[TowerTalk] Ran Short of Concrete

[fred.spinner at gmail.com]

I'd consider drilling in about four pins into the concrete (or anchors of  
some sort, rebar with epoxy, expansion, etc) and then pinning the top  
section to the already poured section. I think in a yard or so of concrete  
that this is a fairly adequate way of making the two blocks solid with each  
other. Typically when one wants to connect sections of concrete together  
you want them mecahnically pinned to each other.

I also agree that dirt around the tower legs is asking for corrosion  
problems. It is too bad that you didn't get more bags before the concrete  
was completely cured, you can add concrete to "semi-cured" concrete to cure  
in progression. Once it's white and solid, it's too late for that though,

I think you likely have enough weight to hold the tower up as it is. You do  
want to keep water off the legs and make sure that smaller section of  
concrete doesn't break up. I'd suggest rebar in it like it was a driveway  
(since it's going to be literally a driveway/sidewalk like slab)...If you  
are 6" below grade, I'd suggest 8" more of concrete taperd off for water  
runoff.

Good luck with it.

Fred W0FMS

On Oct 12, 2010 9:28pm, "Roger (K8RI)" <K8RI-on-TowerTalk at tm.net> wrote:






> 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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