• Journal of Industrial Technology
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• v.24 no.A
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• pp.173-178
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• 2004

It is the purpose of this study to identify comprehensive fatigue characteristics of pavement concretes considering coarse aggregate types. The types of coarse aggregates considered are limestone, sandstone and granite, which are the most representative stones in Korea. The static strength tests were carried out to check the compressive strength, flexural strength at 7 and 28 days, and split tension strength at 56 day in order to minimize the various effect of strength during the test. The results are follows. The comprehensive fatigue models of pavement concretes were developed considering coarse aggregate types. The developed model showed a good relationship between aggregate types. The fatigue models with coarse aggregate types were shown, respectively. The combined fatigue models was also shown.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2006.11a
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• pp.95-98
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• 2006

This study investigates spalling properties of high performance concrete, 60MPa clan, made with the various types of coarse aggregate and adding ratio of polypropylene(PP) fiber. As experimental parameters, totally sixteen specimens of ${\phi}100{\times}200mm$ in size are prepared: one specimen for control without fiber, ten specimens with different coarse aggregate types, along with 0.05, 0.1, 0.15 percent of PP fiber in each. 1 hour fire test is conducted and then spalling appearance, spalling degree and residual compressive strength are examined. In addition, sit specimens made with two types of coarse aggregate site, along with same adding ratio of fiber are supplementally done, and only spalling properties is examined. Test results showed that control concrete and most specimens containing 0.05% of PP fiber exhibited 4 to 3 level of spalling degree, resulting severe explosive spalling, except for the specimen using basalt aggregate(Bc) showing 2 to 3 level of that. Especially, the Bc specimen containing 0.1% of the fiber exhibited that residual compressive strength value was 32%, which is 10% higher than other specimens using limestone or granite. Spalling resistance performance was also effective as aggregate size increase.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.567-572
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• 2002

This research investigates experimentally an effect on the quality performances of the high flowing concrete according to binder types. The purpose of this study is to determine the optimum mix proportion of the high flowing concrete having good flowability, viscosity and no-segregation. For this purpose, two types using belite cement＋lime stone powder(LSP) and furnace slag cement+lime stone powder are selected and tested by design factors including water cement ratio, fine and coarse aggregate volume ratio. As test results of this study, the optimum mix proportion for binder types is as followings. 1) One type based belite cement ; water cement ratio $51^{\circ}C$, fine aggregate volume ratio $43^{\circ}C$ and coarse aggregate volume ratio $53^{\circ}C$, replacement ratio of LSP $42.7^{\circ}C$. 2) Another type based slag cement : water cement ratio $41^{\circ}C$, fine aggregate volume ratio $47^{\circ}C$ and coarse aggregate volume ratio $53^{\circ}C$, replacement ratio of LSP $13.5^{\circ}C$.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.249-254
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• 2003

The thermal coefficient of concrete is measured using dilatometer (AASHTO TP60) and strain gage. Testing parameters such as six different coarse aggregate types, cycles of warming and cooling, specimen shape and measurement types were investigated to evaluate the influencing factors for thermal coefficient of concrete. According to experimental results, the thermal coefficient of concrete made with crushed aggregate showed 9.2 -10.$\mu\varepsilon/^{\circ}C$, , however recycled coarse aggregate classified type II showed a little increasing in comparison with crushed aggregate. The thermal coefficient of concrete made with recycled aggregate was reduced 0.2-0.4$\mu\varepsilon/^{\circ}C$, under temperature cycles. However, specimen shapes were revealed as mainly affecting factors on the thermal coefficient of concrete. Finally the thermal coefficient value determined by the dilatometer device was shown to be similar to the value from PML 60.

• Journal of Life Science
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• v.23 no.2
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• pp.319-323
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• 2013

Protein aggregation can cause diseases and hinder the production of useful recombinant proteins. The present study showed that at least three types of aggregates can be formed from tryptophan synthase ${\alpha}$-subunit (${\alpha}TS$) by varying conditions: (1) an opaque white precipitous aggregate, (2) a transparent gel-like precipitous aggregate, and (3) an unprecipitous aggregate. Macroscopically different aggregate types might suggest different mechanisms underlying aggregation processes.

• Computers and Concrete
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• v.19 no.1
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• pp.33-39
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• 2017

In this study, two types of aggregate were used for making self-compacting concrete. Standard cubic specimens were exposed to different temperatures. Seventy-two standard cylindrical specimens ($150{\times}300mm$) and Seventy-two cubic specimens (150 mm) were tested. Compressive strengths of the manufactured specimens at $23^{\circ}C$ were about 33 MPa to 40 MPa. The variable parameters among the self-compacting concrete specimens were of sand stone type. The specimens were exposed to 23, 100, 200, 400, 600, and $800^{\circ}C$ and their mechanical specifications were controlled. The heated specimens were subjected to the unconfined compression test with a quasi-static loading rate. The corresponding stress-strain curves and modulus of elasticity were compared. The results showed that, at higher temperatures, Scoria aggregate showed less sensitivity than ordinary aggregate. The concrete made with Scoria aggregate exhibited less strain. The heated self-compacting concrete had similar slopes before and after the peak. In fact, increasing heat produced gradual symmetrical stress-strain diagram span.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.71-72
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• 2015

As this study is the one related to the ultra high strength concrete essentially used for high rise buildings, it has analyzed on the flowability of ultra high strength concrete according to the variation of coarse aggregate and fine aggregate. The coarse aggregate was planned as two types including Granite Aggregate (GA) and crushed coarse Limestone Aggregate (LA) while fine aggregate was planned as four types including Sea Sand (SS), Limestone Crushed Fine Aggregates (LFA), Electric Arc Furnace Oxidizing Slag Aggregates (EFA) and Crushed Sand (CS) to perform experiment with a total of eight variables. As a result of analyzing slump flow, 500mm concentration time, U-Box and L-Flow, etc. among the characteristics of fresh concrete, a mix using LA+LFA is determined to show high flowability in case of applying ultra high strength concrete.

• International Journal of Highway Engineering
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• v.13 no.1
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• pp.169-175
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• 2011

Strength is one of the very important factors to evaluate the physical properties of concrete. Aggregate forms the most parts in concrete. Cement as a binder in concrete is also closely related to strength. This experiment was tested to understand the effect of the characteristics of aggregate and cement on the relationship between concrete compressive strength and Shear Wave velocity. It was experimented by the different types of cement and maximum coarse aggregate sizes. Type I cement and rapid setting cement was used. Aggregates from three different regions were used. Aggregate of 19mm and 13mm maximum coarse aggregate sizes was used for grading. The relationship between compressive strength and Shear Wave velocity was tested under the condition of same mixture. LA wear test was used to quantify the characteristics of aggregate. As a result, the relationship between concrete compressive strength and Shear Wave velocity was affected by the types of cement, but regular relationship was appeared regardless of types of aggregate, grading and abrasion ratio.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.11a
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• pp.235-236
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• 2011

This study analyzed flowing and strength properties of mortar depending to fine aggregate types and replacement ratio by using blast furnace slag, red mud, and silica fume that are industrial by products. The findings showed that higher replacement level of fine aggregate increased air content while decreased table flow. In addition, compressive strength showed that the higher replacement level was regardless of fine aggregate types, the lower strength became. Mortar substituted by the dredged sand showed high strength.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.332-333
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• 2018

The master plan for aggregate supply and demand aims to ensure the feasibility viability of mid/long-term aggregate supply and demand by establishing comprehensive plans for regional groups and aggregate types. In addition, It will propose ways to reduce the environmental impact of the development of aggregates and to stabilize aggregate supply and demand across the country. Also, it will seek to promote the stable development of the construction industry through policy and related amendments.