You can (to a point) get higher PSI by increasing the ratio of cement to
sand, but I'm not sure I'd go all the way down to 3:1. I suspect that
would be pretty brittle. The strongest concrete is where the cement
just barely fills the spaces between the sand particles. The angular
sand particles (which are typically VERY hard pieces of silica) have the
effect of scattering the force vectors. Most concrete specs even call
for the use of "sharp" sand. Too much cement and you lose that effect.
In my opinion, a better way to increase the PSI is to decrease the
moisture content, which reduces weakening voids that occur as the water
chemically reacts or evaporates. The curves I've seen indicate that you
can get well over 10,000 PSI by doing that, although of course the stuff
gets pretty stiff. You'd have to be able to tamp or ram it in under the
plate, but I don't see why that should be difficult to do.
73,
Dave AB7E
On 5/25/2011 2:29 PM, Mark Robinson wrote:
> I will be interested to see what others have to say but maybe a 3:1 mortar
> mix would work. 6:1 is normal for brick work as you don't want the mortar
> to be harder than the brick but since this is being applied to concrete a
> 3:1 mix would be much harder and stronger.
>
> Mark N1UK
>
>
>
> ----- Original Message -----
> From: "Kurt Cathcart, KR2C"<Kurt@KuhlRoad.Net>
> To:<towertalk@contesting.com>
> Sent: Tuesday, 24 May, 2011 9:50 AM
> Subject: [TowerTalk] 6000 psi grout
>
>
>> I'm installing a US Tower MA40. The specifications call for filling the
>> area between the base of the mast mount and the top of the concrete with
>> high strength grout. What is this stuff and where would I get it?
>>
>> -Kurt
>> KR2C
>>
>> _______________________________________________
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