• Title/Summary/Keyword: curing methods

Search Result 656, Processing Time 0.037 seconds

Effect of Moisture Loss on Development of Distresses in Concrete Pavements

  • Jeong Jin-Hoon
    • Journal of the Korea Concrete Institute
    • /
    • v.17 no.4 s.88
    • /
    • pp.655-662
    • /
    • 2005
  • Evaporation of concrete influences the development of both initial transverse cracking and delamination in the concrete slab. It was suggested that spatting distress might develop in the slab where the initial transverse cracking occurred by theoretical equations and a field investigation. Thus, efforts to prevent the evaporation of concrete using proper curing methods are required to minimize the distresses of the slabs. Effective curing thickness (ECT) concept was used in this paper to evaluate various curing methods used to prevent the evaporation from concrete. Curing effectiveness quantified by the ECT of different types and amounts of curing compound under various curing conditions was investigated based on the results of laboratory tests. According to the test results, the wind speed is inferred to be a significant factor of the magnitude and continuance duration of the curing effectiveness.

Effect of Far Infrared Curing on Physicochemical Characteristics of Flue-cured Tobacco (원적외선 건조방법이 황색종 잎담배의 물리화학적 특성에 미치는 영향)

  • 복진영;김상범;이종철;이철환;백순옥
    • Journal of the Korean Society of Tobacco Science
    • /
    • v.23 no.1
    • /
    • pp.12-18
    • /
    • 2001
  • This study was conducted to investigate the effect of tobacco curing on far infrared light on the quality of flue-cured tobacco leaves. Physicochemical characteristics such as alkaloid, total sugar, total nitrogen, starch, total phenolic compounds, browning degrees, and color differences, in cured tobacco leaves were compared between hot air and far infrared curing methods. There was no significant difference in sugar/nicotine ratio and nitrogen number between the curing methods, while the contents of ether extract and filling capacity were increase by far infrared curing. Therefore, it was expected that far infrared curing might be effective for high aroma and physical properties of the cured tobacco leaves.

  • PDF

버어리종 잎담배의 건조과정중 암모니아 함량 변화

  • 김삼곤;김영회;김도연;김근수;서철원;배성국
    • Journal of the Korean Society of Tobacco Science
    • /
    • v.20 no.2
    • /
    • pp.231-237
    • /
    • 1998
  • This study was carried out to investigate the effects of curing methods on the concentration of ammonia during curing in burley tobacco leaves. The air-cured tobacco(KB108; Nicotiana tabacum L.) was grown at Chonju Tobacco Experiment Station in 1998 and the tenth leaves from the top on the stalk were harvested. Half of the harvested leaves were cured in normal air curing facility and the other leaves were cured in excessive curing facility. Stalk cut tobaccos were cured in horizontal curing facility. The leaves were sampled every five days from harvesting time to the end of curing(25 days). Ammonia concentration of leaves increased during curing period with a remarkable increase at yellowing stage. The concentration of ammonia was high in the primed cured leaves, while that of the excessive cured leaves was low. It is considered that the lower increase of ammonia in stalk cured leaves may be caused by the translocation from the leaves to the stalk during curing, while that of excessive cured leaves may be caused by the poor decomposition of protein and amino acid during curing by excessive moisture loss and high temperature condition.

  • PDF

Effect of dentin pretreatment and curing mode on the microtensile bond strength of self-adhesive resin cements

  • Youm, Seung-Hyun;Jung, Kyoung-Hwa;Son, Sung-Ae;Kwon, Yong-Hoon;Park, Jeong-Kil
    • The Journal of Advanced Prosthodontics
    • /
    • v.7 no.4
    • /
    • pp.317-322
    • /
    • 2015
  • PURPOSE. The aim was to evaluate the effect of curing mode and different dentin surface pretreatment on microtensile bond strength (${\mu}TBS$) of self-adhesive resin cements. MATERIALS AND METHODS. Thirty-six extracted human permanent molars were sectioned horizontally exposing flat dentin surface. The teeth were divided into 12 groups (3 teeth/group) according to the dentin surface pretreatment methods (control, 18% EDTA, 10% Polyacrylic acid) and curing mode (self-curing vs. light-curing) of cement. After pretreatment, composite resin blocks were cemented with the following: (a) G-CEM LinkAce; (b) RelyX U200, followed by either self-curing or light-curing. After storage, the teeth were sectioned and ${\mu}TBS$ test was performed using a microtensile testing machine. The data was statistically analyzed using one-way ANOVA, Student T-test and Scheffe's post-hoc test at P<.05 level. RESULTS. For G-CEM LinkAce cement groups, polyacrylic acid pretreatment showed the highest ${\mu}TBS$ in the self-cured group. In the light-cured group, no significant improvements were observed according to the dentin surface pretreatment. There were no significant differences between curing modes. Both dentin surface pretreatment methods helped to increase the ${\mu}TBS$ of RelyX U200 resin cement significantly and degree of pretreatment effect was similar. No significant differences were found regarding curing modes except control groups. In the comparisons of two self-adhesive resin cements, all groups within the same pretreatment and curing mode were significantly different excluding self-cured control groups. CONCLUSION. Selecting RelyX U200 used in this study and application of dentin surface pretreatment with EDTA and polyacrylic acid might be recommended to enhance the bond strength of cement to dentin.

Experimental Study to Investigate the Factors Affecting Durability of Spalled Cement Concrete Pavements (스폴링이 발생한 콘크리트 포장의 내구성 영향인자 조사를 위한 실험적 연구)

  • Yoo, Tae Seok;Ryu, SungWoo;Kim, Jin Cheol
    • International Journal of Highway Engineering
    • /
    • v.20 no.2
    • /
    • pp.27-34
    • /
    • 2018
  • PURPOSES : It is necessary to prevent premature failure of concrete pavements caused by durability problems. The purpose of this study was to find factors affecting the durability of concrete pavements, and suggest improvement methods for existing concrete mix design. METHODS : Factors influencing durability were derived from laboratory test data for common field failure conditions and main properties of concrete cores taken from the field. The improvement of concrete properties was investigated by evaluating the performance of existing and proposed mix proportion designs and curing methods. RESULTS : The compressive strength and the absorbing performance of the low Blaine cement and the high-strength mixture were better than those of the Type I cement. Wet curing showed better compressive strength, elastic modulus, coefficient of thermal expansion, and absorption performance than air curing or compound curing. As a result of comparing concrete cores collected in the field, the sections with good durability showed good performance in terms of resistance to chloride ion penetration, absorption, and initial absorption rate. CONCLUSIONS : The absorption performance was considered as a possible foactor affecting durability of cement concrete pavements as a result of field core tests. In order to improve the durability of the pavement concrete, it is necessary to improve the existing mixtures and curing methods.

Investigation on the Water Retention Properties of Cement Mortar by Curing Method (양생방법별 시멘트 모르타르의 보습특성 검토)

  • Lee, Gun-Cheol;Cho, Byoung-Young;Lee, Jeoung-Yun;Kim, Young-Geun
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2009.05a
    • /
    • pp.365-366
    • /
    • 2009
  • Humidity curing of the concrete after placing is significant to ensure the crack resistance, strength, and durability. Generally, there are watering and sheet curing methods as humidity curing methods to the upper part of slab concrete, therefore this study investigates effects of these curing methods to preservation of humidity on the cement mortar.

  • PDF

A Study on the Dimensional Changes through the Curing Method of Denture (의치의 중합방법에 따른 변화에 대한 연구)

  • Lee, Jai-Youl
    • Journal of Technologic Dentistry
    • /
    • v.9 no.1
    • /
    • pp.67-72
    • /
    • 1987
  • This experimental study presented the study on the dimensional changes of occuring for the denture curing methods. The method is as follows: 1. The master die was made of wax. 2. The Silicon Rubber Mold was made into the same 80 casts. 3. The 80 Wax Plate were made of using the Base Plate Wax. 4. Flasking, Wax-wash, & Resin-packing were performed by the general procedures. 5. The curing method is performed through the four curing methods. (A, B, C, D). Table 2 shows the dimensional change after a day. Table 3 shows the dimensional change after soaking for 30 days in water of the degree of 36 Centigrade. As a result, the A curing method is the most denture curing.

  • PDF

Temperature History of the Wall Concrete Subjected to -10℃ depending on Heat Curing Method (-10℃ 조건에서의 보온양생방법 변화에 따른 벽체 콘크리트의 온도이력)

  • Han, Sang-Yoon;Son, Ho-Jung;Cheong, Sang-Hyun;Ahn, Sang-Ku;Han, Cheon-Goo;Han, Min-Cheol
    • Proceedings of the Korean Institute of Building Construction Conference
    • /
    • 2011.11a
    • /
    • pp.255-256
    • /
    • 2011
  • This study investigates the effect of a curing condition on the temperature history and strength development of concrete under -10℃. Combination of various curing methods was applied, i.e. a conventional form was combined with compressed insulation, heat panel and heat cable. Results showed that the concrete cured by a single use of a conventional form resulted in serious deterioration of early strength development. However, other concretes cured by the proposed curing methods maintained the temperature of the concretes between 5 and 20℃, and thus resulted in no frost damage.

  • PDF

A Study about Psychological Counseling Methods for Mental Curing Classified by Sasang Constitution (정신양생을 위한 사상체질(四象體質)별 심리상담방법에 대한 고찰)

  • Kang, Min-Su;Oh, Ji-Won;Yang, Sung-Pil;Koh, Byung-Hee
    • Journal of Sasang Constitutional Medicine
    • /
    • v.30 no.1
    • /
    • pp.43-49
    • /
    • 2018
  • Objectives In modern psychiatry, psychological counseling is important to mental curing. Although there are so many methods for mental curing, but counseling is known as the most efficient methods for mental curing. So, we are going to study about psychological counseling methods according to sasang constitution. Methods We analysed the characters of each constitution, and tried to find out which kind of counseling is suitable for each constitution. Results and Conclusions Soeumin is passive and tend to be depressive. So the self-esteem of soeumin is lower than that of other constitution. So, they mainly need social support and supportive counseling. Soyangin is tend to be extrovert group and easy to have fear. It is mainly caused by cognitive distortion, so they mainly need cognitive therapy. Taeumin is very stable and don't like to move. Taeumin Jeongchung(怔忡) is similar to panic disorder. So they need cognitive therapy and exercise counseling to exercise regularly. Taeyangin is tend to be angry, so they need meditation therapy to quell anger.

The Charncteristics of Organic Sludge in Curing Equipment (유기성 슬러지 양생장치의 건조특성)

  • Jung, Ho-Yun;Park, Jae-Sung;Kang, Jin-Soo;Yun, Hee-Chul;Lee, Yeon-Won
    • Proceedings of the KSME Conference
    • /
    • 2007.05b
    • /
    • pp.3173-3177
    • /
    • 2007
  • Recently, we have many problems on the process of the sludge. In past, the sewage sludge was treated by reclaimed land or thrown away in the sea. But these methods caused environmental pollution. Today, many researchers are studying various methods for reducing its volume. One of these method, this study is to reduce the moisture of sewage sludge and to solidify it using a dryer and curing equipment. In this research, we investigated about design parameter and operation condition of the equipment. The curing equipment reduces the percentage of water content from 30% of dryer to 10%. So, we have to study the curing characteristics and performance of curing equipment. For example, there are internal flow characteristics and change of the percentage of water content. And we investigated the change of data at outlet along the initial condition, temperature, humidity and air flow. Using this data, we achieve the experimental results of curing efficiency by each geometry and operating condition. And we also investigated numerical analysis of internal flow using CFD code. This research is basic study for optimal design of the curing equipment.

  • PDF