Alkaline leaching method for the determination of the chloride content in the aqueous phase of hardened cementitious materials

Castellote, Marta; Alonso, C.; Andrade, Carmen; Castro, P.; Echeverría, M.

doi:10.1016/s0008-8846(00)00449-x

Cited by 33 publications

(21 citation statements)

References 7 publications

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“…Los mayores problemas relacionados con este método son la necesidad de: a) una cantidad relativamente grande de muestra, no siempre disponible y b) un aparato especial y relativamente caro. Recientemente, se han desarrollado algunos métodos de lixiviación, pero sólo se han obtenido resultados satisfactorios para los iones cloruro (18,19). En (18) se propone un método de extracción acuosa, y en (19) se desarrolla un método de lixiviación alcalina, basado en ideas dadas en (20).…”

Section: Introductionunclassified

“…Recientemente, se han desarrollado algunos métodos de lixiviación, pero sólo se han obtenido resultados satisfactorios para los iones cloruro (18,19). En (18) se propone un método de extracción acuosa, y en (19) se desarrolla un método de lixiviación alcalina, basado en ideas dadas en (20). Ambos métodos (18) y (19), han sido validados en un ensayo interlaboratorios sobre análisis de cloruros (21).…”

Section: Introductionunclassified

“…En (18) se propone un método de extracción acuosa, y en (19) se desarrolla un método de lixiviación alcalina, basado en ideas dadas en (20). Ambos métodos (18) y (19), han sido validados en un ensayo interlaboratorios sobre análisis de cloruros (21).…”

Section: Introductionunclassified

“…Hausmann (10) and Gouda (11) (18,19). In (18) a water extraction method has been proposed by AFREM, and in (19) an alkaline leaching method is developed by the authors, based on the ideas given in (20).…”

Section: Introductionmentioning

confidence: 99%

“…In (18) a water extraction method has been proposed by AFREM, and in (19) an alkaline leaching method is developed by the authors, based on the ideas given in (20). Both methods, (18) and (19) have been validated in a Round Robin Test on chloride analysis (21).…”

Section: Introductionmentioning

confidence: 99%

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Determinación del contenido de OH<sup>-</sup> en la fase acuosa de los poros de matrices cementantes por un método empírico de lixiviación

Castellote¹,

Alonso²,

Andrade³

2002

Mater. construcc.

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RESUMENEl método más fiable de determinación de iones hidroxilo en una fase acuosa de materiales cementantes es la extracción de la misma mediante aplicación de presión (pore-pressing). Sin embargo, este método necesita un equipo especial además de una cantidad de muestra relativamente alta. En la presente investigación, se propone la determinación de la concentración de OH' en la fase acuosa del hormigón mediante un método de lixiviación en muestra granulada. El programa experimental se ha realizado a partir de morteros con 5 diferentes materiales cementantes y tres disoluciones de lixiviado distintas. En el tratamiento de los resultados, se han considerado diferentes fenómenos (dilución + disolución de las fases sólidas) que tienen lugar durante la lixiviación, hasta llegar a obtener los resultados obtenidos por la técnica de extracción por presión. La concordancia encontrada es suficientemente buena para todos los materiales ensayados, a pesar de que el mecanismo de la extracción no se ha clarificado en su totalidad y de que son las concentraciones y no las actividades de los iones las que se han tenido en cuenta para los cálculos. Por tanto, en esta etapa de la investigación, el método que se propone se puede considerar como empírico. SUMMARYThe most reliable method to determine the concentration of hydroxyl ions in the aqueous phase of hardened cementitious materials is the squeezing of concrete at high pressures. However, this method needs special equipment as well as a relatively high amount of sample to be carried out. In present research, the determination of the OH concentration in the concrete pore solution is undertaken by a leaching method in granulated samples. The experimental program has been made using mortars with 5 different binders and three different leaching solutions. In the treatment of the results, different phenomena (dilution + dissolution of solid phases) occurring during leaching have been taken into account until reaching the target values validated by comparison with those obtained by means of the high pressure technique. The agreement found is good enough, for every binder tested, in spite of the fact that fully understanding of the leaching mechanism is not achieved and that concentrations and not activities of the ions are taken into account in the calculations. Therefore, the method suggested is empirical at present stage.PALABRAS CLAVE: fase acuosa de los poros, iones hidroxilo, análisis, lixiviación, método empírico.

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Section: Introductionunclassified

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Determinación del contenido de OH<sup>-</sup> en la fase acuosa de los poros de matrices cementantes por un método empírico de lixiviación

Castellote¹,

Alonso²,

Andrade³

2002

Mater. construcc.

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Round-robin test on chloride analysis in concrete — Part II: Analysis of water soluble chloride content

Castellote

Andrade

2001

Mat. Struct.

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In Part I of this paper, general trends in the realisation of this Round Robin Test on chloride analysis in concrete (carried out as part of the work developed by the Technical Committee TC 178-TMC), as well as the results corresponding to total chlorides were given. The present paper reports the results corresponding to the extraction of water soluble chlorides. Results concerning the determination of the penetration front of chlorides by colourirnetric techniques will be given in Part III. A total of 30 different laboratories around the world have participated in this Round Robin Test. All of them have performed analyses of total chlorides, having performed 64 different determinations of total chlorides in triplicate specimens. Among them, 20 laboratories have analysed water soluble chlorides. The total number of different determination of free chlorides, in triplicate specimens, has been of 37. Concerning the colourimetric method, 7 laboratories have taken part in the determinations, being the total number of different determinations of the colourimetric front, of 10. Two different methods of extraction from the solid sample (B1 and B2) have been tested. It was also decided that other methods could also be used to the choice of each laboratory, as "other methods" (I33). (The complete recipes of these methods can be found in Annex 1. The statistical treatment of the data has been carried out according to the International Standard ISO 5725-1981 (F) for the determination of the reliability of testing methods: "Determination of the repeatability and reproducibility by Round Robin tests". Finally, it has been concluded that both methods, B1 and B2, are reliable enough to extract water soluble chlorides from concrete. However the method that each laboratory currently uses (other methods) is not recommendable. Dans la partie I de cet article, les tendances g~n&ales de la r&lisation de l'essai interlaboratoire (effectu~ par la Commission Technique TC 178-TMC) lors de l'analysedu chlorure dans le b~ton, ainsi que les r&ultats du chlorure total ont (t( donn&. Cet article rapporte les r&ultats des chlorures libres. Le front de colorim&ie sera rapport6 dans la partie IIL Une trentaine de laboratoires ont participd a cet essai interlaboratoire, et 64 analyses diff&entes sur des &hantillons triple exemplaire ont dt6 effectu&s. Parmi ces laboratoires, 20 d'entre eux ont analysd les chlorures libres et 37 analyses diffdrentes ont dt( effectu&s en triple exemplaire. Deux m(thodes diff&entes d'extraction des chlorures libres a partir des solides (B1 et B2) ont (t( test&s. Les laboratoires pouvaient avoir le libre choix d'utiliser {, d'autres mdthodes,} (B3). (La recette compl~te de ces m~thodes est report& dans l'annexe i). Pour la ddtermination de la fiabilitd des m(thodes de test, le traitement statistique des donn&s a dt( re'ah's6 en accord avec la norme internationale ISO 5725-1981 (F) : {~D~termination de la rdpdtabitit~ et de la reproductibilit6 par essais interlaboratoires,}. Comme r&ultats finaux, les deux mdthodes, B ...

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Round-Robin test on chloride analysis in concrete—Part I: Analysis of total chloride content

Castellote

Andrade

2001

Mat. Struct.

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Alkaline leaching method for the determination of the chloride content in the aqueous phase of hardened cementitious materials

Cited by 33 publications

References 7 publications

Determinación del contenido de OH<sup>-</sup> en la fase acuosa de los poros de matrices cementantes por un método empírico de lixiviación

Determinación del contenido de OH<sup>-</sup> en la fase acuosa de los poros de matrices cementantes por un método empírico de lixiviación

Round-robin test on chloride analysis in concrete — Part II: Analysis of water soluble chloride content

Round-Robin test on chloride analysis in concrete—Part I: Analysis of total chloride content

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