Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: [1]   Go Down
  Print  
Author Topic: Tower base - anyone take the time to vibrate air bubbles out of wet cement?  (Read 1279 times)
WB8YQJ
Member

Posts: 29




Ignore
« on: August 28, 2010, 05:27:46 PM »

Pouring 1 cubic yard, was advised to rent a machine to take the air bubbles out of the cement. It is a long expensive way to go, is it worth it? tu. Don
Logged
AA4PB
Member

Posts: 13032




Ignore
« Reply #1 on: August 28, 2010, 05:44:50 PM »

I just used an old wood broom handle to stur it around in the hole.
Logged
AC5UP
Member

Posts: 3956




Ignore
« Reply #2 on: August 28, 2010, 06:34:31 PM »

Scrounge up a scrap of 1" iron pipe long enough to reach the bottom of the hole and put a cap on one end.

Pour a foot or so of concrete into the hole then use the capped end of the pipe to stab into it. Concept is to provoke air pockets into breaking loose and rising to the surface. Pour another foot of concrete and do the pole dance again (to coin a phrase). Repeat as needed until you have something that looks like a void-free tower base.

Even though a concrete vibrator is the proper tool for the job it's tough to justify the cost for a one-shot job like a tower base. You can do almost as well with a pipe and a few moments of controlled aggression.

BTW: You probably know this, but concrete needs something like 30 days to come up to 100% of cured strength. If you can give the base a couple weeks before you start thinking about doing the tower part it wouldn't hurt a thing.
Logged

Never change a password on a Friday                
N8CMQ
Member

Posts: 403




Ignore
« Reply #3 on: August 28, 2010, 07:43:15 PM »

Pouring 1 cubic yard, was advised to rent a machine to take the air bubbles out of the cement. It is a long expensive way to go, is it worth it? tu. Don

While you can get away without the vibrator, it is said the concrete is stronger after cure if it was vibrated. It is your choice, to spend or not to spend the money. I would spend it today with my tower base.
Logged

N8CMQ   Jeff
KE5JDJ
Member

Posts: 23




Ignore
« Reply #4 on: August 29, 2010, 06:03:41 AM »

I'd put the extra money into rebar or pipe (hammered like piling), a fiber based product and pouring additional concrete.  Just my 2 cents.
Logged

Necessity is the plea for every infringement of human freedom.
It is the argument of tyrants; it is the creed of slaves.
-William Pitt, British prime-minister (1759-1806)
K6AER
Member

Posts: 3535




Ignore
« Reply #5 on: August 29, 2010, 07:38:31 AM »

Pour the mud slowly and pump with a stick. It will be fine. Wait two weeks before attaching to your concrete base. With one yard of mud you must be putting up a guyed tower?
Logged
WB8YQJ
Member

Posts: 29




Ignore
« Reply #6 on: August 29, 2010, 09:15:16 AM »

I never considered that the bulk of the air bubbles could be removed without an expensive machine, thanks to all since on the day of the project I have enough other things to worry about. The tower is aluminum, very light and I can easily handle each section with one arm. It is 30 feet tall and the engineers tell me that a 28" by 28" by 36" hole is sufficient with 12" above grade (ground level) for a non-guyed 30 foot tower. I sure hope so because I will be climbing it.


Pour the mud slowly and pump with a stick. It will be fine. Wait two weeks before attaching to your concrete base. With one yard of mud you must be putting up a guyed tower?
Logged
KJ6FTS
Member

Posts: 1




Ignore
« Reply #7 on: August 29, 2010, 03:28:48 PM »

Having spent over 20 years in the concrete business, I can honestly say that someone using a vibrator without knowing what they are doing will actually make the concrete weaker. Over vibrate and you can segregate the aggregate from the slurry-not good.
Logged
N4JTE
Member

Posts: 1160




Ignore
« Reply #8 on: August 29, 2010, 05:02:31 PM »

It's less about air boubles and more about the concrete be evenly distributed around the rebar and ties and not bunching up with a thick mix, very unlikely with only one yard. As others have advised just use a pipe, stick, hammer or anything that will push it around, also a tamper will suffice if used before it sets up too much.
Bob
Logged
N2CJ
Member

Posts: 205


WWW

Ignore
« Reply #9 on: August 29, 2010, 05:20:03 PM »

It's less about air boubles and more about the concrete be evenly distributed around the rebar

Exactly. You need to get rid of the voids.
Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!