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Re: Low alkali cement

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David,

The alkali-silica reaction is with the aggregate and if in doubt you can request special testing of your aggregate per ASTM C289 or C1260.  These test are not normally performed unless the local area has a history of ASR aggregate.  The typical practices to control alkali-silica reactivity is to use only well known and tested aggregate or the use of a mineral additive such as fly ash, blast slag, or silica fume which are normally easy to procure and store for a very long time.  The batch plant would not likely want to have to store a special cement just for your pours since it has a much shorter shelf life.  One of the best things to do is to have a long discussion with some of the batch plant operators near the jobsite to find out the history of the local aggregates and any preventative measure they might typically use, if any.  Since many concrete mixes have mineral additives (especial fly ash since it is so "green") for other reasons you may not need to do anything special.

Thomas Hunt, S.E.
Fluor



"Dickey, David" <David.Dickey(--nospam--at)masonandhanger.com>
02/19/2009 01:30 PM
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Low alkali cement





When specifying the type of portland cement to be used in a concrete mix, do you specify low alkali cement?  
 
Do you specify it on all of your projects?  Or none or your projects?  
 
Is there data available that shows areas of the country with siliceous aggregates that could contribute to alkali-silica reaction?  
 
How much more does low alkali cement cost?
 
Is the testing that can be specified to determine the alkali-aggregate reactivity, ASTM C1260, something that is routinely done by the concrete supplier that can be requested, or would the testing be a significant additional cost to the project?
 
Thanks,
 
David Dickey, PE
Lexington, KY
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