How To Straight Run Bitumen
Last updated: 2026-10-16
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Straight run bitumen is produced by distilling crude oil at atmospheric pressure and removing the light fractions, yielding a penetration-grade binder typically between 40/50 and 200/300 pen, with an asphaltene content of 5–15% and a softening point of 35–55°C. To "straight run" bitumen means to select, verify, and purchase this unmodified atmospheric residue — not a cutback, blown, or polymer-modified grade — and match its penetration grade to your climate, mix design, and specification. Most industrial buyers source it in 20–28 MT container loads or 500–3,000 MT bulk cargoes, at USD 380–520 per MT FOB depending on grade, origin, and season.
What Is Straight Run Bitumen and How Is It Made?
Straight run bitumen (also called penetration bitumen or "pen grade") is the residual fraction left after atmospheric and vacuum distillation of selected crude oils. It is not processed with air blowing (which makes oxidized/blown bitumen) and not blended with polymers (which makes PMB).
Production sequence:
- Crude oil enters the atmospheric distillation unit at 340–380°C
- Light ends (LPG, naphtha, kerosene, diesel) are drawn off
- Atmospheric residue (long residue) goes to the vacuum distillation unit
- Vacuum residue (short residue) is the straight run bitumen base
- Final penetration grade is set by blending short residue from different crudes or by controlled vacuum depth
Key properties and typical ranges:
| Property | Test Method | 60/70 Grade | 80/100 Grade | 40/50 Grade |
|---|---|---|---|---|
| Penetration @25°C (0.1mm) | ASTM D5 | 60–70 | 80–100 | 40–50 |
| Softening point (°C) | ASTM D36 | 49–56 | 45–52 | 52–60 |
| Viscosity @135°C (Pa·s) | ASTM D4402 | 0.35–0.45 | 0.28–0.38 | 0.45–0.60 |
| Ductility @25°C (cm) | ASTM D113 | >100 | >100 | >100 |
| Flash point (°C) | ASTM D92 | >250 | >240 | >250 |
| Solubility in TCE (%) | ASTM D2042 | >99.0 | >99.0 | >99.0 |
| Asphaltenes (%) | ASTM D4124 | 10–14 | 7–11 | 13–17 |
Why "straight run" matters: Unmodified bitumen behaves predictably in hot mix asphalt (HMA). It can be re-heated, re-blended, and emulsified without the phase-separation issues common in polymer systems. It also costs 15–40% less per MT than PMB.
How To Choose the Right Penetration Grade: Step-by-Step
Grade selection is driven almost entirely by climate (pavement temperature) and traffic loading. Use the following workflow.
Step 1 — Determine maximum pavement temperature.
- >40°C summer surface temp → harder grade (40/50 or 60/70)
- 30–40°C → 60/70 or 80/100
- <30°C → 80/100 or 100/150
Step 2 — Determine minimum pavement temperature.
- <−10°C → softer grade (100/150 or 160/220) to resist thermal cracking
- >0°C → any pen grade works within the high-temp limit
Step 3 — Apply traffic loading adjustment.
- >30 million ESALs → shift one grade harder
- 10–30 million ESALs → standard grade
- <10 million ESALs → shift one grade softer
Climate-to-grade selection matrix:
| Region / Climate | Recommended Grade | Rationale |
|---|---|---|
| Gulf, Middle East, West Africa | 40/50, 60/70 | High rutting resistance |
| South Asia, Southeast Asia | 60/70, 80/100 | Balanced high-temp performance |
| Southern Europe, North Africa | 60/70, 70/100 | Moderate-high temps |
| Central & Northern Europe | 70/100, 100/150 | Wide temp swing |
| Scandinavia, Canada, Russia | 160/220, 100/150 | Low-temp cracking resistance |
| High-altitude / cold desert | 80/100, 100/150 | Diurnal swing >25°C |
Step 4 — Verify against your local specification.
- EN 12591 (Europe): grades 20/30 to 250/330
- ASTM D946 / AASHTO M20 (US): 40/50 to 200/300
- IS 73 (India): VG-10, VG-20, VG-30, VG-40 (viscosity-graded, correlates to pen grades)
- JIS K2207 (Japan): 20/40 to 200/300
Straight Run vs Modified Bitumen: Cost and Performance Comparison
| Criterion | Straight Run | Oxidized/Blown | PMB (SBS) | Cutback |
|---|---|---|---|---|
| Process | Vacuum residue | Air blown @200–260°C | +3–6% SBS polymer | +15–40% solvent |
| Cost (USD/MT FOB) | 380–520 | 420–560 | 550–750 | 480–620 |
| Storage temp | 150–165°C | 180–200°C | 160–175°C | Ambient |
| Rutting resistance | Moderate | Low | High | Low–moderate |
| Low-temp cracking | Moderate | Moderate | High | Moderate |
| Recyclability | High | Moderate | Low–moderate | Low |
| Best for | HMA, base layers | Roofing, waterproofing | High-traffic surface | Cold patching |
Key economic point: For a 100,000 MT annual program, switching from 60/70 straight run to SBS PMB adds roughly USD 17–23 million per year in binder cost. Many agencies only specify PMB where rutting or fatigue data justifies it.
How To Buy and Verify Straight Run Bitumen from Exporters
Procurement steps with numbers:
1. Request a Certificate of Analysis (COA) for the exact batch — check pen @25°C, softening point, viscosity @135°C, and flash point.
2. Confirm the grade matches your mix design (e.g., 60/70 per ASTM D946).
3. Verify origin and refinery — common sources: Iran, UAE, Saudi Arabia, South Korea, Singapore, Bahrain.
4. Sample first. Lab test a 5 kg sample before committing to a 500 MT+ order.
5. Use a third-party inspector (SGS, Intertek, Bureau Veritas) for pre-shipment inspection — cost USD 800–2,500 per lot.
6. Check packaging: new steel drums (150–182 kg), jumbo bags (1–1.3 MT), or bulk. Drums cost USD 15–25 more per MT than bulk.
Container vs bulk comparison:
| Mode | Typical Quantity | Lead Time | Cost Premium |
|---|---|---|---|
| 20ft container (drums) | 20–28 MT | 20–35 days | +USD 15–25/MT |
| Flexitank | 20–24 MT | 20–35 days | +USD 10–18/MT |
| ISO tank | 20–24 MT | 25–40 days | +USD 8–15/MT |
| Bulk vessel | 500–30,000 MT | 30–60 days | Baseline |
Payment terms: Sight LC most common; CAD and TT for repeat buyers. Typical LC validity 90 days, with 10–15% advance for first orders.
Red flags when sourcing:
- COA numbers that don't match the stated grade
- No third-party inspection offered
- Price >25% below market (usually means blended or off-spec material)
- Vague origin reporting
Price Drivers and Market Timing for Straight Run Bitumen
Straight run bitumen pricing moves with crude oil benchmarks, refinery economics, and seasonal demand.
| Factor | Impact on Price | Typical Range |
|---|---|---|
| Brent crude move of USD 10/bbl | ±USD 25–40/MT | Correlated 0.7–0.85 |
| Seasonal peak (Apr–Sep) | +USD 20–60/MT | Northern hemisphere paving |
| Winter trough (Dec–Feb) | −USD 15–40/MT | Reduced construction |
| Refinery turnarounds | +USD 10–30/MT | Supply tightening |
| Shipping freight (VLCC) | ±USD 5–20/MT | Route dependent |
| Currency (USD strength) | −USD 5–15/MT | For non-USD buyers |
Buying strategy:
- Lock 40–60% of annual volume in Q4 for Q2–Q3 delivery
- Buy spot for the remaining 40–60% when Brent dips below your budget line
- Target delivered cost USD 400–470/MT CFR for 60/70 in most trade lanes
Freight reference rates (bulk, 2024–2025):
| Route | Rate (USD/MT) |
|---|---|
| UAE → India | 25–40 |
| Iran → East Africa | 35–55 |
| South Korea → Australia | 40–65 |
| Bahrain → SE Asia | 45–70 |
| Rotterdam → West Africa | 50–80 |
FAQ: Straight Run Bitumen
What is straight run bitumen?
Straight run bitumen is the unmodified residual product of crude oil distillation, classified by penetration grade (e.g., 40/50, 60/70, 80/100). It contains no polymers or additives and is the standard binder for hot mix asphalt and most paving applications.
What is the difference between straight run and blown bitumen?
Straight run bitumen is distilled at atmospheric/vacuum pressure and retains its natural penetration grade, while blown (oxidized) bitumen is air-blown at 200–260°C to raise softening point. Blown bitumen is used mainly for roofing and waterproofing; straight run is used for paving.
Which penetration grade should I buy?
Match grade to climate: 40/50 or 60/70 for hot regions (>40°C pavement), 80/100 for moderate climates, and 100/150 or 160/220 for cold regions. Add one grade harder for traffic above 30 million ESALs.
How much does straight run bitumen cost per ton?
Straight run bitumen costs about USD 380–520 per MT FOB, or USD 400–470 per MT CFR for 60/70 grade in most trade lanes. Drummed shipments add USD 15–25 per MT over bulk.
How long does delivery take?
Container shipments (20–28 MT) take 20–35 days; bulk cargoes (500–30,000 MT) take 30–60 days depending on route. Pre-shipment inspection and LC processing typically add 5–10 days.
Optimize Your Straight Run Bitumen Cost with 6Tar
Straight run bitumen is a commodity where 1–3% price differences translate to hundreds of thousands of dollars across an annual program. Use the 6Tar cost calculator to model landed cost by grade, origin, freight lane, and payment terms — before you commit to a 500 MT cargo. Plug in your target penetration grade, destination port, and volume, and get an instant CFR estimate that reflects real freight and refining spreads. Start with a free calculation at 6Tar today.