[TowerTalk] FW: concrete

[Roger (K8RI) on TT]

On 11/1/2013 6:24 PM, KM5VI wrote:

This is a bit different.  We were pouring my shop floor which is high 
strength (and lots of fiber). It was taking several truck loads and at 
the truck load price I did the base and guy anchors with the stuff as 
well.  Since then, the price of concrete has skyrocketed. While I 
haven't checked recently it was over 3 times what I paid and I have no 
reason to believe it dropped any.  Steel has come down some, but not a 
lot. Why concrete went so high I don't know.

At any rate mine was a guyed tower so the base receives no where near 
the stress of a self supporting  tower base.This was one of the old 
installations where the short section is set in the concrete, in firm 
soil.  For the less than two yards of high strength concrete we didn't 
even use rerod in the base which only required light sprinkling as it 
remained moist.  At he end of the first week I had two sections up, but 
no more for a month.  The guy anchors had mo load for about 6 weeks and 
the tower went up slowly from there.

I'm planning on waiting a month with the LM470 and it gets a rebar cage 
that is the same as the factory one. That is, when I can get back out 
there and finish it.

This time of year, even having to sprinkle it is rare around here, but 
you do need to cover it some nights to keep the frost away.

73

Roger (K8RI).

> Concrete cures very quickly at first and slows as time progresses - most
> mixes will develop about 2/3rds (or more) of their 28-day strength within
> the first 7 days after placement.  I have erected crank-up towers 10-14 days
> out (without wind) more than once but left them retracted just in case the
> winds came up unexpectedly.  Peak stresses don't develop in the foundation
> if peak loads are not present... the dead weight loading of the tower is
> generally negligible compared to the live wind loading.
>
> KM5VI
>
>
>
> -----Original Message-----
> From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of Rex
> Turvin
> Sent: Friday, November 01, 2013 1:49 PM
> To: towertalk
> Subject: [TowerTalk] concrete
>
> I'm going to be pouring concrete for my base foundation and 3 guy anchors
> next week. Does anyone know how long I need to let it cure beforeI start
> erecting the tower?
> 73 NR6M
>
>   
> ex: KF7NMD
>
>
> Sincerely,
>
>
> Rex Turvin
> www.nr6m.com
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk