Class 6 Aggregate Base Course

Class 6 road base is Colorado's standard crushed aggregate base course, defined under CDOT Section 304. The specification requires a well-graded material from ¾" down to fines, with at least 60% of particles having at least one fractured face — ensuring the interlocking structure needed for load-bearing stability.

Allied Recycled Aggregates produces Class 6 from recycled concrete sourced from demolition projects across the Front Range. Crushed concrete road base compacts to high density, performs well in wet conditions, and develops compressive strength over time — lab tests show approximately 60 psi at 7 days when compacted at optimum moisture.

Common applications: driveways, parking lot sub-base, road construction, utility trench backfill, retaining wall core fill, and structural fill. Using recycled Class 6 diverts concrete from landfills and typically costs less than quarried virgin aggregate.

Gradation Data — Percent Passing

Sieve Size	Allied Test	CDOT Spec	Aurora Spec
1"	100		100
3/4"	99	95–100
1/2"	83
3/8"	73		50–85
#4	54	30–65	35–65
#8	42	25–55
#10	39		25–50
#40	17		15–30
#200	6.7	3–12	3–15