Casting Large Concrete Pavers

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Pouring a concrete foundation is out, since my site conditions won't really allow for it. I can lay a subbase of sand or pea gravel if that would hopeflly preventing the clay from heaving.
Given the responses I am willing to pour thicker paver slabs in place, given that most who have responded think that this would prevent cracking. What is the mimimum thickness - 3", 4"? If I pour to this thickness, can I avoid intalling a subbase, since that would entail a great deal more work?
With regard to the thickness of the concrete being 2" liable to break from the movement and rusting of the rebar, how is this problem avoided with concrete countertops, given that these are generally cast pretty thin and poured in long sections with rebar and remesh from what I have seen? Obviously countertops are subject to less tensile pressure than something being stepped on, but are subject to moisture.
One of the other options I ran across was a company here in CA called Rapid Set (www.rapidset.com/ConcreteMix_data.asp). They make high performance concrete which is great deal more expensive than the bagged Quickrete. It costs about $12 a 60lb bag. I weirdly enough ran into a rep yesterday in the Home Depot who said that if used properly, the stuff is guaranteed not to crack since it is primarly used for roads and other high performance situations. It sets in 15 minutes, but apparently this time can be extended with a set control substance you can by from them. I am going to call them on Monday and see how this could be used, and what adjustments would have be made for my specific situation. Just curious, does anyone have experience with a product such as this?
Naveen
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Concrete does not like to be long and thin no matter how thick it is. As a general rule the length should never exceed 1.5 of the width. You will notice joints tooled or cut into exterior concrete roads, sidewalks, driveways, etc. If the concrete is cracked, try to visualize why. You are bucking an uphill battle other than this next bit.
I was quite surprised by an article in one of my magazines. Here is quite an interesting article from the March issue of Concrete Construction magazine: <http://www.concreteconstructiononline.com/industry-news.asp?sectionIDi1&articleIDE6524 If I had read it elsewhere I would have been a doubting Thomas. It may well give you some of the information you seek.
Concrete countertops are interior and sealed, hopefully the reinforcement won't start to rust. It is the expansion of the rust that destroys the concrete.
There are many different acrylic modifiers to add to the concrete to increase flexural strength. If you have little or no experience with concrete I would be concerned with your ability to keep up with the Rapid Set product.
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That article is a very interesting read. Not only for they were able to achieve, but in understanding the underlying forces that cause concrete to crack. I was not aware of the curling aspect.
Just to show that I am not crazy, you can see some pictures of the paver/slabs I am talking about at the this link http://picasaweb.google.com/naveenreddyla
Any thoughts on how they are making this work? Or is this just wasted money. Mind you I have seen this done on a number of homes.
Naveen
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clipped

Countertops would never be exposed to the amount of water that outdoor applications are. Rusting rebar is a fairly common concern in Florida, with all the balconies on condos....We have had a number of spots on our condo where rebar had rusted and cracked concrete. This occurred on balconies and second-floor deck in open atrium. Salt is an added issue here, but concrete/stucco has to be painted and maintained to slow or stop the problem. Condo across the street had 13 stories of balconies jack-hammered, repaired and painted a couple of years ago.
I would also be concerned with the 8' length pavers cracking from expansion and contraction. We have sidewalks with extremely long sections and all the sections have cracked, roughly in the center.
With your clay soil and the possibility it can heave or shrink from changes in water content, it seems that consistency would be the major issue. If it rains, it will be evenly wet and expand fairly evenly, I would think. Another reason smaller pavers would make a difference...easier to pull up and re-level if the soil moves.
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