Author Topic: Concrete = Steel?  (Read 8171 times)

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Offline b_m_hart

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Concrete = Steel?
« on: August 08, 2008, 03:59 PM »
I've been looking into various types of concrete, and stumbled upon Lafarge Ductal.  This stuff is amazing, it is nearly as strong as structural steel, and has substantial ductility to it (yes, concrete that can bend under load, rather than fracturing).  For reference, I used Quikrete 5000 mix for my counter tops, which cures to a compressive strength of 6000 PSI, which is about twice that of "average" concrete I believe.  This stuff, if prepared properly, can achieve compressive strength up to 33000 PSI, and flexural strength of up to 7200 PSI - so my counter top would fail due to compression before this stuff would fail due to flex, which is pretty amazing.

I am absolutely fascinated by this stuff, and the possibilities of working with it.  My woodworking efforts seem to revolve around figuring out ways to make more intricate molds for concrete.  I checked with the manufacturer (Lafarge) and they don't sell the product, they "license the technology".  Total drag - this means $15K investment, before buying specialized mixing equipment...

So, two questions:

1) Do any of you folks in the construction field(s) know of anyone that works with this product?
2) Have any of you seen this stuff in use?

edit:  Also, I came across this translucent concrete stuff, called LiTraCon.  Haha, anyone know where I can get my hands on unshielded fibre optic cable cores? :)
« Last Edit: August 08, 2008, 05:57 PM by b_m_hart »

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Offline mastercabman

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Re: Concrete = Steel?
« Reply #1 on: August 08, 2008, 04:09 PM »
Never seen that stuff you're talking about,but i also don't see much concrete counter top.
Not much of a market,most people go for granite or solid surface.
We had a concrete top in our show room for 2-3 years,never sold any.
I don't understand!?! I keep cutting it,and it's still too short!

Offline Eli

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Re: Concrete = Steel?
« Reply #2 on: August 08, 2008, 05:52 PM »
Tinker's the concrete man. I expect the title of the thread will suck him in eventually.  :D
Do nothing, stay ahead.

Offline Tinker

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Re: Concrete = Steel?
« Reply #3 on: August 08, 2008, 08:58 PM »
Tinker's the concrete man. I expect the title of the thread will suck him in eventually.  :D

Ya got me, Eli.
problem is, i never heard of either of the products mentioned.

I haven't worked with concrete of any kind since 1981.

I'm much more interested in the stuff you have told me you had looked into in your outback neighborhood.

My son just built a prefab fireplace/pizza oven combo.  he told me the product had been around for a long time.  i went to see it and looked over the literature.  by the time that product had been put on the market, i had been "retired' for twelve or more years. ;D ;D ;D
Tinker

i do still get interrested in some of the new goodies that are out there, but I'll leave the hefting to guys like b_m_hart.
Wayne H. Tinker

Offline Eli

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Re: Concrete = Steel?
« Reply #4 on: August 08, 2008, 09:18 PM »
Alright then.....

BM in my experience, which is limited by and including conventional basements, concrete cisterns, retaining walls, driveways, steps, etc. , concrete is concrete for the most part. It's the mix (calcium sulfate, sand, portland, water proportion) and the add'l additives that determine properties like the ones in the pamphlet. They're adding a proprietary mix of fibers to the portland and sand to get those properties. If you're using Quikrete, you could easily do some experimenting with chopped fibreglass for example, to get some different post cured characteristics. Then there's fly ash, pozzolana, and all kinds of other secondaries. Although Tinker says he doesn't follow developments, nothing really changes too much about it. The most exciting thing was the Romans learning to pour underwater IMO.
Do nothing, stay ahead.

Offline Tinker

  • Posts: 3722
Re: Concrete = Steel?
« Reply #5 on: August 11, 2008, 05:07 PM »
Eli,
A little history.  not woodwork, but related to this off topic topic.
My great uncle  was a civil engineer. (class of '99 from cornell)

His first few years as engineer were spent wandering around the wilds of Canada, Ohio and Kaintucky.

Eventually, he somehow discovered a source of clay, only a days journey by oxen from a supply of limestone.  He fiddled around until he developed the process to make white cement.  He and his partners bought the land where the clay was (Clayton, Mass) and they made cement.  A by product for the white cement was ceramic tiles.  They made all of the tiles for Penn RR Station in NuYawkCity and several of the government buildings in Washington, DC. among the many

When the RR ran thru Pennslyvania thru an area with the exact same clay and limestone, the biz in Clayton, mass colapsed.  The travel from lime quarry to clay  and kilns to fire the clay & lime was a few minutes, whereas the lime in Mass had to be hauled in a days journey by oxen.  The biz collapsed and Uncle went into farming the property.

eventually, i ended up living with him, his wife and his daughter and SIL who farmed the property.  I suppose i came by the masonry interrest honestly.  Haveing spent my pre to mid teen years living and working on the farm, that probably also explains the BS part of my existance.
Tinker


Wayne H. Tinker

Offline Peter Halle

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Re: Concrete = Steel?
« Reply #6 on: August 11, 2008, 05:18 PM »
Thanks for a great story as always.  It is facinating to me hear about what others have had to live and go thru in times and places different than ours.

Peter

Offline Duck

  • Posts: 1
Re: Concrete = Steel?
« Reply #7 on: March 23, 2009, 03:56 AM »
Ductal is an amazing product.  I will be using it for my kitchen countertops as well as floor tiles.  This may be a little late and you may have already discovered how to enhance concrete molds.  A good source is Polytek in Easton, PA. Their -74 and -75 rubbers are ideal for concrete molds. 

http://polytek.com/products/products.htmlLink

Youtube also has several videos covering concrete molds.

Good luck,

Duck
short for Ductal

Offline minimal

  • Posts: 77
Re: Concrete = Steel?
« Reply #8 on: March 23, 2009, 05:33 PM »
I've seen it referred to in a few design/architecture magazines.

But, to restate the IP, where can you get small quantities of it? (e.g. for your countertops...)

Offline ansel

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Re: Concrete = Steel?
« Reply #9 on: April 19, 2009, 12:55 AM »
Lafarge may not sell you the raw ingredients, but they'd be more than happy to show up at your house or jobsite with a few yards of the stuff. I think it's becoming pretty commonplace in home foundations. Ductal is simply Lafarge's version of a PVA (polyvinyl alcohol) reinforced ECC (engineered cementitious composite).

There's nothing really proprietary about Ductal; the secret is the fibers. PVA just happens to be one of the few materials that chemically bonds to concrete which obviates the need for rebar.

I'm no expert, just played around a little with the stuff in art school. Kuraray seems to be the largest manufacturer of concrete-specific PVA fibers and there's some info about basic mix designs on their website:
http://www.kuraray-am.com/pvaf/mixing.php

I had to order an entire 40lb bag of the stuff from Nycon, because it was a new product at the time, but they may sell smaller quantities now. As far as mixing goes, a bakery sized dough mixer is actually ideal, but a heavy-duty drill mixer (like a Hole Hawg) or stand mixer will do for a few buckets of the stuff.

Offline Les Spencer

  • Posts: 487
Re: Concrete = Steel?
« Reply #10 on: April 19, 2009, 09:22 PM »
Encounter concrete counter tops has both rubber reusable molds and fiber for strengthening. You can buy from a local distributor in much smaller quantities.
« Last Edit: April 19, 2009, 09:23 PM by Les Spencer »
Les (near Indy) XL

Offline b_m_hart

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Re: Concrete = Steel?
« Reply #11 on: April 19, 2009, 09:54 PM »
From what I've been reading lately, GFRC is becoming MUCH more commonplace in decorative concrete applications, such as sinks and counter tops.  I'm going to goof around with it some in a while, but have been distracted with other projects around the house.  We've been talking about adding a second bathroom, so we can remodel the existing bathroom.  It's great to be able to ask for new toys for birthday presents, like a hopper gun (and actually get it) for spraying face coats.

Offline Tinker

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Re: Concrete = Steel?
« Reply #12 on: April 25, 2009, 08:13 AM »
Ah Ha!
now we're getting somewhere.
As i said earlier, i have not worked with concrete since 1981 when my trowel machine broke down.
At about the time, a little later the same year, I retired from masonry and cancelled all of my construction mags except those that included landscaping info.  I do remember reading about (as I remember it) fiberglass fibers being mixed into concrete for strength and flexibility. I did, somewhere along the line, talk to other masons who did know something about the mix and they told me you sure did not want the stuff getting against your skin.  That is about all i remember, as at the time, my reading energy was directed solely towards learning as much as possible about raising grass (the kind you mow with mowers >>> not the kind some people hide behind trees in vacant lots and end up putting in pipes for smoke), trees and bushes. 

An interesting side note:  for several years after I had gotten out of the masonry biz, I was beginning to get calls from customers interested in my landscaping assistance.  these were people who i had done mason projects for years before.  also, people who bought houses i had worked on in those days long gone by.  When they called, i remembered working on the properties.  I could NOT remember what I had done there, but i remembered nearly every detail of their yards.  Now, i am sure that somewhere along the way, somebody might just come up with some sort of psychological reasoning as to what sort of work i should have been doing all along  8)

No matter, I do know i do not need to visit my chiropractor as often as I uster. (only once a month now) And that is one huge bonus and for me a great reason for not going back to find out more about concrete.  If I need any concrete work to be done, i just throw out money in the (I hope) right direction and sit back comfortably with a nice cold one in my hand.  And that's enough for me to know  8) ::) ;D
Tinker
Wayne H. Tinker