• Title/Summary/Keyword: length change

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Drying shrinkage and Pore Structure of Blast Furnace Slag Concrete Mixed Alkaline Stimulation (알칼리 자극제 혼입 고로슬래그 콘크리트의 건조수축과 공극구조)

  • Park, Ji-Woong;Lee, Gun-Cheol;Gao, Shan
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2016.10a
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    • pp.32-33
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    • 2016
  • This purpose of this study is to find the properties of pore structure and length change of blast furnace slag cement added alkali powder stimulant on shrinkage reducing agent presence. In length change, the specimen added alkaline stimulant was smaller than normal blast furnace slag concrete. And the specimen added shrinkage reduction agent was confirmed to show smaller rate of length change than the length. In MIP analysis of 1day-age, 0.1㎛ subsequent pore amount of the specimen added alkaline stimulant was significantly smaller value the normal blast furnace slag concrete specimen.

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Properties of Cement Mortar Immersed in Chemical Solution (화학약품용액에 침지한 시멘트모르터의 물성변화)

  • 문한영;김진철;김홍삼;유정훈;이승태
    • Proceedings of the Korea Concrete Institute Conference
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    • 1999.04a
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    • pp.407-410
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    • 1999
  • The 5 types of cement mortar was immersed in the various chemical solutions for 400 days and then the compressive strength and the length change were measured to consider the chemical resistance at required ages. Due to the effect of flyashe and GGBF slag, the compressive strength of blended cement mortar was higher than that of portland cement mortar at long ages. According to the result of length change, the mineral admixture in blended cement had an indluence on reducing the amount of C3A, the cause of making concrete expand, and it made the formation of cements mortar denser so that the length change was much smaller than that of the portland cement mortar. However, the OPC mortar immersed in Na2SO4 solution for 180 days shows 4 times bigger length change chante than the blended cement mortar.

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A Study on the Quality Properties of the Expansive For Dry-Shrinkage Compensation of the Floor Mortar (온돌바닥 모르터의 건조수축보상을 위한 팽창제의 품질특성 연구)

  • 이웅종;이종열;정연식;이순기;정성철
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.10a
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    • pp.155-160
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    • 2000
  • In this paper, we investigated quality properties for the expansive of the CaO-$CaSO_4$ family which used to compensate dry-shrinkage in the floor mortar of On-Dol heating System. This experimental study established the mix condition with quantity of the expansive and is to investigate the relativity between the compress strength and the length change and the relativity between the chemical properties and the length change with the analysis of the physical and chemical properties. As a result of the study, the expansive is controlled by more the CaO than the $CaSO_4$. The relativity between the compress strength and the length change is expressed by exponential function, showing that if the expansive performance is increased, the compress strength is decreased. And the relativity between the chemical properties and the length change is only relative the quantity of the F-CaO among the chemical properties, is expressed by the second order function, showing that if the F-CaO is increased, the expansive performance is increased.

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Physical Characteristics of Cement Mortar Prepared Using Waste Glass and Graphene Oxide (폐유리와 산화 그래핀을 사용한 시멘트 모르타르의 물성 연구)

  • Kim, Kyoungseok;Chu, Yongsik
    • Resources Recycling
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    • v.28 no.6
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    • pp.54-63
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    • 2019
  • This study investigated on the compressive strength and the length change test with using the waste glass and graphene oxide for recycling the waste glass as the aggregate. Curing on 3-day and 7-day, the compressive strength was enhanced as the usage of waste glass was increased. Especially, the huge difference in the compressive strength was observed when the amount of substituting on the waste glass was used on 10~50%. With 50% of waste glass condition, the compressive strength was portionally enhanced as the usage of graphene oxide was increased and its value was 42.6 N/㎟ with 0.2% of graphene oxide. In terms of the length change test, the use of high content of waste glass led length change value to increase, but it was dropped down as the portion of waste glass was above 50%. Furthermore, in the case of using 50% of waste glass, the use of high amount of graphene oxide tended to decrease the length change value. That is, graphene oxide may contribute on boosting the cement hydration reaction and blocking the ion's movement.

Sulfate Resistance of Cement Matrix Containing Limestone Powder

  • Moon Han-Young;Jung Ho-Seop;Lee Seung-Tae;Kim Jong-Pil
    • Journal of the Korea Concrete Institute
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    • v.16 no.3 s.81
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    • pp.433-440
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    • 2004
  • In order to improve the performance of concrete, generally, modern cements often incorporate several mineral admixtures. In this study, the experimental included the flow value, air content of mortar containing limestone powder and length change and compressive strength of mortar specimen immersed in sulfate solutions. From the experimental results, the limestone powder cement matrices improved the physical properties and sulfate resistance of cement matrices at $10\%$ replacement ratio of limestone powder. The $30\%$ replacement ratio of limestone powder was significantly deteriorated in sodium sulfate solution. Irrespective of fineness levels of limestone powder, length change and SDF of mortar specimens with only $10\%$ replacement was much superior to the other replacements.

The Study on the Length Change of Concrete Used Expansive Admixture (팽창성 혼화재를 사용한 콘크리트의 길이변화 특성)

  • 민정기;김영익;서대석;김인수;성찬용
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 1999.10c
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    • pp.289-293
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    • 1999
  • This research was performed to evaluate the longitudinal length change ratio of concrete used the expansive admixture. As the results of this study, the compressive strength was shown the highest value at the used 10% expansive admixture both of the dry and wet curing condition. And the length change ration was shown higher 0.0316% and 0.0529 % than that of control in wet and dry curing condition. But this value was not enough to recover the shrinkage occuring by dry shrinkage. According to this study , we have obtained 10% on normal portland cement concrete as the optimum replacement ration of expansive admixture.

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Characteristics of Concrete Length Change Rate according to Premixed Cement Types and CGS replacement rate (프리믹스 시멘트 종류 및 CGS 치환에 따른 콘크리트의 길이변화율 특성)

  • Han, Jun-Hui;Kim, Su-Hoo;Beak, Sung-Jin;Han, Soo-Hwan;Kim, Jong;Han, Min-Cheol
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2022.04a
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    • pp.154-155
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    • 2022
  • In this study, propose a plan to efficiently utilize CGS, a by-product generated from IGCC, as a mixed fine aggregate for concrete. The effect of the premixed cement types and CGS replacement rate on the overall characteristics and length change rate of concrete was analyzed. As a result of the analysis, the effect of CGS was found to be insignificant, and the effect of cement was found to be dominant.

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The Strength and Length Change Properties of Recycled Aggregate Concrete(RAC) by Compressive Strength Levels (압축강도 수준별 순환골재 콘크리트의 강도와 길이변화 특성)

  • Lee, Bong-Chun;Lee, Jun;Cho, Young-Keun;Jung, Sang-Hwa
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.3 no.4
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    • pp.307-312
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    • 2015
  • This paper addresses mechanical properties and length change performance of the recycled aggregate concretes(RAC) in which natural coarse was replaced by recycled coarse aggregate(RCA) by compressive strength levels(20, 35, 50 MPa). A total of 9 RAC were produced and classified into three series, each of which included three mixes designed with three compressive strength levels of 20 MPa, 35 MPa and 50 MPa and three RCA replacement ratios of 0, 50 and 100%. Physical/Mechanical properties of RAC were tested for slump test, compressive strength, and length change. The test results indicated that the workability of RC could be improved or same by RCA replacement ratios, when compared with that containing no RCA. This is probably because of the RCA shape improving the workability of RAC. Also, the test results showed that the compressive strength was decreased by 9~10% as the RCA replacement ratios increase. However, the length change ratio by the RCA replacement ratios increased regardless of compressive strength levels. At 20 MPa level, the length change ratio was 8~40% which was much higher than that of 4~17% at both 35 and 50 MPa levels. Therefore, it was considered that such admixture addition preventing dry shrinkage is required in order to improve the properties of the RAC at 20 MPa level.

Properties of Non-Shrinkage High Strength Concrete (무수축 고강도 콘크리트의 특성)

  • 조일호;민정기;윤준노;김영익;성찬용
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 1999.10c
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    • pp.283-288
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    • 1999
  • This study is performed to evaluate slump , air content, compressive strength and length change ratio of non-shrinkage high strength ocncrete is achieved by 10% expansive additive contained. The length change ration of non-shrinkage high strength concrete which is in water curing, shows 0.055% expansion in 10% expansive additive contained concrete and 0.308 expansion in 20% expansion additive contained concrete when it is curing 28 days.

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Anti-crease Finish of Cotton/Spandex Knit Fabric(II)-Setting Behaviors of Knit Fabric with Heat Treatment- (면/스판덱스 편성물의 구김방지가공(II)-열처리에 따른 편성물의 세팅 거동-)

  • 박흥수;이명학;김영호
    • Textile Science and Engineering
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    • v.37 no.12
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    • pp.744-750
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    • 2000
  • The methods to decrease crease of cotton/spandex knit fabric using heat treatment were investigated. Dry heat treatment, hot water treatment, and steam treatment were used to set spandex yarn in knit fabric. Length changes of spandex yarn in knit fabric. Length changes of spandex yarn in knit fabric treated or stored under various conditions were investigated. Wrinkle recovery rates, elongation, and tensile strength changes of the fabric were also measured. The length change of the spandex yarn in knit fabric treated with steam was larger than those treated with dry heat and hot water. It increased with increasing extension of spandex yarn in knit fabric. A long loop length of cotton yarn in knit fabric resulted in a smaller length change of the spandex yarn subjected to the same heat treatment due to the low extension of spandex yarn in fabric. The length of spandex yarn in knit fabric increased during storage even at room temperature. The crease of cotton/spandex knit fabric could be removed by setting spandex yarn in the fabric. Considering the strength retention and elongation, steam treatment was found to be the most effective to remove the crease of the knit fabric.