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GreenOaks
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Posts:11
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| 05/16/2008 7:14 PM |
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Paul,
Thanks for the quick response. I found another thread on this forum that discusses the use of fibers in the concrete. From what I'm reading, the material cost is a wash, but the labor savings can be significant.
Thanks,
jeff |
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robinnc
Registered Users
Posts:111
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| 05/16/2008 11:16 PM |
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Have the fibers been approved in anyone's area for code? Just curious.
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Manfred
Registered Users
Posts:42
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| 05/17/2008 9:08 AM |
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Fibers is general have not been approved by code as such. Steel Fibers are a controlled material and need to be added at a certain ratio to concrete at the plant per job specific application, whether it be residential, commercial or institutional. The load calculations need to be completed by an engineer. Since this product is fairly unused in the market and has the "unknown" factor, it is hard for a conventional thinking building inspector to look into a reinforced concrete form wall and see essentially no rebar except for the lintel steel. The steel fiber companies are more than happy to educate the engineer of record and also visit the local ready-mix company for teaching purposes. Logistically it is hard to expect them to go to every residential project, since they are small in concrete volume, and have no exposure pay-off as they would with a bigger commercial project such as a church, school or a shopping mall.
I tried to use steel fibers on a residential project 3 years ago. Even though the local ready-mix company manager was knowledgable about its use they had never used them before. I had to order the fibers through the ready-mix company in a pallet fashion since they could not forsee using the product again in the near future. Pallet size was more than twice as much for what I needed - that pretty much cancelled out the use of fibers for that project.
If you are able to order the fibers quantitative for your project specific and don't have to pay the penalty for a small job it is worthwhile to look into it. The load calculations are done by your engineer and the fiber company engineer computes the pound/yd ratio of steel fiber to concrete. Then there is the question of quality control at the ready-mix company. They are basically on the hook for mixing the fibers into the concrete as per engineered prescription.
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drogers
Registered Users
Posts:68
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| 05/17/2008 10:26 AM |
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| If the metal Helix fiber were to be used could a 4" wall thickness be used? With the reduced amount of rebar in the wall it would seem consolidation would be easier, even though it is only 4". If this were the case then the reduced amount of concrete may offset other expenses (fiber). |
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lkazanov2
Registered Users
Posts:107
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| 05/17/2008 11:44 AM |
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OK guys....just to stay on track. I spoke to Lafarge and they have Agilia Block Fill for this purpose. It is an SCC, 3/8" aggregate, initial 3000psi, will be 6000psi at 28 days. They have poured ICF in the past with this. Lafarge recommended adding an accelerator to the mix to reduce head pressure. What do you all think? They guarantee no consolidation required. I am waiting on a material quote.
Leonard
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Paul Stevens
Registered Users
Posts:119
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| 05/17/2008 2:40 PM |
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They may guarantee no consolidation required, but at the end of the day who is really going to be responsible??
From what I understand about the Agilia SCC, everything must be conpletely closed up, no openings anywhere, and if you have a blow out there goes all of your concrete, just have some floor finishers on hand, just in case. At the end of the day, I don't think the potential problems are worth the worry. I have never had a problem with a 5-6 inch slump and a vibrator on hand. If you keep your head stuck in the wall like I do when I pour, always watching the flow of the crete, you should be able to tell if it will be consolidated or not. Vibrate on occasion, hit the lintels and you should be fine! |
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cmkavala
Registered Users
Posts:754
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| 05/17/2008 5:46 PM |
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I would never add and accelerator for a wall pour?
If you want to slick the mud up to make it flow better add a Super Plasticizer and NO WATER |
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Chris Kavala
chris@southernsips.com
1-877-321-SIPS |
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cmkavala
Registered Users
Posts:754
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| 05/17/2008 5:50 PM |
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Posted By GreenOaks on 05/16/2008 6:22 PM
Manfred,
Would you elaborate on steel fiber vs. rebar placement?
Jeff
Fibers replace the wire mesh not the re-bar, and robinnc they are widely accepted
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Chris Kavala
chris@southernsips.com
1-877-321-SIPS |
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lkazanov2
Registered Users
Posts:107
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| 05/17/2008 6:41 PM |
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Posted By cmkavala on 05/17/2008 5:46 PM
I would never add and accelerator for a wall pour?
If you want to slick the mud up to make it flow better add a Super Plasticizer and NO WATER
Chris,
Why not? If it is an SCC the accelerator makes sense in the sense that once you circle back around for the second lift it is already starting to setup (not completely) but I guess enough to reduce head pressure.
Leonard
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lkazanov2
Registered Users
Posts:107
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| 05/17/2008 6:50 PM |
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Posted By Paul Stevens on 05/17/2008 2:40 PM
They may guarantee no consolidation required, but at the end of the day who is really going to be responsible??
From what I understand about the Agilia SCC, everything must be conpletely closed up, no openings anywhere, and if you have a blow out there goes all of your concrete, just have some floor finishers on hand, just in case. At the end of the day, I don't think the potential problems are worth the worry. I have never had a problem with a 5-6 inch slump and a vibrator on hand. If you keep your head stuck in the wall like I do when I pour, always watching the flow of the crete, you should be able to tell if it will be consolidated or not. Vibrate on occasion, hit the lintels and you should be fine!
Paul,
I agree that the tried and true makes sense. Also I am sure the quote for Agilia is much higher than regular mud. But the Europeans pour SCC all the time and if the ICF can handle it then we are promoting building technology. What I have not heard from this forum is ACTUAL experience with an SCC in an ICF. We can speculate all day as to what it might and might not do but we are getting nowhere. SCC is a better building technology of that I am certain. PCA's RD 134 clearly states that SCC can be poured in an ICF system and with NO INTERNAL VIBRATION. PCA 100-2007 also reiterates that slump >8 can be poured w/o internal consolidation.
Of all the concrete foundations guys that I have talked to they site the biggest problem with ICF is the fact that they cannot verify the pour and the concrete is hidden by the forms. You have to trust the placement and consolidation to achieve the final results. I believe the accepted use of SCC technology would assure proper concrete placement.
Leonard
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cmkavala
Registered Users
Posts:754
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| 05/17/2008 7:05 PM |
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Leonard;
Accelerators shorten the set time of concrete, allowing a cold-weather pour, early removal of forms, early surface finishing, and in some cases, early load application. Proper care must be taken while choosing the type and proportion of accelerators, as under most conditions, commonly used accelerators cause an increase in the drying shrinkage of concrete. |
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Chris Kavala
chris@southernsips.com
1-877-321-SIPS |
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Manfred
Registered Users
Posts:42
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| 05/17/2008 7:22 PM |
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cmkavala & robinnc,
clarification: even though they are widely (widely? what does that mean?) accepted there are no meniton in the code that I know of referring to steel fiber. I thought this was robinnc's question. |
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aronmac
Registered Users
Posts:39
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| 05/17/2008 8:27 PM |
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Ikazanov, I poured an 8" slump on a government project in Pt. Arena, CA, 8" forms, 35' wall heights, 5 different pours. The amount of cages we had in our columns and headers was way over engineered and we had problems with consolidation using 6" and even 7" slump. Some of you guys are probably having a hard time believing that, but you would need to see the pictures to see for yourself. We got it with the 8" slump and internal and external vibration. I am not sure what scc is, but I believe we were using polyheed in the mix (I was one of the installers at the time). Could one of you guys explain to me what scc is?
Rob, i have a friend in our area (in Charlotte) who is a PA / lead AP that is encouraging me to use the helix fiber mix on any icf projects we do together. His name is Clinton Robertson (704) 975-9665 if you want to get any further information about it. |
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cmkavala
Registered Users
Posts:754
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| 05/17/2008 9:01 PM |
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Posted By Manfred on 05/17/2008 7:22 PM
cmkavala & robinnc,
clarification: even though they are widely (widely? what does that mean?) accepted there are no meniton in the code that I know of referring to steel fiber. I thought this was robinnc's question. Manfred;
The international building code states that reinforcement shall be in accordance with ACI 318
I was clarifying that "fibers" as in fibermesh are for slab reinforcement only, I was concerned that someone might try to substitute fibers - steel or fiberglass for re-bar
And are wideley accepted by building departments as an alternative to 6 x 6 - 10/10 WW mesh
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Chris Kavala
chris@southernsips.com
1-877-321-SIPS |
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lkazanov2
Registered Users
Posts:107
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| 05/17/2008 9:43 PM |
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Aronmac,
SCC is "self consolidating concrete." Please see the link to lafarge web site.
Leonard
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GreenOaks
Registered Users
Posts:11
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| 05/17/2008 10:06 PM |
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Posted By cmkavala on 05/17/2008 9:01 PM
Posted By Manfred on 05/17/2008 7:22 PM
cmkavala & robinnc,
clarification: even though they are widely (widely? what does that mean?) accepted there are no meniton in the code that I know of referring to steel fiber. I thought this was robinnc's question. Manfred; The international building code states that reinforcement shall be in accordance with ACI 318 I was clarifying that "fibers" as in fibermesh are for slab reinforcement only, I was concerned that someone might try to substitute fibers - steel or fiberglass for re-bar And are wideley accepted by building departments as an alternative to 6 x 6 - 10/10 WW mesh
Chris,
Don't mean to veer off course, but on another thread on this forum, several individuals are/were talking as if the fiber mesh IS a replacement for the rebar, specifically in ICF walls.
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Alton
Registered Users
Posts:285
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| 05/17/2008 10:18 PM |
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| Fibermesh, as we commonly use it in place of welded wire in concrete slabs, usually consists of 100% virgin homopolymer polypropylene as opposed to steel fibers used in walls. |
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aronmac
Registered Users
Posts:39
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| 05/17/2008 10:32 PM |
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Thank you.
I have learned a lot from you guys on this discussion, and am now interested in using it on my projects. In the past, I have been on jobs where we had a 7" slump with minimal rebar in the wall and were confident that a little bit of external vibrating would consolidate the concrete and it did. (We know it was consolidated because we always check. Sometimes we'll even strip off a section of the block and screrw on a clear fiber glass sheet to the webs so we can see it.) The biggest obstacle was getting the inspector to go for that. I remember being on a job where I had the inspector screaming at me to vibrate on one side of the wall with my boss Jim Deering screaming at me from the other side to stop vibrating. That was a commercial project where we had to have an inspector for the pour. I know for most guys, on most projects, the inspector being on site for the pour won't be an issue, but like you and a few other guys were saying, this is knowledge that we need. I like what you said about the ICF industry being the vehicle for which this new technology in concrete would gain popularity in the U.S.
Through this discussion, I have learned something that should make my job a little easier, but I'm still going to bring the vibraters just in csae. I don't know how much more the cost would be, but I just got quoted 120 a yard in North Carolina.
I'm getting ready to switch to build block as the main block I use from arxx. I say that because one of arxx's weak links is pour day. I don't mean to dis arxx because I believe it is a good block, especially for commercial projects, but I got tired of all the rasping and plaining after pours. I'm hoping I won't have as much of a problem with this other block. And I say that because of what you guys were talking about with the extra weight the scc adds. |
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robinnc
Registered Users
Posts:111
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| 05/17/2008 11:28 PM |
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Posted By GreenOaks on 05/17/2008 10:06 PM Posted By cmkavala on 05/17/2008 9:01 PM
Posted By Manfred on 05/17/2008 7:22 PM
cmkavala & robinnc,
clarification: even though they are widely (widely? what does that mean?) accepted there are no meniton in the code that I know of referring to steel fiber. I thought this was robinnc's question. Manfred; The international building code states that reinforcement shall be in accordance with ACI 318 I was clarifying that "fibers" as in fibermesh are for slab reinforcement only, I was concerned that someone might try to substitute fibers - steel or fiberglass for re-bar And are wideley accepted by building departments as an alternative to 6 x 6 - 10/10 WW mesh Chris, Don't mean to veer off course, but on another thread on this forum, several individuals are/were talking as if the fiber mesh IS a replacement for the rebar, specifically in ICF walls.Exactly.....that's what I was wodering IF fibers are being used and approved by code replacing the rebar with fibers?
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Manfred
Registered Users
Posts:42
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| 05/17/2008 11:30 PM |
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Chris,
thank you for your clarification. It is understood that ACI 318 is the accepted and governing document for any concrete placement considering any imaginable situation (or not). But - and maybe I am dense on this - there is no mentioning in the codes specifically to steel fiber placement in ICF walls other than referencing ACI 318 and subsections.
Further, I thought we were discussing steel fibers in ICF walls and not in slabs. As for walls what does "widely used" mean? In my neck of the woods this technology landed one earth from the moon yesterday so that even seasoned contractors are unwilling or uneasy to listen to the steel fiber gospel. Again, an engineer of record for any project can specify steel fibers with specific load and point load requirements and the contracotor will have to work it out with the fiber company, such as HELIX amongst others, to make sure the local ready mix company is up to par to mix the prescribed dose or ratio of fiber to concrete.
In regards to SCC, to my limited knowledge, ISORAST is poured day in and day out with it with overwhelming success. I know ISORAST has never had a foothold in the US but they are pushing hard now.
I did not mean to hijack this threat from the original SCC content and get into the fiber talk here. Sorry, Leonard. |
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