• 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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• 1998.04a
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• pp.63-68
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• 1998

The fluidity of high flowing concrete can be affected by numerous parameters which characterize either the cement of the admixture. The reactivity of a cement as determined by its chemical composition(especially its $C_3$A content), its fineness and its content in sulfates and alkalies obviously plays a key role in rheology of high flowing concrete in fresh state. Specific properties of high range water reducing AE agent used to enhance the workability of high flowing concrete also exert important influence. The purpose of this experimental study is to investigate and analyze the effect of cement and high range water reducing AE agent in fluidity, setting, compressive strength of high flowing concrete. As a result, we found that fluidity of high flowing concrete is affected greatly by kind of cement and high range water reducing AE agent, also, there is harmonic character between high belite cement and polycarbonic acid high range water reducing AE agent.

• Geomechanics and Engineering
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• v.34 no.2
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• pp.155-171
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• 2023

Aiming at the grouting treatment of water inflow in karst conduits, a visualized experiment system for conduit-type grouting blocking was developed. Through the improved water supply system and grouting system, and the optimized multisource information monitoring system, the real-time observation of diffusion and deposition of slurry, and the data acquisition of pressure and velocity during the whole process of grouting were realized, which breaks through the problem that the monitoring element is easy to fail due to slurry adhesion in conventional test system. Based on the grouting experiments in static and flowing water, the diffusion and deposition behavior of the quick-setting slurry under different working conditions were analyzed. The temporal and spatial variation behavior of the pressure and velocity were studied, and the blocking mechanism of the grouting were further revealed. The results showed that: (1) Under the flowing water condition, the counter-flow diffusion distance of slurry was negatively correlated with the flow water velocity and the volume ratio of cement and sodium silicate (C-S ratio), and positively correlated with the grouting volume. The slurry deposition thickness was negatively correlated with the flowing water velocity, and positively correlated with the grouting volume and C-S ratio. (2) The pressure increased slowly before blocking of the flowing water and rapidly after blocking in karst conduits. (3) With the continuous progress of grouting, the flowing water velocity decreased slowly first, then significantly, and finally tended to be stable. According to the research results, some engineering recommendations were put forward for the grouting treatment of the conduit-type water inflow disaster, which has been successfully applied in the treatment project of the China Resources Cement (Pingnan) Limestone Mine. This study provided some guidance and reference for the parameter optimization of grouting for the treatment projects of water inflow in karst conduits.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.04a
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• pp.278-284
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• 1997

This study dealt with the flowing properties of the super flowing concrete for class F fly ash producted thermal power plant and the application for concrete industry. For this purpose, fly ash is analyzed for confined water ratio($\beta_p$)and the super flowing concrete is tested the flowing properties including flowing velocity, funneling time, height difference of box test and compressive strength. As the result, in order to satisfy the flowing properties of the super flowing concrete using class F fly ash, the optimum mixing conditions are determined water-bindrer ratio 37$\pm$2%, volume ratio of fine aggregates(Sr) 47$\pm$2% and coarse aggregates(Gv) 51$\pm$1%.

• Journal of Korean Society of Rural Planning
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• v.29 no.4
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• pp.191-200
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• 2023

This study aims to estimate the value of environmental services that could be generated by seawater flowing in the Geumgang Estuary by using meta-regression for benefit transfer. The environmental services that can be generated by seawater flowing are assumed to be improved water quality, increased biodiversity, and enhanced water-friendly effect. The analysis was conducted using 122 data from 28 studies from EVIS. The results show that households in the neighborhood where seawater is distributed are willing to pay about KRW 46,918, KRW 7,752, and KRW 7,859 per year for improved water quality, increased biodiversity, and enhanced water-friendly, respectively. The WTP of the national households other than neighboring households was found to be KRW 19,401, KRW 3,206, and KRW 3,250 for the three environmental services, respectively. The WTP for water quality improvement is higher than that for biodiversity increase and water-friendly effect increase, which may be due to the fact that water quality improvement is an environmental service that is close to the use value. In addition, neighboring households have a higher WTP than national households because neighboring households are more likely to evaluate the benefits of seawater flowing as a use value, while national households are more likely to evaluate it as a non-use value.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.12 no.2
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• pp.173-180
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• 2012

This paper proposes a novel optimization algorithm inspired by water flowing and shaking behaviors in a vessel. Water drops in our algorithm flow to the gradient descent direction and are sometimes shaken for getting out of local optimum areas when most water drops fall in local optimum areas. These flowing and shaking operations allow our algorithm to quickly approach to the global optimum without staying in local optimum areas. We experimented our algorithm with four function optimization problems and compared its results with those of particle swarm optimization. Experimental results showed that our algorithm is superior to the particle swarm optimization algorithm in terms of the speed and success ratio of finding the global optimum.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.369-374
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• 1997

This study is the experimental results on the flowing properties of the super flowing concrete (SFC) using limestone (LS), which is to develop the SFC in level of ordinary strength. And this study is described with respect to basic concept, confined water ratio ($\beta_p$) of binder (cement+limestone) in paste, relationship between volume ratio of water-binder (w/b) and addition ratio of superplasticizer in mortar, flowing velocity and funneling time and compressive strength in concrete to replacement ratio of LS. The results of this study is improved to flowing properties in fleshly concrete with increasing replacement ratio of LS. The optimal mixing condition of the SFC using LS in level of ordinary strength is proved W/C 55%, LS 40% and W/C 60%, LS 50%.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.3
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• pp.243-251
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• 2007

This experiment was conducted to investigate the effect of particles on the heat transfer characteristics of fluids flowing in a cold water tube. Plastic beads with 3 different sizes were used as flowing particles with cold water. An experimental test section was composed of concentric double tubes having diameters of 25mm for the inner tube and 50mm for the outer tube. The materials for the inner and outer tubes are copper and PVC respectively. It was found that the particles enhanced the heat transfer coefficient by random and vortex motion in the fluid. Hence the heat transfer coefficients for the fluid with 2mm, 5mm and $2{\times}6mm$ particles were $7%{\sim}37%$ higher than the fluid without the particles.

• Journal of the Korea Concrete Institute
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• v.13 no.4
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• pp.329-335
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• 2001

Recently, in many laboratories and institutes it is being studied on the high flowing concrete widely, which has high fluidity, non-segregation ability and fillingability, and sometimes being applied to the construction field actually. And the fluidity properties of high flowing concrete are influenced according to the several factors ; binder content, water/binder ratio and water content etc. This is an experimental study to compare and analyze the effect of water/binder ratio and water content on the properties of high flowing concrete. For this purpose, the mix proportion of high flowing concrete according to water/binder ratio(W/B : 0.30, 0.35, 0.40, 0.45) and water content (W : 155, 165, 175, 185 kg/㎥) was selected. And then slump-flow, V-lot, L-passing test in fresh concrete, and compressive strength, freezing and thawing test in hardened concrete were peformed. According to test results, it was found that the viscosity of all those high flowing concrete with the water content 175 kg/㎥ was satisfied with 50 cm pass time of slump flow prescribed by Japanese Architectural Standard Specification (JASS 5) - from 3 to 8 seconds. And non-segregation ability of concrete with W/B 0.35 was better than the other mix proportions. Especially, the compressive strength after curing 24 hours(1 day) of all high flowing concrete was higher than that prescribed by JASS 5(50 kgf/㎠).

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04a
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• pp.3-8
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• 1998

This research is to examine the relationships between viscosity and fluidity according to binders in the super flowing concrete. And this research is described with respect to rheology concept, confined water ratio($\beta_p$) of binders in paste and mortar, also investigated experimentally the relationships between the relative flowing ratio ($\Gamma_m$) and the funneling velocity ratio($R_m$) on the mortar state according to the water binder ratio(W/B) and the dosage of the superplasticizer. From the confined water ratio tests, it is found that $\beta_p$ of the class C fly ash is higher than that of the class F fly and limestone in paste and mortar, therefore class F fly ash and limestone and super flowing concrete. The result of test, the optimum mix condition to the compactibility if satisfied when the replacement ratio is 30% and $K_p$ is 0.8 for the case of fly ash and limestone.