[TowerTalk] Extending a concrete base?

[Terry]

I don't know about "adhesive concrete" but there is "concrete adhesive" 
that is applied to old concrete before new concrete is poured over it.  
Typically it's very similar in composition to white glue.

73 de Terry KK6T

Rick Karlquist wrote:
> My neighbors poured a new concrete floor over their
> old one and told me that they used some sort of special
> adhesive concrete that was designed to stick to the old
> work.  They didn't do any rebar pinning and the new
> concrete had to be a fairly thin layer that was not
> able to support the weight on its own without the help
> of the existing concrete.  This job worked perfectly.
> Has anyone heard of this magic concrete?
>
> Rick N6RK
>
>
>
>
>
> K8RI wrote:
>   
>>
>>     
>>> Here's another (maybe stupid) question...
>>>
>>> I have a 25G tower with the bottom section partially embedded in
>>> concrete. Problem is the concrete was poured with the top only about
>>> an inch above ground. The base never moves but the surrounding earth
>>> frost heaves up slightly in winter. Spring snow melt and rain then
>>> deposits dirt and debris on top of the concrete where it then
>>> surrounds the tower legs. The tower is on sloped ground which
>>> promotes this action. I am tired of cleaning the dirt and debris off
>>> it every year and wonder what I can do to eliminate this situation.
>>>
>>> If I clean (wire brush?) the top of the existing concrete, build a
>>> wood form around it and simply pour another few inches of concrete
>>> on top, will I be helping or making matters worse? I am wondering if
>>> the new concrete will adhere to the old stuff adequately, or if
>>> water may tend to get in between old and new layers (where it would
>>> no doubt freeze and cause bigger problems).
>>>
>>>       
>> It's quite likely the junction between new and old would foum a boundray
>> layer where water would penetrate.
>>
>> There have been a couple of good suggestions of etching as well as
>> drilling
>> and using rebar.
>>
>> The typical etch is a dilute Muratic Acid which is then thouroughly washed
>> away.  It comes with directions. Drilling and adding rebar would also help
>> keep the new bonded to the old. However as you are only looking at a
>> couple
>> of inches with out the need for strength you *might* get away by simply
>> doing the acid etch and wash prior to the small pour. OTOH if you have the
>> room adding 6 inches of new concrete would give enough room to drill and
>> pin
>> with rebar and still have enough room to extend the concrete several
>> inches
>> above the rebar pins.
>>
>> Good Luck,
>>
>> Roger (K8RI)
>>
>>     
>>> I have worked with concrete quit a bit, but have never poured new on
>>> top of old. Any advice would be appreciated.
>>>
>>> Thanks & 73,
>>>
>>> Paul N1BUG
>>> _______________________________________________
>>>
>>>
>>>
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>>     
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