• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.242-243
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• 2014

In this study, industrial by-products including blast furnace slag, incineration ash and waste gypsum were used with recycled fine aggregates to manufacture the zero-cement mortar. The replacement ratio of anhydrite gypsum was fixed as 0, 10%, 20% the replacement ratio fo WA1 was fixed as 0.5% and 1.0%, respectively. It could be identified that when the replacement of gypsum was 20% and WA1 of 1.0%, the strength could be in the range of normal strength.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.222-223
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• 2014

In this study, industrial by-products including blast furnace slag, incineration ash and waste gypsum were used with recycled fine aggregates to manufacture the zero-cement mortar.The replacement ratio of dihydrate gypsum and anhydrite gypsum was fixed as 0 and 10%, the replacement ratio fo WA1 was fixed as 0.5% and 1.0%, respectively. It could be identified that when the replacement of gypsum was 10% and WA1 of 1.0%, the strength could be in the range of normal strength.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.773-776
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• 2006

This experimental study is the fundamental report to use the ternary concrete. This study performed to know physical properties of ternary concrete according to replacement ratio of pozzolanic admixtures and curing temperature conjugation. To investigate Strength development properties of according to replacement ratio of pozzolanic admixtures, both fly ash replaced on portland cement in 5, 10 and 15% weight ratios and blast furnace slag replaced on the portland cement in 5, 15, 20, 30 and 40% weigt ratios was used. Also this is studied fresh and hardened concrete properties in condition of curing temperature $10^{\circ}C\;and\;20^{\circ}C$. The followings are the summary of which concluded in this study. Considering the concrete cured over 28 days compressive strength, most replacement ratios of pozzolanic admixtures were higher than plain concrete that. Compressive strength development properties of ternary concrete according to curing temperature conjugation were similar except for early age.

• Journal of the Korea Concrete Institute
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• v.13 no.3
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• pp.237-243
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• 2001

The prediction model is proposed to estimate the variation of compressive strength of fly ash concrete with aging. After analyzing the experimental result with the model, the regression results are presented according to fly ash replacement content and water-cement ratio. Based on the regression results, the influence of fly ash replacement content and water-cement ratio on apparent activation energy was investigated. According to the analysis, the model provides a good estimate of compressive strength development of fly ash concrete with aging. As the fly ash replacement content increases, the limiting relative compressive strength and initial apparent activation energy become greater. The concrete with water-cement ratio smaller than 0.40 shows that the limiting relative compressive strength and apparent activation energy are nearly constant according to water-cement ratio. But, the concrete with water-cement ratio greater than 0.40 has the increasing limiting relative compressive strength and apparent activation energy with increasing water-cement ratio.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2002.05a
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• pp.57-60
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• 2002

Recently, the coal ash production has been increased by increase of consumption of electric power. So it is important to find a reclaimed place and treatment utility for treating coal ash. Accordingly, in this study we performed an experimental study to compare and analyze the Properties of concrete according to W/C and bottom ash replacement ratio. As a result of this study, it was found that the bleeding content was decreased according to decrease of W/C and increase of bottom ash replacement ratio, and the compressive strength of concrete using bottom ash was similar to plain concrete(replacement ratio 0%).

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.10a
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• pp.26-27
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• 2016

This study analyzes the engineering characteristics of mortar according to admixture replacement ratios in cement mortar in a high-intensity ternary system, and changes in FA and BS combination ratios, in order to deduce the optimal combination ratio of FA and BS. Results showed that due to the characteristics of unhardened mortar, flow rate increased with the increase in admixture replacement and FA combination ratios, whereas air quantity decreased and setting time was delayed. Due to the characteristics of light mortar, compression strength decreased at early material ages as the overall combination ratio of FA increased. The FA : BS combination ratio was 2 : 3 on day 28 of material age, proving the best and potentially optimal combination ratio.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.108-112
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• 2005

In this research, the physical properties of fresh concrete using lime stone powder as a part of cement were investigated. Fresh concrete using lime stone powder was prepared with various lime stone powder replacement($5{\sim}12$ volume %) for cement and the quantities of sand aggregate ratio in concrete were 47.3%, 48.5% and 49.4% of ratio of sand aggregate. The workability, flowing characteristics, air content and bleeding of concrete using lime stone powder were tested and the results were compared with those of ordinary portland cement concrete. In the experiment, we acquired satisfactory results at the point of fresh concrete characteristics using lime stone powder within the replacement ratio of $8{\sim}12%$ and the optimum quantity of sand aggregate ratio in concrete was found to be $48.5%{\sim}50%$ of ratio of sand aggregate.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.10a
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• pp.232-238
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• 1996

In this paper, the properties of high-strength concrete are described with respect to materials and mix conditions(water-cement ratio, chemical admixture, replacement of fly ash). As primary purposes of this study, the optimum mix design method of high-strength concrete to decrease unit cement contents is investigated, and the properties of fresh and hardened concretes are tested in terms of slump, air content and compressive strength. As results of this study, workability and strength development of the high-strength concrete depend on the water-cement ratio, replacement ratio of fly ash and dosage of the chemical admixture. The conditions which are proposed optimum mix design of the high-strength concrete show W/C 37%, S/A 42~45% and unit cement content 470~480kg/$\textrm{m}^3$. Based on the results, the applicability of high-strength concrete in site is clearly proved.

• Journal of the Korean GEO-environmental Society
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• v.15 no.8
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• pp.51-58
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• 2014

In this research, the composite grounds including original clay and soil-cement were constructed for conducting uniaxial compression test. Strength and deformation properties were analysed using results of laboratory tests with variations of water content of clay, replacement ratio and cement content. Numerical simulation using 3D distinct element method was conducted for soil cement. For strength of composite ground that contains more than cement contents of 15 %, it is more effective to increase cement content than increase of replacement ratio. Strength and elastic modulus of composite ground could be predicted by regression equations using uniaxial compression strength of clay, cement content of soil cement and replacement ratio. For strength and elastic modulus of soil cement, which is most important things for predicting final strength and elastic modulus of composite ground, numerical simulation using the distinct element method adapted bonding model could be used to verify laboratory test, and predict strength and elastic modulus.

• Journal of the Korea Concrete Institute
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• v.21 no.1
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• pp.55-64
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• 2009

This study is aimed to derive the optimum mix proportion of the combined self compacting concrete according to cement types (blast-furnace slag cement and belite cement) and to propose the basic data to field construction work after evaluating the quality properties. Specially, lime stone powder (LSP) as binder and viscosity agent are used in the combined self compacting concrete because slurry wall of an underground LNG storage tank should be kept stability of quality during concrete working. Replacement ratio of LSP is determined by confined water ratio test and main design factors including fine aggregate ratio ($S_r$), coarse aggregate ratio ($G_v$) and water-cement ratio (W/C) are selected. Also, quality properties including setting time, bleeding content, shortening depth and hydration heat on the optimum mix proportion of the combined self compacting concrete according to cement type are compared and analyzed. As test results, the optimum mix proportion of the combined self compacting concrete according to cement type is as followings. 1) Slag cement type-replacement ratio of LSP 13.5%, $S_r$ 47% and W/C 41%. 2) Belite cement type-replacement ratio of LSP 42.7%, Sr 43% and W/C 51%. But optimum coarse aggregate ratio is 53% regardless of cement types. Also, as test results regarding setting time, bleeding content, shortening depth and hydration heat of the combined self compacting concrete by cement type, belite cement type is most stable in the quality properties and is to apply the actual construction work.