[TowerTalk] Concrete with air.

[kr7x at comcast.net]

Julio:

What they are suggesting is higher strength concrete 25Mpa which is about 3600 psi. The air is air entrainment. 5% is the value you should look for. This will improve the conrete's durability especially freeze-thaw durability. I know you VE3's live in the temperate zone but every little bit helps. Mpa is the abbreviation for Mega-Pascals the metric measure of pressure or in this case force per unit area.

Regards
Lonberg Design Group, Ltd.
H. Lonberg, P.E., S.E., PEng.
President

-------------- Original message -------------- 
From: "J.G.Castellano" <caste at sympatico.ca> 

> Hello, 
> 
> I am installing a Trylon tower and the foundation drawing calls for 3,000PSI 
> concrete (20MPa), when I explained what I was doing one of the concrete 
> companies recommended 25Mpa with air. Can someone please explain what is the 
> difference. 
> 
> 73, 
> Julio VE3FH 
> 
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