• Title/Summary/Keyword: Drying Shrinkage Crack

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Performance review of ultra-low shrinkage concrete by field application (현장적용을 통한 초 저수축 콘크리트의 성능 검토)

  • Kim, Kang-Min;Lee, Hyun-Seung;Seo, Tae-Seok
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2022.11a
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    • pp.211-212
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    • 2022
  • In this study, the cracking control performance of ultra-low shrinkage concrete was investigated by the field application. As a result, drying shrinkage crack occurred in normal concrete wall, but no crack occurred in ultra-low shrinkage concrete wall. It is determined that the drying shrinkage crack control effect of the ultra-low shrinkage concrete is excellent.

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Crack Characteristics of Soil Concrete Using Volcaniclastic and the Crack Repair Method (화산쇄설물을 사용한 소일콘크리트의 균열특성과 보수방법에 관한 연구)

  • Hong, Chong-Hyun
    • Journal of Environmental Science International
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    • v.19 no.6
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    • pp.737-746
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    • 2010
  • Restraint to drying shrinkage is the most common cause of concrete cracking. In many applications, drying shrinkage cracks are inevitable. In this paper, the surface cracks of soil concrete caused by drying shrinkage were considered to become an one of concrete textures. So, laboratory shrinkage tests were conducted and the results were applied to the field applications. The study results were summarized as follows; First, the use of vinyl sheets and concrete polymers helped to control the concrete cracking. Second, crack propagation usually started at the interfaces of soil concrete slabs and the cracks grew to the inner slabs. Third, surface cracks of soil concrete slabs could be an one of good concrete textures

Effect of Admixtures on Drying Shrinkage Crack of Hardened Cement Mortar (시멘트경화체의 건조수축균열에 미치는 혼화재의 영향)

  • 이승한;이종석
    • Proceedings of the Korea Concrete Institute Conference
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    • 1995.10a
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    • pp.229-233
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    • 1995
  • In this study we have the properties of drying shrinkage crack of hardened cement mortar using admixtures. The drying shrinkage cracking test process has been examined by the restrained drying shrinkage strain by restraining rate measuring properties of strain-with- restraint by JIS original proposal and keeps a flow value of mortar about 100$\pm$5%. The results show that the usage of shrinkage reducing agent 1.5% was effective on the control of drying shrinkage in OPC and CP by restraining rate 20% and strain-with-restraing 20~30 $\mu$, the usage of expansion agent 0.45% was effective by restraining rate 50~60% and strain-with-restraint 40~80$\mu$, and the effectiveness was increased with shrinkage reducing agent. Also. admixtures such as Flyash, CP and NC reduced restrained shrinkage and drying shrinkage cracking and more with shrinkage reducing agent

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Influence of Shrinkage Reducing Agent on Drying Shrinkage of Mortar (모르타르의 건조수축에 미치는 수축저감제의 영향)

  • 이승한;정용욱;박정섭
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.10a
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    • pp.563-566
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    • 2000
  • The study is to examine the drying shrinkage reducing method of mortar using organic shrinkage reducing agent. According to the experiment result, when 2% and 4% of organic shrinkage reducing agent were added, 40% and 50% of the shrinkage rate of mortar were obtained. Also, in the cracking test of plate-shape specimen, the usage of shrinkage agent 2% reduced about 60% of the total cracking length compare to total cracking length the usage of portland cement, the usage of shrinkage agent 4% was not happened crack until 90 days. Accordingly, the usage of shrinkage agent show good effect in prevention of crack.

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Durability Evaluation of Ternary Blend Concrete Mixtures adding Ultra Fine Admixture (고분말도 혼화재를 첨가한 삼성분계 시멘트 콘크리트의 내구성 평가)

  • Ahn, Sang Hyeok;Jeon, Sung Il;Nam, Jeong-Hee;An, Ji Hwan
    • International Journal of Highway Engineering
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    • v.15 no.5
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    • pp.101-110
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    • 2013
  • PURPOSES : The purpose of this study is to evaluate the durability of ternary blended concrete mixtures adding ultra fine admixture. METHODS : From the literature review, crack was considered as the main distress failure criterion on concrete bridge deck pavement. To reduce the initial crack development due to drying shrinkage, CSA expansion agent and shrink reduction agent were used to ternary blended concrete mixtures as a admixture. Laboratory tests including chloride ion penetration test, surface scaling test, rapid freeze & thaw resistance test, non restrained drying shrinkage and restrained drying shrinkage test were conducted to verify the durability of ternary blended concrete mixtures. RESULTS : Based on the test results, proposed mixtures were verified as high qualified durable materials. Expecially initial drying shrinkage crack was not occurred in ternary blended concrete mixtures with CSA expansion agent. CONCLUSIONS : It is concluded that the durability of proposed ternary blend concrete mixture was acceptable to apply for the concrete bridge deck pavement.

A Study on the Influence Factors on Crack Properties of CFRD Face Slab Concrete (CFRD 차수벽 콘크리트의 균열 특성에 미치는 각종 영향요인에 관한 연구)

  • 최세진;임정열;김완영;김무한
    • Journal of the Korea Concrete Institute
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    • v.12 no.6
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    • pp.109-117
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    • 2000
  • CFRD(Concrete Faced Rockfill Dam) face slab concrete has a much capability to occur crack due to drying shrinkage, plastic shrinkage and bad compaction etc. Because of these cracks of concrete induce structural problem and decrease durability of dam, it is need to reduce crack of face slab concrete. This is an experimental study to analyze the influence factors on crack properties of CFRD face slab concrete. For this purpose, various mix proportion of CFRD face slab concrete and concrete using PPF(polypropylene fiber0 and fly ash was selected. And tests for drying shrinkage, bonding strength, water permeability and plastic shrinkage were performed, and then CFRD D and PPC of those mix proportion were placed in CFRD field. According to test results, it was found that the bonding strength of C1(compact sufficiently) was higher about 10~20% than that of C2(compact insufficiently). And the engineering properties of PPC(concrete using PPF) and FAC(concrete using fly ash) were better than those of the others ; the permeability of PPC and FAC after 8 weeks curing was little lower than that of CFRD D, and plastic shrinkage crack of PPC and FAC was lower 40~60% than crack of CFRD D.

Analysis of Characteristics in Low-shrinkage Cement Treated Base (저수축 시멘트 안정처리 기층의 특성분석)

  • Lee, Seung-Woo;Jeon, Beom-Jun;Kim, Jong-Won
    • International Journal of Highway Engineering
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    • v.6 no.2 s.20
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    • pp.61-70
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    • 2004
  • Cement treated Soil has superior characteristics as pavement-base including strength, curability, hardness, freezing resistance. However drying shrinkage of Cement treated base has been indicated as disadvantage, since reflection crack of surface layer is induced from drying shrinkage of cement treated base. This study propriety about low-shrinkage cement treated base that can control shrinkage of cement and control reflection crack at asphalt overlay & concrete slab.

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Field Application of the Concrete with the Combination of Drying Shrinkage-Reducing Superplasticizer and Double Layer Bubble Sheet (건조수축 저감형 유동화제 및 2 중 버블시트를 사용한 콘크리트의 현장적용)

  • Han, Cheon-Goo;Oh, Chi-Hyun;Shin, Jae-Kyung
    • Journal of the Korea Institute of Building Construction
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    • v.7 no.1 s.23
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    • pp.107-113
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    • 2007
  • This study investigates the filed application in Daebul Free Trade Zone applying both a flowing method using drying shrinkage-reducing superplasticizer(SRS) and an insulating curing method using double layer bubble sheet. Test results showed that fresh concrete satisfied target slump and air content. A structure adding SRS significantly decreased the total bleeding capacity and accelerated the setting time. As for the crack occurrence, the structure applying the flowing method and double bubble sheets simultaneously exhibited the most favorable crack endurance, while conventional concrete showed more than 1mm size of crack in overall. In addition, a structure applying the flowing concrete method partially presented the micro crack. For the area proportion of crack occurrence, the structure using the double bubble sheets indicated 9.8%, while others applying flowing concrete method was 28%, compared with that of conventional one. For the compressive strength of specimens, standard curing specimens indicated $3{\sim}33%$ higher value than that of specimens cured besides the field construction. The specimens containing SRS improved the strength of $2{\sim}6MPa$, which is $10{\sim}22%$ higher than that of conventional concrete.

Field Application of Concrete Using Drying Shrinkage-Reducing Superplasticizer (건조수축 저감형 유동화제를 사용한 콘크리트의 현장적용)

  • Shin, Jae-Kyung;Oh, Chi-Hyun;Choi, Jin-Man;Lee, Seong-Yeun;Han, Min-Cheol;Han, Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2006.11a
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    • pp.13-16
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    • 2006
  • This study investigates filed application in Daebul Free Trade Zone of a flowing method using drying shrinkage-reducing superplasticizer(SRS) and an insulating curing method using double bubble sheets. Test showed that fresh concrete satisfied target slump and air content. A structure adding SRS significantly decreased the total bleeding capacity and accelerated the setting time. As for the crack occurrence, the structure applying the flowing method and double bubble sheets simultaneously exhibited the most favorable crack endurance, while conventional concrete showed more than 1mm size of crack in overall, and a structure applying only the flowing method partially presented micro crack. For the area proportion of crack occurrence, the structure using the double bubble sheets indicated 9.8%, while others applying flowing method was 28%, compared with 100% of conventional one. Standard curing specimens had about $3{\sim}6%$ higher compressive strength than that of specimens cured at adjacent field construction. In addition, using SRS improved about $5{\sim}7MPa$, than that of conventional concrete at 91 days elapse.

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Evaluation on the shrinkage crack of concrete with crack self-healing agent (균열 자기치유형 혼화재 적용 콘크리트의 수축균열 평가)

  • Hong, Seok-Beom;Yoo, Jo-Hyeong;Kim, Woo-Jae
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2014.05a
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    • pp.82-83
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    • 2014
  • Concrete with self-healing admixture can reduce the crack width by using a compound for chemical reaction with incoming water and carbon dioxide through the crack. Also, concrete with self-healing admixtures can reduce early-age shrinkage crack by using a inorganic expansive agent. In this research, we perform the basic workability test and compressive test. Also, We measure the drying shrinkage of concrete specimen. Finally, we make mock-up (3m X 3m X 0.23m) and monitor the crack width and length for 3 months.

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