Were it my pour, I'd use a day laborer to dig out the area for me,
frame it with 2x12s, and wire in some reinforcement mesh. I'd have
the laborer try to keep the bottom flat, but if he overdug an area, I
wouldn't have it filled in with loose dirt. I'd leave it to be filled
with crete. Concrete likes a very firm base, which keeps it from
Then I'd hire a concrete finisher the day I had the concrete truck do
the pour. He'd make sure it was flattened and smoothed, then once it
set up a bit, he'd very lightly broom it for better traction.
After it's cured for a week, I'd come back and fit the asphalt to the
concrete for a smooth transition.
The good thing about concrete is that only the first yard costs a lot.
The rest comes along for the ride. Around here, it's $140 for the
first yard but only $500 or so for a ten yard load of it.
If you use your own dump truck and laborer, it shouldn't cost you over
$1,000 all together. Just do it!
Happiness lies in the joy of achievement and the thrill of creative effort.
-- Franklin D. Roosevelt
You might went to search on the internet for " Soil Stabilization ".
And then see if there is anyone in the Chicago area that does it. I
am not sure what kind of mess the fork lifts are making. So there
some possibility that soil stabilizers can be injected through the
asphalt and avoid having to use any concrete. Anyway some thing to
check on. I vaguely remember that they used soil stabilization when
they built BART in Ca. On the other hand they did not use it when
they built the VMPB at Kings Bay.
You might be fine with 6" thick concrete if it's constructed properly
- think about it like you're building a section of an Interstate
Highway. They need to dig down deep, say 18 - 20" and put down
geo-fabric and drain tiles and sumps to get rid of the water, it has
to stay dry under there. Any water underneath will frost heave it.
Then you put down 10" to 12" of Road Base - crushed stone, gravel &
sand blend, and have it compacted. And a 2" - 3" layer of Asphalt as
an interstitial layer - it will allow the concrete to flex a bit.
Then you use the pre-fabbed heavy rebar mats for freeway lanes, it
comes in standard sections (12' X 20'?) and drops into place like
Lego. They come epoxy coated so it doesn't rust inside the concrete
and make it all come apart from the inside.
And be sure to put the pre-fabbed dowel & sleeve sections between the
slabs where you will place bender-board expansion strips or
diamond-saw the expansion joints. It's a nifty trick - two sleeves
for the two sides, and a captive floating dowel right at the join
point. That way it can expand and contract horizontally but the
sections can't heave vertically between each other.
Build it like that, and you'll never have to do it again, Ever.
But it would cost a bloody fortune - so figure on putting down a
healthy layer of Road Base and drainage, compact it well, and a simple
slab pour on top - that should go 20 years for your uses.
--<< Bruce >>--
Describe the mess the forklifts make. It sounds as if the asphalt is
not on stable soil so if they sit in one place they cause dents. I
think the cheap way is to inject soil stabilizers thru the asphalt.
Got a similar problem here with the driveway put down over a clay
soil. When it gets warm enough to dig, I am going to put in some sub
surface drainage. Which ought to help. Then I am going to look into
having someone inject stuff through the asphalt.
Before the driveway was put in, they should have mixed a bunch of lime
in the soil.
Let me rephrase my answer. Talk to some professional engineers in
your area on how to do it. Do not completely rely on the opinions
here. I would expect an engineer would ask for samples of the soil
beneath the asphalt before he made any recommendations. Civil
Engineers design roads, airport runways and building foundations.
He's being goofy...
--asphalt is classified as a flexible paving material and it will displace
under sufficiently heavy loading even if it's been laid over a solid
Or at least that's what they taught in tech school back in the late 70's
Very flexible. Near here in hot sunny TX there is a highway overpass
that has a left turn lane on a slight downhill slope to a stoplight.
When they originally built it that area was asphalt. In the warm weather
every car coming to a stop at the light was pushing a small wave of
asphalt ahead of it. They eventually tore it up and redid it in
How about the ultimate cheap method.
Remove the pavement from the area you want to stiffen up.
Break up the soil real good down as deep as you can go without
destroying everything. Now take about half of the loose stuff out and
put a sand/gravel mix in it's place. Buy a bunch of bags of portland
cement and till it into the dirt/gravel mix real well, Now WATER the
crap out of the area and then roll it down smooth. Water it some more
and roll it some more. Then let it set for a couple weeks. Now pave over
the top and you should have a nice solid lot. You would be doing the
homeowners version of soil cement and if you add the correct amount of
cement per SQ/FT it will handle just about anything you would ever put
I did this for an area that was prone to washing out a few years ago.
When the water level was very low it all got dug out and repaired, Then
once it was in place I kept it wet and raked it so it was a bit rough.
Then put a small amount of loose dirt on it and planted some fast
growing grass. It hasn't moved at all and this area was washing away at
about 3 feet a year. Plus it looks like dirt (until you kick it) so it
doesn't look like a big concrete block stuck in the ground. For my
application this was a BIG plus. For you it doesn't really matter but it
would be a LOT cheaper than digging all of it out. You could then do
just the smaller area with solid concrete and save money.
Steve, I think that what you did is a fine approach for certain
applications, but, I think, for heavy solid tire forklifts I need
regular solid concrete, with a proper road base and all.
I want it done, but at the same time I am budget conscious.
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