What Is Oxidized Bitumen
Last updated: 2026-10-17
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Oxidized bitumen (also called blown bitumen or industrial asphalt) is a dark, semi-solid or solid bitumen produced by blowing air through penetration-grade bitumen at 240–280°C for 4–10 hours, which raises its softening point to 90–150°C and reduces penetration to 10–40 dmm. It is not a naturally occurring product — every ton is a manufactured grade, and global export volumes run roughly 3–4 million tonnes per year. The oxidation process increases asphaltene content from around 10–15% to 25–40%, which is exactly why oxidized bitumen resists flow at high temperatures and is used in roofing, waterproofing, pipe coating, and mastic production.
What Is Oxidized Bitumen and How Is It Made
Oxidized bitumen production starts with 60/70 or 80/100 penetration bitumen as feedstock. The process is straightforward but energy-intensive:
1. Feedstock charging — penetration-grade bitumen is pumped into an oxidation tower (vertical or horizontal) and heated to 240–280°C.
2. Air blowing — compressed air is injected at 300–500 m³ per hour per 100 tonnes of bitumen. Oxygen reacts with the hydrocarbons, forming asphaltenes and increasing molecular weight.
3. Reaction time — 4–10 hours, depending on target grade. Higher softening points require longer blowing.
4. Quenching and cooling — the blown bitumen is cooled, then poured into 25 kg, 50 kg bags, drums, or blocks, or shipped in bulk tankers for hot application.
5. Quality testing — softening point (ring and ball), penetration (25°C, 100 g, 5 s), flash point, solubility, and loss on heating.
Blowing does not add chemicals — the change is purely oxidative. Loss on heating is typically under 1%, and flash point stays above 230°C, which makes the material stable in storage.
| Process Parameter | Typical Value |
|---|---|
| Oxidation temperature | 240–280°C |
| Air rate | 300–500 m³/h per 100 t |
| Blowing duration | 4–10 hours |
| Asphaltene before / after | 10–15% → 25–40% |
| Softening point after | 90–150°C |
| Penetration after | 10–40 dmm |
| Loss on heating | <1% |
| Flash point | >230°C |
Oxidized Bitumen: Types, Grades, and Global Specifications
Oxidized bitumen is sold under two naming conventions, and buyers must confirm which one applies before ordering. R-grades (R85/25, R95/25, R115/15) follow the European/ASTM "softening point / penetration" format. I-grades (I-95/25, I-115/15) follow the older BS 3690 style. A 115/15 grade, for example, means softening point 115°C and penetration 15 dmm — the two numbers are not interchangeable.
| Grade | Softening Point (°C) | Penetration (dmm, 25°C) | Penetration (dmm, 46°C) | Common Use |
|---|---|---|---|---|
| 85/25 | 85–90 | 25 | — | Waterproofing membrane, roofing felt |
| 90/10 | 90–95 | 10 | 35–45 | Pipe coating, insulation |
| 95/25 | 95–100 | 25 | 55–65 | Roofing, adhesive |
| 105/35 | 105–110 | 35 | — | Mastic, sealants |
| 115/15 | 115–120 | 15 | 35–45 | Pipe coating, high-temp waterproofing |
| 150/5 | 150–155 | 5 | — | Specialty industrial coating |
Price benchmarks (2024–2025 export, FOB Middle East / Asia):
- Oxidized bitumen 85/25 to 95/25: USD 380–520 per tonne in bags
- Oxidized bitumen 115/15: USD 450–600 per tonne in bags
- Bulk drum pricing is typically USD 30–60 lower per tonne than bagged
- Minimum order quantity: 20 FCL (airtight steel drums), or 1–2 MT for trial orders
Freight from Jebel Ali or Bandar Abbas to a European port adds USD 60–120 per tonne. Total landed cost at a European warehouse for 115/15 grade sits around USD 550–720 per tonne depending on volume.
Oxidized Bitumen vs Penetration Bitumen vs Modified Bitumen
Buyers frequently confuse these three, but they behave differently in service.
| Property | Oxidized Bitumen | Penetration Bitumen | SBS/APP Modified Bitumen |
|---|---|---|---|
| Softening point | 90–150°C | 45–60°C | 70–110°C |
| Penetration @25°C | 10–40 dmm | 40–200 dmm | 25–60 dmm |
| Asphaltene content | 25–40% | 10–15% | 12–22% |
| Production | Air blowing | Vacuum distillation | Polymer blending |
| Main use | Roofing, waterproofing, pipe coating | Road paving, prime coat | Premium roofing membranes |
| Relative price | USD 380–600/t | USD 320–480/t | USD 550–800/t |
| Heat resistance | High | Low | High |
| Flexibility at low temp | Low | Moderate | High |
- Oxidized bitumen wins on heat resistance and cost but is brittle at low temperatures.
- Penetration bitumen is flexible and cheap but melts on hot roofs.
- SBS/APP modified bitumen combines both but costs 30–60% more.
For flat roofs in hot climates (Middle East, South Asia, Sub-Saharan Africa), oxidized bitumen remains the dominant choice because a 115/15 grade will not slump at 70°C ambient roof surface temperature.
Applications and Consumption Data
Oxidized bitumen consumption is concentrated in construction and industrial sectors. Approximate global end-use split:
- Roofing and waterproofing membranes — 55–60%
- Pipe and pipeline coating — 15–20%
- Mastics, sealants, and adhesives — 10–12%
- Electrical insulation and cable compounds — 5–7%
- Foundry and specialty industrial — 3–5%
Key application details:
- Roofing felt: oxidized bitumen 85/25 and 95/25 are standard. A single 1,000 m² roof build-up uses 1.5–2.5 tonnes of oxidized bitumen.
- Pipe coating: 115/15 grade, applied at 3–6 mm thickness, protects buried pipelines. One kilometer of 24-inch pipe consumes roughly 18–25 tonnes.
- Mastic production: usually a blend of oxidized bitumen 105/35 with limestone filler; softening point in the finished mastic sits at 90–110°C.
- Cable filling compounds: require low penetration and high dielectric strength; typical consumption is small, 50–200 kg per production batch.
Top exporting countries: Iran, Iraq, UAE, Saudi Arabia, South Korea, and China. Iran accounts for an estimated 35–45% of global export tonnage for oxidized bitumen, largely due to feedstock availability and competitive pricing. Top importers: India, Turkey, UAE, Egypt, Bangladesh, and Nigeria.
| Application | Typical Grade | Consumption per Unit |
|---|---|---|
| Roofing felt (1,000 m²) | 85/25, 95/25 | 1.5–2.5 MT |
| Pipe coating (1 km, 24") | 115/15 | 18–25 MT |
| Mastic batch (1 MT) | 105/35 | 400–600 kg bitumen |
| Cable compound (per batch) | 90/10 | 50–200 kg |
Packaging, Storage, and Shipping
Oxidized bitumen is shipped in several formats, and the right choice depends on the buyer's melting capacity and climate.
- Airtight steel drums (150–180 kg net): Most common for container shipment, 20 FCL per 20-ft container, moisture-proof.
- Polypropylene bags (25 kg or 50 kg): Cheaper, but risk of blocking in hot weather — not recommended for tropical destinations without ventilated storage.
- Blocks/pallets (1 MT or bulk): Used domestically in the producing country, rarely exported.
- Bulk tankers (hot liquid 180–200°C): Only for domestic or short-sea routes with heated receiving tanks.
Storage guidance:
- Store in dry, shaded, ventilated areas below 40°C.
- Shelf life in drums: 24 months; in bags: 12–18 months in cool conditions.
- Stacking limit: maximum 4 drums high to avoid deformation and blocking.
- Never store near open flame — flash point is above 230°C, but molten bitumen ignites if overheated past 280°C.
FAQ: What Is Oxidized Bitumen
Q1: What is oxidized bitumen made from?
Oxidized bitumen is made from penetration-grade bitumen (usually 60/70 or 80/100) by blowing hot air through it at 240–280°C for 4–10 hours. The oxygen reaction increases asphaltene content to 25–40% and raises the softening point to 90–150°C. No polymers or additives are required.
Q2: How much does oxidized bitumen cost per tonne?
Export prices in 2024–2025 range from USD 380–520 per tonne for 85/25–95/25 grades and USD 450–600 per tonne for 115/15 grade, FOB Middle East or Asia. Landed cost in Europe or Africa typically adds USD 60–120 per tonne for freight and handling.
Q3: What is the difference between 115/15 and 95/25 oxidized bitumen?
The first number is the softening point in °C and the second is penetration in dmm at 25°C. So 115/15 is harder and more heat-resistant (115°C softening point) than 95/25 (95°C softening point). Use 115/15 for pipe coating and high-temperature waterproofing; use 95/25 for standard roofing felt.
Q4: Can oxidized bitumen be used for road paving?
No. Oxidized bitumen is too brittle at low temperatures for road paving and would crack under traffic loads in winter. Road construction uses penetration-grade or polymer-modified bitumen instead. Oxidized bitumen is reserved for roofing, waterproofing, pipe coating, mastics, and industrial applications.
Q5: What is the minimum order quantity and lead time for oxidized bitumen export?
A typical minimum order is 20 FCL (about 20 tonnes in drums) or 1–2 MT for trial shipments. Lead time from Iran, UAE, or Iraq is usually 10–20 days for production plus 15–35 days ocean transit depending on destination. Buyers should confirm grade, packaging, and test certificates (softening point, penetration) before booking.
Calculate Your Oxidized Bitumen Cost Before You Buy
Grade selection, bagging, freight, and port charges can swing your landed cost by USD 100–150 per tonne — and choosing the wrong grade costs even more in failed waterproofing. Before you request a quote, run your numbers through the 6Tar cost calculator to compare FOB price, freight, packaging, and duties for 85/25, 95/25, and 115/15 in one place. It takes two minutes, and it tells you exactly what a tonne of oxidized bitumen will cost at your warehouse door — so you negotiate from data, not guesswork.