Oxidized Bitumen vs Modified Bitumen: Key Differences, Properties & Which to Choose
Oxidized vs modified bitumen is one of the most important — and most frequently misunderstood — distinctions in the bitumen industry. Both materials start from the same petroleum bitumen base, both are used in roofing and waterproofing, and both are sometimes called “special grade” or “treated” bitumen. Yet they are produced by fundamentally different processes, have very different molecular structures, and are optimized for different performance requirements and applications.
Understanding the difference between oxidized bitumen and modified bitumen is critical for engineers, architects, roofing contractors, membrane manufacturers, and waterproofing specifiers. The wrong choice can result in premature membrane failure, thermal cracking, cost overruns, or warranty disputes. The right choice delivers decades of reliable performance.
The global polymer modified bitumen market was valued at USD 12.15 billion in 2025 and is projected to reach USD 15.41 billion by 2029 at 6.1% CAGR (Research and Markets, 2025). Oxidized bitumen, meanwhile, remains the dominant raw material for membrane manufacturing — it is the base material upon which most modified bitumen products are built. In this complete guide, RAHA Bitumen’s technical team explains every dimension of the oxidized vs modified bitumen comparison: production, chemistry, properties, grades, applications, costs, and a definitive selection guide.
The short answer: Oxidized bitumen is produced by air blowing and offers high heat resistance and waterproofing at low cost — ideal for industrial applications. Modified bitumen takes oxidized bitumen as its base and adds polymers (SBS rubber or APP plastic) to enhance flexibility, UV resistance, and cold-temperature performance — at higher cost. Modified bitumen is made from oxidized bitumen, not instead of it.
What Is Oxidized Bitumen?
Oxidized bitumen — also called blown bitumen or blown asphalt — is produced by the controlled air blowing process: penetration grade bitumen is heated to 240–300°C and hot compressed air is injected through it. Oxygen reacts with the bitumen molecules through oxidation, dehydrogenation, and condensation polymerization, fundamentally transforming its molecular structure from a flexible “sol” to a rigid “gel” network.
Key characteristics of oxidized bitumen:
- Softening point: 85°C–155°C (far above penetration bitumen’s 42–60°C)
- Penetration: 5–40 dmm (hard to very hard)
- Penetration Index (PI): +2 to +8 (low temperature susceptibility)
- Molecular structure: Gel type — cross-linked asphaltene network
- Asphaltene content: significantly increased during production (up to 50%+)
- Production method: air blowing only — no polymer additions
Common grades: 85/25, 90/40, 95/25, 105/35, 115/15, 150/5
Standard: ASTM D312 (Types I–IV), BS 3690, EN 13304
What Is Modified Bitumen?
Modified bitumen — also called polymer modified bitumen (PMB) — is produced by blending bitumen (typically oxidized bitumen or penetration grade bitumen) with polymer additives that enhance specific performance properties. The polymer modifier physically and/or chemically interacts with the bitumen molecules, creating a composite material with superior flexibility, UV resistance, and temperature performance compared to unmodified bitumen.
The two dominant polymer systems are:
SBS-Modified Bitumen (Elastomeric)
Styrene-Butadiene-Styrene (SBS) is a thermoplastic elastomer — a synthetic rubber. When blended with bitumen at 160–185°C, SBS forms a three-dimensional elastic network within the bitumen matrix. The result is a material that behaves like rubber — it stretches and recovers under load, making it highly resistant to fatigue cracking, thermal cycling, and movement.
- Type: Elastomeric — rubber-like behavior
- Softening point: typically 100–130°C
- Cold flexibility: excellent — down to -20°C to -28°C without cracking
- Elongation at break: >600% — far superior to oxidized bitumen
- UV resistance: good — SBS polymer protects the bitumen from oxidative aging
- Aging resistance: SBS modification curbs the oxidation process, slowing down the aging of bitumen and ensuring longevity, while SBS has inherent UV-resistant properties which offer better protection against ultraviolet rays
- Market share: SBS-modified bitumen accounted for nearly 60% of the total PMB market volume in 2024, about 15.4 million tons, due to its superior elasticity, flexibility, and ability to resist rutting and thermal cracking
Application method: Torch-on, cold adhesive (no open flame needed), or self-adhesive
→ See: SBS Modified Bitumen grades
APP-Modified Bitumen (Plastomeric)
Atactic Polypropylene (APP) is a thermoplastic — a plastic polymer. When blended with bitumen, APP creates a harder, more rigid material with a very high softening point and excellent heat and UV resistance. APP-modified bitumen has a very high temperature tolerance and is appreciated for its ease of installation. When time is a factor, APP is often the best choice for quick installation as less attention to detail is required in the heating of the membrane. APP is typically chosen in hotter climates as it has higher temperature flexibility when compared to SBS.
- Type: Plastomeric — plastic-like behavior
- Softening point: typically 130–160°C
- Cold flexibility: moderate — in temperatures below 23°F (-5°C) the material becomes brittle
- UV resistance: excellent — superior to SBS
- Heat resistance: superior — preferred in hot climates
- Installation: torch-applied primarily (melts to liquid at ~150°C)
→ See: APP Modified Bitumen Membrane
The Critical Relationship: Modified Bitumen Is Made FROM Oxidized Bitumen
This is the most important and most frequently misunderstood aspect of the oxidized vs modified bitumen comparison:
Modified bitumen does not replace oxidized bitumen — it is built on top of it.
In the manufacture of SBS and APP modified bitumen membranes, oxidized bitumen is the primary raw material — typically comprising 60–80% of the final membrane compound by weight. The polymer (SBS or APP) is added to the oxidized bitumen to enhance specific properties.
Production sequence for APP modified bitumen membrane:
- Start with penetration grade bitumen (60/70 or 80/100)
- Air blow to produce oxidized bitumen grade 115/15 or 95/25
- Blend hot oxidized bitumen with APP polymer at 170–190°C
- Apply to polyester or fiberglass carrier mat
- Surface finish with mineral granules or film
- Finished APP membrane product
This means that RAHA Bitumen’s oxidized bitumen — particularly grades 115/15 and 95/25 — is the direct raw material feedstock for APP and SBS modified bitumen membrane manufacturers worldwide.
Complete Property Comparison Table
| Property | Oxidized Bitumen | SBS Modified Bitumen | APP Modified Bitumen |
|---|---|---|---|
| Production Method | Air blowing of penetration bitumen | Blending bitumen + SBS rubber | Blending bitumen + APP plastic |
| Polymer Content | None — pure bitumen | 4–15% SBS rubber | 20–30% APP plastic |
| Molecular Structure | Gel — cross-linked asphaltene network | Interpenetrating polymer network | Plastomeric matrix |
| Softening Point | 85°C – 155°C | 100°C – 130°C | 130°C – 160°C |
| Cold Flexibility | Moderate — brittle below -10°C | ⭐ Excellent — down to -28°C | Moderate — brittle below -5°C |
| Heat Resistance | Excellent (up to 115–150°C) | Good (up to 100–130°C) | ⭐ Excellent (up to 130–160°C) |
| Flexibility / Elongation | Low — rigid material | ⭐ Excellent — >600% elongation | Moderate — plastic behavior |
| Elastic Recovery | None — plastic deformation | ⭐ Excellent — rubber-like recovery | Poor — permanent deformation |
| UV Resistance | Poor — degrades under UV | Good — SBS protects bitumen | ⭐ Excellent — APP resists UV |
| Aging Resistance | Moderate — oxidative aging continues | ⭐ Excellent — SBS retards aging | Good — APP retards aging |
| Waterproofing | ⭐ Excellent — near-zero permeability | Excellent | Excellent |
| Material Cost | ⭐ Lowest | Medium-High | High |
| Installation Method | Hot-applied (220–230°C) | Torch, cold adhesive, self-adhesive | Torch-applied primarily |
| Service Life | 20–30 years | 25–40 years | 25–35 years |
| Primary Standard | ASTM D312, BS 3690 | EN 14695, ASTM D6163 | EN 14695, ASTM D6222 |
Performance Differences Explained
1. Low-Temperature Flexibility – The Biggest Difference
This is where oxidized bitumen and SBS modified bitumen differ most dramatically. When oxidized asphalt gets cold, it gets brittle. When you modify flux asphalt with SBS, it allows the asphalt to flex in cold weather without cracking or breaking.
For roofing and waterproofing in cold climates — Scandinavia, Canada, Russia, Central Europe, high-altitude locations — this difference is decisive. A roof membrane that cracks in winter allows water ingress that causes structural damage. SBS-modified membranes are specifically engineered to maintain flexibility down to -28°C, far below what oxidized bitumen can tolerate.
Application implication:
Cold climate (<-5°C winter temperatures) → SBS modified bitumen essential
Tropical/hot climate (>30°C summer temperatures) → Oxidized bitumen or APP modified bitumen preferred
2. Elastic Recovery – Why SBS Is Preferred for Movement-Prone Structures
Modern buildings move. Thermal expansion and contraction, structural settlement, wind loading, and seismic movement all create stress in roof membranes and waterproofing systems. Because of the rubber used in its construction, SBS-bitumen is more flexible when compared to the plastic used in APP. This flexibility means it has recovery properties, making it capable of withstanding stresses created by wind, temperature fluctuation and expansion and contraction.
Oxidized bitumen has no elastic recovery — once deformed, it stays deformed. This makes it unsuitable for applications where significant structural movement is expected. SBS modified bitumen, by contrast, can stretch and return to its original shape repeatedly — like rubber.
3. UV and Aging Resistance – Long-Term Performance
Exposed bitumen roofing membranes face constant UV radiation that degrades the bitumen over time. SBS-modified bitumen withstands heat and UV weathering better than oxidized asphalt, providing better durability.
APP-modified bitumen offers the best UV resistance of all three types, making it particularly suitable for exposed roof systems in sunny climates without a mineral granule protective layer.
4. Heat Resistance – Critical for Hot Climates
In hot climates — the Middle East, Africa, South Asia, Southeast Asia — roof surface temperatures regularly exceed 70°C in summer. Both oxidized bitumen and APP-modified bitumen excel in these conditions due to their high softening points. APP is typically chosen in hotter climates as it has higher temperature flexibility when compared to SBS.
SBS-modified membranes, while adequate for most climates, are less heat-resistant than APP — SBS can soften and flow if the roof surface temperature approaches its softening point.
5. Cost – The Economic Factor
Oxidized bitumen is dramatically less expensive than modified bitumen. SBS and APP polymers are petroleum-derived specialty chemicals that add significant cost per tonne. A typical APP membrane contains 20–30% APP polymer by weight — a costly component. SBS membranes similarly carry a significant polymer cost premium.
For large-scale industrial and infrastructure projects where cost is a primary driver and long-term performance requirements can be met by oxidized bitumen, the cost advantage of unmodified oxidized bitumen is compelling.
Applications – Which Type Is Used Where
Where Oxidized Bitumen Is the Standard Choice
| Application | Why Oxidized Bitumen | Best Grade |
|---|---|---|
| Pipe coating (bitumen enamel) | High heat resistance, cost, proven 50+ year track record | 95/25 |
| Carpet tile backing | Dimensional stability, cost, heat activation in paint ovens | 115/15 |
| Sound dampening felt | High density, viscoelastic damping, cost | 85/25 |
| Canal & dam lining | Waterproofing, flexibility, large-area cost | 90/40 |
| Automotive undercarriage | Corrosion protection, stone chip resistance, cost | 85/25 |
| APP/SBS membrane raw material | Primary feedstock for modified membrane manufacturing | 115/15, 95/25 |
| Hot-climate BUR roofing | High softening point, cost | 95/25, 115/15 |
Where Modified Bitumen Is the Standard Choice
| Application | Why Modified Bitumen | Type |
|---|---|---|
| Cold climate roofing membranes | SBS flexibility down to -28°C prevents cold cracking | SBS |
| Exposed roofing (no mineral cover) | APP superior UV resistance | APP |
| High-movement building roofs | SBS elastic recovery accommodates structural movement | SBS |
| Premium waterproofing membranes | Enhanced durability, longer service life | SBS or APP |
| Hot-climate exposed membranes | APP high softening point prevents flow | APP |
| High-performance road surfaces | SBS 28% higher rut resistance, 35% improved fatigue strength | SBS |
| Airports and bridges | PMB superior performance under heavy, repeated loading | SBS |
Oxidized Bitumen vs SBS vs APP – Roofing System Comparison
Roofing is the application where the oxidized vs modified bitumen decision is most critical. Here’s how the three types compare specifically for roofing:
| Parameter | Oxidized Bitumen (BUR) | SBS Modified Membrane | APP Modified Membrane |
|---|---|---|---|
| Best climate | Hot & temperate | Cold & temperate | Hot & tropical |
| Cold performance | Poor below -10°C | ⭐ Excellent to -28°C | Moderate to -5°C |
| Heat resistance | ⭐ Excellent to 115–150°C | Good to 100–130°C | ⭐ Excellent to 130–160°C |
| Crack bridging | Limited (1–2mm) | ⭐ Excellent (>10mm) | Moderate (3–5mm) |
| Service life | 20–30 years | 25–40 years | 25–35 years |
| Cost per m² | ⭐ Lowest | Medium-High | High |
| Installation skill | High (hot work) | Medium | Medium |
| Fire risk | High (hot kettle) | Low (cold adhesive option) | Medium (torch required) |
How to Choose: Oxidized Bitumen vs Modified Bitumen
Choose Oxidized Bitumen when:
- ✅ Cost is the primary constraint — oxidized bitumen is significantly cheaper
- ✅ Application is pipe coating, carpet tile, sound dampening, or automotive
- ✅ Climate is hot or temperate (not extreme cold)
- ✅ You are manufacturing APP or SBS membranes (oxidized bitumen is your raw material)
- ✅ Large-area applications (canals, dams) where material volume is high
- ✅ Built-up roofing (BUR) in hot climates
Choose SBS Modified Bitumen when:
- ✅ Cold climate — winter temperatures below -5°C
- ✅ Building has significant structural movement or thermal cycling
- ✅ Long service life is more important than upfront cost
- ✅ Fire safety — cold adhesive or self-adhesive application needed
- ✅ High-performance road surfaces (highways, airports)
- ✅ Premium roofing or waterproofing specification
Choose APP Modified Bitumen when:
- ✅ Hot climate — roof surface temperatures exceed 60–70°C in summer
- ✅ Exposed membrane (no protective mineral/gravel overlay) — UV resistance critical
- ✅ Fast installation — APP’s liquid melt behavior is faster to torch-apply
- ✅ Tropical climate roofing in Middle East, Africa, South Asia
- ✅ Cost slightly lower than SBS but better UV resistance needed
The Market Picture – Oxidized vs Modified Bitumen Global Trends
Understanding market trends helps buyers and specifiers anticipate where the industry is heading:
Oxidized bitumen demand: Steady growth driven by industrial applications (pipe coating, carpet tile, automotive), infrastructure expansion in emerging markets, and continued dominance as the raw material feedstock for modified membrane manufacturing. The bitumen membrane market overall is growing at 6–8% CAGR through 2030.
Modified bitumen (PMB) market: The polymer modified bitumen market size grew from USD 11.41 billion in 2024 to USD 12.15 billion in 2025 at 6.5% CAGR, and is expected to reach USD 15.41 billion by 2029 at 6.1% CAGR, driven by road construction expansion, increased demand for durable pavements, and rising infrastructure investments.
SBS vs APP split: SBS-modified bitumen accounts for nearly 60% of total PMB market volume due to its superior elasticity, flexibility, and ability to resist rutting and thermal cracking, especially in high-traffic and temperature-variable regions. APP holds approximately 15% of global PMB tonnage, growing in niche hot-climate applications.
Key growth driver for PMB: More than 62% of road development agencies now adopt polymer-modified formulas due to 28% higher rut resistance and 35% improved fatigue strength compared to standard bitumen.
Why Source Both Types from RAHA Bitumen?
RAHA Bitumen (RABIT) supplies both oxidized bitumen grades and polymer modified bitumen to customers in over 100 countries — covering the full range of bitumen product types needed for roofing, waterproofing, road construction, and industrial applications.
Oxidized bitumen supply: Full grade range 75/25 to 150/5 — the raw material backbone for membrane manufacturing and industrial applications
PMB supply: SBS-modified grades PG 58-16 through PG 82-22, APP modified membranes
- Consistent quality — SGS and Bureau Veritas third-party verified
- Full documentation: TDS, MSDS, COA for every shipment
- Multiple packaging: bulk tanker, drums, meltable polyamide bags
- Fast global delivery from Isfahan, Iran via Dubai, UAE hub
- Technical support for grade selection and application guidance
📞 Contact our technical team:
Dubai Office: +971 56 281 7292 (WhatsApp)
Email: info@rahabitumen.com
Frequently Asked Questions
What is the main difference between oxidized bitumen and modified bitumen?
Oxidized bitumen is produced by air blowing penetration bitumen — no polymer additions. It is hard, heat-resistant, and cost-effective, used for pipe coating, carpet tile, roofing felts, and industrial applications. Modified bitumen adds SBS rubber or APP plastic to a bitumen base (usually oxidized bitumen), enhancing flexibility, UV resistance, and cold-temperature performance at higher cost. Modified bitumen is built from oxidized bitumen — the two are complementary, not competing.
Is modified bitumen better than oxidized bitumen?
Neither is universally “better” — they are optimized for different applications. SBS modified bitumen is better for cold climates, high-movement structures, and long-service-life roofing where the premium is justified. APP modified bitumen is better for hot-climate exposed roofing with UV resistance requirements. Oxidized bitumen is better for pipe coating, carpet tile, sound dampening, large-area waterproofing, and any application where cost is the primary driver and the climate does not require polymer-enhanced cold flexibility.
Is APP modified bitumen made from oxidized bitumen?
Yes. APP modified bitumen membranes use oxidized bitumen — typically grade 115/15 or 95/25 — as their primary raw material, comprising 60–80% of the membrane compound by weight. The APP polymer (20–30%) is blended into the hot oxidized bitumen. This is why RAHA Bitumen’s oxidized bitumen grades are direct feedstock materials for APP membrane manufacturers worldwide.
Which is better for hot climates — oxidized bitumen or APP modified bitumen?
Both perform well in hot climates due to their high softening points. For hot-applied BUR roofing and industrial waterproofing, oxidized bitumen grades 95/25 or 115/15 are cost-effective and reliable. For exposed membrane roofing where UV resistance is critical, APP modified bitumen offers superior protection. For extreme heat (roof surface temperatures >70°C), APP modified bitumen’s higher softening point (130–160°C) provides additional margin of safety.
What is the service life difference between oxidized bitumen and modified bitumen membranes?
A properly installed oxidized bitumen (BUR) roofing system typically lasts 20–30 years. SBS modified bitumen membranes typically achieve 25–40 years service life. APP modified bitumen membranes typically achieve 25–35 years. The longer service life of modified membranes partially offsets their higher upfront cost over the full building lifecycle.
Can oxidized bitumen be used to make modified bitumen?
Yes — this is exactly how it works. Membrane manufacturers purchase oxidized bitumen (typically grade 115/15 or 95/25) from producers like RAHA Bitumen and blend it with SBS or APP polymer to produce modified bitumen compounds for membrane manufacturing. The quality and consistency of the oxidized bitumen feedstock directly affects the quality of the finished modified membrane product.
Summary – Oxidized vs Modified Bitumen at a Glance
| Parameter | Oxidized Bitumen | SBS Modified | APP Modified |
| Base Material | Penetration bitumen (air blown) | Bitumen + SBS rubber | Bitumen + APP plastic |
| Cold Flexibility | Moderate | ⭐ Excellent (-28°C) | Moderate (-5°C) |
| Heat Resistance | Excellent | Good | ⭐ Excellent |
| UV Resistance | Poor | Good | ⭐ Excellent |
| Cost | ⭐ Lowest | High | High |
| Service Life | 20–30 years | 25–40 years | 25–35 years |
| Primary Use | Industrial, pipe coating, carpet tile, BUR roofing, membrane feedstock | Cold climate roofing, high-movement structures, roads | Hot climate roofing, exposed membranes |
| PMB Market (2025) | — | ~60% of PMB volume | ~15% of PMB volume |
Related Products & Pages:
→ All Oxidized Bitumen Grades
→ Oxidized Bitumen 115/15 — primary APP membrane feedstock
→ Oxidized Bitumen 95/25 — SBS/APP membrane feedstock
→ Polymer Modified Bitumen (PMB)
→ APP Modified Bitumen Membrane
→ Oxidized Bitumen vs Penetration Bitumen
→ Oxidized Bitumen for Roofing
→ Oxidized Bitumen for Waterproofing
→ Blown Asphalt Production Process
Key References
- Research and Markets (2025). Polymer Modified Bitumen Market — Global Forecast to 2029.
- Market Reports World (2026). Polymer Modified Bitumen Market Size — SBS at 60% of PMB volume.
- CE Center / SOPREMA Inc. (2025). SBS-Modified Bitumen Roofing — Technical Guide.
- BMI Group UK (2025). SBS vs APP Roofing Explained.
- SOPREMA UK (2026). Types of Bitumen: SBS vs APP.
- Zhang et al. (2021). SBS Modified Bitumen with Organic Layered Double Hydroxides: Compatibility and Aging Effects. Materials, MDPI. DOI: 10.3390/ma14154201
- ASTM D312/D312M. Standard Specification for Asphalt Used in Roofing. ASTM International.
- ASTM D6163. Standard Specification for SBS Modified Bituminous Sheet Materials.
- ASTM D6222. Standard Specification for APP Modified Bituminous Sheet Materials.
Page last updated: May 2025 | Published by RAHA Bitumen Co. (RABIT) | Dubai, UAE & Isfahan, Iran
