On 10/12/2010 11:42 AM, Steve Bagley wrote:
> Hello All,
>
> Another concrete question... I mixed 45 80lb bags yesterday (electric
> mixer) and still ran short! My guess is that I have one cubic yard in the
> ground with the tower base in it. I am about 6 inches below grade.
>
> Thoughts on how to rectify this? Add more concrete on top? Fill the top
> with gravel for drainage? Fill the top with topsoil?
There are a couple of important points:
What is the soil like?
If the soil is sandy or solid then the amount of concrete is not
terribly important. It serves two functions. To keep the tower from
sinking, or the base from moving sideways. I've put many a tribander up
at 50 feet with just a "dirt base" for the guyed tower.
The worrisome part is the top of the concrete being below grade. IF you
don't live in a arid location, the tower legs at the surface of the
concrete is a prime location for rust. You do not want the surface of
the concrete where the tower legs enter to be below grade if water or
even moisture can collect there.
If not in an arid location the top of the concrete needs/must be "above
grade"
Also you can't normally just pour fresh concrete on top of cured
concrete and expect a complete bond and seal. IOW it leaves a seam for
water to get to the tower legs and creates a weak spot. After a few
years I've seen the legs separate as neatly as if they were sawn off.
There are several brands of concrete "patch" that will bond to cured
concrete and are meant for resurfacing driveways. This stuff will become
part of the underlying concrete even if it's only a quarter inch thick.
I'd get a bag of this stuff, make sure the top of the tower base is
clean and then mix up a bag and pour it on. Then pour the rest of the
concrete to get the top of the base above grade. The reason for not
adding more "patch" is the stuff is around $26 USD per bag.
IOW clear out the dirt, put in a form so the top will be at least 4 to
6" above grade, do the patch and then the pour. Talk with the people
who sell the patch material and follow the guidelines for the patch and
pour.
I'd certainly seek out the advise of some one who works with this stuff.
73 and good luck,
Roger (K8RI)
> My son worked his butt off helping me! Any ideas would be greatly
> appreciated.
>
> Tower is going to be an Ameritower, 50 foot with a Mosley TA-33. Guyed, of
> course.
>
> Steve, N2MAI
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