• Title/Summary/Keyword: time of setting

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Analysis of Early-age Property of JPCP Slab of Incheon International Airport (인천국제공항 줄눈콘크리트 슬래브의 초기재령 특성분석)

  • Sun, Ren Juan;Jeong, Jin-Hoon;Cheon, Sung-Han;Lim, Jin-Sun
    • 한국방재학회:학술대회논문집
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    • 2007.02a
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    • pp.335-339
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    • 2007
  • A jointed plain concrete pavement(JPCP) slab was tested in Incheon International Airport construction work to study the early-age property of JPCP slab. The temperature and moisture data of the concrete slab had been collected and analyzed. The setting time of the concrete was decided by using the maturity method. The initial setting time is 2 hours 40 minutes after the placement of the slab. The investigation and analysis of the slab began from the initial setting time. The strains of different locations and different depths of the slab show different variation character.

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Estimation of Setting Time and Compressive Strength of Ternary Blended Concrete Applying Estimator (추정계를 활용한 3성분계 콘크리트의 응결 및 압축강도 추정)

  • Park, Jae-Woong;Lim, Gun-Su;Kim, Jong;Han, Min-Cheol;Han, Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2023.05a
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    • pp.143-144
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    • 2023
  • This study aimed to evaluate the feasibility of estimating the setting time and compressive strength in Ternary Blended Concrete(TBC) using Settimeter, Strength meter, and Hybrid meter. It was determined that the hardness values at the initial setting time and final setting time of Settimeter, Hybrid meter, and at the 5 MPa of Strength meter were not affected by the mixing ratio of TBC. However, future studies need to consider the errors caused by the instability of the measurement surface during condensation and the state of the measurement surface after hardening.

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Setting Estimation of Cement Paste Using New-type Embedded Sensor (매입형 센서를 활용한 시멘트 풀의 응결 시간 측정)

  • Shin, Kyung-Joon;Lee, Do-Keun;Seo, Dong-Wan;Yoo, Chul-Min;Lim, Min-Hyuk;Lim, Sung-Hwan
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.4 no.4
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    • pp.483-488
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    • 2016
  • The present study proposes an economical embedded ring-sensor that can measure a strain behavior of cement paste and mortar in early age. Using the proposed ring-sensor, the experimental method is proposed that can measure the setting time of the cement paste and mortar conveniently. The experimental study has been conducted using the mixtures of which W/C are 0.30, 0.35, 0.40, and 0.45. From the test result, the setting times measured by convectional test methods such as vicat method and penetration resistance method are compared with the setting time proposed by this study. The result reveals that the proposed ring-sensor can effectively measure the early age behavior so that can evaluate the time when the contraction starts. In addition, the contraction starting time can be regarded as a rational setting time, which is similar to the initial setting of convectional test methods.

The Characteristics of the Change in dry Contraction Length of Dry Mortar for Each Cosmetic Period using an Improved Durometer (개량형 Durometer를 활용한 미장시기별 Dry Mortar의 건조수축 길이변화 특성)

  • Han, Soo-Hwan;Hyun, Seung-Yong;Hwang, Yin-seung;Yoon, Chi-Whan;Han, Min-Cheol;Han, Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2021.11a
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    • pp.190-191
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    • 2021
  • This study is conducted to provide a method to estimate the setting time and early age compressive strength using D type durometer.Test results indicated that the use of D type Durometer attached with modified needle, which was designed to secure improved accuracy in setting and compressive strength, enables to estimate setting time and the compressive strength at early age.

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Quantitative Analysis of Hydrate of Sugar-based Super Retardign Agent Mixed Cement Paste Using Rietveld Method (리트벨트법을 이용한 당류계 초지연성 혼화제 혼입 시멘트 페이스트의 수화생성물 정량 분석)

  • Hyun, Seung-Yong;Hu, Yun-yao;Kim, Su-Hoo;Kim, Jong;Han, Min-Cheol;Han, Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2021.11a
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    • pp.74-75
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    • 2021
  • This study attempted to study the setting time and compressive strength according to the sugar type through XRD. Setting time was found to be delayed the most when mixing white sugar, and setting time was promoted when mixing Saccharin and Aspartame. It was found that when white sugar and Grosvener siraitia were mixed, the compressive strength was higher than that of Control. Aspartame the age passed, C3S decreased and Ca(OH)2 increased.

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Prediction of Setting Time of the Cement Mortar Considering Equivalent Age (등가재령에 의한 시멘트 모르터의 응결시간 예측)

  • Choi, Hyun-Kyu;Son, Ho-Jung;Baek, Dae-Hyun;Lim, Choon-Keun;Han, Min-Cheol;Han, Cheon-Goo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2010.05a
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    • pp.331-332
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    • 2010
  • This paper present a method to estimate the setting time of cement mortar incorporating admixtures under various curing temperature conditions by appling maturity based on equivalent age. It is indicated that equivalent age using setting time can be a proper method to predict setting time and it also exhibited comparable relativity between prediction value and measurement value.

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Setting Properties of Concrete with the Combination of Mineral and Chemical Admixture (광물질혼화재와 화학혼화제의 조합사용에 따른 콘크리트의 응결특성)

  • Kim Jong;Song Seung Heon;Jeon Chung Keun;Han Min Cheol;Oh Seon kyo;Han Cheon Goo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2004.11a
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    • pp.505-508
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    • 2004
  • This paper investigated the setting and compressive strength of concrete with the combination of mineral and chemical admixture. According to test results, plain concrete with high early strength development type AE water reducing agent(HEAEWRA) and $10\%$ of CKD respectively had earlier setting time than concrete with AE water reducing agent by $0.5\~1.5$ hours. Setting time of concrete with retarding type AE water reducing agent(RAEWRA) and FA $30\%$, BS $60\%$ respectively retarded by as much as $4\~7.5$ hours compared with plain concrete. Plain concrete with HEA WRA, $10\%$ of CKD and RAEWRA had higher strength than that of AE water reducing agent by as much as 5MPa at 28days. From the result of the paper, it is found that the combination of mineral admixture and setting accelerating or retarding agent can reduce the hydration heat cracks by setting time difference and hydration heat reduction effects.

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The Study on the Strength Properties of High Volume Fly-Ash Concrete (플라이애시를 다량 사용한 콘크리트의 강도특성에 관한 연구)

  • Paik, Min-Su;Lee, Young-Do;Jung, Sang-Jin
    • Journal of the Korea Institute of Building Construction
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    • v.2 no.4
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    • pp.169-176
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    • 2002
  • To study of binder and fine aggregate a lot of replacement fly-ash concrete, initial characteristics, standard environment of curing temperature $20^{\circ}C$, hot-weather environment, cold weather environment of curing temperature $5^{\circ}C$. Flash concrete tested slump, air contest, setting and Hardening concrete valuated setting period of form, day of age 3, 7, 28 compression strength in sealing curing. Underwater curing specimen compression strength of age 3. 7, 28day used strength change accordingly fly-ash concrete curing temperature. Purpose of study is consultation materials in field that variety of fly-ash replacement concrete mix proportion comparison and valuation. (1) Setting test result, fly-ash ratio of replacement higher delay totting time. Same volume of fly-ash ratio of replacement is lower fly-ash ratio of replacement fine aggregate delay setting time. Setting test in curing temperature $35^{\circ}C$ over twice fast setting in curing temperature $20^{\circ}C$ and all specimen setting delay in curing temperature $5^{\circ}C$. F40 specimen end of setting about 30 time. (2) Experiment result age 28day compression strength more fisher plan concrete then standard environment in curing temperature $20^{\circ}C$, cold weather environment in curing temperature $5^{\circ}C$, most strength F43 is hot-weather environment in curing temperature $35^{\circ}C$ replacement binder 25%, fine aggregate 15%. (3) Hot-weather environment replacement a mount of fly-ash is a same of plan concrete setting period of form. Age 28day compression strength replacement a mount of fly-ash more hot-weather concrete then plan concrete.

Relationship between Apparent Viscosity and Line-Spread Test Measurement of Thickened Fruit Juices Prepared with a Xanthan Gum-based Thickener

  • Kim, Sung-Gun;Yoo, Whachun;Yoo, Byoungseung
    • Preventive Nutrition and Food Science
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    • v.19 no.3
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    • pp.242-245
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    • 2014
  • The flow behaviors of three thickened fruit juices (orange, apple, and grape juice) prepared with a commercial instant xanthan gum (XG)-based thickener that is marketed in Korea were investigated at different thickener concentrations (1.0%, 1.5%, 2.0%, 2.5%, 3.0%, and 3.5%) and setting times (5 and 30 min) using a rheometer and a line-spread measurement method. The flow distance values measured by the line-spread test (LST) were compared with the apparent viscosity (${\eta}_{a,50}$) values measured with a sophisticated computer-controlled rheometer. The ${\eta}_{a,50}$ values of the juices increased as thickener concentration increased, whereas their flow distances decreased. The ${\eta}_{a,50}$ values at the 30-min setting time were much higher than those at the 5-min setting time, indicating that the setting time before serving or consuming thickened juices can affect viscosity values. Plots comparing ${\eta}_{a,50}$ values to LST flow distances revealed strong exponential relationships between the two measures ($R^2$=0.989 and $R^2$=0.987 for the 5- and 30-min setting times, respectively). These results indicate that the LST can be a suitable instrument for evaluating the viscosity of thickened fruit juices prepared with different XG-based thickener concentrations and setting times for the dysphagia diet.

A Fundamental Test of Temperature Crack Reduction Method Application by Setting Time Control of Large-Scaled Mat Foundation Mass Concrete (초대형 매트기초 매스 콘크리트의 응결시간조정에 의한 온도균열저감 공법적용의 기초적 실험)

  • Han, Cheon-Goo;Lee, Jae-Sam;Noh, Sang-Kyun
    • Journal of the Korea Institute of Building Construction
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    • v.9 no.3
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    • pp.95-101
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    • 2009
  • Constructing large-scale mat foundation mass concrete is increasing for the stability of building structure, because a lot of high rise building are being built in order to make full use of limited space. However, It is of increasing concerns that because limited placing equipments, available job-site and systems for mass concete placement in construction field do not allow to place great quantity of concrete at the same time in large scale mat foundation, consistency between placement lift can not be secured. And also, it is likely to crack due to stress caused by the difference of hydration heat generation time. To find out the solution against above problems, this study is to reconfirm the performance of normal concrete designed by mix proportion and super retarding concrete. The Fundamental test shows what happens if low heat proportioning and control method of setting time are applied at the job-site of newly constructed high rise building. The test result show that slump flow of concrete has been somewhat increased as the target retarding time gets longer, while the air content has been slightly decreased but this is no great difference from normal concrete. The setting time shows to be retarded as target retarding time gets longer, the range of retarding time increases. It is necessary to increase the amount of mix of super retarding agent in the proportion ration by setting curing temperature high since outdoor curing is about 6 hours faster than standard curing, which means the temperature of the concrete will be higher than the temperature of the surrounding environment, due to its high hydration heat when applying in a construction site. The compressive strength of super retarding concrete appears to be lower than normal concrete due to the retarding action in the early stage. However, as the time goes by, the compressive strength gets higher, and by the 28th day the strength becomes the same or higher than normal concrete.