• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.4
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• pp.596-603
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• 2020

In this paper, an experimental study was conducted to investigate the applications of bottom ash, which is an industrial by-product obtained from thermal power plants. Bottom ash was used as fine aggregate in this study, and an experiment was conducted to determine the characteristics of the bottom ash aggregate. In addition, 25, 50, 75, and 100% contents of crushed (natural) fine aggregate were replaced with bottom ash aggregate to produce concrete mixture including bottom ash. Thereafter, test results of the unit weight, ultrasonic velocity, compressive strength, and thermal conductivity of bottom ash concrete were obtained. Moreover, the effect of the curing ages of 28 and 91 days on the material characteristics of bottom ash concrete were identified. Test results showed that bottom ash used as fine aggregate had pozzolanic reaction. Finally, based on the extensive experimental results, relationships between thermal conductivity and unit weight, ultrasonic velocity, and compressive strength was suggested.

• Magazine of RCR
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• v.12 no.3
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• pp.8-13
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• 2017

• Magazine of RCR
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• v.12 no.3
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• pp.14-22
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• 2017

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.3
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• pp.122-129
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• 2016

In this study, we developed a pressing device which can reproduce the pressure of concrete inside the conveying pipe as a part of the basic study to development of high fluidity concrete under high pressure pumping. Using this pressing device, we evaluated a absorption properties of aggregate that are crushed coarse aggregate, river gravel and lightweight coarse aggregate according to pressure of coarse aggregate and aggregate inside a high fluidity concrete, focused on the reduction of unit water quantity by pressure. In addition, it was evaluated the compressive strength of high fluidity concrete about before and after of pressive. Test a result, case of condition under the high pressure of 250 bar, absorption ratio of crushed coarse aggregate and river gravel were not increased above the surface absorption, absorption ratio of lightweight coarse aggregate was increased than the surface absorption.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.3
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• pp.216-223
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• 2019

The objective of this study is to propose a reliable stress-strain model in compression for lightweight concrete using bottom ash aggregates and air foam(LWC-BF). The slopes of the ascending and descending branches in the fundamental equation form generalized by Yang et al. were determined from the regression analyses of different data sets(including the modulus of elasticity and strains at the peak stress and 50% peak stress at the post-peak performance) obtained from 9 LWC-BF mixtures. The proposed model exhibits a good agreement with test results, revealing that the initial slope decreases whereas the decreasing rate in the stress at the descending branch increases with the increase in foam content. The mean and standard deviation of the normalized root-square mean errors calculated from the comparisons of experimental and predicted stress-strain curves are 0.19 and 0.08, respectively, for the proposed model, which indicates significant lower values when compared with those(1.23 and 0.47, respectively) calculated using fib 2010 model.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.11a
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• pp.73-77
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• 2008

Structural lightweight concrete will reduced total loads of supporting sections and foundations in archtectural and civil structures. So, the lightweight concrete can be used widely for various purpose in the archtectural and civil structures. This paper were examined the influence of the mixing factor on the fresh and hardened properties of lightweight concrete that are used 2types of the differences properties of lightweight aggregates. According to types of lightweight aggregates, the case of synthetic lightweight aggregate are have need higher s/a; 2~4% on mixing proportion. Lightweight concrete was somewhat exhibit lower compressive strength than ordinary concrete. However it was not showed a marked difference. According to types of lightweight aggregates, the case of synthetic the lightweight aggregate are highest performance in fresh and hardened concrete.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.218-219
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• 2018

This study analyzed the unit weight and compressive strength properties of lightweight concrete using high volume blast furnace slag powder by the mixing ratio of lightweight coarse aggregate to investigate the properties of lightweight concrete using domestic artificial lightweight aggregate.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.11a
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• pp.113-116
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• 2008

In these days, properties of concrete has been demanded to be high performance because concrete structure was bigger and higher. So studies on high strength concrete and lightweight concrete has been frequently done. But lightweight concrete has been used to limited non-structural elements in th country. Lightweight aggregate mixed with lightweight concrete was only coarse aggregate in case of the structural lightweight concrete. In the country studies on the lightweight concrete was poor and unvaried. Also it is difficult to be practical use of lightweight concrete was that it has been expensive. It was study on the using fine lightweight aggregate with lightweight concrete to crushed by-products and wastes to get to make foamed glass with recycled glass. So it was tested by fine aggregate standard and mixed with.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2006.05a
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• pp.23-26
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• 2006

The study about the concrete to use recently a light weight aggregate, processed actively. And concrete pumping with a high pressure pump has been popularized, the mechanical development, such as high pressure pumps or pipes, is progressing rapidly. Concrete placing by pumping has the advantage of the reduction of the construction period with workability, easiness of work and the increase of placing, but the quality variation of concrete is caused by pumping is seldom considered, including the increase of the pipe length by high-rising and large-sizing, there by the loss of the unit quantity of water, with pumpability or workability deteriorated. In this research, we will compare and analyze before pumping and after pumping samples of ready-mixed light weight concrete. The result of study as follow. The case of a light weight concrete which the low slump is more decrement compared with high slump light weight concrete in after pumping samples. After pumping the water by pressure of a pump was absorbed to the aggregate inside, and it showed an increase of compression strength about $5{\sim}20%$.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.4A
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• pp.385-393
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• 2009

This study grasped the relationship between relative humidity in concrete and concrete shrinkage followed by pre-absorbed water of porous lightweight aggregates through measurements of concrete shrinkage and humidity and comparisons with established research results. It was showed that shrinkage reduction effect of lightweight concrete is 36% at 7 days early ages and 25% at 180 days long-term ages when water-binder ratio is 0.3. It also showed that shrinkage reduction effect is 19% at 7 days and 16% at 180 days when water-binder ratio is 0.4 and 37%, 32% when water-binder ratio is 0.5. The moisture supply effect of lightweight aggregates was remarkable at early age within 7~10 days irrespective of water-binder ratio. In case of waterbinder ratio is 0.3, the relationship between shrinkage and internal humidity of concrete has been underestimated regardless of applied existing model type and in case of water-binder ratio is 0.4, 0.5, measurement values are relatively similar with existing model equations. Finally this study did regression analyses about the relation among the humidity change and the shrinkage strain as a high-degree polynomial and derived parameters that can connect moisture movement analysis with differential shrinkage analysis in case of considering relative humidity at the time by moisture movement analysis of concrete.