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Studies of alkali-silica reaction — part II effect of air-entrainment on expansion

✍ Scribed by A.D. Jensen; S. Chatterji; P. Christensen; N. Thaulow

Publisher
Elsevier Science
Year
1984
Tongue
English
Weight
475 KB
Volume
14
Category
Article
ISSN
0008-8846

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✦ Synopsis

From an extensive petrographic investigation of concrete samples suffering from alkali-silica reaction, it has been hypothesized that a deliberately introduced air-bubble system will reduce expansion due to alkali-silica reaction. The above hypothesis has been tested using mortar bars made from 35 sand types of differing degrees of alkali-silica reactivity. The results show that on the average the introduction of 4% air decreased the expansion by about 40%. A petrographic examination of mortar bars has shown that in the case of reactive sand the air-bubbles tend to get filled up by gel, but the air-bubbles remain empty in the case of unreactive sand. It has also been noted that this filling up of the air-bubbles will decrease their effectiveness in a freezethaw environment.

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