• Journal of the Korea Institute of Building Construction
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• v.12 no.4
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• pp.451-459
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• 2012

At the Korea Land and Housing Corporation(LH), concretes with high design strength of 50 MPa and 80 MPa that are composed only of ordinary Portland cement, blast furnace slag, and fly ash are developed. To determine whether the developed high strength concretes have the same properties when they are produced in batch plant(B/P) condition in the ready mixed concrete plant, and as existing high strength concretes, field tests are performed and material properties are evaluated. To investigate the material properties of the high strength concretes before and after pumping, compressive strength, flowability, air content, hydration temperature, pumping and compactability are evaluated. In field tests, before and after pumping, flowability satisfied the relevant criteria. In terms of air content, while it was slightly decreased after pumping, it satisfied the requirements. Hydration temperature criteria were satisfied, and compactability was excellent as well. The study found that the developed ternary high strength concretes have the same properties as existing high strength concretes. They can also be useful for the construction of high-rise buildings, as they are economical.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.05c
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• pp.69-73
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• 2009

Plan of concrete pumpability test or the theoretical character knowledge in the mechanic is become accomplished with character. But the character knowledge of the concrete is not considered appropriately, The theoretical background and assumed fact is a little different representative characteristic of the concrete. Concrete pumping experiment result it leads consequently and is produced the coefficient of friction which in concrete type and sending in more pressure it follows changes must grasp the tendency which. But until currently the majority experiment and research did not pass by this process. Grasps the coefficient of friction change tendency which it follows in concrete type and when pumping concrete more pressure data fundamentally from the experimental research which it sees consequently under providing the man with underdeveloped genital organ.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.04a
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• pp.382-387
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• 1996

Three concrete filled steel tubular columns with six inner diaphrams are constructed and tested under field conditions. The size and shape of three columns are exactly same. The cross section is $40\times40cm$, and the height is 9m. Each column is constructed with normal concrete, CFST concrete, and high flowing concrete, respectively. Concrete is pumped into bottom parts of steel tubular columns from a concrete pump on the ground. Test data indicate that the slump flow of the concrete place in the top of the column is lower than that of the concrete before pumping by about 10~20cm. Slump flow loss of high flowing concrete caused by pumping is high compared to the other concretes. Concrete pump pressure of high flowing concrete is somewhat higher than that of CFST concrete.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.2
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• pp.195-202
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• 2016

In general, piston pumps are frequently used for concrete pumping. Filling coefficient signifies the ratio volume of a hydraulic cylinder to volume of concrete inside the cylinder. Therefore, it may be considered as a parameter directly affecting the flow rate and efficiency for concrete pumping. However, accurate analyses on this aspect have not yet been performed. In this paper, the data measured from horizontal pipeline pumping tests for 350m and 548m in length was analyzed to identify the relationships of rheological properties of concrete and stroke time with the filling coefficient. In addition, an equation allowing prediction of the filling coefficient from rheological properties of concrete and stroke time has been suggested.

• Advances in concrete construction
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• v.16 no.5
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• pp.231-241
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• 2023

The purpose of this study was to evaluate the practical application of high-flowing concrete for a steel-concrete panel (SCP) module for a liquefied natural gas (LNG) storage tank. We evaluated the physical properties and filling performance of the developed concrete for the SCP module. First, slump tests were performed to evaluate the performance of the proposed standards for the filling tests. All the concrete mixes showed satisfactory performance. Based on the results of the previous study, the reliability of the required time measured using the T₅₀₀ test and the rheometer results measured before and after pumping was 0.94, indicating that segregation and blocking should not occur. L-box and U-box tests were conducted before and after pumping. All the recommended standards showed satisfactory performance. The SCP structural module for LNG storage tanks was fabricated to a full scale to evaluate its practical application at the final site. Satisfactory filling performance was confirmed for all the specimens.

• Magazine of the Korea Concrete Institute
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• v.25 no.3
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• pp.29-33
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• 2013

• 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.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.613-616
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• 2006

Development of construction technology and various condition is realized by high-rise buildings and so concrete placing by pressure pump has been developed in with the trend of large-size and high-rise building. So, it is judged that reservation of the basic data for standard of quality control standard Code by the prediction and this to a quality change exact here is urgent. In this study it is going to carry out experimental research for a physical-properties change searching examination of the concrete by the after pressure change factor which does not become hard by the pumping method of construction.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.801-804
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• 1999

The interest in workability and quality control of concrete is increasing as to improve quality of concrete structure according to industrialization. Therefore, it is the aim of this study to evaluate the quality of flowing concrete and systematize quality control by analyzing the data of the quality control of concrete through a basic quality control system for improvement of the concrete in pumping flowing concrete for construction industy.

• 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.