Posted By Alton on 30 Nov 2011 05:31 PM
nd96,

Your project with all of that congested rebar would have been a prime candidate for LaFarge's Agilia mix.  It flows so well that on small projects the hose would not have to be moved and vibrating may not have been needed.  In fact, this mix flows so well that the slump test actually measures spread instead of slump.  Unfortunately, the Agilia mix is not available everywhere and it costs more than regular mix but less workers are needed which may help offset the extra cost for the special mix.

Alton - i've copied your post on Agilia from a previous thread. Hope that okay? I'm wondering if anyone has used it in ICF? It was tested by the U.o Calgary in ICF construction. Needless to say, its not used in the ICF industry here. The way I see it is It is designed to self level so it does not support itself at all! All the weight of wall pour is exerted on the bottom block. One of my suppliers used it on a basement south of town and everything went good till about four feet. Than everything and I mean everything flowed right out through a number of blowouts!

A slightly higher slump would have been a little easier for my storm shelter project, but I can definitely see how too high a slump could be a major problem for ICF's. If the concrete can flow though the walls without any vibration, it can also all flow out a single blowout and turn a small problem into a huge mess.

Both of the last two postings makes good points that we should keep in mind.  Hopefully, as we gain more experience with Agilia mixes (there are more than one mix), we will learn how to use it well in Insulated Concrete Forms as we already have with metal forms.  I think we will discover that the rate of placement may be different for very fluid mixes like Agilia in ICF.  For instance, cold weather may require a slower placement to allow the concrete to gain some stiffness to take some of the hydraulic pressure off of the EPS forms.

cold weather may require a slower placement

Or the right accelerating or retarding admixtures to get a fairly fixed set time, independent of temperature. Even better might be some accelerating admixture that gets added "on the fly" as the concrete leaves the truck.

Agilia is just a self consolidating concrete (SCC), right? Nothing new?

jonr, This is what I do. I add a mid to high range water reducer on site. The products that i use have a usefull life of about 45 minutes so having them added at a batch plant can be a problem since some of my jobs can be an hour and a half from the plant. I'm starting to use more ad mixes they are invaluable for a person using icf's.

nd96's project didn't really have much congestion in the walls, it was mostly around the beam/ joists. He used a higher slump there and smaller aggregate (I think?) so that consolidation wouldn't be too much of an issue.

On a side note, I've seen a 3/8" mix with mid-range WR fill up an 8 ft high trial pour in about a minute without a blow-out. Consolidation was flawless.

I, for one, would like to hear any stories that come out of the use self-consolidating concrete. Just for my own edification, about how much more (%) is self-consolidating concrete over one with MRWD?

If the concrete is not too cold going in (warmed at the plant if necessary), the insulation should keep it warm enough to not affect initial set too bad, unless it's so cold you shouldn't be out there anyway! I tend to shy away from recommending accellerators, but that could just be one of my idiosyncrasies.

I experimented with a mix though not SCC was pretty close. Less aggregate, more fines,40% fly ash and hige range water reducer. I used it in a last truck pour. The concrete flowed from one corner 65', around another corner 35' and out around a 12x12 porch with 2 corners. It was amazing to watch flom the scaffolding. Never moved the pump hose. I haven't had the guts to do a full pour but I have used a HWD with a standard 3000lb mix with great results. This time of year the temps drop well below freezing and even with the redi-mix cos. adding hot water to the mix you want to pour the stiffest slump possible while increasing the flow. Generally I pour a 3 slump and add water reducer to increase flow. As far as the cost of the experimental mix I think it add $20 per yard but part of that was also the supplier of the concrete wanting to see how it worked. I think this is a way for the icf business to be able to say the walls are fully consolidated.

Posted By smartwall on 07 Dec 2011 08:30 AM
I experimented with a mix though not SCC was pretty close. Less aggregate, more fines,40% fly ash and hige range water reducer. I used it in a last truck pour. The concrete flowed from one corner 65', around another corner 35' and out around a 12x12 porch with 2 corners. It was amazing to watch flom the scaffolding. Never moved the pump hose. I haven't had the guts to do a full pour but I have used a HWD with a standard 3000lb mix with great results. This time of year the temps drop well below freezing and even with the redi-mix cos. adding hot water to the mix you want to pour the stiffest slump possible while increasing the flow. Generally I pour a 3 slump and add water reducer to increase flow. As far as the cost of the experimental mix I think it add $20 per yard but part of that was also the supplier of the concrete wanting to see how it worked. I think this is a way for the icf business to be able to say the walls are fully consolidated.

This sounds more like a grout mix than a concrete mix. I wonder how it effects the overall bending strength of the finished product?

I've heard it range from $10/yard to 50% extra cost. Strength needed is a big factor.