Bill, I'm hardly a genius. You want a solution here goes. Don't try and pour a 11' wall with 2 workers, should have a least 4 for that kind of pour. As I said originally 2 for the vibrator alone one as a floater and one pouring. I would pour a 11' wall in four lifts not 2 this isn't a race and this gives the vibrator a chance to do it's job if you use one, other wise you can skip this step. 1.75" head vibrator with a least a long enough whip to get to the bottom of the wall where graveling and segregation is most likely to occur. Bill I know your in the business, don't know about bobsim, but I'm amazed you think this is a good representation of how a job should be done. Gives me question about your jobs.

I'm curious why Fox Block would say "1 inch or less" for the head size? Blowouts? The need for a bigger motor?

jonr. cant be blowouts. fox says they are industrial strength icf! if they say it it must be so.

Professional ICF installers don't do 3 and 4 lifts for a normal wall say 10ft or even 11ft wall we do 2 lifts...why because we eliminate the drop and separation of the aggregate, not to go into details that you wont understand but the wedge of concrete your create in the wall moves down the wall, flowing evenly. i hate giving away trade secrets we have worked years to perfect, but YOU DON'T HAVE TO VIBRATE THE ENTIRE WALL IF YOU POUR IN TWO LIFTS. the first lift gets you up to the top of the doors and typically windows, the next you top out, so you ELIMINATE the DROPPING CONCRETE as much as possible, that concrete has to be vibrated, some as well as any headers as needed, only an amateur would drop concrete in lifts of 2-3 feet has nothing to do with RUSHING the job, its about doing a professional job, the REAL REASON they do 2-3 ft lifts is because the ICF Form they are using CANT HANDLE THE CONCRETE LOADED, usually a cheaper block and there are plenty of them, everyone is scared to death of a blowout and for good reason, the whole myth of vibrating is a FUNCTION OF POUR HEIGHT...PERIOD, if you are a dropper- you are a vibrator, if your a professional you can pour 7-8 foot at one time NO PROBLEMS AND NO VIBRATOR! If you don't have the Bs to do an 8ft lift...maybe you should look at another ICF FORM? its that simple!

Naegli, you may have just cut you own throat with that post. We'll save it even if you delete it, Genius.

Wyco here with a 14' whip and 1" square head.... That and another for window bucks. One up on scaffolds and one down. Internal vibration is key. We learned on 4" core and going to 6" was a breeze. We also prefer 4k pump mix with 3/8 rock...

Hadn't read the Naegli post before. I'm with you Leon. He must use SVC.

Poured 6" Nudura basement walls 10' high 2 weeks ago in 3 lifts. Even using plastisizer in each load of concrete he consolidated with a gas operated 1.5" head. After removing some foam blocking for a porch lintel, we could see the bubble/void free concrete. Feel confident we have a solid wall. Mix was 4k psi & small stone. Didn't seem like we saw much bleed water either.

Sounds like you covered all the bases. Good job. The add mix reduces the amount of water in the mix, hence less bleed water but stronger concrete.

What was the consensus on checking for voids? Use a spotlight on the other side of the wall at night?

Most voids aren't a total lose of concrete, but a form that is not totally filled. Use a long narrow screw driver.

If I recall the guy at the my ICF training course said he did not vibrate much at all. And he was a rep for a major brand. That being said I would for any project I do.

Most icf manufacturers push the use of pencil vibrators, which I have posted before are useless. The bottom line is that they are more worried about a blow out than a segregated wall pour. The blowouts give them bad press, but the wall that isn't consolidated properly is the problem of the installer. Vibrating is the only way to assure a solid wall... I had 2 corners blowout 2years ago on a wall that we hadn't even started to vibrate. The blocks were from a major manufacturer. It happens and you have to be ready for it. I had a discussion with a rep. for a major manufacturer 4 months ago and I asked him about vibrating. He told me they call it "consolidation" and they never mention it to "newbies' or the infrequent user unless they bring it up.

Portland Cement Association (PCA) did a very detailed and in-depth study of concrete consolidation and ICFs. The ICF panels were filled with low- (3”), medium- (6”) and high-slump (8”-10”) concrete and vibrated with wood blocks, saws, sanders, and internal vibrators. They also filled test panels with a self-consolidating concrete (SCC).

When you look at the cutaways of the ICFs (click above link) it is downright scary to see the huge voids in some of these forms. The belt and suspender approach is a good flowable mix (6" or greater) and the use of internal vibrators. Bagging on the wall with blocks of wood and using orbital sanders proved a waste of time. You only get one chance to get it right, so prepare and talk it out with your ICF contractor.

The Conclusion:

 “Internal vibration was found to provide adequate consolidation for concrete with a slump of 6 inches or greater. In areas of high rebar congestion, such as lintels and corners, caution must be used in order to achieve adequate consolidation… As an alternative to internal vibration, adequate consolidation also was achieved through the use of a flowable, high-slump concrete.”

“We recommend the pencil head [3/4 inch diameter] for ICFs and the 1 1/8 inch head for the larger forms,” Carcanagues says. “It depends on the width of the form and the slump of the concrete. If it’s a wet mix, say 6- or 7-inch slump, we’ll use the pencil head. A stiff mix with a 3-4 inch slump needs a bigger head. The biggest thing about internal vibration is technique. Its not just dragging it through the concrete,” he states.

Hopefully it goes without saying that one doesn't get high slump just by adding more water (although this seems to be a common approach).

Is there a consensus that pea-gravel should be used to help with consolidation?

Some installers will not use pea gravel if a boom pump is used.  Pea gravel has more surface area that requires more cement to glue the aggregate together for the same PSI.  Pea gravel is often limited to when using a line pump.  Boom pumps may cost more per hour but the concrete mix can contain larger aggregate.

Pea gravel should always be used on 6" or 8" forms because it flows better, when you get into bigger forms you can use a bigger size aggregate. You have to realize that the webs and rebar cause a restriction to flow. In order to overcome these you have to increase slump {not by adding water] and vibrate. You also have to look at the form construction and choose a form that has the least amount of restriction in the design of there webs. There is one form that I would not even attempt to pour because it's web design doesn't allow for good flow. The fussier the web design the harder the consolidation will be. It ain't rocket science.

Pea gravel should always be used on 6" or 8" forms because it flows better, when you get into bigger forms you can use a bigger size aggregate. You have to realize that the webs and rebar cause a restriction to flow. In order to overcome these you have to increase slump {not by adding water] and vibrate. You also have to look at the form construction and choose a form that has the least amount of restriction in the design of there webs. There is one form that I would not even attempt to pour because it's web design doesn't allow for good flow. The fussier the web design the harder the consolidation will be. It ain't rocket science. Lbear the PCA study in Las Vegas was done on 4' high wall sections. The complexity of the pour increases with height.

Pea gravel is not required on Polycrete walls because the 4mm steel wire cross tie system will not impede the flow of concrete like bulky plastic ties do. Secure buildings with #8 and #9 rebar, double faced on 6" centers are regularly accomplished using standard 5/8" aggregate. These walls are vibrated the same as a conventionally formed CIP wall and are no more likely to blow out than a conventionally formed wall. This is because the EPS panels contain a welded wire mesh that reinforces the foam and allows it to withstand 1,600 lbs per sqft of lateral pressure during the pour.