Title: How To Make Concrete That Will Not Suffer Deleterious Alkali-Silica Reaction
Author(s): Bryant Mather
Publication: Symposium Paper
Appears on pages(s): 127-133
Keywords: Aggregate; Alkali-aggregate reaction; Expansion; Petrography; Pozzolan
Excessive expansion of concrete due to alkali-silica reaction will not occur if any one of the following circumstances exists: (1) the aggregate is insufficiently reactive; (2) the pH of the pore fluid is not too high; (3) the amount of reaction product formed is not sufficiently large or not sufficiently expansive so that its expansion can cause damage; or (4) there is not enough available water to cause the reaction to progress so as to develop the expansive product and to be available for imbibition by the product so as to cause it to swell and disrupt the concrete. Put the other way around, excessive expansion can occur only if there is enough potentially expansive alkali-silica reaction product and water so that, as the product takes up the water and swells, the concrete expands excessively. Hence, what is needed to avoid excessive expansion is to be able to predict the probable reactivity of the available aggregates, the probable mechanisms by which the pH of the pore fluid might get well above 13, and, when justified, select and implement appropriate precautions against the undesirable consequences of these eventualities. Published by Elsevier Science Ltd. All rights reserved.