• 한국안전학회지
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• 제31권5호
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• pp.109-116
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• 2016

This study presents the results of experiments to investigate the effect of polymer type and curing temperature on the mechanical properties of polymer mortar. Setting time of two types of polymers, hardening-delayed polymer(HDP) and rapid hardening polymer(RHP), was tested to check the working time. Additionally, flexural strength, compressive strength, and splitting tensile strength was investigated for mortars using these polymers. From these results, it was confirmed that, irrespective to curing temperature, RHP mortar at the curing age of 24h develops the similar mechanical properties to maximum properties and HDP mortar is more sensitive to the curing temperature. In addition, it should be noted that RHP mortar and HDP mortar are suitable in winter and summer, respectively.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2008년도 춘계 학술논문 발표대회
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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.

• 한국연초학회지
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• 제20권2호
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• pp.160-165
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• 1998

The Joint curing barns for flue-cured tobacco is a favorite with the tobacco farmers in Korea. However, most of farmer utilizing the joint curing barns indicated many problems such as high temperature and noise in the working room and a dry of cured leaves in the storage room. A structure of Joint curing barns has been modified to meet the needs of tobacco farmers. Compared with the unimproved joint curing barns, the improved one showed that the noise of workshop decreased about 7.7～10.8db, the amount of $CO_2$ decreased 40～50ppm in a working room and 80～100ppm in a machine room. Ammonia gas decreased 0.29mg/㎥ and the temperature of a working room dropped about 2.1～3.5$^{\circ}C$. The amount of air flow in a working room increased 23.2% at a site being 2m away from the entrance and 30.8% at a center. The inner temperature of the improved storage room showed that maximum temperature dropped about 3$^{\circ}C$, minimum temperature was high about 2$^{\circ}C$. The highest relative humidity was low 6%, the lowest one increased high about 10% when compared with the unimproved joint curing barns.

• Elastomers and Composites
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• 제52권4호
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• pp.266-271
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• 2017

This study describes the influence of the amount of curing agent and curing temperature on the kinetics of polyurethane elastomers. The urethane prepolymer series was prepared by reacting toluene diisocyanate with polytetramethylene ether glycol at $80^{\circ}C$ for 1 h, and 4,4'-methylene bis(2-chloroaniline) was used as the curing agent. The ratio of the amine group of the curing agent to the isocyanate group of the urethane prepolymer was controlled from 0.85 to 1.05 at curing temperatures ranging from 80 to $120^{\circ}C$. The curing rate of the urethane prepolymer was monitored by observing the change in heat flow during the curing process using differential scanning calorimetry (DSC). As either the content of curing agent or the curing temperature was higher, the conversion rate to the polyurethane elastomer was high. The DSC results were compared with those obtained from using real-time FT-IR.

• 한국식품과학회지
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• 제28권3호
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• pp.458-463
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• 1996

생강의 저장 전처리 효과를 보기 이ㅜ하여 충남 서산에서 수확한 햇생강을 wounding 처리후 온도조건 25, 30, $35^{\circ}C$및 습도조건 83%, 93% RH에서 $1{\sim}7$일간 curing시켜 실험실용 저장고($12^{\circ}C,$ 95% RH)에 보관하였다. 일정한 온 습도에서 curing 기간이 길수록 생강의 중량은 감소되었고, 온도 및 curing기간이 일정할 때 습도가 높을수록 중량감소는 작아졌다. Curing 기간동안 발아율은 $30^{\circ}C$, 90% RH이상의 조건에서 촉진되었으며, 곰팡이 발생은 전반적으로 나타났으나 특히 $35^{\circ}C$에서 curing기간이 길어질수록 상대적으로 진행이 빨랐다. 상처부위 표면의 경도는 93% RH일 경우가 83% RH보다 모든 온도조건에서 대체로 높은 경향을 보였으나, 전체적으로 볼 때 curing조건에 상관없이 일반적으로 높일 수 있었다. Curing 처리된 생간의 저장기간중(60일간) 수분의 손실로 인한 중량감소는 30일경 $2.0{\sim}8.2%,$ 60일경 $7.2{\sim}14.2%$의 범위를 보였다. 실험 결과들을 종합하여 screening하면 93%RH, $25^{\circ}C$에서 3일간의 curing이 저장기간중 품질변화를 최소화시킬 수 있는 것으로 나타났다.

• 한국건설순환자원학회논문집
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• 제6권4호
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• pp.127-133
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• 2012

본 연구에서는 양생온도가 혼화재 치환 고강도 모르타르의 자기수축에 미치는 영향에 대하여 실험적으로 고찰하였다. 혼화재료는 실리카흄, 고로슬래그, 플라이애시의 3종류로서 치환률은 10, 20, 30%의 3수준으로 하였고 양생온도는 5, 20 및 $35^{\circ}C$의 3수준으로 계획하였다. 연구결과 양생온도가 높아질수록 혼화재 치환률이 감소할수록 응결시간은 단축되는 것으로 나타났으며, 양생온도에 따른 자기수축의 경우 양생온도가 증가할수록 수화반응속도 증가에 의해 자기수축이 커지는 것으로 나타났다. 또한 SF나 BS를 사용한 경우 자기수축이 플레인보다 증가하는 것으로 나타났고, FA의 경우는 플레인과 큰차이가 없거나 약간 감소하는 경향을 보였다. 또한 적산온도에 의한 자기수축 평가결과 동일한 적산온도에서 양생온도별 자기수축량의 차이가 크게 나타나 온도민감도를 보다 정확하게 고려할 수 있는 방법이 요구되었다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 가을 학술논문 발표대회
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• pp.175-176
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• 2022

By studying the characteristics of matrix insulated through heat generated through oxidation of iron powder, the basic research results on the possibility of buffering and applicability of Cold weather concrete as a curing method are presented. In order to prevent freezing due to a sharp decrease in temperature in the initial stage of curing, iron powder (Fe), powder activated carbon, which is a small amount of porous carbonaceous adsorbent, and salt (NaCl) as an oxidizing agent are replaced with iron powder admixture. As the curing temperature increases, the strength tends to increase, and when replacing the admixture at the same curing temperature, the strength slightly decreases. This is determined as a result of generating iron oxide through an oxidation reaction of iron powder, activated carbon, and NaCl generating a large amount of pores in the matrix. In addition, the internal temperature tends to increase as the mixing substitution rate increases, and it is judged that the oxidation heat of the iron powder mixture affects the increase of the internal temperature during curing. The higher the replacement rate of the iron powder mixture, the slightly lower the strength, but it is determined that freezing and melting that may occur in the early stage of curing can be prevented due to an increase in the initial internal temperature.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2007년도 춘계학술논문 발표대회
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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.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1996년도 봄 학술발표회 논문집
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• pp.107-111
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• 1996

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 days of water curing may be as follwings; the presteaming period does not affect seriously and less than $30^{\circ}C$/hr-the rate of temperature rise and less 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.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2004년도 학술대회지
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• pp.11-14
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• 2004

The object of this study is vibrating compaction and curing method in the production process of Design concrete for precast concrete(Design-PC) product. From change of vibrating compaction time and pre-curing time. curing temperature which would be factors of product quality in Design-PC concrete production. and research of optimized steam curing condition from relations between curing condition and strength development. basic data of vibrating compaction time and concrete steam curing method for Design-PC will be presented.