Calculating asphalt tonnage requires knowing the density of different asphalt mix types. Each type has specific weight characteristics that affect the total tonnage needed for your project.
Standard Asphalt Mix Densities
Hot Mix Asphalt (HMA)
- Density: 2 tons/yd³
- Weight per unit: 110 lbs/(SY·IN)
Warm Mix Asphalt (WMA)
- Density: 1.9 tons/yd³
- Weight per unit: 105 lbs/(SY·IN)
Porous Asphalt
- Density: 1.8 tons/yd³
- Weight per unit: 100 lbs/(SY·IN)
Recycled Asphalt Pavement (RAP)
- Density: 1.85 tons/yd³
- Weight per unit: 102 lbs/(SY·IN)
Superpave Mix
- Density: 2.1 tons/yd³
- Weight per unit: 115 lbs/(SY·IN)
Stone Matrix Asphalt (SMA)
- Density: 2.05 tons/yd³
- Weight per unit: 112 lbs/(SY·IN)
Premium Dense Mix
- Density: 2.15 tons/yd³
- Weight per unit: 118 lbs/(SY·IN)
Calculation Methods
Method 1: Using Cubic Yards
Formula: Tonnage = Volume (cubic yards) × Density (tons/yd³)
Method 2: Using Square Yards and Thickness
Formula: Tonnage = Area (square yards) × Thickness (inches) × Weight per unit ÷ 2000
Real-Life Example: Residential Driveway
Let’s calculate the asphalt tonnage needed for a residential driveway project:
Project Specifications:
- Dimensions: 20 feet wide × 50 feet long
- Thickness: 3 inches
- Asphalt Type: Hot Mix Asphalt (HMA)
Step-by-Step Calculation:
Step 1: Convert dimensions to square yards
- Area = 20 ft × 50 ft = 1,000 square feet
- Convert to square yards: 1,000 ÷ 9 = 111.11 square yards
Step 2: Calculate using Method 1 (Cubic Yards)
- Volume = 111.11 SY × (3 inches ÷ 12) = 111.11 × 0.25 = 27.78 cubic yards
- Tonnage = 27.78 yd³ × 2 tons/yd³ = 55.56 tons
Step 3: Verify using Method 2 (Square Yards × Thickness)
- Tonnage = 111.11 SY × 3 inches × 110 lbs/(SY·IN) ÷ 2000
- Tonnage = 36,666.3 lbs ÷ 2000 = 18.33 tons
Alternative Calculation Using Weight per Unit:
- Total weight = 111.11 SY × 3 IN × 110 lbs/(SY·IN) = 36,666.3 lbs
- Convert to tons: 36,666.3 ÷ 2000 = 18.33 tons
Practical Tips for Contractors
Add 5-10% Extra Material
Always order 5-10% additional asphalt to account for:
- Compaction variations
- Subgrade irregularities
- Waste during application
Consider Compaction Factor
The density values provided are for compacted asphalt. Loose asphalt may require 15-25% more material before compaction.
Cost Estimation Example
Using our driveway example with HMA at $100 per ton:
Total cost: 20.16 tons × $100/ton = $2,016
Base requirement: 18.33 tons
With 10% extra: 18.33 × 1.10 = 20.16 tons