Alkali-Silica Reaction in Concrete from Hiwassee Dam, North Carolina Tennessee Valley Authority.
ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MISS
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The TVA requested a petrographic examination of concrete cores from Hiwassee Dam to determine whether an alkali-silica reaction had occurred. There is substantial cracking of the concrete in the dam and such a reaction could be responsible for the cracking. Construction of Hiwassee Dam was completed in 1940, so the concrete is over 38 years old. Signs of alkali-silica reaction were found in the top and bottom portions of two 6-in.-diam cores taken from the dam. The main signs of the reaction were white alkali-silica gel in some voids, on old broken surfaces or at aggregate-paste contacts, and the presence of reaction rims on many particles of the brown quartzite. Some cracking of aggregate and paste was also detected. The presence of this reaction does not automatically prove it was the cause of the cracking in the concrete, but it would seem to be a reasonable assumption that it was one cause of the cracking since no other evidence of potentially deleterious chemical or physical damage was found. This conclusion is based on laboratory observation only. Author
- Ceramics, Refractories and Glass
- Civil Engineering