• 한국연초학회지
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• 제16권2호
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• pp.139-143
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• 1994

This study was carried out to control the stalk curing period in Burley Tobacco, for its period was longer than 40 days. The 5 methods were treated to shorten the stalk curing period. The curing period was shortened for 1~3 days by the harvesting methods and the amount of predehydration, but it was shortened for 8 days by the hanging methods(sloping and horizontal curing)and the hanging density(90 plants/3.3m2) without the decrease of quality. In the ventilating condition of the curing house, the curing period could be controlled for 5 dyes with the quality like the conventional cured leaves by closing the curing house from the late curing stage. But when the curing house was not ventilated earlier, however the curing period was shortened but its quality was decreased.

• 한국도로학회논문집
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• 제19권2호
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• pp.67-74
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• 2017

PURPOSES : The objective of this study is to ascertain the curing period of cementless cold central plant recycled asphalt base-layer, using mechanical analyses and specimen quality tests on the field. METHODS : Cold central plant recycled asphalt base-layer mixture was produced in the plant from reclaimed asphalt, natural aggregate, filler for the cold mix, and the modified emulsion AP using asphalt mix design and plant mix design. In order to examine the applicability of the curing period during the field test, the international standards for the possibility of core extraction and the degree of compaction and LFWD deflection were analyzed. Moreover, Marshall stability test, porosity test, and indirect tensile strength test were performed on the specimens of asphalt mix and plant mix design. RESULTS : The plant production process and compaction method of cementless cold central plant recycled asphalt base-layer were established, and the applicability of the optical moisture content for producing the mixture was verified through the field test. In addition, it was determined that the core extraction method of the conventional international curing standard was insufficient to ensure performance, and the LFWD test demonstrated that the deflection converges after a two-day curing. However, the back-calculation analysis reveals that a three-day curing is satisfactory, resulting in a general level of performance of dense asphalt base-layer. Moreover, from the result of the specimen quality test of the asphalt mix design and plant mix design according to the curing period, it was determined that the qualities satisfied both domestic and international standards, after a two-day curing. However, it was determined that the strength and stiffness after three-day curing are higher than those after a two-day curing by approximately 3.5 % and 20 %, respectively. CONCLUSIONS:A three-day curing period is proposed for the cementless cold central plant recycled asphalt base-layer; this curing period can be demonstrated to retain the modulus of asphalt-base layer in the field and ensure stable quality characteristics.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 봄 학술발표회논문집(II)
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• pp.695-702
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• 1998

The purpose of this study is to investigate the mechanical properties of precast concrete cured by accelerated curing methods such as, steam curing method and warm water curing method varing maximum temperature of curing along to the period of curing. Some specimens are cured by accelerated curing method(warm water curing method) and then deposited in the storehouse. The others are deposited in the storehouse directly. All of these are cured until being tested to compare these two group's mechanical characteristics for each period 3days, 7days, 28days. The goal of this comparison is to estimate the efficiency of accelerated curing method in the case of precast concrete stocked in the field or warehouse for a long term and to make guide line for factory manager to make a economical products of concrete of a good quality. We can conclude some guide lines 1) It is not efficient to cure concrete with accelerated method at higher than 80℃. 2) The continuing of curing period more than 36hr makes damage to concrete in using accelerated curing method. 3) The strength revelation of concrete cured by accelerated curing methods, added rice husk ash more delayed than OPC concrete done but the strength of maximum value is higher than OPC concrete. 4) It is not efficient to use accelerated curing method in the case of storing the products for more than 7days in the aspect of mechanical properties.

• Advances in concrete construction
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• 제5권4호
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• pp.359-375
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• 2017

This paper presents a study of the properties and behavior of self-compacting concretes (SCC) in the hot climate. The effect of curing environment and the initial water curing period on the properties and behavior of SCC such as compressive strength, ultrasonic pulse velocity (UPV) and sorptivity of the SCC specimens were investigated. Three Water/Binder (W/B) ratios (0.32, 0.38 and 0.44) have been used to obtain three ranges of compressive strength. Five curing methods have been applied on the SCC by varying the duration and the conservation condition of SCC. The results obtained on the compressive strength show that the period of initial water curing of seven days followed by maturation in the hot climate is better in comparison with the four other curing methods. The coefficient of sorptivity is influenced by W/B ratio and the curing methods. It is also shown that the sorptivity coefficient of SCC specimens is very sensitive to the curing condition. The SCC specimens cured in water present a low coefficient of sorptivity regardless of the ratio W/B. Furthermore, the results show that there is a good correlation between ultrasonic pulse velocity and the compressive strength.

• 한국작물학회지
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• 제28권2호
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• pp.252-257
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• 1983

버어리종 대말림시 백화엽발생을 방지하고 건조기간을 단축하기 위하여 시험을 수행하였던 바, 결과를 요약하면 다음과 같다. 1. 건조실내 온도는 흑색비닐피복구 및 환기창이용구가 관행구보다 $3^{\circ}C$정도 높았으며, 탈수속도는 환기창이용구가 훨씬 빨랐다. 2. 백화엽발생율은 완전대말림구가 높았고, 지면을 30cm 판 처리가 낮았다. 3. 수량감소는 완전대말림구가 컸다. 4. 품질 및 대금은 환기창이용구 및 지면을 30cm판 구가 높았다. 5. 물리성은 줄말림용 차광막처리가 비교적 양호하였다. 6. 백화엽발생을 억제하기 위하여는 첫째, 본포에서 치마름엽과 과숙엽을 방지하고, 둘째, 하위엽은 1-2회 수확한 후 대베기를 실시하며, 셋째, 갈변후에는 건조기간을 단축시키기 위한 온습도관리에 유의해야 할 것으로 생각된다. 7. 버어리종 담배의 물리성을 향상시키면서 건조중 백화의 원인이 되는 산소 및 수분과의 반응을 억제시킬 수 있는 방법에 대하여는 앞으로 더욱 검토가 요구된다.

• Structural Engineering and Mechanics
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• 제58권6호
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• pp.989-999
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• 2016

Moist curing of concrete is a time consuming procedure. It takes minimum 28 days of curing to obtain the characteristic strength of concrete. However, under certain situations such as shortage of time, weather conditions, on the spot changes in project and speedy construction, waiting for entire curing period becomes unaffordable. This situation demands early strength of concrete which can be met using accelerated curing methods. It becomes necessary to obtain early strength of concrete rather than waiting for entire period of curing which proves to be uneconomical. In India, accelerated curing methods are used to arrive upon the actual strength by resorting to the equations suggested by Bureau of Indian Standards' (BIS). However, it has been observed that the results obtained using above equations are exaggerated. In the present experimental investigations, the results of the accelerated compressive strength of the concrete are used to develop the regression models for predicting the short term and long term compressive strength of concrete. The proposed regression models show better agreement with the actual compressive strength than the existing model suggested by BIS specification.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회 논문집(II)
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• pp.939-944
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• 2000

This study examines both strength development and pore volume of high temperature curing mortar, using a blast-furnace slag powder (BFS). This study experiments with various pre-steaming period, differing curing temperature and the replacement of BFS. According to the results, the strength development of BFS mortar is stronger when higher curing temperature are used(as opposed to standard curing). Also, regardless of the curing method, pore volume decreases as the curing time increases. From these results we can identify the optimum conditions required pre-steaming period, differing curing temperature and the replacement to produce BFS mortar properties.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 봄 학술논문 발표대회
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• pp.91-92
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• 2022

This study is a basic study on carbonation curing technology of concrete using supercritical CO₂, and carbonation curing was carried out by exposing concrete to supercritical CO₂ for a certain period of time. In the case of conventional carbonation curing, long-term curing was performed for several weeks by controlling the concentration of CO₂, but by using supercritical CO₂, more rapid carbonation curing was carried out using constant temperature and pressure conditions to improve durability through surface modification of concrete. This experiment was conducted with the goal of deriving the optimal carbonation curing conditions by measuring the carbonation depth by exposing concrete for a certain period of time to conditions above the supercritical level. As a result, it was confirmed that the carbonation depth increased as the curing time increased, and the curing time could be shortened compared to the carbonation curing according to the existing CO₂ concentration.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2017년도 추계 학술논문 발표대회
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• pp.77-78
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• 2017

In this study, the effect of insulation curing for mass concrete wall according to thickness and curing period was evaluated by thermal analysis.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 춘계 학술논문 발표대회
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• pp.126-127
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• 2014

At construction sites, due to the reason of inconvenience and difficulties of producing and using curing equipment and when it comes to measuring compression strength of the actual structure, strength of structure concrete according to general standards which are suggested in concrete standard specification are assessed. However, this method does not consider various variables of the sites such as kinds concretes and sizes of frame works so that it is not easy to measure proper curing period and strength. Thus, this study reviews description of strength development according to In-situ temperature system and analyzes and compares properties of strength development of the existing curing methods such as sealing curing so that it provides basic materials for period of removal of molds.