[TowerTalk] Mixing concrete for a base

[jimlux]

Don Snider wrote:
> How about the quick-dry concrete used for fence posts? Can this be used for
> towers? My hamshack is on Chincoteague island with a water table about 18
> inches down. Most people use the quick dry concrete for general projects
> because it will dry in the water but is it strong enough for an antenna
> base? The only other option may be to put well taps in and pump the water
> our while the concrete drys.
> 

Concrete will cure in water, as long as the water isn't washing it away. 
  The curing is a chemical reaction, after all, not an evaporation of 
the water.  They actually "pond" water on the top of big slabs to 
improve the curing.

A bit of browsing at the cement.org website... they add more lime to 
concrete being poured underwater, so it stiffens faster so it's not 
diluted by the surrounding water.

Maybe "quick-dry" and "hydraulic" are the same basic thing, under 
different names.