• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.33-38
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• 2002

Concrete placed under cold weather has some defects such as the decrease of initial strength by hydration delay, strength unrecovery at unhardened concrete freezing, and structural failure and crack by expansion pressure. So, in this study, we tried to evaluate the JIS mortar which was made under cold weather using de-icing agency. In mortar test, the do-icing agency increased compressive strength under standard curing, and the de-icing agency made by NaNO$_2$ gave the highest strength. However, as pre-curing time under 21$^{\circ}C$ was short, the de-icing agency made by NaNO$_2$ and Ca[NO$_3$]$_2$ had the highest strength.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2002.05a
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• pp.21-26
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• 2002

This paper is intended to verify the efficiency of anti-freeze agent and insulating form by analyzing the temperature history and the property of strength-increase about the concrete that is placed in the insulating form and normal form, using new type anti-freeze agent in batcher plant According to the results about the temperature history, while the lowest temperature shows 3$^{\circ}C$ in case of normal concrete + euroform, 4$^{\circ}C$ in case of normal concrete + insulating form, it shows 6$^{\circ}C$ in anti-freeze agent + the insulating form, so the effect is most favorable. The compressive strength with mixing anti-freeze agent or not, shows high in order of standard curing, structure-managing and open air-placed specimen and the concrete mixing anti-freeze agent shows the highest compressive strength-increase.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2006.11a
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• pp.29-32
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• 2006

Experimental test results of field construction, Cheongju University Educational Liberal Art Building, applying the insulating curing method on slab concrete showed that the quality of concrete in fresh and hardened state satisfied all target values. Temperature history of slab concrete in A and B area secured more than $7.8{\sim}9.2^{\circ}C$ higher than outside atmosphere. After completing certain curing period of time on the surface of the structure, crack occurrence was not found. It is concluded that the preventing vaporization of moisture by the insulating curing method reduces plastic and drying shrinkage as welt as improves durability.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.167-168
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• 2020

In this study, we attempted to present a method for diagnosing the depth of the early frost damage concrete using organic pigments under the cold weather. As a result, it is considered that the organic pigment did not penetrate into the voids of the concrete that had been damaged by the early frost damage and only the surface was adhered. Therefore, when fine particles that can be melted in water and pass through voids are used, it is analyzed that it can penetrate damaged part of the concrete.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.5
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• pp.27-34
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• 2018

Concrete placed under hot weather condition suffers from larger slump loss, rapid moisture evaporation due to high air temperature. Proper measures for material, transportation and curing should be taken to prevent the quality deterioration of the concrete under hot weather condition. In Korea, Although the period of hot weather concrete in Korea occupies only 2 months, there are a lot of quality problems including plastic, drying shrinkage and cold joint. Therefore, the objective of this paper is to investigate and compare the temperature history and crack occurrence of the concrete, which was placed in the actual apartment house construction field under hot weather condition, in response to the application of surface covered curing blankets including PE film, single layer clear bubble sheet, white colored bubble sheet and aluminum metalized bubble sheet. Test results indicated that the application of white colored bubble sheet and aluminum metalized bubble sheet showed most favorable results in terms of reduction in temperature rise and crack occurrence as well as easiness in handling. But, due to light reflection by aluminum metalized bubble sheet, it is believed that white colored bubble sheet is preferable.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2006.05a
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• pp.15-18
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• 2006

The test result of mat concrete applying both hydration heat difference and insulation curing method on new construction of Cheongju university educational building are summarized as following. Both fresh concrete and compressive strength properties were satisfied In aimed value. Setting time of concrete incorporating 15% of fly ash(FA) retarded 1.2 hour than control concrete. Temperature history of mali concrete indicated that the highest temperature of center was exhibited at $126^{\circ}C$ after 51 hours while the highest temperature of upper section was $10.6^{\circ}C$ after 46 hours. Temperature Difference between center and surface was managed at less than $6^{\circ}C$ during whole curing period. In addition the temperature of upper section secured more than $3.3^{\circ}C$ while the temperature of outside was indicated at less than $-10^{\circ}C$. Maturity by parts of construction secured more than $30^{\circ}C$ DD higher than outside at 3 days. The more number of times, applying insulation curing method by double bubble sheets, increased, the higher economic effect was secured. Overall it was clear that applying both double bubble sheets and hydration heat difference method on this new construction can resist hydration heat crack, early frost demage and strength decrease. It also significantly contributed quality improvement of cold weather concreting

• Magazine of the Korea Concrete Institute
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• v.13 no.3
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• pp.83-91
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• 2001

• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.11a
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• pp.53-56
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• 2008

This paper is to investigate the change of the period of hot weather concrete with elapse of age based on climate data. Climate data for 30 years and 5 years are used respectively. Determination of the period of hot weather concreting on architectural execution in Korea according to the specifications of AIJ, KSCE, and ACI are discussed. According to the research, the period of hot weather concreting with each specification in most regions lasts over 35 days. Compared with the period of cold weather concreting in hillside and inland area, coastal areas have shorter period in the same latitude. The period of hot weather concreting tends to decrease with high latitude. As expected, with the elapse of age, the period of hot weather concrete exhibited to decrease, especially, big city like Seoul, Busan etc had remarkably increased period by as much as a week. This is due to the global warming and industrialization effect with the elapse of age.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.05a
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• pp.17-20
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• 2005

This paper reported the temperature history of concrete placed at deck plate slab under cold climate condition by varying with surface insulating type. No curing sheet and simple insulation curing including non-woven fabric, double layer bubble sheet, the combination of double layer bubble sheet and non-woven fabric dropped temperature below zero within 24 hours, which caused frost damage at early age. On the other hand, the combination of double layer bubble sheet and non-woven fabric and double layer bubble sheet and styrofoam maintained minimum temperature above $4^{\circ}C\;and\;8^{\circ}C$, respectively. Based on core test results compressive strength of concrete with the combination of double layer bubble sheet and non-woven fabric and double layer bubble sheet and styrofoam was higher than those with other curing method due to good insulation effect.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.05a
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• pp.67-68
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• 2013

In this paper, the compressive strength of an insulating gang form member, which was developed to improve the cold weather concreting quality, and a general gang form member was measured by age to examine the compressive strength characteristics of the two members compared with the standard curing test piece.