[TowerTalk] RE: Erecting tower

[gdaught6 at stanford.edu]

On 5 Dec 2003 at 10:50, WD0M wrote:

> I just poured a base for a self-supporting US Towers TX-455 - the
> local concrete guys said 7 days is sufficient.  I used 4000 psi concrete

My concrete guy (actually retired concrete guy, but doing occasional 
jobs to pick up a few bucks) explained it to me this way, which 
seemed very logical.

You can take the forms off after 24+ hours, because it's set up 
satisfactorily by then.  In about a week, it'll be at about 75% 
strength, so you can do pretty much whatever building you need to do 
after that time.  After a month it's up to full rated strength, and 
although it continues to cure, it changes very little after that.  So 
your 4000 psi concrete is at about 3000 psi after a week.

I hasten to add that I'M NOT the concrete expert, but just repeating 
what I was told.

73,


George T. Daughters, K6GT