In my humble opinion vibrating is bad, to much vibrating seperates the concrete contents & can quickly lowers your PSI to nearly zero, I prefer to use a slump of 6+, this allows the concrete to move freely thru the webs/wall & consolidate underneath almost any window sill w/out the need of a vibrator. When a sill does need vibrating it should be done w/ care & caution to avoid blowouts & concrete seperation.

Your position very well may receive some vehement disagreements on this forum!

Based on my one time of building I would tend to agree with you. When we were pouring the walls on my house the concrete contractor I hired was very much opposed to vibrating, except as needed to get the concrete to flow under the window sills. He ordered a 6+ slump pebble mix with extra cement, 5 or 6 bag mix, I don't remember which, to improve flowability. I removed some foam later, and did a number of jabs with a pick, and found no voids at all. From all indications consolidation was very good. It looked like there may have been a good deal of small air bubbles entrained in the concrete but that is of very little, if any, consequence in a wall not subjected to severe lateral loads.

rd, do a search on consolidation, vibration, and vibrating, in this forum. You'll find a lot of energetic discussion about this very topic during the past two years.

You need to have good consolidation, and vibration is the most commonly (not universally) accepted method to achieve that. But flowability is the real key. Strength is secondary. You're not building a bridge.

Read the PCA 2003 paper on consolidation at their website. It's available in their bookstore at no cost. It's RD134. Kind of takes the opinions out of this topic and replaces it with fact.

I have never even heard of Hebel AAC prior to this posting.  Where are they manufactured and sold?

You don't install any reinforcing steel in those AAC blocks?  If not, I seriously doubt that it would be anywhere near as strong as steel reinforced concrete in ICF walls.   Without some steel reinforcing and poured columns in those AAC blocks, there is no way you can say they have all of the benefits of ICF.

Having to deal with tornadoes and potential earthquakes where I am building, strength is the primary benefit of the ICF walls that I am looking for.  The R value,  thermal mass, air tightness, and ease of construction are secondary.

Well spoken Arkie, thanks for the sensible input, I wasted a bunch of time w/ a potential ICF client, the deal was starting to derail, when he brought up the "benefits" of ACC I immediately quit taking his calls. It was time to move on.

After reading the pca rd 134 report i was somewhat perplexed about the high slump pouring and self consolidating concrete without vibrating.Up until now i thought high slump was to be avoided but their information showed little extra form pressure due to the high slump.If any icf installers would like to wade in on this subject i would love to hear your opinions on this and from any installers that use scc.thanks

Relative to the thread question: vibration (preferably internal) is necessary and absolutely mandatory for all commerical work that I am aware of. Ask your engineer. If you are using a form that cant take it consider using one of several that can. ACI 318 - 4 feet of lift per hour lifts maximum and you should vibrate each lift into previous lift. Concrete must be vibrated to release the air properly - even if it being poured at a high enough slump to run under the windows.

I get an occasional call where and installer says that he's gone 12 feet in one pass without any problem -- the strength of the form is not the point - concrete should be vibrated for proper consolidation.

Regarding AAC - it may or may not be a good product - i don't know but it's not the subject of the thread. At least two ICFs have UL 4 hour ratings see U930 for example. Haven't seen AAC UL rating but would be interested in their UL classification for my records. Regarding ICF vibration, although a requirement for non self consolidating mix designs is never a problem for me or the many installers i work with. If you are an installer and don't believe in consolidation for some reason I would bet your engineer would be in shock if he knew. Regards.

How can you make the claim that Hebel AAC has a comparable R-Value to ICF?

From what I have gathered on the net, AAC has a typical R Value of 1.25/inch.  Those 8" thick AAC blocks are only going to have an R value of ~10.

Take a typical ICF wall with  2.5" of EPS foam on either side  at  an R value of 4.0/inch and you  get  an R value of ~20 before any concrete is poured or surface treatments are applied.

How is that comparable?  Frome the above I see the typical ICF having 100% better R value than AAC.

http://www.toolbase.org/Technology-Inventory/Foundations/autoclaved-aerated-concrete

According to the following test report link, Hebel AAC 8" thick blocks have steady state R values of 6.4 for the higher strength, higher density formulations and up to 10 for the lowest strength, lowest density blocks.

http://www.icc-es.org/reports/pdf_files/ICC-ES/ESR-2447.pdf

There have been several threads here on the board discussing the benefits or lack thereof of thermal mass in walls.  Its benefits with respect to "effective" R value is entirely dependent on your location and climate.  You may get an effective R multiplier of 3 or so in the desert southwest where there are large temperature swings during a 24 hour period.  The effect is much less so in the humid south and southeast where temperature swings during a 24 hour period are much less dramatic and is essentially nill in the far north.

I'm not sure where you came up with an effective R value of up to 40 unless you were describing a block thicker than 8", especially considering that you stated an 8" block had up to an effective R value of 27 in a thread on SIPs expected life.

And here again, ICF shines with respect to thermal mass benefits as poured concrete has a typical density of 5x that of highest R value AAC block.

Back to the thread topic (sort of).  How do you consolidate the concrete grout in those 3" or 4" diameter steel reinforced vertical reinforcement columns required at all corners and on each side of openings as described and shown in the attached test report?

l like the cosolidation answers, but how do YOU consolidate YOUR walls

Use a pencil vibrator. If you don't own one, you can rent them cheap. Don't resort to banging 2x4s with a hammer. If you are going to do that you should just upgrade to using a recipricating saw without the blade.

It looks like Mr. Kimble's posts disappeared.

A pencil doesn't really get the job done. In the study they used a 3/4" pencil with an area of influence of 3". Which means you have to overlap your drops by less than 3" to be effective. I use a 1 3/4" square head. Never had a problem with a blowout. The use of pencil vibrators started long ago because many of the old forms could take anything bigger. I've vibrated jobs with 2 1/2" a couple of times. Kinda increases the pucker factor but no problems.

Arkie,

 

Yeah not sure why my comments have been erased. Guess somebody doesn't like to talk about alternative building materials?

Re: concrete consolidation. I appears the "what" to use to vibrate has been addressed quite well. In the "how" department, someone mentioned above the need to avoid mix segregation by over vibrating and we avoid this by keeping the vibrator moviing. For heavy steel situations (rebar) often in commerical work i do prefer the pencil just to make sure that you are able to retrieve the wand ;). Regards.

We always pour our walls w/ 6'' slumps icf pea stone mix. That being said, it is the guy who's on the pump which has to watch the flow of the concrete to make sure it's flowing as it should and let the others know which area needs to be vibrated if in doubt that the concrete hasn't settled as it should have.
Around and on top of openings is where it is most crutial to be on the ball since lintels are the most frequent area where voids may occur because of all the steel involved for strenght issues. Tapping on the wall is good practice to know if a void has occured.
Pencil vibrating is whithout a doubt, IMHO, the best way to consolidate. With the mix as it should be a simple down and up is what's needed. A good way to know if the pencil has done it's job is a drop in height of concrete and some water atop of the poured wall.

We have experienced with both pencil and exterior vibrating and the pencil still remains our instrument of choice.

About the commercial jobs, they are more than often required to be vibrated by code, if I may put it this way, and from an intallers point of view I wouldn'do without because of the lack of room for concrete due to overengeneering.

My 2cents worth.
Cheers!

Not that at all. It's the blatant advocacy for a specific name product by someone associated with that product, particularly when they are not buying an ad spot to help support the forum.