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Qualificazione di aggiunte minerali per la prevenzione della reazione espansiva alcali-silice in conglomerati cementizi

pubblicazioni - Articolo

Qualificazione di aggiunte minerali per la prevenzione della reazione espansiva alcali-silice in conglomerati cementizi

The effectiveness of four different types of supplementary cementing materials (condensed silica fume, coal fly ash, blast furnace slag, and natural pozzolan) (SCMs) in preventing deleterious expansion due to alkali-silica reaction (ASR) was assessed using the ASTM C1260 mortar-bar expansion test and two siliceous aggregates of different alkali-reactivity. The test results were interpreted on the basis of both a percent expansion criterion and a kinetic parameter, ln k, the latter being derived from the correlation of expansion results with a kinetic equation. It was found that the kinetic parameter, ln k, is a suitable judgement criterion for the qualification of SCMs against ASR. A good correspondence between the effective dose levels of SCMs determined with such a kinetic parameter and a percent expansion criterion is obtained, especially if the 14-day expansion limit of 0.15% instead of 0.10% is used to interpret the ASTM C1260 test results.

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