand have poor particle shape and plenty of mikes micro particle, the quality of concrete using crushed sand deteriorated. Therefore, this study evaluated engineering property of concrete with replacement ratio of crushed sand and EEZ sand applied evaluation result to fundamental data for quality control of concrete using crushed sand and EEZ sand and The result of this study have shown that quality of concrete using crushed sand and EEZ sand and The compressive strengh of concrete up to 50, 70% EEZ sand replacement by crush sand, nearly equal to that of general sand.

• International Journal of Concrete Structures and Materials
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• v.6 no.4
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• pp.231-237
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• 2012

Recently, it has been difficult to get natural sand for concrete due to an insufficient supply in Korea. Crushed sand was thought as a substitute and previous research has been focused on low fluidity and normal compressive strength (24-30 MPa). Study on high performance concrete using crushed sand is hardly found in Korea. In this study it was investigated that the effect of the crushed sand on fluidity and compressive strength properties of high performance concrete. Blending crushed sand (FM: 3.98) produced in Namyangju, Kyunggido and sea sand (FM: 2.80) produced in Asan bay in Chungnam. The final FMs of fine aggregate were 3.50, 3.23, and 3.08. W/B was set as 0.25 to get high performance. With the test results an analysis of relationship was performed using a statistical program. It was shown that strength property of concrete using crushed aggregate at the very early age or after specific time was mainly affected by strength development properties of binders instead of the crushed sand.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.106-111
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• 2003

This paper is to investigate the characteristics of a concrete in which river sand is partially substituted with crushed sand. Since river sand has a relatively small fineness modulus, there is a need to increase the fineness modulus of sand used in the manufacture of concrete. In an experiment, it was observed that when river sand had a fineness modulus of 2.0~2.4 and crushed sand had a fineness modulus of 2.8~3.5, the substitution rate of the crushed sand was preferably within the range of 25~50%. The experimental results also revealed that as the substitution rate of the crushed sand increased, the flowability of the concrete tended to increase. However, when the substitution rate of the crushed sand reached 75% or more, the workability of the concrete was considerably poor. Further, as the substitution rate of the crushed sand increased, the air content and the bleeding rate of the concrete were low.

• International Journal of Concrete Structures and Materials
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• v.4 no.2
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• pp.97-104
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• 2010

The crushed limestone sand is an abundant material in Tunisia, which induces many environmental problems. Indeed, available stocks of siliceous sand drastically decrease because of its massive use in hydraulic concrete. Some recent research works, carried out in Tunisia, concluded that crushed limestone sand may be used in concrete manufacture instead of siliceous sand traditionally used. In this context, an experimental study was achieved in order to quantify the influence of a partial or total substitution of siliceous sand by crushed limestone sand on hydraulic concrete performances. Preliminary chemical and physical tests on crushed sand indicated that it presented the minimum requirement for its use as aggregate in hydraulic concrete. 79 concretes were then prepared with siliceous sand, crushed limestone sand and a mix of the two sands. Their slump value and compressive strengths were measured on plain concretes. Complementary structural tests on reinforced concrete beam were also performed. The results proved that crushed limestone sand concretes showed workability and mechanical performances closed to those of siliceous sand concretes.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.11a
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• pp.63-66
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• 2005

Recently, Trouble of sand supply is occurred according to exhaustion of natural sand resources. therefore, various measures are proposed for solution of trouble of sand supply also the government settled trouble of sand supply through application of crushed sand. but because both crushed sand are poor against general sand, they lead to lowering of qualify of ready-mixed concrete. Therefore, this study evaluated engineering property and durability of concrete using crushed sand and applied evaluation result to fundamental data for quality control of concrete using crushed sand. The results of this study have shown that quality of concrete using crushed sand independently is poor against general concrete. but, the workability, compressive strength and durability of concrete mixed crushed sand with genera can improve on those of concrete used general sand.

• Journal of the Korea Institute of Building Construction
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• v.3 no.3
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• pp.107-112
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• 2003

This study is to investigate the properties of concrete with crushed sand on site and to propose a quality guideline for its use as artificial sand and concrete. From our experimental result in laboratory and site, we found that demand water of concrete with crushed sand for target slump increased by 18kg/m3 compared to mixed sand and l8kg/m3 compared to sea sand respectively. The compressive strength increased by around 3∼6% when compared to concrete with sea sand. Accordingly, our study showed that the combined sand mixed with sea sand would be desirable to obtain workability and strength of concrete including dry shrinkage and bleeding test. Furthermore, the optimal replacement percentage of crushed sand was 50% with sea sand. As such, crushed sand would be sufficient as fine aggregate for concrete in terms of economic efficiency and quality. Crushed sand, on the other hand can only be used as fine aggregate when VFS(Very Fine Sand) is below 3.5 percentage of weight of sand and particle shape is above 55 percentage. Also, the particle shape and microsand passing NO.200 sieve should continually be improved to increase workability of concrete on site.

• Journal of the Korea Institute of Building Construction
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• v.5 no.1 s.15
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• pp.63-68
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• 2005

Generally, aggregate may limit the workability, strength and durability of concrete, and good concrete cannot be made with aggregate of bad property including low strength, bad shape and grading. But recently, it has been insufficient in quantity to collect good natural aggregate because of exhaustion of aggregate resources. In case of Korea, the using ratio of crushed stone occupies about 97 percent of total coarse aggregate, and ratio of crushed sand occupies about 18.3 percent of total fine aggregate. This is an experimental study to compare and analyze the properties of crushed sand for concrete in capital region and concrete according to the replacement ratio of crushed sand to improve quality and mix design of concrete using crushed sand. According to test results, it was found that nearly all the properties of crushed sand satisfied with the value recommended by KS. And it is recommended that FM of crushed sand should be lowered by improvement of manufacture system or grading adjustment should be used because FM of crushed sand was a bit higher.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.443-446
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• 2005

Recently, according to increase use of concrete which is the main material of construction, the natural aggregate of good quality is more and more decreased. Most of all, among the concrete materials, the development of alternation materials of sand is urgently needed. In this study, investigating the production equipment and the sample of crushed sand company and analyzing properties of sand, manufactured mortar by the KS to use crushed sand as the fine aggregate of concrete material. The experiment result is as follows. 1. The density, an absorptivity, and the amount of 0.08mm passage ratio of crushed sand, and the mortar used crushed sand satisfied KS. The mechanical results is similar to sea sand. 2. The crushed sand which used impact crusher instead of cone crusher for 3rd or 4th crusher was similar properties to sea sand, so it is judged that impact crusher has high effect of particle shape improvement of crushed sand.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04a
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• pp.147-152
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• 1998

This study is to investigate the application of concrete with crushed sand on site. As a result, it is showed that the combined sand mixed with sea sand is very desirable for obtaining workability and strength of concrete, and the optimal replacement percentage of crushed sand is 50% with sea sand. After all, the crushed sand could be sufficiently used as a fine aggregate for concrete in the aspect of economical efficiency and quality, but the particle shape and microsand passing No.200 sieve should be firstly improved for increasing workability of concrete on site.