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On-spec CDOT Class 6 aggregate base course stockpiled on a Colorado jobsite
CDOT Class 6 Base

CDOT Class 6 base course, produced on-site in Colorado.

Class 6 is the base the spec calls for. CrushRite produces it on your jobsite to CDOT Section 703, crushed and screened from recycled concrete or native rock and held to the gradation, so the base goes down where you need it without trucking in virgin aggregate.

Request a Bid 719-304-4873
The Spec

What Class 6 base actually is.

Class 6 is a dense-graded aggregate base course defined under CDOT Section 703. It is the standard structural layer placed under pavement on Colorado roadway and site work, valued because a true Class 6 gradation compacts to a tight, stable, free-draining base. The whole point of the spec is consistency, so the layer performs the same everywhere it is placed.

Producing it well is a gradation problem, not just a crushing problem. That is why the crusher and screen run closed-circuit: to hold the band across the whole production run rather than drifting as the feed changes.

What defines it
  • ▸ Dense-graded aggregate base course under CDOT Section 703
  • ▸ 3/4 inch nominal top size, well graded through to a controlled fines content
  • ▸ Plasticity and durability held within the CDOT base-course limits
  • ▸ Placed and compacted to the project's density requirement
Recycled or Native

Same spec, from the feed that makes sense for the job.

Class 6 can be produced from recycled concrete aggregate or from native rock and pit-run. On a tear-out, the smart feed is the concrete already on the ground, which is the heart of our concrete crushing and recycling work. On a job with native material, we run that instead. Either way the output is held to the same Class 6 band.

When the existing base on a road has drifted off spec rather than been torn out, the related service is road base re-screening, which reclaims the base in place to the same target.

How It Works

Held to the band, run to run.

The crusher and screen do the work together, and the gradation is sampled off the run so the base that goes down is the base the spec asked for.

01

Confirm the spec and the feed

Lock the target as CDOT Class 6 to Section 703, or the engineer's curve, and confirm the feed: recycled concrete, native rock, or pit-run.

02

Crush to size

The Kleemann MR110Zi impact crusher reduces the feed to the top size the gradation requires.

Equipment specs →
03

Screen closed-circuit

The MS19Z double-deck screen runs closed-circuit with the crusher, returning oversize and pulling the product to the Class 6 band in a controlled loop.

Equipment specs →
04

Sample and verify

Sample gradation reports are produced from the run, with independent third-party lab verification when the prime or engineer of record requires it.

05

Stockpile and place

The WA500 loader stockpiles on-spec base ready to place to grade, staged where the road or pad is going down.

Equipment specs →
Where It Goes

What Class 6 base is placed under.

▸ Base course under CDOT and municipal pavement sections
▸ Subdivision and access road base
▸ Commercial parking lots and laydown yards
▸ Structural base under slabs and flatwork
▸ Shoulder and widening base on resurfacing work
▸ Pipe and utility trench base and backfill to spec
FAQ

CDOT Class 6 base, answered.

If yours isn't here, call 719-304-4873. Nick picks up himself.

What is CDOT Class 6 base? +
CDOT Class 6 is a dense-graded aggregate base course defined under CDOT Section 703, with a 3/4 inch nominal top size and a controlled gradation down through the fines. It is the standard structural base placed under pavement on Colorado roadway and site work, chosen because it compacts to a tight, stable, well-draining layer.
Can Class 6 base be made from recycled concrete? +
Yes. Recycled concrete aggregate is crushed and screened to the Class 6 gradation the same way virgin rock is, and it makes a dense, well-graded base that compacts and drains. Producing it from the concrete already on a tear-out is the core of our concrete crushing and recycling work, and it skips importing virgin base.
Do you provide gradation reports on the Class 6 you produce? +
Sample gradation reports can be produced from the production run, and we partner with independent labs for third-party verification when the prime or engineer of record requires certified results. Send the spec with your bid request so we set the testing up front.
Is Class 6 the same thing as road base? +
Road base is the general term for the compacted aggregate layer under a pavement or surface. Class 6 is a specific CDOT gradation of road base. So Class 6 is road base, but not all road base meets the Class 6 spec, which is the distinction that matters on CDOT and municipal work.
Can you produce Class 6 on our jobsite instead of trucking it in? +
Yes, and that is the point of producing it on-site. We bring the crusher and screen to the material, run it to the Class 6 band, and stockpile it where the base is going down. Send the tonnage, the feed material, and the spec and we will plan it. Call 719-304-4873 with the project.

Need Class 6 base on your job?

Send the tonnage, the feed material, and the spec. We will produce it on-site to grade.

Request a Bid 719-304-4873