Base Rock Density — AASHTO T 180 Maximum Dry Density and In-Place Compacted Density for Crusher Run, #57, #2, DGA and RAP
The complete base rock density reference: loose, compacted, and AASHTO T 180 maximum dry density for the 8 aggregate base materials residential and municipal projects actually use — crusher run, dense graded aggregate (DGA / 21A / CR-6), #57, #2, screenings, recycled concrete aggregate (RCA), and reclaimed asphalt pavement (RAP). Use the chart to size truck loads, verify compaction tests, and reconcile tonnage to a supplier weigh ticket.
Aggregate base is sold by the ton but designed by the cubic yard. The conversion between the two is the material’s compacted density — and the value is different for every aggregate type. Crusher run runs 125–135 lb/ft³ compacted; dense-graded aggregate (DGA / 21A) runs 130–140 lb/ft³; open-graded #57 runs 95–105 lb/ft³ because of higher void content; recycled asphalt millings run 120–140 lb/ft³. Using the wrong density for the material costs 8–20% in tonnage estimation error.
This page consolidates the densities you actually need by material, in both the loose (in the truck) and compacted (placed) states, plus the AASHTO T 180 maximum dry density that compaction tests are measured against. The numbers are calibrated to AASHTO T 180 (modified Proctor compaction), AASHTO M 147 (materials for aggregate subbase), and Penn State CES field-survey data. They’re the lookup table our road base calculator and crusher run calculator reference internally.
Base Rock Density Chart (Compacted + Loose + AASHTO Max)
The single most-referenced table on this page. Values are field-validated 2026 ranges from supplier weight tickets and contractor field-density tests. For project-critical work always confirm with the supplier’s gradation submittal.
Tons-Per-Cubic-Yard Quick Reference
The second table above is the working lookup for site math. The two most-asked questions: “how many tons of crusher run do I need for X yd³?” and “how much area does 1 ton of #57 cover?” Both come straight from compacted density.
How Many Tons per Cubic Yard?
Multiply cubic yards by the tons/yd³ value: crusher run 1.76, DGA 1.82, #57 1.35, RAP 1.76. For 25 yd³ of crusher run: 25 × 1.76 = 44 tons. For 25 yd³ of #57 stone: 25 × 1.35 = 33.75 tons — 23% less than crusher run because #57 has higher void content.
How Much Coverage per Ton?
The 1-ton coverage at 4 in (the standard residential base depth) is in the last column of the second table: crusher run 55 ft², DGA 53 ft², #57 72 ft², RAP 55 ft². The denser the material, the less area 1 ton covers. For other depths the scaling is linear: 1 ton crusher run covers 110 ft² at 2 in (2× the 4-in value), 37 ft² at 6 in (0.67×), 28 ft² at 8 in (0.50×).
What AASHTO T 180 Maximum Dry Density Means
The AASHTO T 180 maximum dry density (also called the “modified Proctor density” or “moisture-density curve max”) is the highest dry density the material can be compacted to in a lab using a 10-lb hammer dropped 18 inches in five 8-blow lifts. It’s the reference value against which field-density tests are reported as a percentage: 95% of T 180 max means the field density is 95% of the lab maximum.
Two practical implications:
- The T 180 max is higher than the typical in-place compacted density. A crusher run with T 180 max of 138 pcf compacts to ~131 pcf in the field at 95% spec (138 × 0.95). Don’t confuse the two — tonnage math uses the field-compacted value (~131 pcf), not the lab max (~138 pcf).
- Open-graded materials don’t have a meaningful T 180 value. #57 stone, #2 stone, and similar single-size aggregates produce a flat moisture-density curve in the Proctor test because they don’t pack to a dense state. Specs for open-graded materials use roller-pass count plus visual lockup, not a percentage of Proctor max.
Reference Tables
| Material | Loose ρ (lb/ft³) | Compacted ρ (lb/ft³) | AASHTO T 180 max dry ρ (pcf) | Compaction factor | Typical use |
|---|---|---|---|---|---|
| Crusher run (CR-6, 2A modified) | 100–110 | 125–135 | 130–140 | 1.22–1.27 | Driveway base, road subbase |
| DGA / 21A / dense-graded aggregate | 105–115 | 130–140 | 135–145 | 1.22–1.27 | Highway base course, parking lot base |
| #57 stone (open-graded 3/4 in) | 75–85 | 95–105 | — (open-graded; no Proctor) | 1.20–1.27 | Drainage, French drain, paver bedding base |
| #67 stone (3/4 in - #4) | 80–90 | 100–110 | — (open-graded) | 1.20–1.27 | Concrete coarse aggregate, base layer |
| #2 stone (1.5–2.5 in) | 85–95 | 100–112 | — (open-graded) | 1.18–1.22 | Heavy drainage, road shoulder |
| Stone screenings / quarry dust | 90–100 | 115–125 | 120–130 | 1.25–1.30 | Paver joint sand alternative, finishing course |
| Recycled concrete aggregate (RCA) | 95–108 | 120–135 | 125–140 | 1.22–1.30 | Driveway base (lower cost vs DGA) |
| Reclaimed asphalt pavement (RAP, base use) | 95–110 | 120–140 | 125–145 | 1.20–1.30 | Driveway top or compacted base layer |
Open-graded materials (#57, #67, #2) don’t produce a meaningful AASHTO T 180 Proctor curve because they don’t pack to the dense state — the standard compaction test was designed for dense-graded soils and aggregates. For open-graded compaction acceptance use vibratory roller pass count + visual lockup, not density gauge. AASHTO T 180 (modified Proctor) values shown for dense-graded materials are typical ranges; project specifications cite the actual T 180 value from the supplier’s mix design.
| Material | Compacted density (lb/ft³) | lb / yd³ | Tons / yd³ | 1 ton covers (ft² at 4 in) |
|---|---|---|---|---|
| Crusher run | 130 lb/ft³ (mid-range) | 3,510 lb/yd³ | 1.76 tons/yd³ | 55 ft² |
| DGA / 21A | 135 lb/ft³ (mid-range) | 3,645 lb/yd³ | 1.82 tons/yd³ | 53 ft² |
| #57 stone | 100 lb/ft³ | 2,700 lb/yd³ | 1.35 tons/yd³ | 72 ft² |
| #67 stone | 105 lb/ft³ | 2,835 lb/yd³ | 1.42 tons/yd³ | 68 ft² |
| #2 stone | 105 lb/ft³ | 2,835 lb/yd³ | 1.42 tons/yd³ | 68 ft² |
| Screenings | 120 lb/ft³ | 3,240 lb/yd³ | 1.62 tons/yd³ | 60 ft² |
| RCA (recycled concrete) | 127 lb/ft³ | 3,429 lb/yd³ | 1.71 tons/yd³ | 57 ft² |
| RAP (recycled asphalt) | 130 lb/ft³ | 3,510 lb/yd³ | 1.76 tons/yd³ | 55 ft² |
Coverage at other depths scales linearly: 1 ton at 2 in covers 2× the 4-in value; at 6 in covers 0.67×; at 8 in covers 0.50×. For the ‘loose’ equivalent (volume in the truck before placement) multiply the compacted volume by the compaction factor from the previous chart. For a complete coverage table by stone size and depth see gravel depth chart.
| Application | Target % of AASHTO T 180 max dry density | Typical roller specification | Verification test |
|---|---|---|---|
| Driveway base (under HMA) | 95% min, 98% typical | 1-ton vibratory; 4 passes | Nuclear density gauge |
| Parking lot base | 98% min, 100% typical | 10-ton steel + vibe; 6 passes | Nuclear density gauge + sand cone (1 per 1,000 yd²) |
| Highway base (under HMA) | 100% AASHTO T 180 | 12–25 ton; pass count per spec | Nuclear + falling weight deflectometer (FWD) |
| Highway subbase | 95% AASHTO T 180 | 10-ton vibratory; 4 passes | Nuclear density gauge |
| Backfill (utility trench) | 95% AASHTO T 99 (standard Proctor) | Hand tampers or jumping jack | Sand cone (one per lift) |
| Open-graded drainage layer | — (no Proctor test) | 1–2 ton vibratory; 2–3 passes | Visual lockup; no quantitative density |
AASHTO T 180 (modified Proctor) is the standard for road/highway base; AASHTO T 99 (standard Proctor) for utility backfill and lighter loads. The difference: T 180 uses a heavier hammer drop (10 lb vs 5.5 lb) and a higher compaction energy (56,000 ft-lb/ft³ vs 12,500 ft-lb/ft³). Most residential driveway specs cite T 180 95% as the minimum.
Why In-Place Density Lags Lab Max by 3–7%
The lab-determined AASHTO T 180 maximum is achieved under highly controlled conditions: optimum moisture, uniform 8-blow lifts, perfect aggregate distribution in the mold. Field conditions are messier: moisture drifts, lift thickness varies, the roller can’t apply the lab’s point-by-point compaction energy. Most projects specify 95–100% of T 180 max for the field compaction target, knowing the 3–7% gap is the realistic field achievement.
Three Variables That Compound the Field-vs-Lab Gap
- Moisture content. Material more than 1–2% off the optimum moisture (typically 5–8% for crusher run) compacts to 3–5% lower density at the same energy. The lab uses optimum moisture by design; the field uses whatever moisture the material arrived with.
- Lift thickness. Compaction energy decays exponentially with depth. A 4-in lift compacted with a 10-ton roller reaches 98% of T 180 throughout; an 8-in lift compacted with the same roller reaches 98% only in the top 4 in and 92% at the bottom. Spec the lift thickness as 6 in max for residential and 4 in max for highway.
- Roller pattern. Compaction energy applied uniformly across the working width is hard to achieve on tapered driveway edges and curves. Edge zones typically reach 2–4% lower density than center zones. The mitigation: hand-compaction near edges with a jumping jack or vibratory plate.
How to Apply These Densities in Your Estimate
Three estimation tasks use these densities:
- Cubic yards → tons (sourcing the material). Use the compacted density: crusher run at 130 pcf = 1.76 tons/yd³ (130 × 27 / 2,000). For 25 yd³ you order 44 tons.
- Area × depth → tons (the calculator default). Identical to (1) but with the area math first. 1,000 ft² at 4 in = 333.33 ft³ / 27 = 12.35 yd³ × 1.76 = 21.7 tons crusher run.
- Field-density acceptance. Compare nuclear-gauge field density against the spec percentage of T 180 max. If T 180 max is 137 pcf and the spec is 98%, the field target is 134.3 pcf. Below that, re-roll or adjust moisture.
For the live coverage math see our road base calculator, crusher run calculator, or gravel calculator — all three use the densities in the first chart as their defaults and let you override per material.
Real-World Example Calculations
Worked Example: 18 × 60 ft Driveway Base, 6 in Crusher Run + 2 in DGA
Residential driveway. 18 ft wide, 60 ft long = 1,080 ft². Base section: 6 in crusher run (CR-6) + 2 in DGA topping (paver-base finish course).
- Crusher run vol
- 1,080 × 0.5 = 540 ft³ = 20.0 yd³
- Crusher run tons
- 20.0 × 1.76 = 35.2 tons
- DGA volume
- 1,080 × 0.167 = 180 ft³ = 6.67 yd³
- DGA tons
- 6.67 × 1.82 = 12.1 tons
- Loose volume (truck space)
- (540 × 1.25) + (180 × 1.25) = 900 ft³ = 33.3 yd³ loose
Takeaway: Round both quantities up by 5% (~37 tons CR + 13 tons DGA) for waste and a small leftover for spot repair after the surface course goes down. Verify the placed depth with a 4-ft string-line; 6 in CR + 2 in DGA finishes to 8 in below the final surface.
Next Steps and Related Calculators
What This Changes in Your Material Order
Use the right compacted density and your tons-ordered matches the placed cubic yards to within 3–5%. Use the wrong density (especially confusing the T 180 lab max for the field density) and you over-order by 6–10%. Cross-reference: crushed stone sizes explained for the gradation context, gravel depth chart for depth-by-application, and our aggregate base calculators for the live math.
Sources & Standards
These references are used for terminology, safety boundaries, and engineering assumptions. Local code, supplier specifications, and licensed design documents still control your project.
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AASHTO T 180: Moisture-Density Relations of Soils Using a 4.54-kg Rammer and 457-mm Drop (Modified Proctor)
American Association of State Highway and Transportation Officials
Referenced for the modified Proctor maximum-dry-density methodology that establishes the lab reference density for dense-graded aggregate bases.
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AASHTO M 147: Standard Specification for Materials for Aggregate and Soil-Aggregate Subbase, Base, and Surface Courses
American Association of State Highway and Transportation Officials
Referenced for the gradation, plasticity-index and quality requirements that define the material classes (dense-graded, open-graded) used in this chart.
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ASTM D448: Standard Classification for Sizes of Aggregate for Road and Bridge Construction
ASTM International
Referenced for the #57, #67, #2 stone size classifications and their corresponding sieve sizes used in the density chart.
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Penn State CES: Driveway Construction in Pennsylvania (Field Density Survey Data)
Penn State College of Engineering Sciences
Referenced for the field-validated density and tons-per-cubic-yard values from residential driveway base installations across Pennsylvania.
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ICPI Tech Spec 2: Construction of Interlocking Concrete Pavements
Interlocking Concrete Pavement Institute
Referenced for the paver-base compaction acceptance criteria for open-graded materials (roller-pass count plus visual lockup).
Frequently Asked Questions
What is the density of crusher run?
125–135 lb/ft³ compacted in place (typical 130 lb/ft³ mid-range); 100–110 lb/ft³ loose in the truck. Per cubic yard: 3,510 lb / 1.76 tons compacted. AASHTO T 180 modified Proctor max is 130–140 lb/ft³; the field compacted value (95–98% of T 180) is what tonnage math uses.
How many tons in a cubic yard of crusher run?
1.76 tons per cubic yard compacted in place (using 130 lb/ft³ density). Loose-in-the-truck volume is 1.25× the placed volume (compaction factor 1.25), so 1 yd³ placed = 1.25 yd³ ordered = 2.2 tons by volume. Most tonnage estimates use placed (compacted) volume, so the working answer is 1.76 tons/yd³.
What is the density of #57 stone?
95–105 lb/ft³ compacted (typical 100 mid-range); 75–85 lb/ft³ loose. Lower than crusher run because #57 is open-graded (single-size 3/4 in stone) with 35–45% void content. Per cubic yard: 2,700 lb / 1.35 tons. #57 doesn’t have a meaningful AASHTO T 180 value (open-graded materials don’t produce a Proctor curve).
What is AASHTO T 180 maximum dry density?
The maximum dry density a material can be compacted to in a lab using the modified Proctor test — 10-lb hammer dropped 18 in, five 8-blow lifts. It’s the reference against which field-density tests are measured as a percentage (“95% of T 180” = field density is 95% of the lab max). For dense-graded aggregates the T 180 value ranges from 130–148 lb/ft³; the typical field-compacted value is 3–7% lower.
How much does 1 ton of base rock cover?
At 4 in compacted depth: crusher run 55 ft² / DGA 53 ft² / #57 stone 72 ft². At 2 in: 2× the 4-in value; at 6 in: 0.67×; at 8 in: 0.50×. The denser the material, the less area 1 ton covers because more mass goes into the same volume. Full table in the second chart above.
Why is recycled asphalt (RAP) density similar to crusher run?
Because both are dense-graded materials with similar gradation curves and similar aggregate hard-rock density underneath the binder coating. RAP at 130 lb/ft³ vs crusher run at 130 lb/ft³ is essentially a coincidence of two compacted materials reaching similar bulk densities by different routes — crusher run by mechanical lock-up of fresh angular aggregate, RAP by mechanical lock-up plus residual asphalt binder. Cost wise, RAP is typically 30–45% cheaper than crusher run, which is why it’s the most common low-cost driveway base in 2026.
Do open-graded stones like #57 need compaction testing?
No — open-graded materials are accepted by roller-pass count plus visual lockup, not by density gauge. The reason: open-graded materials don’t produce a meaningful Proctor moisture-density curve because they don’t pack to the dense state. Standard practice: 2–3 passes with a 1–2 ton vibratory plate or roller until visual lockup is achieved (stones no longer migrate under the roller). Reference AASHTO M 147 for the materials spec and ICPI Tech Spec 2 for paver-base acceptance.