• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.21-24
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• 2006

An experimental investigation was earned out to evaluate the fire performance of high strength concrete column made with different section size. Two different high strength concrete columns measuring 3,428mm in height and with the same tie spacing of 150mm were prepared to evaluate the effect of section size of $305{\times}305mm$ and $500{\times}500mm$ on the fire resistance. Compressive strength was 138MPa at the time of fire resistance fire testing. Based on the test result, fire resistance of column with the larger section of $500{\times}500mm$ exhibited the better performance than that of the smaller section of $305{\times}305mm$. The former withstood against the very high temperature over 240minutes, while the latter resisted during 176minutes.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.349-352
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• 2006

Pull-off test is generally used as a method of evaluating bond strength of FRP with concrete at the job site. However, pull-off test damages FRP composites and the maximum pull-off strength is limited up to tensile strength of concrete. Accordingly, it is required to set-up a test method that can simply evaluate bond performance of structural adhesive. This study suggested compression and bending test of epoxy resin as test methods that can indirectly evaluate performance of adhesive, as well as standardized test specification for different types of specifications from various countries. In this study, the section dimension of compression and bending test specimens is unified, and standard test specimen size is achieved by test results.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.369-370
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• 2009

This study aims to find an optimum mix proportions for high-performance shotcrete using industrial by-product from power plants. Compressive strengths of various mix proportions with varying amount of fly ash were verified if they meet the required limits.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.563-564
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• 2009

Ultra-High Performance Concrete (UHPC) compared to normal concrete is exhibiting extremely high strength characteristics with compressive strength and tensile strength reaching 200MPa and 15MPa, respectively. The mechanical characteristics of UHPC can be thus exploited advantageously in the construction of structure through the reduction of the cross-sectional area and fabrication of slim and light-weight of the structural members. In the case where the structural member is made of UHPC, the occurrence of crack can be prevented by releasing the restraint provided by the form in due time. This research performs parametric study of the failure characteristics of concrete such as failure energy and softening curve suggested by the viscous crack model approximating the failure of concrete. The scope of this research contains the results of tests performed to investigate the strength of UHPC during early elapsed time.

• International Journal of Concrete Structures and Materials
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• v.1 no.1
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• pp.57-61
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• 2007

This study investigated the mechanical and durability performance of roller-compacted concrete (RCC) with fly ash for dam applications. A test program studied the effects on the properties of fresh and hardened RCC with fly ash replacement ratio, as well as the long-term durability of the resulting mixture. Fly ash replaced 20, 30, 40, and 50% by mass of the cement. Laboratory tests of the compressive strength, splitting tensile strength, shear strength, chloride ion permeability, abrasion, and drying shrinkage were conducted. The test results demonstrated that 30% fly ash replacement is an optimum level, and that this mixture has excellent mechanical and durability properties.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.136-137
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• 2014

In this study, fundamental performances of high strength concrete with ERCO has been analysed according to mock-up test. The following results could be made as the conclusion. For the fresh concrete, flowability and air content decreased with the addition of ERCO, and all the specimens satisfied the target range. For the strength properties, all the specimens with different nominal strength showed higher compressive srength than Plain which with 0% dosage of ERCO.

• Journal of the Korean Ceramic Society
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• v.33 no.5
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• pp.519-523
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• 1996

Calcium hydroxide produced by cement hydration decreases the durability and the compressive strength of cement mortars. Pozzolanic property of meta kaolin and silica fume allows to avoid this drawback. Calcium hydroxide consumption according to pozzolanic raction is evaluated by Fourier differential thermal analysis. Particulary the properties of high performance and high strength of cement mortar containing above 10% meta kaolin and silica fume were resulted in the pozzolanic activity.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.10a
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• pp.185-188
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• 2004

Regarding some of the components of the Korean Tilting Train eXpress(TTX), the lightweight-vehicle development was mainly focused to this study, and so as using the materials, the existing material, steel or aluminum carbody was changed to the composite carbody with both design and manufacturing methods. Therefore the evaluation of the performance of joint strength between composite and metallic boundary area, especially the under frame and the carbody was required, and the compressive and the bending tests were conducted as the sub-scale specimen. In this evaluation, there was involved the sufficient strengths at the joint area between the underframe and the carbody, and is resulted as the increment of the safety factor through the observation of failure conditions.

• 한국도로학회:학술대회논문집
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• 2010.09a
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• pp.99-107
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• 2010

A permanent deformation model was developed in this study based on the shear properties of asphalt mixtures such as cohesion and friction angle. Triaxial compressive strength (TCS) and repeated load permanent deformation (RLPD) tests on the three types of asphalt mixtures are performed at various loading and temperature conditions to correlate shear properties of asphalt mixtures to rutting performance. It is observed from the tests results that the ratio of shear stress to strength accurately identifies the mixture rutting performance. It could take care of not only mixture types but also load and temperature conditions dependences. Three different versions of the permanent deformation model based on different input levels are proposed and verified using the tests data. The proposed model based on the ratio of shear stress to strength can successfully predict the permanent deformation of various asphalt mixtures all the way up to the 10% of permanent strain including all three stages of permanent deformation in a wide range of loading and temperature conditions without changing model coefficients.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.408-415
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• 1997

Bond strength of reinforcing bar to high-performance concrete using Belite cement is explored using beam end test specimen. The key parameters for the bond test are slump of concrete, top bar effect, and strength of concrete in addition to concrete covers. Specimen failed in the typical brittle bond failure splitting the concrete cover as the wedging action. The test results show that for the group with portland cement I using superplasticizer additional slump does not decrease the bond strength of the top bar is less than bond strength of bottom bar, but the top bar factor satisfy the modification factor for top reinforcement. The result also show that bond strength is function of square root of concrete compressive strength and cover thickness. More detailed evaluation will be conducted from the test specimen with high strength concrete using the belite cement.