Crushed Concrete Driveway Install That Stays Put

Gravel prices have climbed in most regions, and a quote for virgin crushed stone on a long driveway can run past what the whole project was supposed to cost. A crushed concrete driveway is the obvious cheaper option, but done wrong it ruts, sheds rebar and turns into a lumpy mess within a couple of seasons.

Done right, recycled concrete aggregate packs harder than many natural gravels, because the leftover cement fines rebind when wetted and rolled. I have put down dozens of these driveways for rural and suburban clients. Here is how to buy the right material, how much you need, and the grading steps that make it last.

What a crushed concrete driveway actually is

Recycled concrete aggregate, often sold as RCA or recycled crusher run, comes from demolished slabs, curbs and foundations. A crushing plant breaks it down, pulls out most of the steel with magnets, and screens it into sizes. The two products you will use are:

3/4 inch minus (dense graded). Stone from 3/4 inch down to dust. This is the workhorse for both base and surface because the fines fill voids and lock up.
1.5 to 3 inch clean. Larger pieces with little fine material, useful as a bottom layer on soft or wet ground.

The fines are the secret. Crushed concrete contains unhydrated cement particles that react with water. After a few soak and dry cycles plus traffic, the top layer gets a slightly cemented crust that resists washboarding better than rounded river gravel.

Cost and quantity for a typical driveway

Prices vary by region, but in most of the areas I work, recycled concrete runs $12 to $30 per ton delivered in 15 to 20 ton loads, against $25 to $50 per ton for virgin crushed limestone. Loose crushed concrete weighs about 1.2 to 1.3 tons per cubic yard.

Driveway size	Depth (compacted)	Approx. tons	Material cost at $20/ton
12 ft x 50 ft	6 inches	16 to 18	$320 to $360
12 ft x 100 ft	6 inches	32 to 36	$640 to $720
12 ft x 200 ft	8 inches	85 to 95	$1,700 to $1,900

Those tonnage figures include roughly 20 percent extra for compaction loss. Material always settles more than people expect. For heavy trucks, deliveries or a soft subgrade, plan on the deeper sections described in our guide to gravel base depth for truck traffic.

How to install it step by step

Strip and shape the subgrade. Remove sod and topsoil down to firm mineral soil, usually 4 to 8 inches. Shape a crown of about 2 percent, or 1/4 inch per foot, from the centerline to each side so water leaves the surface.
Compact the subgrade. Roll or plate compact until a loaded pickup leaves no visible rut. Soft spots should be dug out and filled with the larger 1.5 to 3 inch material.
Decide on fabric. On clay or wet ground, a woven geotextile under the stone stops the base from punching into the mud. Our breakdown of geotextile fabric under a driveway covers when it pays and when it is wasted money.
Place the base in lifts. Spread 3/4 inch minus in lifts of no more than 4 inches loose. Wet each lift until it is damp but not muddy, then roll it with a vibratory roller or plate compactor. Two to four passes per lift is typical.
Finish with the crown. Blade the final lift to match the subgrade crown and roll again. Make sure edges are slightly lower than the shoulder so water does not pond at the side.
Let it cure under traffic. Light vehicles are fine immediately. Avoid heavy dump trucks for the first week if you can, and water it once or twice during dry spells to help the fines bind.

The counter-take: skip the free demolition concrete

Every few months someone tells me a contractor down the road will dump broken slabs for free. Take a hard pass unless it has gone through a crusher and screening plant. Unscreened demolition debris carries chunks of rebar, wire mesh, brick, asphalt shingles and sometimes wood. Rebar ends work their way up through the surface after a winter or two and puncture tires. Big chunks also leave voids that the fines cannot fill, so the driveway settles unevenly.

Buy from a recycler that screens to a spec and runs magnets. Ask to see a pile before ordering. A good load looks uniform, gray to light tan, with fines throughout and no visible steel. Paying $20 a ton for that beats spending a Saturday with a pry bar pulling wire out of your driveway.

One more buying tip: ask whether the recycler mixes in crushed asphalt or brick. A small amount is common and harmless, but a load that is a third asphalt will behave more like millings, softening on hot days. If you want that, buy millings on purpose. If you want the cement fines to bind, insist on mostly concrete.

Drainage and slope problems to watch for

Crushed concrete is alkaline. Fresh material can raise runoff pH, which matters if your driveway drains straight into a pond, a stream or a vegetable garden. Route runoff into a grassed swale first, where soil buffers it. After the first few months of rain the effect drops off sharply.

Steep grades are another concern. On sections above about 10 percent, any crushed aggregate surface tends to wash during heavy storms. Add water bars or a shallow diversion every 50 to 100 feet, and read our notes on how much slope a driveway can handle before you commit to stone on a steep run.

Maintenance after the first year

Expect to add a thin topping of 1 to 2 inches of fresh 3/4 minus every three to five years, depending on traffic. Re-crown with a box blade or grader when you see water standing in the wheel paths. Fill potholes when they first appear, because a 2 inch dip becomes a 6 inch hole by spring. More grading guidance is in the driveways and access roads section.

Frequently asked questions

Is crushed concrete better than gravel for a driveway?

For most residential driveways, crushed concrete performs as well as crushed limestone and usually costs less. The cement fines help it bind into a firm surface. It is better than rounded river gravel, which never locks together.

How thick should a crushed concrete driveway be?

Plan on at least 6 inches compacted for cars and pickups on firm soil. Go to 8 to 12 inches, sometimes with a larger stone bottom layer and fabric, for heavy trucks or clay subgrades. Place it in 4 inch loose lifts so each layer compacts fully.

Does crushed concrete harden over time?

It does firm up noticeably. Leftover cement particles react with water, and repeated wetting, drying and traffic create a tight crust on top. It never becomes solid concrete, but it resists rutting better than most loose gravel.