Asphalt Density Explained — Why 145 lbs/ft³?
145 lbs/ft³ (2,322.7 kg/m³) is the standard reference density for hot mix asphalt. Here's where it comes from and when to use a different value.
Why Density Matters
Density converts volume to weight (tonnage). Wrong density → wrong tonnage → wrong cost estimate.
Density Ranges by Mix Type
| Mix Type | Density (lbs/ft³) |
|---|---|
| Standard dense-graded HMA | 142–150 |
| Stone Matrix Asphalt (SMA) | 146–153 |
| Polymer-Modified (PMA) | 146–151 |
| Open-Graded Friction Course | 125–136 |
| RAP millings (compacted) | 120–130 |
| Cold mix | 110–125 |
When to Ask Your Supplier
For SMA, PMA or specialty mixes, request the mix-specific density from the Job Mix Formula (JMF). A 3–5% density variation on a large project can mean a significant tonnage difference.