I have gotten some estimates for an asphalt drive over my old concrete,well some of the people giving me quotes are telling me that the asphalt willnot last 2 years over the concrete,but the other three says it will be OK,what do you all think?
It is going to cost around $1600,is there going to be a problem puting it over the concrete?

Thanks

 

why are you in need of a new driveway would be the first question I would ask... is the concrete cracked?? if so, there will be a maintenance problem because the concrete expands and contracts at a different rate than the asphalt. I can't say that it won't last 2 years but I think you will start to see reflective cracking in the asphalt within 1 year.

my qualifications are that I'm a civil engineer and did research on this subject in college.

 

The first crack in the asphalt (due to the expansion differences stated by graphite), then some rain and some freezing.... You'll see that this separates the asphalt from the concrete very efficiently

AlpineRAM

 

How's the run-off? If water can stand on the concrete it can stand under the concrete. (Freezes I'm sure in the Michigan winters causing it to "float".) How long is the driveway? It's relatively easy to haul away broken concrete with a tractor w/loader (but troublesome to break it up next to buildings.) My brother replaced his concrete drive last year with new concrete. Believe it or not new concrete was cheaper than asphalt down here. The person he hired, hauled the old away to a fill at a construction site which is exactly what I'd do. If I was going with asphalt though I would first spread 4-6" of washed stone first.
Nat

 

Think of asphalt as a slow flowing liquid that will go wherever the base material goes. If the base (concrete or otherwise) moves, the asphalt goes with it. This also means that a poorly drained base will freeze & heave causing the asphalt to pull apart.

 

if you really want to go with asphalt, try to get quotes for removal of existing concrete pavement, placement of a compacted drainable base, a 2" lift of base asphalt and a 2" lift of finish asphalt....

 

But then, why do they put concrete under asphalt before they do highways?? patch work to fix holes and cracks in road all get concreted before pave with asphalt!

 

it's not concrete... it's a compacted base material to add strength and drainage to the asphalt driving surface.

not in Kansas...pot"holes" and cracks in concrete panels are supposed to be cut out and replaced with equal strength concrete.

 

Well,I beg to differ!! At least here in Iowa , We- {I am a driver for Croell redi-mix} have dumped plenty of concrete in patches and repair work befor asphalt! They fill up to the top of road and then the whole road gets about 2 inches ground off of it! resurficing it for a layer or 2 of asphalt usaully 1-lift is 2-3inches and they do 2 lifts. the patch work that we pour is usaully 6-10 inches depending on which contractor, or road, or what D.O.T inspector is there!

 

living in the great white north, we refuse to pave over concrete, as it is a guaranteed failure after 1 year. And since the contractor that I work with from time to time actually puts a warranty on his work, there is no way that he will do something that will cost him in the long run.

The asphalt separates from the concrete, and basically flakes apart.

 

you "fill" to the top of the road and then mill 2 inches off?? what logic is behind this mode of action. why mill freshly poured concrete. If the state of Iowa is overlaying 4 - 6 inches of asphalt (on top of the "repaired" holes and cracks) more power to the aphalt producers whose pockets are being lined by the tax-payers of your ever forgiving state. Not too mention that you compromise overpass clearance and shoulder side-slopes.... Go Iowa asphalt producers.

 

Dave, I'd get a quote to include removing the old concrete; then a couple of quotes on paving with either asphalt or concrete. I'd also ask about life expectancy of each option - you often get what you pay for.

How long do you plan on staying there? 5 years? 15 years?

If you want to cosmetically improve the driveway for a quick sell, maybe the $1600 is worth it. But do you want to risk possibly dropping $1600 every couple of years?

 

Here in Kalifornia, years back they started making all the hwys of concrete. They all seemed to fail eventually and were tougher to repair than asphalt. pot holes were cracked craters. They eventually planed the top and put asphalt on top. Now there even worst. Seriously, the roads in Tijuana are better. BTY if you wanna calc your asphalt tonage here is a formula. Asphalt is 12lbs per square foot at one inch thick. figure your square footage, how thick your gonna go. Say 1000 sqft at 4" thick. 1000sqft x 12lbs x 4" thick = 48000 lbs divided by 2k (ton) = 24 tons. Last I checked round here it was $60 or so a ton.

 

Thanks for all the replies,to lay asphalt over my existing concrete will be $1500 to tear up the old concrete and back fill with lime stone and asphalt will be $3500,I can get a new concrete drive for $5500.
I may just go with new concrete,I wasnt planning on spending over $2000 but I guess I will have too