Does anyone out there have experience using an Oztec rebar shaker instead of dropping the vibrator head inside the wall cavity?

I have not used an Oztec, I have one from another manufuacturer...which I don't use.

Many factors can cause a bar shaker to react differently and not necessarily properly, i.e. slump, stone mix, etc.

Internal vibration is by far the best way to ensure proper consolidation

I have an exterior vibrator that is cool. It has maybe an 8" round, flat, thick plastic head and it goes in the chuck of a drill. Great for light vibration. I don't know the name of it though.

Don't know about the Oztec rebar shaker. I would think it would only work with any degree of impact if all the vertical and horizontal rebar are tied together. That way the whole rebar grid is shaking. If they are not tied than I think they are a waste of money as far as the ICF wall is concerned. In CMU holes I can see the advantage since the holes are isolated.

Used the exterior vibrator like icfconstruction described. It worked great for a brick ledge situation. Having said all this, internal vibration is still the best measure to achieve consolidation unless you pour self-consolidating-concrete (SCC) like they are using in Europe and other continents.

Used one on one job, never again, I believe that wood forms would receive it well, but not ICF.

Mark Ross

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My understanding the Rebar shaker, like the 3/4" vibrator head were both originally designed with concrete block in mind.  I have a rebar shaker and it is in the box of things that I use to remind me to give more thought to my purchases. 

Please tell me what problems you had with the rebar shaker in ICFs. I have used mine for core filling blocks up to 12" and it works great. What should I watch for if I try it on ICFs?


Thanks,
Skipper Smotherman

The performance compared to a 1.25 to 1.5" vibrator is badly lacking.  It is to slow to work with. 

Tom, On what size ICFs would you consolidate with 1.25 to 1.5" vibrators? For 6" forms, I've read 3/4" or no more than 1". Sound right? Dave

Hey Tom, I have one of those boxes too, filled with hundreds, if not thousands of dollars worth of tools that I will never use again.

If anyone wants to try a shaker (air powered), pay for the postage and I will loan you mine, but the test is remove some foam after you pour and you will see lack of consolidation compared to internal vibration.

Dave, Paul and I were on a job, vibrator broke, sent a guy to the rental store while we were still pouring, he comes back with a 2" head, this was an 8" wall, very carefully it was dropped in...and I tell you that house has some of the best consolidated lintels I have ever seen in my life...not to mention all the liquid squirting out between the block seams...it was actually kind of funny to see, Paul got dirty that day.

Dave,
We have used vibrators pt and including 2.5" vibrators in forms as small as 5".  Not for the faint of hart.  We typically pour a true 5 slump 3/4" granite agriagate 3000 psi concrete.  No ad mixes at all.  typically use at least 1.25" on a regular basis.  Oztec and Wacker's. We Always internally vibrate.  Vibrating is not a clean job on pour day, but neither is the pump hose operation. 

Chris, my shaker is also air powered.  A real waste of money. 

Is the main reason for the larger diameter heads to enlarge the area of influence and increase the spacing of your pokes?

My hat's off to you pros. Helped a friend pour a half dozen 15" dia 6' tall columns and consolidated with an electric 1.25" dia. 6' long whip. Think I'm gonna have to do some weight lifitng if I'm the one vibrating our future home walls. I think the solution is to have someone else do it, but train well. Thanks, Dave

Tom:

Good post however you should have elaborated.

1.5" works well with 4" slump concrete placing less than 500psf at the bottom of a 6" thick 10' wall per lift. Most forms will take this. It requires a faster rate of use, more widely spaced (we have been using two cores if I am correct Tom, I dont know if the guys have opened it up much yet, maybe Eldon), however also provides a lot better consolidation. Additionally, you may want to extrapolate on the concrete, reinforcement, including the use of Helix, proper concrete placement (amazingly with no mess) and form construction, which also plays a major roll in the success of this method. Yes, I have been pouring 3.5-4" slump 3/4" aggregate for about 12 years now, in approx 1.2 m square feet of 6" forms, however without the right training, it may not work for everyone. The advantage is cheaper concrete, less labor, ease in form construction, lowered reinforcement requirements, stronger conrete and in general, a lot less work.

Mark Ross