Improved control of alkali-silica reaction by combined use of admixtures

✍ Scribed by J.E. Gillott; H. Wang

• Book ID: 103001422
• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 506 KB
• Volume: 23
• Category: Article
• ISSN: 0008-8846
• DOI: 10.1016/0008-8846(93)90051-a

✦ Synopsis

Expansion of mortar or concrete caused by alkali silica reaction (ASR) is known to be reduced by certain pozzolans, by air-entrainment, by some retarders and by decrease in the alkali content of the material. Those methods of controlling expansion have been used individually and in combination in mortar bars made with 2 % highly expansive opal. Their effectiveness has been evaluated by comparing the expansion of these bars with one another and with that of controls containing opal but no mineral or chemical admixtures. The bars containing both a retarder and silica fume showed essentially the same reduction in expansion as bars containing silica fume only. The bars containing a combination of a retarder and an air-entraining agent showed greater reduction in expansion than the bars containing either retarder or air-entraining agent when used separately. It is concluded that combined admixtures supplement one another and have the best chance of improving performance significantly only when in each case reduction in expansion depends upon a different mechanism.