• Title/Summary/Keyword: freezing, thawing

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Effect of Concrete Coating Materials for the Improvement of Concrete Durability (콘크리트 표면도장에 의한 내구성증진 효과)

  • 문한영;김성수;안태송;김홍삼
    • Proceedings of the Korea Concrete Institute Conference
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    • 1999.04a
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    • pp.433-436
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    • 1999
  • Long-term durability of the reinforced concrete structures exposed to marine environment deteriorates seriously by the attack of the chloride ion from see water results in corrosion of steel reinforcement in concrete. Their coating effect is aluminum oxide-isocyanate-based coating material, resistance of chloride penetration, carbonation and freezing and thawing resistance were compared to acryl-based coating material and sealer type o waterproofing material. Aluminum oxide-isocyante-based and acryl-based coating material show higher resistance to chloride penetration and carbonation than the sealer type do waterproofing material and aluminum oxide-isocyanate-based coating resist about 99% of chloride penetration. Resultants to the accelerated test for freezing and thawing, coating concrete show higher resistance than non-coating concrete, respectively.

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Freezing and Thawing Resistance of Latex Modified Concrete with Latex Content (라텍스 혼입에 따른 LMC의 동결융해 저항특성평가)

  • 이주형;정원경;김동호;이봉학;원치문;이정호
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.10a
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    • pp.497-502
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    • 2000
  • This study was performed to change the latex content for properties of freezing-thawing resistance. When styrene-butadiene latex is added to portland cement, aggregate and water, a concrete with the color, consistency and workability of ordinary conventional concrete results, but with 20% to 35% less water. When cured, the concrete consists of hydrated cement and aggregate interconnected by a film of latex particles. In general, increasing the amount of latex will produce concrete with increased tensile and flexural strength and lower modulus of elasticity. Air entrainment has been used in conventional concrete for the past 50 years to impart freeze-thaw resistance. Latex modified concrete does not need additional air entrainment for freeze-thaw resistance provided adequate cure occurs.

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The Service Life Prediction of Concrete with Crushed Sand in Condition of Freezing and Thawing (동결융해작용을 받는 부순모래 콘크리트의 수명예측)

  • Kang, Su-Tae;Ryu, Gum-Sung;Park, Jung-Jun;Lee, Jang-Hwa;Koh, Kyung-Taek
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.11a
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    • pp.739-742
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    • 2005
  • In this study, we predicted the service life against the freezing and thawing. as a result, we found that in the case of using the low quality crushed sand with high water-cement ratio, there is the possibility of deterioration. but in any other case, we concluded that there is no chance to deteriorate if we have the required air contents by using AE agent. we are going to improve the method to evaluate more exactly the durability of the concrete with crushed sand by acquiring data from the specimen which are exposed to field for long time.

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Evaluation of Durability Properties of Cement Matrix Using the Polymer of Powder Type (분말형 폴리머를 사용한 시멘트 경화체의 내구성 평가)

  • Kim, Seong-Soo;Jung, Ho-Seop;Lee, Jeong-Bae;Yoon, Ha-Young;Koh, Joon-Ho
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.11a
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    • pp.495-498
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    • 2005
  • It was investigated the durability of the concrete to improve construction materials with polymer cement mortar in this study. With the popularity of repair and rehabilitation material, some mixtures composed of Ethylene Vinyl Acetate(EVA) was studied. Ethylene Vinyl Acetate(EVA) carried out tests to determine its properties which a include: freezing-thawing resistance test, carbonation test, and chemical resistance test. Result of freezing-thawing resistance test, mass change ratio and chemical resistance test, mass change ratio decreased of 12 and $15\~45\%$ as compared with control mortar. Carbonation depth decreased $3.7\~5.6mm$ as polymer-cement ratio increased $1\~4\%$.

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Durability Properties of Loess Mortar Using Eco-friendly Loess Binder (친환경 황토 고화재를 사용한 황토 모르타르의 내구 특성)

  • Jung, Yong-Wook;Lee, Seung-Han;Jang, Seok-Soo;Yeo, In-Dong;Choi, Jong-Oh
    • Proceedings of the Korea Concrete Institute Conference
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    • 2010.05a
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    • pp.287-288
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    • 2010
  • The purpose of this study aimed to evaluate properties of water resistance, disease of freezing and thawing and XRF of Loess mortar using non-cement binder to solve reduction of durability by freezing and thawing on exiting Loess bicycle load.

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Effects of Solubilization Pretreatment of Wastewater Sludge on Anaerobic Digestion (하수슬러지의 혐기성 소화에 미치는 가용화 전처리의 효과)

  • Park, Ki Young;Kim, Dae Young;Chung, Tai Hak
    • Journal of Korean Society of Water and Wastewater
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    • v.14 no.1
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    • pp.117-126
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    • 2000
  • Solubilization pretreatments were conducted to enhance the anaerobic digestion of the waste activated sludge. Four pretreatment techniques including heating, sonication freezing and thawing, and enzyme addition were employed to solubilize the waste activated sludge under various conditions. Thermal pretreatment by heating showed the highest efficiency compared with other methods, and freezing and thawing was confirmed as a feasible alternative of solubilization as well as the pretreatment of dewatering. There is a clear correlation between the solubilization efficiency of the waste activated sludge and the gas production. Batch digestion results showed the cumulative gas production as much as four times after thermal pretreatment as compared with that by the control sludge without pretreatment. As a result, hydrolysis or solubilization pretreatment might play a significant role in the high rate digestion of the waste activated sludge.

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Durability Properties of Low Carbon Green Concrete (저탄소 그린콘크리트의 내구 특성)

  • Cho, Il Ho;Sung, Chan Yong
    • Journal of The Korean Society of Agricultural Engineers
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    • v.55 no.6
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    • pp.11-17
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    • 2013
  • This study was performed to evaluate the chlorine ion penetration resistance, chemical resistance and freezing and thawing resistance used ordinary portland cement, crushed coarse aggregate, crushed sand, river sand, fly ash, limestone powder, blast furance slag powder and superplasticizer to find optimum mix design of low carbon green concrete for structures. The performance of low carbon green concrete used fly ash, limestone powder and blast furnace slag powder were remarkably improved. This fact is expected to have economical effects in the manufacture of low carbon green concrete for offshore structures. Accordingly, the fly ash, limestone powder and blast furnace slag powder can be used for offshore structure materials.

Study on the Freezing Conditions for the Frozen-Dough Preparation of Bread (냉동생지 제조를 위한 냉동조건 탐색)

  • Hahn Young-Sook
    • Journal of the East Asian Society of Dietary Life
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    • v.14 no.5
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    • pp.443-448
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    • 2004
  • In order to investigate the optimal factors for frozen dough production, the freezing and thawing condition such as temperature and time, storage period and the effect of ingredient addition were determined. A pre-fermentation of dough at 30℃ for 120 minutes was appeared to be the best for the production of frozen dough. The dough was frozen at -18℃ and then stored for 7 days. The quality of frozen dough was found to be optimal when thawed at 30℃ for 80 minutes. As ingredient of frozen dough, an addition of 3% of yeast and 4% of butter was good as well as the addition of skim milk and sugar in terms of fermentation capacity after thawing.

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Durability of Polymer-Modified Mortars Using Redispersible Polymer Powder (재유화형 폴리머 분말을 사용한 폴리머-시멘트 모르타르의 내구성)

  • Yeon, Kyu-Seok;Joo, Myung-Ki;Jeong, Jung-Ho;Jin, Xing-Qi;Lee, Chi-Won
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.05b
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    • pp.537-540
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    • 2005
  • Durability of the polymer-modified mortars using the redispersible SBR and PAE powder-modified mortars were experimentally investigated. Results of a previous study were used to determine the mix proportion that optimized the strength, and the freezing-thawing resistence, the carbonation depth and the chloride intrusion depth of the mortar for various polymer-cement ratios were studied. After 300 freezing-thawing cycles, the rate of weight reduction decreased from 7 to below 2 $\%$ as the polymer-cement ratios increased from 0 to 15 $\%$, and, on the 150 cycle basis, durability index increased from 60 to 98. Carbonation depth decreased from initial value of 5.5 to about 2.5 mm and chloride intrusion depth did from 3.5 to 1.5 mm

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Chemical Resistance Characteristics of Concrete Surface Coating Agent with Flexibility (유연성을 갖는 콘크리트 표면보호재의 내화학적 특성)

  • Han, Sang-Hoon;Yoon, Ju-Yong;Lee, Byung-Ro;Hong, Ki-Nam
    • Journal of the Korean Society of Safety
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    • v.27 no.3
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    • pp.96-103
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    • 2012
  • The purpose of this study is evaluate the ability of coating materials developed in order to prevent the durability deterioration of the concrete structure. Neutralization test, freezing and thawing test, and sulfate resistance test were performed in this study. Test results show that the developed coating material is effective against durability deterioration.