16 Min Field Read • Updated October 2026
✓ Quarry Scale Calibrated
Gravel & Crushed Stone Sizing & Tonnage Guide: AASHTO #57 vs. Crusher Run, Quarry Densities & Compaction Loss
⚡ Aggregate Tonnage & Coverage Quick Reference
Standards: ASTM C29 / AASHTO T19
A civil aggregate reference for contractors, site estimators, and property builders. Decipher standard quarry numbering, calculate true loose-to-compacted volume loss, convert scale weights across all rock geologies, and engineer durable driveway cross-sections.
1. The Two Aggregate Families: Open-Graded Clean Stone vs. Dense-Graded Base
When purchasing crushed rock from commercial quarries, all materials fall into two distinct engineering classifications based on grain size distribution (ASTM C136):
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Open-Graded Clean Stone (AASHTO #57, #4, #8):
Crushed angular rock that has passed through vibrating mechanical screens to wash out all rock dust and fine particles. Because there are no microscopic particles filling the void spaces between rock facets, the material maintains 35% to 45% open void space. Water drains freely through the stone at hydraulic conductivity rates exceeding 10^{-1} cm/s. It is self-draining, non-frost-susceptible, and will never compact into an impervious crust. -
Dense-Graded Aggregate with Fines (Crusher Run, DGA, ABC, #21A):
An engineered blend of crushed angular rock (3/4-inch to 1-inch maximum size) combined with a controlled proportion of mineral fines and rock flour (screenings passing the #200 sieve). When wetted to optimum moisture content and rolled with a vibratory roller, the fine dust particles act as a hydraulic bonding agent, packing into the interstitial voids to form an impermeable, high-bearing-capacity road base (CBR > 80%).
2. Standard AASHTO M43 & ASTM D448 Sizing Matrix
Quarry aggregate designations across North America follow standard sizing screens established by AASHTO M 43 and ASTM D448. The visual scale below illustrates exact stone sizes from large ballast down to mineral dust:
AASHTO M43 / ASTM D448
| Designation | Nominal Sieve Range | Grading Type | Primary Construction Applications | Loose Density (Tons/yd³) |
|---|---|---|---|---|
| #1 & #2 Ballast | 2.0″ to 4.0″ | Open-graded clean | Construction site tracking pads, deep stabilization over clay | 1.30 – 1.35 |
| #3 & #4 Stone | 1.0″ to 2.5″ | Open-graded clean | Drywell drywells, heavy road base foundation, riprap backing | 1.25 – 1.30 |
| AASHTO #57 Stone | 1/2″ to 1.0″ | Open-graded clean | French drains, retaining wall drainage column, concrete aggregate | 1.20 – 1.25 |
| Crusher Run / DGA / #21A | 3/4″ to #200 Dust | Dense-graded with fines | Asphalt/concrete road base, driveway foundation, paver subbase | 1.35 – 1.45 (1.55 rolled) |
| #8 Pea Gravel | 1/8″ to 3/8″ | Open-graded rounded | Utility pipe bedding, exposed aggregate, decorative pathways | 1.30 – 1.35 |
| #10 Stone Dust (Screenings) | Passing #4 Sieve (1/4″) | Pure mineral fines | Horse arena footing, asphalt filler, paver joint sanding | 1.25 – 1.35 |
3. Micro-Structural Mechanics: Open-Graded vs. Dense-Graded Aggregate
Understanding particle distribution dictates whether an aggregate acts as a hydraulic conduit (water filter) or a structural load-bearing slab:
CROSS-SECTION MICROGRAPH
4. Compaction Shrinkage Factors & The Loose-to-In-Place Ratio
When aggregate is delivered in a dump truck, it arrives in a loose, aerated state. Once spread on a roadbed and compacted with a vibratory plate or smooth-drum roller, the void volume decreases significantly:
ASTM D1557 MODIFIED PROCTOR
If your driveway project requires 10 compacted cubic yards of Crusher Run road base, ordering 10 cubic yards guarantees you will fall 2 inches short across the entire driveway. You must apply a 1.22 to 1.25 multiplier:
10 Compacted yds³ × 1.22 = 12.2 Loose yds³ → 12.2 × 1.40 tons/yd³ = 17.1 Tons to Dispatch
5. Quarry Rock Densities: Geological Weight Variations
Crushed stone is priced and sold at the quarry scale by the US Short Ton (2,000 lbs), but excavation contractors dig and grade in cubic yards (27 cu ft). Mineral density varies significantly based on regional bedrock geology:
| Parent Mineral Geology | Specific Gravity | Loose Weight (lbs/yd³) | Loose Tonnage Factor | Compacted Tonnage Factor |
|---|---|---|---|---|
| Granite / Gneiss (Standard Piedmont) | 2.65 – 2.70 | 2,700 lbs | 1.35 tons/yd³ | 1.50 tons/yd³ |
| Dolomitic Limestone (Midwest/South) | 2.55 – 2.65 | 2,500 – 2,600 lbs | 1.25 – 1.30 tons/yd³ | 1.45 tons/yd³ |
| Basalt / Diabase Trap Rock (Pacific NW / Northeast) | 2.90 – 3.05 | 3,000 – 3,200 lbs | 1.50 – 1.60 tons/yd³ | 1.75 tons/yd³ |
| Washed Quartz River Gravel | 2.60 – 2.65 | 2,650 – 2,750 lbs | 1.32 – 1.38 tons/yd³ | 1.45 tons/yd³ |
| Recycled Crushed Concrete Base (RCA) | 2.20 – 2.40 | 2,200 – 2,400 lbs | 1.10 – 1.20 tons/yd³ | 1.35 tons/yd³ |
6. Field Case Study: How Many Tons is 6 Yards of Gravel?
“How many tons is 6 yards of gravel?” is one of the most frequent takeoff calculations requested by contractors and property owners. The exact answer depends on material selection:
Clean #57 Drainage Gravel (6 yds³)
6 × 1.25 tons/yd³ = 7.50 tons (15,000 lbs). Dispatched in one standard tandem dump truck.
Crusher Run / DGA Base (6 yds³)
6 × 1.40 tons/yd³ = 8.40 tons (16,800 lbs). The mineral fines add 1,800 lbs of weight compared to clean stone.
Washed Pea Gravel #8 (6 yds³)
6 × 1.35 tons/yd³ = 8.10 tons (16,200 lbs). Rounded quartz particles settle more tightly than crushed open-graded rock.
7. The 3-Tier Heavy-Duty Gravel Driveway Cross-Section
Pouring 4 inches of loose gravel directly over lawn turf creates a mud bog within two rainy seasons. The vector blueprint below illustrates the standard civil engineering cross-section for a rural or residential gravel driveway:
FHWA GRAVEL ROAD DESIGN STANDARDS
8. Hauling Logistics: Dump Truck Types & Tailgate Spreading
When ordering bulk aggregate from a quarry, delivery charges represent 30% to 50% of the total ticket price. Selecting the correct truck class minimizes per-ton freight fees:
| Dump Truck Classification | Axle Count | Legal Payload Capacity | Volumetric Capacity | Turning Clearance Required |
|---|---|---|---|---|
| Single Axle (City Dump) | 2 Axles | 5 to 7 US Short Tons | 4 to 5 cubic yards | Standard residential driveway, tight gates |
| Tandem Axle | 3 Axles | 12 to 14 US Short Tons | 8 to 10 cubic yards | Moderate turning radius, suburban driveways |
| Tri-Axle / Quad-Axle | 4 to 5 Axles | 18 to 22 US Short Tons | 14 to 16 cubic yards | Heavy commercial, requires 14-ft vertical clearance |
| End Dump Tractor-Trailer | 5 Axles | 24 to 26 US Short Tons | 18 to 22 cubic yards | High-volume roadwork, wide open level turnaround |
When dispatching your order, ask the quarry if the driver can “tailgate spread”. Experienced dump truck drivers adjust the tailgate limit chains so the gate opens only 2 to 3 inches. As the dump bed rises, the driver slowly drives forward in creeper gear, spreading an even 2- to 3-inch ribbon of gravel along the driveway. This saves 4 to 6 hours of backbreaking manual shovel and wheelbarrow work!
9. Frequently Asked Questions (Aggregates & Gravel)
Why did my gravel driveway sink into the mud?
The gravel sank because it was poured directly over soft clay without a woven geotextile separation fabric. Vehicle point loads push heavy rock downward into saturated subgrade while pumping muddy clay upward through the voids. A $100 roll of 200-lb tensile woven fabric prevents this permanently.
Can I use pea gravel for a vehicle driveway?
No. Pea gravel (#8 stone) consists of smooth, rounded river pebbles. Under vehicle tires, rounded pebbles act like ball bearings—they slip past each other and cannot interlock. Tires will rut and spin out. Use angular crushed stone (#57 or Crusher Run) which mechanically interlocks under wheel pressure.
Scale Tonnage Engine
Calculate Gravel Tonnage for Your Project Footprint
Model cubic yards, scale weight in US short tons, and dump truck load counts across all rock varieties.