• Title/Summary/Keyword: Chloride penetration test

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An Experimental Study on the Strength of Recycled Concrete with Steam Curing (증기양생 재생콘크리트의 강도특성에 관한 실험연구)

  • Lee, Myung-Kue;Kim, Kwang-Seo;Lee, Keun-Ho;Jung, Sang-Hwa
    • Journal of the Korea Institute of Building Construction
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    • v.5 no.2 s.16
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    • pp.89-95
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    • 2005
  • Various tests are performed with the recycled concrete including compressive strength, flexural strength, splitting tensile strength, bonding strength and chloride ion penetration test. The basic data obtained from the presented test could be accumulated for the purpose of utilization in concrete structure. Most of the strength tests show that strength decrease a little extent with increasing substitution ratio of recycled coarse aggregate except splitting tensile test for the concrete with $100\%$ recycled fine aggregate. But in case of the $50\%$ substitution of recycled coarse aggregate, compressive strength, flexural strength and bonding strength are almost equal to the normal concrete. Chloride ion penetration test shows that the penetration amounts of chloride ion becomes more in proportion to the substitution ratio of recycled aggregate. But most of the results show that the permeability of recycled concrete is proper to use. The results of present study nay imply that the use of recycled aggregate for steam curing concrete is possible but the substitution ratio of recycled aggregate should be determined through further studies.

A Study on the Chloride ion Penetration Characteristic of Concrete containing Ground Granulated Blast Furnace Slag (고로슬래그미분말 치환 콘크리트의 염화물 침투특성에 관한 연구)

  • 김현수;지남용
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.05a
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    • pp.997-1002
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    • 2001
  • There are two types of chloride in concrete; one is added as concrete materials' chloride when concrete's mixing, and .the other is penetrated from the air and sea water in the sea-shore area. These chlorides penetrate into concrete, and they are accumulated inside the concrete with aging. This study aimed to evaluate the chloride ion penetration resistance of concrete containing GGBFS in the sea-shore area. Therefore, the specimens made with the replacement ratios(0, 0.30, 0.45, 0.60) of GGBFS were put into 3% NaCl solution according to the chloride accelerating test of JCI-SC3, and then investigated the weight changes, compressive strength, chloride ion with the depths of the specimens by aging. The result is that the diffusion coefficient of chloride ion is decreased with the increase of replacement ratios when compared to OPC

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Effect of Water-Cement Ratio and Aging on the Characteristics of Chloride Ions Diffusion in Concrete (물-시멘트비와 재령이 콘크리트의 염소이온 확산특성에 미치는 영향)

  • 배수호;정영수;김진영;하재담;심은철;임병탁
    • Proceedings of the Korea Concrete Institute Conference
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    • 2002.05a
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    • pp.737-742
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    • 2002
  • The chief factors for the penetration and diffusion of chloride ions in concrete are water-cement ratio(w/c), aging, thickness of cover concrete, chloride ions concentration of given environment, wet and dry conditions and etc. In this study, effect of w/c and aging on the characteristics of chloride ions diffusion in concrete were researched when environmental factors for the penetration and diffusion of chloride ions were constant. For this purpose, the voltages passing through the diffusion cell were measured by using accelerated test method using potential difference, and then diffusion coefficients of chloride ions by using Andrade's method were estimated for 44%, 49.5% and 55% of w/c, respectively. As a result, correlation among diffusion coefficients of chloride ions, w/c and aging were concluded through multiple regression model.

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Effect of Curing Conditions on the Characteristics of Chloride Ion Diffusion in Concrete (콘크리트의 염소이온 확산특성에 미치는 양생조건의 영향)

  • 임병탁;배수호;정영수;심은철;하재담
    • Proceedings of the Korea Concrete Institute Conference
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    • 2003.05a
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    • pp.715-720
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    • 2003
  • The chief factors for the penetration and diffusion of chloride ions in concrete are water-cement ratio(W/C), aging, curing conditions, chloride ions concentration of given environment., wet and dry conditions and etc. In this study, of these factors effect of curing conditions such as standard and outdoor curing on the characteristics of chloride ions diffusion in concrete were researched when environmental factors for the penetration and diffusion of chloride ions were constant. For this purpose, the voltages passing through the diffusion cell were measured by using accelerated test method using potential difference, and then diffusion coefficients of chloride ions by using Andrade's method were estimated for 44%, 49.5% and 60% of w/c, respectively. As a result., according to curing conditions correlation among diffusion coefficients of chloride ions, W/C and aging were concluded through multiple regression model.

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A Study on the Prediction of Corrosion of Steel in Concrete Exposed to Sawater (해수에 노출된 콘크리트내의 철근부식 예측에 관한 연구)

  • 오병환;장봉석;장승엽;박대균
    • Proceedings of the Korea Concrete Institute Conference
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    • 1999.04a
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    • pp.411-414
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    • 1999
  • In this study, the characteristics of concrete strength according to age/curing condition and the penetration mechanism of seawater into the concrete has been studied. To this end, a comprehensive experimental program has been setup. The major test variables include the type of cement and the type of mineral admixture. The strength test as well as corrosion test have been conducted to explore the effects of chloride ion penetration on the properties of concrete. The experimental results and the developed theory in the present study can be efficiently used to analyze the chloride ion penetration and to estimate the durability of concrete structures.

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Chloride Diffusion in Mortars - Effect of the Use of Limestone Sand Part II: Immersion Test

  • Akrout, Khaoula;Ltifi, Mounir;Ouezdou, Mongi Ben
    • International Journal of Concrete Structures and Materials
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    • v.4 no.2
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    • pp.109-112
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    • 2010
  • Part I of this study was devoted to the electrical accelerated chloride diffusion in mortars. In this second part, natural chloride diffusion has been investigated for four types of mortars under exposure to a 0.5 mol/L NaCl solution for a period of up to 35 days. Two different types of sand were used for the production of test samples: siliceous sand (used as a reference) and limestone sand (used in this study). The effect of water to cement ratio and exposure time on the diffusion coefficients of mortars was also investigated. In this study, the total and free chloride content and penetration depth of mortar were measured after immersion, and Fick's second law of diffusion was fitted to the experimental data to determine the diffusion coefficient. Their results show that the use of crushed limestone sand in mortar had a positive effect on the chloride resistance. The apparent diffusion coefficient in all specimens was smaller than that in siliceous sand mortar. However, the chloride penetration of these mortars was increased as exposure time progressed.

Automatic categorization of chloride migration into concrete modified with CFBC ash

  • Marks, Maria;Jozwiak-Niedzwiedzka, Daria;Glinicki, Michal A.
    • Computers and Concrete
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    • v.9 no.5
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    • pp.375-387
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    • 2012
  • The objective of this investigation was to develop rules for automatic categorization of concrete quality using selected artificial intelligence methods based on machine learning. The range of tested materials included concrete containing a new waste material - solid residue from coal combustion in fluidized bed boilers (CFBC fly ash) used as additive. The rapid chloride permeability test - Nordtest Method BUILD 492 method was used for determining chloride ions penetration in concrete. Performed experimental tests on obtained chloride migration provided data for learning and testing of rules discovered by machine learning techniques. It has been found that machine learning is a tool which can be applied to determine concrete durability. The rules generated by computer programs AQ21 and WEKA using J48 algorithm provided means for adequate categorization of plain concrete and concrete modified with CFBC fly ash as materials of good and acceptable resistance to chloride penetration.

Characteristics of Chloride Penetration due to Sprinkle of the Deicing Salt on the Concrete Pavement (제설제 살포에 따른 콘크리트 포장의 염화물 침투특성)

  • Park, Jin-Ro;Kim, Myung-Yu;Yang, Eun-Ik;Yi, Seong-Tae;Park, Rae-Geun
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.11a
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    • pp.475-478
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    • 2005
  • Deicing salt has been generally used for traffic safety in winter, and the amount is increasing every year. However, deicing salt may induce the decrease of bond strength, surface scaling, and environmental pollution, etc. the purpose of this paper is to suggest the fundamental data on safety and durability for concrete structures through the estimation of chloride concentration profile and chloride diffusion coefficient. According to the test results, the critical chloride concentration($0.9\~1.2kg/m^3$)was measured at depth $23\~30mm$, and the limit chloride concentration($0.3kg/m^3$)was reached to depth 40mm. Also the surface chloride amount indicates 3.45kg per concrete unit weight, and the results showed the possibility of corrosion by deicing salt penetration.

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The Penetration and Diffusivity of Chloride ion into Concrete using Blended Cement (혼합계시멘트를 사용한 콘크리트의 염화물이온 침투 및 확산특성)

  • Yang, Seung-Kyu;Kim, Dong-Seuk;Um, Tai-Sun;Lee, Jong-Ryul
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.05b
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    • pp.489-492
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    • 2006
  • A chloride is an important deteriorating factor which governs the durability of the reinforced-concrete structures under marine environments. Also, the main penetration mechanism of chloride ion into concrete is a diffusion phenomenon and numerous methods have been proposed to determine the diffusion coefficient of chloride ion quickly. In this study, electrically accelerated experiments were carried out in order to evaluate diffusion coefficient of the chloride ion into concrete. The methods were diffusion cell test method in which the voltage of 15V(DC) was applied. The type of cement is blended cement in which the admixtures of blast-furnace slag and fly ash were used. In conclusion, the diffusion coefficient of chloride ion is much affected according to mineral admixtures and the diffusion coefficient of ternary blended cement showed very low values. it is presumably said that this result is due to highly densified pore structures by the aid of slag substitution and pozzolanic activity of fly ash.

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Comparision of Test Methods for Estimating Chloride Ion Diffusion Coefficient in Concrete (콘크리트중의 염소이온 확산계수 추정 실험법의 비교)

  • 문한영;김홍삼;문재흠;한아름
    • Proceedings of the Korea Concrete Institute Conference
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    • 1999.10a
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    • pp.787-790
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    • 1999
  • To estimate durability of reinforced concrete structures located in or nearby seawater, many different kinds of accelerated tests for evaluation of chloride ion permeation in concrete were proposed. At present the only standardized test is the ASTM C 1202(RCP test). This test method is used to estimate the concrete's resistivity of the chloride penetration in concrete by using the total charges passed and sometimes used to calculate the chloride diffusion coefficients. However, this test may lead to an erroneous chloride diffusion coefficient. So this test method was compared with the modified Dhir's test and the traditional concentration diffusion test. Experimental results showed that the diffusion coefficients determined the RCP test and the PD Index gave wrongous values, but the diffusion coefficient acquired by considering a migration term was nearly the same to the CD Test.

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