• International Journal of Concrete Structures and Materials
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• v.10 no.1
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• pp.39-46
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• 2016

In this study, different proportions of glass beads used for road marking were added into the concrete samples to reduce the temperature gradient through the concrete pavement thickness. It is well known that decreasing the temperature gradient reduces the risk of thermal cracking and increases the service life of concrete pavement. The extent of alkali-silica reaction (ASR) produced with partial replacement of fine aggregate by glass bead was investigated and compressive strength of concrete samples with different proportion of glass bead in their mix designs were measured in this study. Ideal results were obtained with less than 0.850 mm diameter size glass beads were used (19 % by total weight of aggregate) for C30/37 class concrete. Top and bottom surface temperatures of two different C30/37 strength class concrete slabs with and without glass beads were measured. It was identified that, using glass bead in concrete mix design, reduces the temperature differences between top and bottom surfaces of concrete pavement. The study presented herein provides important results on the necessity of regulating concrete road mix design specifications according to regions and climates to reduce the temperature gradient values which are very important in concrete road design.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.1A
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• pp.95-100
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• 2009

This study proposed mix proportions of early strength pavement concrete for large size area using calcium nitrate. Therefore, we used type III cement with calcium nitrate. Laboratory tests conducted to air content, slump loss test, setting time test, compressive strength test and flexural strength test. Our early strength pavement concrete mixture proportion proposed in this study for large size area attained the required compressive strength of 21 MPa and a flexural strength of 3.8 MPa, which allowed it to be opened to traffic within 8 hours. Based on test results, we suggested optimum mix proportions of early strength pavement concrete for large size area using calcium nitrate.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10a
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• pp.307-312
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• 1998

Recently the study on high flowing concrete which has high workability and Self-compacting is being proceeded actively in the university and corporative laboratory. There are some cases that has been applied to the field. This high flowing concrete has higher fluidity and segregation resistance than Plain of flowing concrete. And it is being focused as a remarkable know-how which can make high-quality concrete and reduction effect of labor force. This properties of high flowing concrete are influenced by the relationship of several factors; binder content, water binder ratio and unit water content. It is the aim of this study to propose reference data at mix design of high flowing concrete, after comparing and analyzing the fluidity and strength properties of high flowing concrete according to water binder content ratio and unit water content.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.151-154
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• 1999

The lining concrete of water tunnel is a structure that is constructed to prevent from corroding of the rock around tunnel and reduce the deterioration of geology by flowing water, and to improve the durability of tunnel, which must not only economy, stability but also satisfy the engeneering properties of concrete. This is an experimental study to analyze th usability of fly in the tunnel lining concrete. For this purpose, after select the mix proportion of plain concrete and concrete using fly ash(the replacement of 15 and 30% by weight of cement) to satisfy slump, air content and compressive strength through the mix design, the test of slump, setting time, compressive strength, tensile strength, drying shrinkage and adiabatic temperature rise was performed. According to test results, it was found that FA 15 concrete was more effective than the others to reduce drying shrinkage as well satisfy other engineering properties.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10c
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• pp.1-6
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• 1998

Recently, as to destruction and renovation of aged building, waste concretes have been reclaimed near foreshore and filled up underground. Recycling demolished concrete as aggregate helps to settle economic and environmental problems of obtaining superior aggregates from natural sources and to dispose waste concretes. An experimental study was carried out to investigate the strength characteristics of no-fine concrete containing recycled aggregates. The cement-aggregate weight ratios of 1: 5, 1: 6, 1: 7 and water-cement ratios of 30, 35, 40, 45% were chosen for the mix design of no-fine concretes. The compressive and splitting tensile strength at 7 and 28 days were measured for 12 different mixes. On the basis of test results, the optimum mix proportion of no-fine concrete containing recycled aggregates was determined and applied to the production of retaining wall block.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.275-280
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• 2001

Recently, self-compacting concrete is applied in order to achieve workability improvement and rationalization in construction. But self-compacting concrete using viscosity agent has a difficulty in practical use because viscosity agent is invested small quantity and by man-power. Therefore in this paper we have been focused on the development and practical use of self-compacting concrete by hydraulic composition containing the segregation-reducing agent. According to mix variable, we find out right quantity of water, binder and rate of admixture replacement, and also we find out the optimum mix proportion. In the result, self-compacting concrete by hydraulic composition containing the segregation reducing agent gave satisfaction with standard and its demand will increase in the future.

• Advances in materials Research
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• v.4 no.3
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• pp.179-192
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• 2015

The study presents a preliminary investigation on the applicability of Shirasu (a pyroclastic flow deposit characterized by high percentage of volcanic glass) in geopolymer. Comparative study on compressive strength and internal pore structure has been done between geopolymers with alkali activated Shirasu and fly ash as aluminosilicates. Mortar mix proportions are selected based on variations in ratio of alkaline activators to aluminosilicate and also on silica to alkali hydroxide ratio. From the experimental study, Shirasu geopolymer exhibited fairly good compressive strength. Mix proportion based on silica to alkali hydroxide ratio is observed to have profound effect on strength development.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.189-190
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• 2010

Yeoju-Bo is a large massive concrete structures that require the reduction of working period of construction. In this study, we optimized the mix proportion of internal/external concrete and physical properties like compressive strength, semi adiabatic temperature rise in laboratory. And we also performed thermal analysis to verify the thermal cracking. Lastly we measured the hydration heat and the thermal cracking in site to verify the safety of massive concrete structure.

• Journal of the Korean Graphic Arts Communication Society
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• v.28 no.2
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• pp.13-30
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• 2010

Existing domestic ink market had some problem because of dependence on CPP import, increasing cost, competitive price. For this reason, previous speed of research and developments are very slow. Therefore, develop the new waterborne type of non-chlorine resin, enhance the nation's position with manufacturing outstanding products. Through this thesis, the purpose is mix the polar resin and non-chlorine resin with many proportion and manufacturing better product than existing resin. Pilot production samples have run the test of adhesion, transparency, water resist and resist high pressure car washing. In conclusion, this thesis found that mix acryl Urethane resin and Non-Chlorine resin is the optimum condition.

• Journal of the Korea Institute of Building Construction
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• v.12 no.5
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• pp.468-477
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• 2012

This study aimed to mix and test mortar incorporating activated Hwangtoh to improve the Hwangtoh brick bond strength of brick structures. To do this, the bond strength correlation of mortar was analyzed by means of materials and experiment factors and levels, and the optimum conditions were suggested after analyzing the physical properties of brick and the mix ratio of mortar and additive. Furthermore, the compressive strength and bond strength were found to be in inverse proportion, and in terms of the materials and mixing level, W/C ratio, substitution ratio of activated Hwangtoh, and fine aggregate grading were shown to have a considerable influence on the strength. In conclusion, the optimum mixing conditions to improve the bond strength are found to set W/C ratio at 65% and replacmenet ratio of activated Hwangtoh at 10%.