Mise en evidence du role essentiel des ions OH− dans les reactions alcali-silice

✍ Scribed by W. Prince; R. Perami

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 402 KB
• Volume: 23
• Category: Article
• ISSN: 0008-8846
• DOI: 10.1016/0008-8846(93)90172-6

✦ Synopsis

The mechanism of alkali-silica reaction has been investigated using a sample of cristobalite. It has been noticed in the studied cases, that the reaction products are not gels but some crystallized phases such as KHSiO 5 and Na2SiO 3. It has been shown that the main factor of the process is the OH-ions availability. Thus, to prevent structure from deterioration by alkali-reaction, one has to deplete the medium with OH-ions. RESUME: On 6tudie le m6canisme de la r6action alcali-silice h l'aide d'un 6chantillon de cristobalite. On constate que clans les cas 6tudi6s, les produits de r6action ne sont pas des gels mais des phases nettement cristallis~es tels que KHSiO5, Na2SiO 3. On montre que le facteur essentiel du processus r6side darts la disponibilit6 des ions OH-. C'est sur ce param~tre qu'il conviendrait d'agir lorsqu'on veut r6duire les risques d'alt6ration par r6action alcali-silice.