• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.271-272
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• 2010

This thesis is researched to compare the shrinkage of lightweight concrete depending on depth to normal concrete. It is used artificial lightweight aggregate which has 20% of pre-absorb value by lightweight concrete. When water-binder ratio is 30%, average shrinkage of lightweight concrete section decreased than normal concrete, but differential shrinkage of lightweight concrete section increased. However water-binder ratio is 40%, average shrinkage and differential shrinkage of lightweight concrete section decreased than normal concrete.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.546-549
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• 2010

현대사회에서 점차 경량콘크리트의 활용도에 대한 관심이 높아지고 있으나 이에 관한 연구실적은 아직까지 미비하다. 경량콘크리트는 그 특성상 가벼운 자중과 높은 에너지 흡수성을 가지고 있다는 점에서 방호벽에 적용 가능한 재료로 볼 수 있다. 이에 본 연구에서는 이러한 점을 고려하여 경량 방호벽에 대한 컴퓨터 시뮬레이션을 통한 경량콘크리트 방호벽의 거동해석을 수행하였으며, 이를 위해 미세역학기반 경량콘크리트 모델을 상용 유한요소 프로그램인 ABAQUS에 적용하여 경량콘크리트 압축공시체에 관한 해석을 선 수행하였다. 이를 통해 도출된 손상변수를 통하여 실제 방호벽에 대한 정적 하중 시뮬레이션을 수행하였다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.6
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• pp.112-121
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• 2013

FRP reinforced lightweight concrete structures can offer corrosion resistance and weight reduction effect simultaneously, so practical use of the structures may be expected afterwards. But to make concrete structures using lightweight concrete and FRP bar, that can resist external forces without internal slip of the FRP bar, it is very important to understand bond characteristic between lightweight concrete and FRP bar. During that time, a lot of studies for bond behaviors of FRP bar in normal concrete were conducted, but studies for bond behavior of FRP bar in lightweight concrete are very limited to date. So, bond characteristic between lightweight concrete and helically deformed GFRP bar was investigated in this study. Three main parameters were considered in experimental investigation: type of rebar, concrete type, and compressive strength of lightweight concrete. As an experimental result, it could be known that bond strength of helically deformed GFRP bar in lightweight concrete was 0.49 times bond strength of steel reinforcement in normal concrete.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.377-380
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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 use widely for various purpose in the archtectural and civil structures. However, the performance of lightweight concrete is essentially dependent of properties of used lightweight aggregates. So, in this paper were examined the fresh and hardened properties of lightweight concrete that are used 3types of the differences properties of lightweight aggregates from lower water-ratio to higher water-ratio of concrete mixing regions. Lightweight concrete was somewhat exhibit larger slump loss than ordinary concrete. Also, the development of compressive strength was lower than ordinary concrete, however it was not showed a marked difference. According to types of lightweight aggregates, the case of synthetic lightweight aggregate are highest performance in fresh and hardened concrete, but it is should be to evaluate the structural performance testing as anchoring and bond strength with reinforcing steel bars.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.5
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• pp.551-557
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• 2010

The purpose of this study is to estimate experimentally the flexural behavior, capacity and validity of existing regulation of net tensile strain in lightweight concrete beams and polymer modified lightweight concrete beams. One normal weight concrete beam and four lightweight concrete beams, three polymer modified lightweight concrete beams were constructed as same figure and attempted to evaluate the difference of strength and ductility in specimens of different net tensile strain in extreme tension steel. Test results are indicated in terms of load-deflection behavior and ductility index. As the value of net tensile strain increased, the flexural strength and stiffness of specimen decreased but ductility index increased in both of lightweight concrete beams and polymer modified lightweight concrete beams. It is considered that to achieve similar ductility index of normal weight concrete, net tensile strain in extreme tension steel should exceed 0.005 for lightweight concrete beam and polymer modified lightweight concrete beam.

• Journal of the Korea Concrete Institute
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• v.22 no.2
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• pp.159-169
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• 2010

A multiphysics model analysis including moisture transport, heat transfer and solid mechanics and experiments on the normal and light weight concrete were carried out in order to study the effect of preabsorbed water in the light weight aggregates on the drying and shrinkage characteristics of concrete. Consequently, with fixed water-cement ratio, loss of water content of normal and light weight concrete were compared and the results showed that the lightweight concrete lost less moist than the normal concrete in early age and long term which was by moist supply effect. Accordingly, shrinkage strain size and distribution of lightweight concrete were decreased, and shrinkage reducing effect was efficient in early age with water cement ratio 0.3 and in both early age, and long term with water cement ratio 0.5. The comparison of analysis results and exaperimental results indicate that characteristic values of moisture transport and the relation humidity and shrinkage strain from this study are resonable for application for other differential shrinkage analysis in lightweight concrete.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1A
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• pp.219-228
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• 2006

Because of the advantage of light weight, lightweight concrete is frequently applied to long-span bridges and high-rise buildings. In the country, there is not enough experience for the long-span bridges using lightweight concrete. This paper presents results of an experimental study on the punching shear strength of high-strength lightweight concrete slabs. Four test slabs are fabricated using high-strength lightweight concrete and normalweight concrete and at the center of the test slabs, simulated wheel load is applied until failure. The compressive strengths of lightweight concrete and normalweight concrete are 47MPa and 32MPa, respectively. The test results show the failure mode of all specimens are punching shear and the behaviors of high-strength lightweight concrete slabs are very similar to that of normalweight concrete slabs. Based on the test results, it is discussed the safety and serviceability of high-strength lightweight concrete bridge decks.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.255-256
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• 2010

I think application properties to lightweight concrete of Chinese lightweight Aggregate will be considered according to the Grain Size, and shows by a reference data for efficient utilization of Chinese lightweight Aggregate to settle the problem that self-weight of concrete is excessive.

• Magazine of the Korea Concrete Institute
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• v.10 no.3
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• pp.219-226
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• 1998

본 연구에서는 경량콘크리트보의 거동을 연구하는데 적용될 수 있는 비선형해석이 나타나있다. 콘크리트에 대한 2축 실험 자료를 사용하여 경량콘크리트의 구성모델을 만들었다. 구성모델에서 콘크리트의 비선형성은 주응력비에 따른 강도증감계수와 탄성계수의 변화에 따른 비선형저감계수를 사용하여 나타내었다. 유한요소 모델해석에서 콘크리트는 8절점을 가진 사각형요소로 하고 철근은 1차원 선형요소로 가정하여 해석하였다. 유한요소해석으로부터 얻어진 수치해석결과와 실험실에서 행한 실험결과를 비교하였다.

• Journal of the Korea Concrete Institute
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• v.22 no.4
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• pp.559-566
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• 2010

Fifteen lightweight concrete mixes were tested to evaluate the effect of maximum size of coarse aggregate and the replacement level of natural sand on the various properties of fresh lightweight concrete. The different properties, such as water absorption against the elapsed time, pore size distribution and micro-structure of lightweight aggregates used, influencing on the workability of fresh concrete were also measured. Test results showed that the initial slump of lightweight concrete decreased with the increase of the replacement level of natural sand. The slump of all-lightweight concrete sharply decreased by around 80% of the initial slump after 30~60 minutes. The air content and bleeding rate of lightweight concrete were significantly affected by the replacement level of natural sand as well as the maximum size of coarse aggregates. Empirical equations recommended in ACI 211 and Korea concrete standard specifications underestimated the air content of the lightweight concrete, indicating that the underestimation increases with the decrease of the replacement level of natural sand. In addition, equations to predict the air content and bleeding rate of lightweight concrete were proposed based on the test results.