Calcium hydroxide attack on feldspars and clays: Possible relevance to Cement-aggregate reactions

Aardt, J.H.P. van; Visser, Susan A.

doi:10.1016/0008-8846(77)90046-1

Cited by 59 publications

(19 citation statements)

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“…It is, therefore, more likely that at higher levels of alkali augmentation (and hence at higher pH levels), alkalis in the aggregate may become more available for release into solution, making the alkali contribution from the powdered glass relative to the total free alkali in circulation less significant. Such a contribution has been observed previously (Blight, 1981;Constantiner and Diamond, 2003;Kawamura et al, 1989;van Aardt and Visser, 1977).…”

Section: Discussionsupporting

confidence: 53%

Evaluation of powdered glass cullet as a means of controlling harmful alkali–silica reaction

Dyer¹,

Dhir²

2010

Magazine of Concrete Research

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It has been proposed that glass derived from container glass recovery can act to control harmful alkali-silica reaction in concrete when included in powdered form. However, the high sodium content of the material raises concerns about whether the release of this element could ultimately exacerbate the reaction. This paper reports on a study carried out on concrete mixes containing aggregate combinations known to undergo harmful alkali-silica reaction in combination with powdered glass, to establish its efficacy at controlling alkali-silica reaction. Glass suppressed expansion for a finite period of time, before expansion reached levels similar to or greater than the controls. It is therefore concluded that the use of powdered container glass is not suitable for controlling alkalisilica reaction. However, it is proposed that the sodium contribution from container glass is, in many cases, irrelevant, since the alkali contributions from the reactive aggregate combinations themselves appear to outweigh those from the glass.

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Section: Discussionsupporting

confidence: 53%

Evaluation of powdered glass cullet as a means of controlling harmful alkali–silica reaction

Dyer¹,

Dhir²

2010

Magazine of Concrete Research

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“…Both zeolite and clay minerals have been synthesized using different starting materials and over a range of temperatures, solution compositions and pHs. Under high solution pH conditions similar to those expected in the cement-shale system, varying types of zeolites have been observed to grow and precipitate (Donahoe et al, 1984;Donahoe and Liou, 1985;Hawkins, 1981;van Aardt and Visser, 1977). Especially applicable to this study are those experiments conducted in the Na hydroxide systems (Barth-Wirshing and H/511er, 1989), where the starting material used was rhyolitic glass and the precipitation of analcime was observed.…”

Section: Introductionmentioning

confidence: 80%

Low Temperature Experimental Investigation of the Effect of High pH Naoh Solutions on the Opalinus Shale, Switzerland

Chermak

1992

Clays and clay miner.

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Abstract--Batch reactor experiments were performed at 150~ 175~ and 200~ to determine the effect of high pH NaOH solutions on the mineralogy of the Opalinus shale. In these experiments, the change in solution quench pH at 25~ solution composition, and mineralogy were monitored as a function of time for up to ~40 days. Runs were performed in 50 ml titanium hydrothermal reactor vessels. Each reactor was charged with 0.5-5.0 g of the 80-200 mesh size fraction of Opalinus shale, and 25 ml of solution (0. l and 0.01 M NaOH). The general sequence of reaction products observed under these high pH conditions include first the formation of analcime, followed by vermiculite, and finally Na-rectorite formation.

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“…Así, podemos apreciar si los áridos son o no reactivos dependiendo de los efectos que la reacción árido-álcali ha causado en cada superficie en un punto determinado (19)(20)(21)(22). Por ejemplo, en el estudio de una de las corneanas se aprecia como se disuelve el cristal de biotita después del tratamiento alcalino (Figura 6).…”

Section: Método De Reactividad Superficial: Microscopía Electrónica Dunclassified

“…The results obtained upon studying the surfaces of the aggregates allowed us to determine whether an alkali-aggregate reaction had taken place (19)(20)(21)(22). For example, it was clear upon studying one of the hornfels that the biotite crystals had dissolved upon base treatment ( Figure 6).…”

Section: Surface Reactivity Investigation: Scanning Electron Microscomentioning

confidence: 99%

Reactividad árido-álcali en áridos empleados para hormigón

et al. 2010

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RESUMENEste trabajo pretende contribuir al conocimiento de las reacciones de interacción entre los áridos y los componentes de la fase intersticial del hormigón y determinar si estos áridos, empleados posteriormente en la fabricación del hormigón, son reactivos y por tanto susceptibles de provocar una disminución progresiva de sus propiedades iniciales.Para la caracterización de cada árido se ha realizado un estudio petrográfico, fundamental a la hora de determinar su posterior comportamiento en términos de reactividad frente a diversos factores. Seguidamente, se ha analizado la reactividad potencial de diferentes áridos silicatados (pizarras, gneis, corneanas, granitos, cuarcita y serpentina) mediante los dos métodos normalizados existentes: el método químico para la determinación de la reactividad potencial de áridos y el método acelerado en probetas de mortero; y para contrastar ambos hemos seguido el método de la reactividad superficial.Los resultados determinan que algunos áridos son susceptibles de reaccionar con los componentes de la fase intersticial de hormigón. La observación de su textura antes y después del ataque denota la existencia de esta interacción.Palabras clave: reacción álcali-sílice, degradación, expansión, mortero, SEM. SUMMARYThe aim of this work is to contribute to the knowledge of the interactions between aggregates and the components of the interstitial phase of concrete and to determine whether those aggregates that are subsequently used in the manufacture of concrete are reagents and are therefore likely to undergo a progressive deterioration of their initial properties.An initial petrographic study of each aggregate is performed in order to be able to determine its subsequent behaviour and reactivity under the influence of various factors. The potential reactivity of different silicaceous aggregates (slates, gneiss, hornfels, granites, quartzite and serpentine) is then determined by a chemical method for evaluating the potential reactivity of aggregates and an accelerated method in mortar specimens, and finally the surface reactivity is investigated.The results of these studies suggest that some aggregates are able to react with the components of the interstitial phase of concrete. The existence of this kind of interaction is confirmed by the results of the surface investigations before and after the basic reaction.Keywords: alkali-silica reaction, degradation, expansion, mortar, SEM. INTRODUCCIÓNUna reacción álcali-silicato se produce cuando interaccionan áridos, que contienen minerales silicatados potencialmente reactivos, con los álcalis del cemento. Esta reactividad lleva consigo la formación de geles que en presencia de humedad se expanden, manifestándose en agrietamientos y movimientos diferenciales y con ello, una disminución drástica de la durabilidad (1-5) Por tanto, este proceso viene determinado en gran medida con la humedad relativa del ambiente y la tensión mecánica a la cual esta sometida cada elemento estructural (6-11).Las fases de la reacción árido-álcali se pueden...

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Calcium hydroxide attack on feldspars and clays: Possible relevance to Cement-aggregate reactions

Cited by 59 publications

References 1 publication

Evaluation of powdered glass cullet as a means of controlling harmful alkali–silica reaction

Evaluation of powdered glass cullet as a means of controlling harmful alkali–silica reaction

Low Temperature Experimental Investigation of the Effect of High pH Naoh Solutions on the Opalinus Shale, Switzerland

Reactividad árido-álcali en áridos empleados para hormigón

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