- Author
-
Struble, L. J.
- Title
- Influence of Cement Pore Solution on Alkali-Silica Reaction.
- Coporate
- National Bureau of Standards, Gaithersburg, MD
- Sponsor
- Purdue Univ., West Lafayette, IN
- Report
-
NBSIR 87-3632,
May 1987,
284 p.
- Keywords
-
cements
|
aggregates
|
alkali
|
alkali-silica
|
concretes
|
expansion
|
expression
|
pore solution
|
reactive aggregate
|
silica
|
reaction kinetics
|
limestone
- Abstract
- To improve our understanding of certain details of alkali-silica reaction mechanisms, expansion studies were carried out using cements with various alkali contents and distributions and certain reactive aggregates. These studies indicated an influence of the cement alkali distribution on expansion due to alkali-silica reaction. Pore solutions expressed form limestone mortars prepared from the same cements were shown to consist primarily of hydroxyl and alkali ions, with pH levels ranging from 13.4 to 14.0. When composition results were compared with the expansion results of mortars containing opal, the levels of hydroxyl and alkali ions were shown to influence the expansion. Reactions of the aggregates in model pore solutions produced various levels of silica correlated directly with the mortar-bar expansion levels produced by each aggregate and proportion. Thus expansion appears to be a function of the extent of the reaction of aggregate in pore solution, which depends on the material, its proportion, and the solution pH level, and is further influenced by the amount of sodium or sodium plus potassium in the pore solution.