• Title/Summary/Keyword: concrete quality

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Feasibility Study the Assessment Factor of Quality Performance Index in Expressway Concrete Pavement (고속도로 콘크리트 포장에 대한 품질평가지수 평가인자의 적정성 검토)

  • Lee, Seung Woo;Kim, Gyung il;Ko, Dong Sig;Hong, Seung Ho
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.37 no.1
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    • pp.133-141
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    • 2017
  • Traffic volume increases according to highway expansion and industrial development which causes repetitive defect and durability degradation on pavement. The research of quality assurance system used abroad has introduced Korea. Korea Expressway Corporation (KEC) has developed a Quality Performance Index (QPI) that quantitatively assesses the level of quality of the final product, and practical applications. Assessment factor on concrete pavement consisted of pavement thickness, compressive strength, IRI and spacing factor. Assessment factor on concrete pavement is determined by empirical evaluation factor from abroad. In this study, analysis of evaluation factors of concrete pavement by using pavement life prediction simulation and measured data were evaluated with consideration of feasibility of the assessment factor. Pavement life, performance and durability are affected by pavement thickness, compressive strength, IRI and spacing factor in assessment factor on concrete pavement, QPI.

An Experimental Study on the Quality Deviation of Concrete Using Premixed Cement and Non-Premixed Cement (프리믹스 혼합시멘트를 사용한 콘크리트의 품질편차에 관한 연구)

  • Bae, Jun-Young;Kim, Jong-Back;Cho, Sung-Hyun;Roh, Hyeon-Seung;Kim, Jung-Hwan;Park, Seung-Bum
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.11a
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    • pp.569-572
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    • 2008
  • This study carried out to evaluate the quality deviation according to Premixed and Non-Premixed cement for normal and high strength concrete using blast furnace slag and fly ash. The results of experiment are founded that concrete using premixed cement have more performance than non-premixed cement at a point of view for the quality deviations both strength and Chloride ion diffusion. Therefore, it is desirable that premixed cement should be used to decrease strength deviation in high strength concrete and durability deviation in normal strength concrete.

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The Study on Earlier Evaluation of Concrete Strength Using Electric Resistance Method (전기 저항법을 이용한 콘크리트 조기 강도 판정에 관한 연구)

  • 김화중;이도현;윤상천;박정민;최신호
    • Proceedings of the Korea Concrete Institute Conference
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    • 1995.04a
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    • pp.130-135
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    • 1995
  • We can consider that the study on early evaluation of strength of concrete is useful to raise safety of building and utility of quality control of concrete is useful to raise safety of building and utility of quality control of concrete. In this paper, was proposed to method early to predict strength of concrete with key parameters, such as Water/Cement(W/C) ratio and Sand / Aggregate(S/A) ratio. Through a series of experiment, the obtained results are summarized as follow. $\circled1$ The ratio of resistance was decteased as the increase of W/C ratio. $\circled2$ The maximum value for the ratio of resistance and compressive strength was presented in the case of 40% S/A ratio. $\circled3$ The relationship. of the ratio of resistance and compressive strength on 28days according to the change of W/C and S/A ratio is to be: $F_{28}=-0.00104R^2 + 2.263R - 935.5$ (W/C Ratio) $F_{28} = 0.007R^2 - 10.693R - 4269.1$ (S/A Ratio)

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Properties of High-strength and Carbonation of Concrete with Overseas Cement (해외시멘트를 사용한 콘크리트의 고강도 및 중성화 특성)

  • 이성복;하부도언;이도헌;지남용
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.04a
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    • pp.237-242
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    • 2000
  • Recently, the importation of overseas cement has been increasing and the spot materials of different quality from Japan have to be treated in overseas construction work for technical cooperation with neighboring countries. However, a study on the quality of those oversea materials has not yet been carried out systematically, especially cement among those materials. Accordingly, in this study the properties of high-strength concrete with oversea cement imported from four countries in East Asia and South-east Asia were investigated under normal and high temperature condition, including the carbonation of normal-strength concrete under normal temperature. As a result, it is found that the required of normal-strength concrete will be expected regardless of temperature condition when the flowability is ensured by selecting the appropriate superplaticizer and dosage of it, and the carbonation rate of normal-strength concrete with overseas cement is approximately the same as that with Japanese one under the condition of the same compressive strength.

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A Study on the Bleeding Property of Flowed Concrete Due to Different Types of High Range Water Reducing Admixtures (고성능감수제 종류에 따른 유도화콘크리트의 Bleeding특성)

  • 김기수;하재담;김동석;신규연;유규홍
    • Proceedings of the Korea Concrete Institute Conference
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    • 1997.10a
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    • pp.321-326
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    • 1997
  • Recently, High Range Water Reducing Admixture be used increasingly in other to improve the demanded properties (fluidity, strength, durability etc.) and workability in concrete. These kinds of agent govern quality characteristics (air content, setting time, slump, bleeding etc) by the difference of its dispersing mechanism and performance in manufacture of flowed concrete. Accordingly, in this study, for the purpose of high quality construction in site, the comparative experiment of dispersing ability due to commercially available three types of agent were carried out in paste, mortar and concrete using tow types of cement (I, V). In conclusion, the bleeding reduction by the dispersing ability of agents was verified in the fresh properties of flowed concrete with sea water resistance.

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Performance test of Concrete IoT Management System for concrete early-age quality control (콘크리트 초기 품질관리를 위한 CIMS의 개발성능 Test)

  • Lee, Young-Jun;Choi, Yoon-Ho;Seo, Hang-Goo;Hyun, Seung-Yong;Han, Min-Cheol;Han, Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2019.05a
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    • pp.161-162
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    • 2019
  • The aim of the research is analyzing the performance of the concrete IoT management system invented with similar technique from 'G' company to certify the performance of CIMS. As a results, the compressive strength assessing performance was compared. Since both systems assess concrete compressive strength with maturity method based on measured concrete temperature, both systems measured concrete temperature similarly, and maturity was calculated similarly. Therefore, the assumed compressive strength values were similar for both systems. Therefore, through the test, compressive strength assessing performance of CIMS was considered as a similar level of the 'G' company's system. Furthermore, it is considered that the CIMS has an additional advantage of reusability, adding capability of additional sensor, and wider range of Bluetooth communication.

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A Study on the Characteristics of Concrete Use Crushed Aggregates Produced in Busan Suburbs (부산근교에서 생산된 부순골재를 사용한 콘크리트의 특성에 관한 연구)

  • Bae Won Mahn;Beak Dong Il;Jang Hui suk;Kim Myung Sik
    • Proceedings of the Korea Concrete Institute Conference
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    • 2004.11a
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    • pp.193-196
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    • 2004
  • The objective of in this study makes investigation into the characteristics of concrete as to properties and blended ratio of crushed aggregates through experimental researches. In this research observed crushed quality characteristic of crushed aggregates that is produced in representative stony mountains of Busan suburbs (Yang-san, Kim-hea, Jin-hea). And wished to investigate the quality change and characteristics of concrete with variation of blend ratio of crushed sand(50, 60, 70, 80, 90, $100\%$). Measured the air contents and slump to investigate properties of fresh concrete, and unit weight and compressive strength in age of 7, 28, 60, 90 days to investigate properties of hardened concrete.

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Computer Program for Quality Control of Ready Mixed Concrete (레디믹스트 콘크리트의 품질관리 프로그램 개발)

  • 최재진;박원태
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.3 no.1
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    • pp.20-26
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    • 2002
  • To make practical application of mixing test results to concrete mix design, experimental tests of concrete were done and the relationship between cement-water ratio and compressive strength of concrete was obtained. A computer program which can be used for data base of air content, slump and compressive strength test results was developed. The program draws $\bar{X}$-R or X-Rs control charts and has data sheets for arrangement of material test results. The computer program also helps calculation of concrete mix proportions for mixing tests and contains dictionary of concrete technical terms.

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