Edison Coatings wrote:
>
> > But as a materials scientist, I have to take exception with your  
> classification of natural cement as a pozzolan.  Pozzolans are any 
> type of reactive silicate (usually glassy or poorly crystalline) that 
> require lime to be activated.  The reaction is caclium hydroxide (from 
> the lime) with the base-soluble silica (from the pozzolan) producing 
> caclium-silicate-hydrates, essentially the same primary binder 
> material created through the hydration of most cements (natural or 
> otherwise).
>
> > John Walsh
>
> John, thank you for your comments, which I always find enlightening, 
> knowledgeable and valuable. I was first introduced to the concept of 
> cement as a pozzolan during one of the early lime conferences, where 
> data was presented comparing the "pozzolanic activity of portland 
> cement" vs. brick dust, clay and a handful of other materials. I don't 
> doubt that you are correct on this point, and that cement is not a 
> true pozzolan as you have defined it. So I wonder if the terminology 
> hasn't now been redefined, even if only by common usage, however 
> incorrectly, to include anything that reacts with lime to form calcium 
> silicate hydrates?
>
> Mike E
>
John & Mike,

I hate to ask at the risk of putting the chemical phobic to sleep but is 
there a place that I can go look online to see an illustration of the 
creation of this calcium-silicate-hydrate binding? I am curious why they 
are tenacious. Are there more electrons shared?

John: and welcome to BP.

thnx,
Ken

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