• Magazine of the Korea Concrete Institute
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• v.10 no.1
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• pp.101-108
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• 1998

시멘트 대체재로 사용하는 플라이애쉬(0, 10 , 30 ,50 %)를 혼입한 콘크리트의강도발현을 관찰하기 위해 각각 21$^{\circ}C$에서 수중양생과 85$^{\circ}C$에서 증기양생방법을 채택하여 실험하였다. 수중양생한 보통 콘크리트는 플라이애쉬 혼입량이 증가할수록 조기재령에서는 낮게 강도발현을 하였으나. 28일 압축강도를 기준으로 하여 물.시멘트비를 변화한 배합비(결합재량 증가)의 실험결과는 조기강도발현이 향상되었다. 특히 플라이애쉬를 30%혼입한 콘크리트는 우수하게 강도발현을 하였다. 그리고 동일한 28일 압축강도를 갖는 배합비(결합재량 증가)에서 증기양생한 플라이애쉬콘크리트는 보통콘크리트보다 강도발현이 비슷하거나 향상되었으며, 양생온도는 플라이애쉬콘크리트의 강도발현에 많은 영향을 미치는 것으로 관찰되었다.

• Journal of the Korea Institute of Building Construction
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• v.18 no.3
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• pp.267-275
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• 2018

This study is to investigate the effect of various temperature and humidity conditions on the strength and efflorescence of alkali activated slag cement(AAS) using the red mud. As a result of examining the strength and efflorescence characteristics of AAS mixed with red mud according to the curing conditions, The compressive strength and flexural strength were the highest at 28 days, but the absorption rate, efflorescence area and soluble $Na^+$ elution were lowest in standard wet curing compared to the air curing, high temperature curing and low temperature curing.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.11a
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• pp.194-195
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• 2013

Recently, it is the tendency that the CO₂ gas generated in the manufacturing process is increased every year in case of the portland cement used in the most of constructions and civil engineering field. The method that uses the mineral admixtures as the cement substitute material in order to be more serious and as much as it occupies 7% of the global CO₂ gas outlet amount such as 1 ton produces the cement and it ejects the CO₂ gas of 0.4~1.0 ton, etc conclude this problem is examined. Therefore, PVA fiber was mixed into the inorganic binder recycling the blast furnace slag, which is the industrial byproduct with the purpose studying the Geo polymer which doesn't use the cement at all silica fume, red mud, and etc. In addition, the water curing temperature was differentiated and the strength characteristic of the curing body tried to be examined.

• Magazine of the Korea Concrete Institute
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• v.8 no.4
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• pp.141-148
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• 1996

The pulished works on Accelerated Curing Effect were generally performed around from 1960 to 1970th century for 18 to 24 hours - total curing periods. It is not possible to define the effect of temperature rise because those results were obtaine mainly by using the manually operated steam-curing tank. Thus, it may not be available to apply those data immediately on the domestic PC wall production line. The testing specimens were made from the standard mix proportion according to those of domestic PC factories to establish a basic data for the Accelerated Curing Effect. The experimental tests were conducted according to the conditions of each sub-curing periods. By comparing the results of compression tests on de-molded and 28-day water-curing specimens, we find that the most effective curing condition to obtain more than the required design strength after 28 day of water curing may be as follows: the presteaming period does not affect seriously and less than$30^{circ}C/hr$- the rate of temperature rise andless than $82^{circ}C$ - maximum temperature are necessary. It seems that post-curing procedure is very important factor to increase the effect of accelerated curing.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.100-101
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• 2014

The global warming because of the CO₂ emission and solution about this emerge as the international enviroment problem. Particularly, it is the absolutely it is needed for reducing the CO₂ in the cement industry and harmful material actual condition. And the construction of home and abroad and material manufacturers tries for the technology development for the carbon dioxide and harmful material reduction which the portland cement in manufacture is usually emitted along with the increase of concerns about the environment-friendly concrete and panel. Therefore, in this research, the compressive strength of the inorganic binder and flexural strength tries to be measured in order to draw the inappropriate high temperature cure time of the ternary system inorganic binder using the blast furnace slag, red mud, silica fumewhich is the industrial byproduct with the cement substitute material, and etc.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.4
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• pp.54-61
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• 2023

In this paper, the compressive strength, pore characteristics, and chloride diffusion coefficient were measured at 28 days of age in order to examine the influence of curing conditions for the chloride diffusion and pores in concrete cured under extreme condition. According to the test results, the compressive strength was improved as the relative humidity increased. Additionally, higher compressive strength was observed when the specimens were cured at 35℃. However, the compressive strength of specimens cured at 45℃ was decreased. Meanwhile, the chloride diffusion coefficient decreased with an increase in curing temperature and relative humidity, indicating a difference compared to the trend observed for compressive strength. On the other hand, the excellent correlation showed between compressive strength and chloride diffusion coefficient, porosity and chloride diffusion coefficient when the concrete cured under water. However, when the concrete cured under extreme condition, this correlation was significantly reduced compared to the water curing case. In contrast, it has been determined that there is no significant correlation between the average pore size and chloride diffusion coefficient, regardless of the curing conditions.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.273-274
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• 2009

The curing method used on domestic sites for checking the concrete compressive strength of a structure. The curing method used for testing the specimens must be the standard ponding curing method (20${\pm}$%$2^{\circ}$C). However, because in-placed concrete is exposed to open air and cured under the seasonal temperature changes, the compressive strength of a real structure is different from the tested compressive strength. Therefore the curing method suggested in this research, which sets the internal conditions of the structural specimens as the conditions of the applied curing method. this thesis suggests the specimen curing method that most closely re-enacts the compressive strength of the concrete used on the structural specimens

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.2
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• pp.67-73
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• 2016

When assessing crack initiation of fiber reinforced concrete, usually tensile strength or flexural strength is becomes indicator, but also depend on the curing effect take place during the production of specimen. In general, after conducting concrete specimen is cured by water at temperature $20{\pm}3^{\circ}C$ in laboratory, and accomplished the assessment of strength, but most of concrete structure is kept in drying condition after moist curing through the prescribed period. However, unlike these trends that technological advances have been made, influence of the difference of curing method on crack strength is not yet clear. Therefore, in this study, it is examined on the effect of curing methods affecting the mechanical property of fiber reinforced concrete, especially crack strength.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.965-968
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• 2008

The KS F 2403 method used on domestic sites for checking the compressive strength of a structure, sets the compressive strength of the concrete used in structural specimens as the compressive strength of testing specimens. Under this regulation, the curing method used for testing the specimens must be the standard ponding curing method (20$\pm$2$^{\circ}$C). However, because in-placed concrete is exposed to open air and cured under the seasonal temperature changes, the compressive strength of a real structure is different from the tested compressive strength. (Therefore,) This thesis first identifies the distinct characteristics of the strength development by applying the curing method listed under the KS and used for testing specimens on compressive strength tests; the atmospheric curing method, the sealed curing method, and the structural specimen core strength testing methods used for the in-sites quality checks including reckoning of the compressive strength of the structural specimens and form-demolding period; and the curing method suggested in this research, which sets the internal conditions of the structural specimens as the conditions of the applied curing method. Then, the thesis suggests the specimen curing method that most closely reenacts the compressive strength of the concrete used on the structural specimens

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.1
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• pp.139-146
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• 2015

The amount of by-product from sulphur increases in domestic industrial facilities. However, the amount of its consumption is limited so that the amount of unused sulphur continues to increase. Therefore, in this study, the use sulfur polymer as the concrete surface protecting material was conducted. The compressive strength showed that as the substitution ratio of filler increased up to 40%, the compressive strength also increased. A high compressive strength was shown at the curing temperature of $40^{\circ}C$ (SS, FA) and $60^{\circ}C$ (OPC) according to the type of filler. The difference of compressive strength between air dry curing and water curing was insignificant so that there was no significant influence of moisture during curing process. The evaluation result of bond strength showed that the highest bond strength was shown at the air-dry condition of $40^{\circ}C$ regardless of type of filler. Bonding didn't occur properly during water curing in comparison to air dry curing. Also, in case of the specimen cured at $60^{\circ}C$, discoloration and hair cracks appeared due to the influence of temperature, and the highest bond strength was shown at the substitution ratio of 20% (SS, FA) and 30% (OPC) according to the type of filler. The releasing test result of harmful substance showed that no harmful substance was released, so there is no harmfulness in the surface protecting material using sulfur polymer. As a conclusion drawn in this study, it is most appropriate to substitute silica by approximately 20%, mix and cure at the air-dry condition of $40^{\circ}C$ in order to use sulfur polymer as the surface protecting material.