Oxidized bitumen 150/5 is the hardest grade in the blown bitumen range — a softening point around 150 °C with a penetration of roughly 5 dmm. It is not a roofing binder and it will not behave like one. This is an industrial hard grade used where the material has to stay rigid at temperatures that would soften anything else: electrical insulating compounds, battery sealing, pipe coating enamels and rubber compounding.
RAHA Gilsonite supplies oxidized bitumen 150/5 against ASTM D312 or against a buyer’s own specification where a project standard applies. This page sets out the specification, the melting and application temperatures the grade actually needs, where it belongs and where it does not, and how it compares with the softer grades in the range.
What is oxidized bitumen 150/5?
Oxidized bitumen — also called blown bitumen or blown asphalt — is produced by blowing air through hot penetration grade bitumen at around 240 to 260 °C. Oxygen reacts with the maltene fraction and converts it toward asphaltenes. Consequently, the binder becomes harder, the softening point climbs and the penetration falls.
Reading the grade designation
The grade designation reads softening point over penetration. In oxidized bitumen 150/5, the 150 is the ring and ball softening point in degrees Celsius and the 5 is the penetration at 25 °C in tenths of a millimetre. Both figures carry a tolerance, which is why the specification below shows ranges rather than exact numbers.
Why 150/5 sits apart from the rest
What makes 150/5 different from the rest of the family is the extent of the blowing. Roofing grades such as 85/25 and 90/40 retain enough flexibility to be laid on a roof and to move with a building. However, at 150/5 that flexibility is gone. The material is brittle at ambient temperature and behaves closer to a hard resin than to a bituminous binder. That is the point — it is specified where rigidity and heat resistance matter more than elasticity.
Oxidized bitumen 150/5 specification
| Property | Unit | Specification | Typical result | Test method |
|---|---|---|---|---|
| Softening point (ring & ball) | °C | 145–155 | 150 | ASTM D36 |
| Penetration @25 °C, 100 g, 5 s | dmm | 0–10 | 5 | ASTM D5 |
| Loss on heating | wt % | 0.5 max | 0.2 | ASTM D6 |
| Flash point (Cleveland open cup) | °C | 300 min | 315 | ASTM D92 |
| Solubility in trichloroethylene | wt % | 99 min | 99.5 | ASTM D2042 |
| Specific gravity @25 °C | — | 1.02–1.10 | 1.05 | ASTM D70 |
| Ductility @25 °C | cm | Not specified | — | ASTM D113 |
| Ash content | wt % | 0.5 max | 0.2 | ASTM D2939 |
Ductility is not specified for hard oxidized grades. At a penetration of 5 dmm the material fractures rather than stretches, and a ductility figure would carry no useful information. Where a project specification demands one, say so at the enquiry stage — it usually means the wrong grade has been named. Full test method definitions are maintained by ASTM International.
Applications of oxidized bitumen 150/5
The applications below all share one requirement: the compound must not soften, creep or flow in service, and it must tolerate heat that would destroy a roofing grade.
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Electrical insulating compounds
Cable jointing compounds, potting and filling compounds for transformers and switchgear. The high softening point prevents flow at operating temperature and the material is dielectrically stable.
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Battery sealing compound
Sealing the case and terminal posts of lead-acid batteries. Needs acid resistance, dimensional stability at bonnet temperature and no cold flow.
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Pipe coating enamel
Base for hot-applied enamel on buried steel pipelines, blended with filler and reinforced with glass wrap. Provides a hard, impermeable anti-corrosion layer.
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Rubber and tyre compounding
Processing aid and extender in rubber compounds where a hard, high-melting bituminous phase is wanted rather than a soft one.
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Briquette and carbon binder
Binder for coal and charcoal briquettes and for carbon products, where it carbonises cleanly and holds shape during curing.
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Paints and protective coatings
Black japan, bituminous paints and anti-corrosion primers where a hard film is required. Often blended with gilsonite for gloss and hardness.
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Sound deadening and undercoating
Automotive and appliance damping compounds that must stay in place through oven curing and through the vehicle’s service life.
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Chemical and industrial mastics
Jointing and filling compounds for tanks, ducts and industrial floors where heat resistance governs.
Where oxidized bitumen 150/5 does not belong
Do not specify 150/5 for roofing felt, waterproofing membrane, expansion joints or any application that involves movement. Furthermore, at ambient temperature the material has almost no flexibility and it will crack. For membrane manufacture the grades to look at are 85/25, 90/40 and 95/25; for general waterproofing and adhesive work, 115/15 or 105/35.
How 150/5 compares with the other oxidized grades
Reading down this table is the quickest way to confirm whether 150/5 is really the grade your specification needs.
| Grade | Softening point | Penetration | Class | Principal use |
|---|---|---|---|---|
| 150/5 | 145–155 °C | 0–10 dmm | Hardest | Electrical compounds, battery sealing, pipe enamel, rubber |
| 115/15 | 110–120 °C | 10–20 dmm | Hard | Waterproofing, adhesives, sealing compounds, pipe coating |
| 105/35 | 100–110 °C | 30–40 dmm | Medium | Roofing felt, membrane, general waterproofing |
| 105/15 | 100–110 °C | 10–20 dmm | Hard | Sealing, jointing, industrial mastics |
| 95/25 | 90–100 °C | 20–30 dmm | Medium | Roofing membrane, damp proofing |
| 90/40 | 85–95 °C | 35–45 dmm | Softer | Roofing felt, membrane manufacture |
| 90/15 | 85–95 °C | 10–20 dmm | Medium | Adhesive and sealing work |
| 90/10 | 85–95 °C | 5–15 dmm | Hard | Pipe coating, industrial compounds |
| 85/40 | 80–90 °C | 35–45 dmm | Softer | Membrane, roofing, damp proof course |
| 85/25 | 80–90 °C | 20–30 dmm | Medium | The volume roofing grade worldwide |
| 75/35 | 70–80 °C | 30–40 dmm | Softest | Damp proofing, low-temperature climates |
| 75/25 | 70–80 °C | 20–30 dmm | Softest | General waterproofing, jointing |
The full range is listed on our oxidized bitumen grades page.
Melting and application temperatures
This is where 150/5 catches out crews used to roofing grades. A softening point of 150 °C means the material is not workable anywhere near the temperatures used for 85/25. Therefore it needs materially more heat, and the window between workable and degraded is narrower.
| Operation | Temperature | Notes |
|---|---|---|
| Melting | 220–245 °C | Indirect heating only. Melt the full charge and homogenise before drawing off |
| Pumping | 230–250 °C | Lines and pumps must be heat traced or the material will set in them |
| Application / blending | 230–250 °C | Working window is short. Plan the transfer before you start heating |
| Absolute maximum | 260 °C | Above this the material cokes, fumes heavily and the softening point drifts |
| Hot holding | Not recommended | Melt per batch. Prolonged hot holding hardens the grade further |
Safety at these temperatures
The flash point is 300 °C minimum, so there is margin, but the working temperature is high enough that fume generation, thermal burns and water contamination all become serious. If the material foams, spits or crackles as it heats, water is present — stop heating immediately rather than trying to drive it off. Handling guidance for bituminous binders is published by Eurobitume and the Asphalt Institute, and is worth reading before commissioning a melting station.
Packing, storage and shipping
| Packing | Unit weight | Per 20′ container | Notes |
|---|---|---|---|
| Kraft paper bag | 25 kg | Up to 25 MT palletised | Most common. Meltable bag options available so the bag goes into the melter |
| Carton | 25 kg | Up to 22 MT | Better protection for long transit and rough handling |
| New steel drum | 180–190 kg | 80 drums ≈ 15 MT | Requires cutting or a drum melter at destination |
| Jumbo bag | 1,000 kg | Up to 22 MT | Lowest packing cost per tonne where handling equipment exists |
Storage and shelf life
Because it is already fully blown, oxidized bitumen 150/5 stores well — two to three years in sealed packing kept dry and out of direct sun. There is very little left for atmospheric oxygen to react with, so chemical ageing runs slowly.
The realistic failure mode is physical rather than chemical. In hot climates blocks fuse together under stacking pressure, and kraft bags degrade under UV. Store on pallets, under cover, no more than two tiers high, and keep the batch number filed with the certificate of analysis.
Customs classification
For customs purposes the grade falls under HS 2713.20, petroleum bitumen. Drummed and bagged material at ambient temperature is generally not classified as dangerous goods for sea carriage, although most shipping lines and destination customs still require the safety data sheet with the booking.
Quality control and certification
Every shipment leaves with a batch certificate of analysis stating the lot number, the production date, the standard tested against and each test with its method and measured result. We accept third-party inspection at loading by SGS, Bureau Veritas, Intertek or any surveyor named in your contract.
Two things to check on any oxidized bitumen certificate
First, confirm it carries a batch number and a production date rather than only typical values — a document without them describes a grade, not a cargo. Second, read softening point and penetration together. Moreover, a binder can meet the softening point and miss the penetration, and for a hard grade like 150/5 that combination usually means under-blowing.
Frequently asked questions about oxidized bitumen 150/5
What does 150/5 mean in oxidized bitumen?
The first number is the ring and ball softening point in degrees Celsius, so approximately 150 °C. The second is the penetration at 25 °C in tenths of a millimetre, so approximately 5 dmm. Both carry a tolerance in practice: the specification runs 145–155 °C for softening point and 0–10 dmm for penetration.
What is oxidized bitumen 150/5 used for?
Electrical insulating and cable jointing compounds, lead-acid battery sealing, hot-applied pipe coating enamels, rubber and tyre compounding, briquette binders, bituminous paints and sound deadening compounds. What these share is a need for rigidity and heat resistance rather than flexibility.
Can I use 150/5 for roofing or waterproofing membrane?
No. At a penetration of 5 dmm the material is brittle at ambient temperature and will crack under any movement. For roofing felt and membrane the correct grades are 85/25, 90/40 or 95/25. If a specification names 150/5 for a roofing application, it is worth going back to the specifying engineer before ordering.
What temperature do I melt oxidized bitumen 150/5 at?
Melt at 220 to 245 °C and apply or blend at 230 to 250 °C, using indirect heating. Do not exceed 260 °C — above that the material cokes and the softening point drifts. Hot holding is not recommended; melt per batch instead.
What is the difference between oxidized bitumen 150/5 and 115/15?
115/15 has a softening point around 115 °C and a penetration of 10 to 20 dmm, so it retains some workability and is used for waterproofing, adhesives and sealing compounds. 150/5 is substantially harder and higher melting, and belongs in electrical, battery and pipe coating compounds. They are not substitutes for one another.
Is oxidized bitumen 150/5 the same as blown asphalt 150/5?
Yes. Oxidized bitumen, blown bitumen and blown asphalt all describe the same product — penetration grade bitumen that has been air-blown at high temperature to raise the softening point and reduce the penetration. The naming varies by region rather than by product.
What is the shelf life of oxidized bitumen 150/5?
Two to three years in sealed packing kept dry, on pallets and out of direct sun. Because the material is already fully blown there is little left to oxidise, so chemical ageing is slow. The practical limit is physical — blocks fusing together under heat and stacking pressure, and bag degradation under UV.
What is the HS code for oxidized bitumen?
HS 2713.20, petroleum bitumen, which covers all oxidized and penetration grades. National tariffs add further digits, so confirm the full code with your customs broker. Note that gilsonite and other natural bitumen fall under a different heading.
Is oxidized bitumen classified as dangerous goods?
Bagged or drummed material at ambient temperature is generally not regulated for sea carriage. Bulk bitumen carried hot at or above 100 °C is UN 3257, Elevated Temperature Liquid, Class 9. The safety data sheet is supplied with every booking regardless.
What is the minimum order quantity?
One full 20′ container, roughly 22 to 25 MT depending on packing. Mixed grades in one shipment are accepted provided each grade reaches one full container. Loading is from Jebel Ali, Mersin or Bandar Abbas on FOB, CFR or CIF terms.
Can you supply against our own specification?
Yes. Where a project or a customer standard applies rather than ASTM D312, send the specification rather than the grade name and we will confirm what meets it before you order. If two grades would both work and one is cheaper, we will say which.
Related grades and technical pages
Other hard grades: oxidized bitumen 115/15, 105/15 and 90/10. Roofing and membrane grades: 85/25, 90/40 and 95/25. The complete list is on the oxidized bitumen grades page.
Where a compound needs additional hardness, gloss or higher softening point than blown bitumen alone can deliver, gilsonite is frequently blended in — see gilsonite specification, gilsonite in paint and gilsonite in ink. For the difference between air-blown and naturally occurring hard bitumen, see natural bitumen and gilsonite bitumen.
Request a quotation for oxidized bitumen 150/5
Send us the quantity, packing, discharge port and the specification your contract names. We will confirm what the certificate of analysis will state, quote FOB, CFR or CIF, and tell you honestly if a different grade would suit the application better.
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