• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.39-40
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• 2022

This study is intended to examine the curing effect of the combination of the bubble sheet on the concrete by analyzing the temperature profile and core strength of the simulated concrete structure. The test results relvealed that the average temperature of the concrete applying photothermal sheet overlapped with the double bubble sheet at the bottom was 23.5℃, which had the highest insulation and insulation effect compared to other types of surface insulation curing sheets, and the core strength increased by up to 56%.

• Journal of the Korea Concrete Institute
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• v.15 no.3
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• pp.392-399
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• 2003

This paper discusses the validities of insulating curing of cold weather concreting at early stage by applying insulation forms. Tests were carried out using modified insulating form combining existing insulating form and various other insulations in order to develop improved insulation form. Temperature history of concrete using various insulating forms and insulation was measured to determine most effective combination of insulting form. According to results, as for the wall form, under the curing temperature of $-10^{\circ}C$, the temperature of concrete using Euro form drops sharply before 24 hours and lasts below $0^{\circ}C$ for 7 hours. The temperature of concrete using the form combining Polypropylene panel, styrofoam and plywood panel keep above $0^{\circ}C$. And, it is confirmed that the form mentioned above has a favorable effects on enhancing strength development of concrete and the cost to make the forms shows more reasonable than that of existing forms. However, as for the combination methods of insulation form for slab, which is composed of insulating form at the bottom of slab and various surface curing materials at the top of slab, in case of exposed condition at the top of slab, temperature history of concrete goes below $0^{\circ}C$ after 10 hours. In case of the combination of vinyl sheet and curing blanket, it drops below $0^{\circ}C$ after 42 hours. However, in case of the combination of vinyl, styrofoam and curing blanket, it does not go below $0^{\circ}C$ until 55 hours. Accordingly, compared to the case of exposure and the combination of vinyl and curing blanket, it indicates that the combination mentioned above has more effective insulating performance.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.781-784
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• 2008

In this paper, insulating effect and strength development of concrete under low temperature are reported varying curing sheets. According to test results, in temperature -5$^{\circ}$C concrete subject to exposure and air cap condition, result in a frost damage at early age by a fall of below zero temperature. Mean while, the combination of PE film and non-woven fabric maintained around 3 $^{\circ}$C within first 24 hours since placement. For double bubble sheets, concrete temperature maintained above 7$^{\circ}$C due to its excellent heat insulating capability. As a result of core strength test, strength of specimens cured with viny + non-woven fabric and double bubble sheets had higher strength than strength of other specimens due to good heat insulation effect at early age.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.445-446
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• 2010

Water existed inside of bubble sheet applied at the job site sometimes results in undesirable heat insulation capability of bubble sheet. Therefore, the objective of this paper is to examine experimentally the effect of water presence in bubble sheet on heat insulation capability and strength of the concrete cured with double bubble sheet.

• Journal of the Korea Institute of Building Construction
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• v.10 no.5
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• pp.121-128
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• 2010

The present research examined heat insulation performance according to change of various laid construction conditions of double bubble sheet being used as material for heat insulation & curing construction of cold weather concrete, and its results are as follows. First, the change in a laid period of bubble sheet within 4 hours and the change in water content inside bubble sheet overall showed similar temperature history and maturity without a big difference in terms of the temperature history of concrete according to construction factors, but it could be confirmed that when a structure was thin or several bubble sheets are laid, requisites unfavorable for initial curing of concrete can occur if a lagger distance between sheets is generated. In terms of the compressive strength of concrete core specimens, it appeared that the initial compressive strength is declined when conditions unfavorable for concrete curing such as delay of a laid period of bubble sheets, induction of large distance between sheets, increase of water content inside bubble sheets and thinness of a structure of placing concrete, etc. were applied, but it appeared that as its age passes, the difference becomes small.

• Journal of the Korea Concrete Institute
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• v.26 no.3
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• pp.287-297
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• 2014

Heat of hydration of mass concrete is one of the most important factors that significantly affect structural quality and construction period. Therefore, appropriate methods to control heat of hydration are essential technologies for mass concrete construction. In this study, probability of thermal cracking was checked by thermal analysis prior to the construction of a turbine foundation in a domestic power plant. Subsequently, changes of concrete mix proportion and an effective curing method were proposed to control heat of hydration of mass concrete structures. Concrete manufactured by slag cement was proposed instead of concrete produced by ordinary Portland cement, and an automated curing method was proposed to improve the curing method using typical moist curing with blanket. The automated curing method maintains the temperature difference between center and surface of concrete below a setting value by temperature monitoring. Concrete with slag cement was used for actual construction. One of two identical turbine foundations was cured by an insulated curing method, and the other was cured by the automated curing method to compare the curing methods. And then, the effects of control of heat of hydration were evaluated based on temperature/strain monitoring and crack investigations.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2007.04a
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• pp.1-4
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• 2007

This study investigated the applicability of insulation curing method with double layer bubble sheets to the man concrete subjected to cold weather. Temperature history of the mass concrete indicated that the highest temperature of center section was exhibited at $34^{\circ}C$ while the that of surface section was $25^{\circ}C$. Difference between center and surface was shown to be less $10^{\circ}C$ when the temperature of center section was peak section, and thereby associated temperature cracking index was calculated 1.5, and occurrence probability of temperature cracking was 5%, so there was no temperature cracking caused by internal restraint. No temperature crack was observed by naked eye. It was clear that early frost demage and temperature cracking could be restrained due to reducing temperature difference between inner part and outside in the case double bubble sheets applied to insulation curing method in cold weather. The maturity of mass concrete is higher than outside about $72\sim89^{\circ}$ DD, so it was demonstrated to prevent early frost demage and ensure strength excellently. Insulation curing method with double bubble sheets was more economic than heating curing method.

• Journal of the Korea Institute of Building Construction
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• v.4 no.2
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• pp.113-118
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• 2004

This study is a basic experiment on quality management of the compression strength of high strength concrete, aiming. at quality management of high strength mass concrete by giving the temperature hysteresis of the mass test pieces to managerial test pieces. Different from ordinary concrete, high strength concrete generally shows the temperature high rising caused by hydration heat inside the concrete. It is known that, in mass concrete, thermal stress occurs due to the difference in temperature between the inside and the outside, which causes a significant difference in compression strength between structure beams and managerial test pieces. It is also reported that there is a large difference between the compression strength of cylindrical managerial test pieces of standard underwater curing and the strength of structure beam concrete. Thus, this study made concrete test pieces in an optimal mix ratio for each strength level, and also created thermal insulation curing box and managerial test pieces. Then it carried out comparative analysis in relation to core strength and suggested equipment and a technique that can control the strength of high strength concrete mass more conveniently and accurately.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.11a
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• pp.21-25
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• 2008

In this paper, the temperature history and the strength development of concrete corresponded to various bubble sheets layer and curing temperature. Based on the results, In case of the test temperature of -5℃, concrete subject in the exposure condition, result in a frost damage at initial stage by a fall of below zero temperature. In case of the combination of PE film and non woven fabric was after 36 hour, and combination of bubble sheet over double, a tremendous insulating effect of bubble sheet over double is confirmed due to the temperature of concrete fall of below zero temperature after 60 hours. Meanwhile, regarding the -15℃ of temperature, special measure for insulation curing is necessary to secure stability against early frost damage because frost damage was not affected by the lapping thickness of bubble sheet subjected to severe cold weather condition.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.05a
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• pp.57-60
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• 2008

This study investigated the results of insulation heat curing method using double layer bubble sheet in slab concrete and mass concrete in cold weather environment. First of all, when double bubble sheets are applied, it was shown that slab concrete was protected from early freezing by remaining between 6 and 15℃ even in case outside temperature drops -9℃ below zero until the 2nd day from piling, and in the case of mass concrete, with the maximum temperature difference between the center and surface less than 4℃, crack occurrence index was close to 2 and no hydration heat crack occurred by internal constraint. The insulation heat preservation curing method using the double bubble sheet applied in this field prevented early freezing owing to stable curing temperature management, deterring concrete strength development delay at low temperature, and obtained the needed strength. Also, it was proven that the method is highly effective and economic for cold weather concrete quality maintenance through curing cost reduction like construction period shortening and labor cost reduction, etc by reducing the process of temporary equipment installation and disassembling.