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[SEAOC] Re: [SEAOC] Reactive aggregate

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I would like to know if anyone has some information on how we determine if 
coarse or fine aggregate for concrete is reactive or not.
Here in S. Calif., I usually specify the coarse aggregate to be " San 
Gabriel" rock, heavy media processed or coarse aggregate of a equal or lower 
reactivity.  And the sand or fine aggregate we specify to be moorpark sand or 
sand of a equal or lower reactivity.
These are sources that we know produce aggregate of low potential for 
What tests are there to determine the "equal" qualification, and what numbers 
do I look for in these test results?
I know there is a test for Alkalinity Reduction that is usually given in 
millimoles/liter.  Also a dissolved silica number also given in millimoles 
per liter.  I believe these are tests per ASTM C289.
What do these numbers mean and what should I be looking for to be certain 
that our aggregate will have a low potential for reactivity?  Are there other 
tests or means to determine the reactive potential of aggregate?


Lynn Howard