No more cracked garage floors.

[Ozarker]

The University of Michigan has developed bendable concrete.

 

[Dargo]

Awesome! I hope that is right. A neighbor owns most all of the concrete companies around me and talked me into using that around my pool area last year. The stuff I used is somewhat of a compromise in that I still have more gravel than what is in the article you posted, but I still have as much fiber. Mine will not bend that much. I was still hesitant to go completely with a product that he told me was entirely new to the US market.

He also told me that I didn't need to go as thick, so I could come out with the same basic cost. However, since it is still new, I went ahead and went with 4" on all of my patio area around my pool. The building commissioner likes it around pools because it has no metal in it that can conduct electricity. I did not have to bolt a heavy gauge copper ground wire to every steel panel in the sides of my pool since I used the new ECC conctete. Hey, so far it hasn't cracked! /forums/images/graemlins/grin.gif

 

[mathey]

I see that this is something new...'cause the previous fiber concrete still cracks... /forums/images/graemlins/shocked.gif

 

[Durbob]

I worked construction for almost 20 years and i only used fiber mesh concrete one time. And it cracked worse then any other concrete i poured. The problem is that once it does hairline crack it can really seperate because the little fibers are broken. With concrete that has wire in it , it can still hairline crack but wont seperate because the wire won't let it. I'll take wire in concrete anyday until they have proven this works over time.

Dur

 

[mathey]

I did both (wire and fiber) in the deck around my pool...it has several hairline cracks, but none have seperated...YET

 

[Dargo]

I guess you can call me a "fence sitter". I went with the "new" fiber stuff around my pool. So far, so good; no cracks yet. I can't tell if there are any in the joints because they are filled.

In my driveway I'm slowly finishing with concrete (over 900' total - that is why it is being "slowly" done), I'm staying with 5000 psi 6" concrete with #6 gauge wire matting and #10 rebar sticks on all edges and running parallel with the driveway direction. It has cracked, but it hasn't gone anywhere! I don't expect it to do anything different. No kitty hair in it though, just regular 5000 psi stuff.

 

[frank_f15]

i have never workrd with concete( and never want to /forums/images/graemlins/grin.gif) but a good friend of mine and an expert with concrete, says all concrete will get hair line cracks. true or not?

 

[LarryD]

I don't consider myself an expert in concrete by any means but I've been involved in more pours than I can count (7600yds in 3 days on one occasion).

If the base is compacted, the batch is right, the concrete is kept moist (slow hydration), and control joints are cut at appropriate spans, there shouldn't be any errant cracking.

I want to emphasize errant cracking. One of my current projects involves making an area to strap an EA-6B to the deck and run it up to 80% power. The outer sections were 14" thick and control joints were cut in while it was still green, about 12 hours. The joints were 2" deep and within 2 days the joint cracked all the way through, just like it was supposed to. All large concrete areas will crack as it cures, all we can do is control where those cracks go.

 

[willywildes]

that is the one thing a concrete company will guaranty, no mater how it's placed . It will crack. some bigger than others.

 

[Durbob]

I have found it to be true, Also the slower it sets the better. I have always heard that concrete poured under water (bridges) is the strongest because it takes so long to really set.