• 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.

• Journal of the Korea Concrete Institute
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• v.17 no.2 s.86
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• pp.293-302
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• 2005

This study describes data from determination of the optimum mix proportion and site application of the mass concrete placed in bottom slab and side wall having a large depth and section as main structures of LNG in-ground tank. This concrete requires low heat hydration, excellent balance between workability and consistency because concreting work of LNG in-ground tank is usually classified by under-pumping, adaptation of longer vertical and horizontal pumping line than ordinary pumping condition. For this purpose, low heat Portland cement and lime stone powder as cementitious materials are selected and design factors including unit cement and water content, water-binder ratio, fine aggregate ratio and adiabatic temperature rising are tested in the laboratory and batch plant. As experimental results, the optimum unit cement and water content are selected under $270kg/m^3$ and $l55{\~}l60 kg/m^3$ separately to control adiabatic temperature rising below $30^{\circ}C$ and to improve properties of the fresh and hardened concrete. Also, considering test results of the confined water ratio($\beta$p) and deformable coefficient(Ep), $30\%$ of lime stone powder by cement weight is selected as the optimum replacement ratio. After mix proportions of 5cases are tested and compared the adiabatic temperature rising($Q^{\infty}$, r), tensile and compressive strength, modulus of elasticity, teases satisfied with the required performances are chosen as the optimum mix design proportions of the side wall and bottom slab concrete. $Q^{\infty}$ and r are proved smaller than those of another project. Before application in the site, properties of the fresh concrete and actual mixing time by its ampere load are checked in the batch plant. Based on the results of this study, the optimum mix proportions of the massive concrete are applied successfully to the bottom slab and side wall in LNG in-ground tank.

• Food Science of Animal Resources
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• v.18 no.3
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• pp.203-208
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• 1998

The study was carried out to screen mutagenicity of smoking materials for the determination of optimum smoking temperature for meat products. Wood materials employed for smoking were oak and apple trees. Temperatures of the generator for manufacturing of smoke flavoring were set to 250$^{\circ}C$, 400$^{\circ}C$ and 500$^{\circ}C$, respectively. Mutagenic activities of smoke flavoring were assayed according to Ames test using Salmonella typhimurium TA98 and TA 100. In oak wood smoke flavoring, Salmonella typhimurium TA98 without S-9 mix showed strong mutagenic activities at the concentration of 6$\mu\textrm{g}$/plate(250$^{\circ}C$), 4$\mu\textrm{g}$/plate(400$^{circ}C$) and 6$\mu\textrm{g}$/plate(500$^{\circ}C$). Salmonella typhimurium TA100 with S-9 mix showed strong mutagenic activities at the concentration of 10$\mu\textrm{g}$/plate(250$^{\circ}C$), 20$\mu\textrm{g}$/plate(400$^{\circ}C$) and 10$\mu\textrm{g}$/plate(500$^{\circ}C$). Salmonella typhimurium TA98 with S-9 mix showed strong mutagenic activities at the concentration of 30$\mu\textrm{g}$/plate(250$^{\circ}C$), 40$\mu\textrm{g}$/plate(400$^{\circ}C$) and 20$\mu\textrm{g}$/plate(500$^{\circ}C$). Salmonella typhimurium TA100 with S-9 mix showed strong mutagenic activities at the concentration of 30$\mu\textrm{g}$/plate(250$^{\circ}C$), 50$\mu\textrm{g}$/plate(400$^{\circ}C$) and 20$\mu\textrm{g}$/plate(500$^{\circ}C$). Salmonella typhimurium TA100 without S-9 mix showed strong mutagenic activities at the concentration of 10$\mu\textrm{g}$/plate(250$^{\circ}C$), 20$\mu\textrm{g}$/plate(400$^{\circ}C$) and 20$\mu\textrm{g}$/plate(500$^{\circ}C$). Salmonella typhimurium TA98 with S-9 mix showed strong mutagenic activities at the concentration of 30$\mu\textrm{g}$/plate(250$^{\circ}C$), 40$\mu\textrm{g}$/plate(400$^{\circ}C$) and30$\mu\textrm{g}$/plate(500$^{\circ}C$). Salmonella typhimurium TA100 with S-9 mix showed strong mutagenic activities at the concentrations 30$\mu\textrm{g}$/plate(500$^{\circ}C$). Salmonella typhimurium TA100 with S-9 mix showed strong mutagenic activities at the concentration of 30$\mu\textrm{g}$/plate(250$^{\circ}C$), 20$\mu\textrm{g}$/plate(400$^{\circ}C$) and 30$\mu\textrm{g}$/plate(500$^{\circ}C$). From these results, it could be concluded that optimum smoking temperature for meat products should be set below 400$^{\circ}C$, that the compounds like benzo[a]pyrene etc. contain a variety of mutagenic potentials, which could be generated at the higher smoking temperature.

• Advances in concrete construction
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• v.7 no.4
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• pp.263-275
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• 2019

In the present work, Granulated Blast Furnace Slag (GBFS) and Fly ash (FA) were used as partial replacement of Natural Sand (NS) and Ordinary Portland Cement (OPC) by weight. One control mix, one with GBFS, three with FA and three with GBFS-FA combined mixes were prepared. Replacements were 50% GBFS with NS and 20%, 30% and 40% FA with OPC. Preliminary investigation on development of compressive strength was carried out at 7, 28 and 90 days to ensure sustainability of waste materials in concrete matrix at room temperature. After 90days, thermo-mechanical study was performed on the specimen for a temperature regime of $200^{\circ}-1000^{\circ}C$ followed by furnace cooling. Weight loss, visual inspection along with colour change, residual compressive strength and microstructure analysis were performed to investigate the effect of replacement of GBFS and FA. Although adding waste mineral by-products enhanced the weight loss, their pozzolanicity and formation history at high temperature played a significant role in retaining higher residual compressive strength even up to $800^{\circ}C$. On detail microstructural study, it has been found that addition of FA and GBFS in concrete mix improved the density of concrete by development of extra calcium silicate gel before fire and restricts the development of micro-cracks at high temperature as well. In general, the authors are in favour of combined replacement mix in view of high volume mineral by-products utilization as fire protection.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1208-1213
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• 2011

The objective of this study is to analyze rut resistance and moisture susceptibility of warm mix asphalt(WMA) mixture. The deformation strength ($S_D$), which is known to have high correlations with the high-temperature deformation resistance of dense grade mixture, was used as a tool, together with wheel tacking (WT) test, for evaluating warm mix asphalt mixture's rut resistance.

• Bulletin of the Korean Mathematical Society
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• v.49 no.2
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• pp.319-327
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• 2012

The equations of a multifluid interpenetration mix model are analyzed. The model is an intermediate mix model in the sense that it is defined by partial pressures but only a single global pressure and a single global temperature. It none-the-less avoids the stability difficulty. It is shown that the model is hyperbolic so that it is mathematically stable.

• The Journal of the Korean dental association
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• v.10 no.8
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• pp.531-534
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• 1972

The author measured exothermic temperature of the 5 kinds of zinc phosphate cement and 3 kinds of copper phosphate cement during setting process. Cements were mixed on the glass slab with flexible steel spatula at room temperature (25.8℃) for one minute (spatulating speed was 100 strokes per minute) and placed in the incubator of which temperature was held at 37℃ and thermometer was inserted into the cement mass. The powder liquid ration was 3.0gm:1ml and 1.5gm:1ml. The results were as follows. 1) The heat generated after mixing these cements was under 47.22℃. 2) The range of thermal change of the zinc phosphate cements during setting process was wider than copper phosphate cements. 3) The exothermic temperature from the thin mix was higher than thick mix. 4) The exothermic temperature of the zinc phosphate cements was higher than copper phosphate cements.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.148-151
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• 2004

The hardening of concrete after setting is accompanied with nonlinear temperature distribution caused by development of hydration heat of cement. Especially at early ages, this nonlinear distribution has a large influence on the tensile cracking. As a result, in order to predict the exact temperature distribution in concrete structures it is required to examine thermal properties of concrete. In this study, the coefficient of air convection for concrete mix of nuclear power plant, which presents thermal transfer between surface of concrete and air, was experimentally investigated with variables such as velocity of wind and types of form. The coefficient of air convection obtained from experiment increases with velocity of wind, and its dependance on wind velocity is varied with types of form. This tendency is due to a combined heat transfer system of conduction through form and convection to air. The coefficient of air convection for concrete mix of nuclear power plant obtained from this study was well agreed with the existing models.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.273-276
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• 2004

Recently. cold weather constructions were popularized because of the importance of construction term. The special method about mix design and curing of concrete was being planned to conduct cold weather constructions, but these method were not considered in a low temperature time. A Strength revelation of concrete is delayed in a curing condition of low temperature. If a construction was loaded in this case, cracks or remaining deformations are generated in a construction. So, a strength revelation characteristic in early age was investigated to secure early strength of concrete in curing condition of a low temperature. In this study, the method about concrete mix design was presented to secure construction safety in a low temperature time.

• Journal of the Society of Disaster Information
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• v.9 no.1
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• pp.56-64
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• 2013

The study examines the quiet pavement using fine-size aggregates and warm-mix technique to reduce traffic noise. In order to evaluate the quality of pavement, mix design and laboratory tests were carried out. Test results showed that using 10mm aggregates can reduce the cantabro loss compared with 13mm aggregates due to increase contact area between aggregates. Mixing and compaction temperatures of warm mix quiet pavement should be determined by gyratory compactor test because it is used high viscosity asphalt binder. Using warm-mix additive could reduce compaction temperature by about $15^{\circ}C$. Noise measurement and permeability tests were conducted at the test road for evaluation of the field performance. All of quiet pavements meet the standard of permeability and have sufficient porosity. Noise reduction of the quiet pavement using fine-size aggregates is more effective than that using 13mm aggregates. In particular, the effect of noise reduction was noticeable at low speeds.