OT - Should I have my driveway poured now or spring

Hello everyone. I'm in the middle of building a new house. We should be moving in around Dec. 1st. We're at the point where we could pour the driveway now or wait until spring. I'm torn because I'd like to have it done and avoid the winter on a gravel drive, but I don't want the ground to settle more and cause the driveway to sink.

It will be a concrete drive about 20 yards long from the curb to the garage. I know concrete will eventually crack and that can't be avoided, I just don't want the big bump as you pull into the driveway like my old house were the driveway setteled so much.

After some advice from a neighbor I'm "water staking" in front of my garage (started today). I've got a 4-5 ft long copper pipe with a valve on one end where I can hook up my hose. In some places it is very hard to work into the ground, but in other spots it slides right in.

So what do you guys think?

Was the ground in the drive way area been disturbed moved or haul in?

If so, it would be better to wait till spring. Driving over it all winter and with the freezing and thawing should eliminate the voids.

If it is "built" properly there would be no problem. In the glacial till here, where you can't depend on percolation, road specs call for 12 inches of sand under sixteen inches of compacted road base crusher run two inch gravel, compacted to test by radiation receiver test unit. If finished grade is going to be lower than ground surface to the side, under drain is required. Then if your 'crete contractor properly installs the reinforcing mesh and you specify a heavy mix you can invite the fully loaded oil delivery truck on it after two weeks of cure.

I waited 15 years for my drive to settle. Poured it 5.5 inches thick, 25 X 35 ft. Put wire in it and hasn't cracked in 8 years.

(quoted from post at 17:28:31 10/08/11) I waited 15 years for my drive to settle. Poured it 5.5 inches thick, 25 X 35 ft. Put wire in it and hasn't cracked in 8 years.

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eorge, do you live outside of Charleston WV?

I have seen a new drive way flex under heavy equipment.What are the neighbors using?Concrete wont work here.

I would wait, unless the soil has been backfilled a layer at a time and really tamped to original compaction. I've seen too many contractors in a hurry to complete the job, pour the concrete and a few yrs later steps are hanging or the driveway sags cause the soil gives way.

Thanks for your thoughts. Here's a little more info. The garage floor is higher than the ground use to be. I think the driveway is probably 3 ft higher than the original ground level. They also dug quite a bit in order to pour the footings for the garage.

The picture is of the garage before they backfilled.

I usually fill in front of the garage with gravel where they dug for
the foundation. I never put fill dirt back in a driveway under
concrete no matter how good it gets packed. I only fill with
gravel and compact it or drive on it till the very end of the
construction process. That said, the last house I did, the gravel
was packed as hard as any gravel road. The crew I hired to pour
the concrete came in with their skid steer and tour it all up so
they could level it easier. They put it back in and ran the packer
over it twice and poured. I let them know what I thought of it but
not much else I could do. Some concrete guys say your better to
have a soft layer right under the concrete but I always tried to
get it compacted as hard as I could. Whatever you do, put a cut
line about 5 ft. out from the front of the door so that it will crack
there as that is where they usually crack first. 34 plus years of
trying to figure it out.

I'd wait. Rain & time & spring thaw sure settle ground a lot. I'd doubt that high a fill in your pics got packed down in 6 inch lifts?

--->Paul

What part of the country? (Does the ground freeze hard?) Sand or clay? Will you need to bring in additional fill?

The longer you wait, obviously the more compacted it will become. But sand compacts less than clay, so if it's sandy you can probably get it pretty well compacted just driving over it or with a vibratory compactor.

Check to see if you'll need some additional fill to bring it to grade. If so, haul in some limestone (or whatever sort of crushed rock you have locally). Grade it for the pour, then drive over it all winter. You'll have a decent driveway for the winter and a very solid base for your concrete when you pout it in the spring.

At this point in the year I would be more concerned about how cured the concrete would be the first time I had to throw salt on it this winter.

The issue is not really the concrete cure, but the ground settling. I
poured mine right away and it is hollow under the driveway. I would
let the ground settle over the winter.

Typically in construction, when an area is excavated, the undisturbed level is where footings and other similar structural components are placed, to avoid settling. Other situations where it was over excavated, the back fill has to be suitable in gradation, moisture level, etc. and compacted in 12" lifts to a desired compaction level. Each lift can be tested easily for percentage of compaction with a (Troxler)nuclear density meter, in the old days before these they did proctor tests etc. Some materials like quality gravel, with composite sizes of aggregate that will compact to 95%-100%, which I believe is better than undisturbed, which if I recall correctly is around 85%. We used to build small earthen dams and the undercut was excavated out to a certain level and compacted 100% to make it impermeable. The material used had to be suitable with the right moisture content, or it would not compact.

The compaction you have depends on the material placed in the excavated area and how it was compacted. If it was a suitable material known to compact like mentioned above with a vibratory roller, plate compactor, split drum sheepsfoot vibratory roller like a walk behind in lifts or increments within the range of the particular machine, you would be fine to place a slab on it. Fill should be at least 85% like undisturbed, but the only way to know is testing each lift. Ideally you want suitable material as a subbase onto bearing undisturbed, like around here you can undercut to a relatively shallow level, fill with gravel, crushed stone road base like what NYS DOT calls Item #4 compact and place a slab.

If you have questionable material, or unknown fill from your site that you don't know how it compacts, has been filled in the cut and maybe tamped with a backhoe bucket, no vibratory roller or some other hap-hazard method to backfill, you may very well get settling. If you know the material does compact and can bear loading, but was not compacted using a vibratory roller or the like, yes, I'd wait til spring or excavate again, compact in lifts, up to your subbase, compact that, form, then place your slab. Its not going to hurt to let the weather settle it in, you could place some subbase material, grade compact, use as a temporary wear course this winter, then regrade, add more subbase etc. compact, then place the slab.

The fill material has to be suitable, with an optimum moisture content to compact properly, if not it may not, could be unstable, and do a myriad of things under different conditions. The underslab area should also be well drained, or constructed so it does not trap water.

I live in West Central Indiana. I hired a professional to pour the driveway. My drive was done as one pour. Only had forms on the sides and end. To keep the drive from moving next to the garage, we dug down and the drive is resting on the garage's footer.

Had the same guy pour my 30x40 pole barn. It is 6 inches thick and was done in one pour. Just used wire, not fiberglass. The sides of the pole barn act as the forms. Had to form up the garage door opening . The next day, the guy comes back and cuts in the expansion joints, which has never cracked.

If it's done right, there won't be cracks.

Thanks everyone... I plan on waiting until spring. I've heard from many people here and elsewhere suggesting waiting.

I've also been "injecting" water into the dirt within 3 ft from the garage doors and I've found that there are many air pockets. Just confirms it for me that I need to wait.

For those who asked, I'm in NW Illinois.