Oxidized Bitumen 115/15, also called blown asphalt 115/15, is the hardest grade in common commercial use: a softening point of 110 to 120 °C against a penetration of just 10 to 20 dmm. It is specified where the material has to stay rigid and dimensionally stable at temperatures that would soften any other grade — electrical insulation, pipe coating, industrial waterproofing and construction in the hottest climates. ZUMRUT INT Co. supplies it in 25 kg bags and cartons, palletised and shrink-wrapped, with a batch certificate of analysis issued before every shipment.
Oxidized Bitumen 115/15 specification
These are the specification limits we supply against. The sheet is available as a downloadable PDF, and a batch certificate of analysis with the actual test results is issued before every shipment.
| Property | Method | Unit | Specification |
|---|---|---|---|
| Softening point (ring and ball) | ASTM D36 | °C | 110–120 |
| Penetration @25 °C, 100 g, 5 s | ASTM D5 | dmm | 10–20 |
| Specific gravity @25 °C | ASTM D70 | — | 1.05 approx. |
| Ductility @25 °C | ASTM D113 | cm | 1.5 min |
| Flash point (Cleveland open cup) | ASTM D92 | °C | 250 min |
| Loss on heating | ASTM D6 | wt % | 0.2 max |
| Solubility in CS₂ | ASTM D4 | wt % | 99.5 min |
| Spot test | AASHTO T102 | — | Negative |
The ductility figure is the one to read carefully. At 1.5 cm minimum, 115/15 is the least extensible grade we supply — roughly a quarter of 90/40. That is the trade for its heat resistance, and it is why the grade belongs on surfaces that do not move.
What the numbers mean
In oxidized grades the first number is the softening point in °C and the second is the penetration in dmm. So 115/15 softens at about 115 °C and has a penetration of about 15. Penetration grades such as 60/70 use the opposite convention, where both numbers describe penetration — which is why a buyer crossing between the two systems can order something several times harder than intended.
The grade is produced by blowing air through penetration grade bitumen at roughly 250–300 °C. Oxygen reacts with the lighter fractions, molecular weight rises, and the softening point climbs far above the feedstock. 115/15 sits at the long end of that process: more blowing, higher softening point, lower penetration.
Looking at the whole oxidized range rather than this one grade? The oxidized bitumen overview sets out every grade we supply and how to choose between them.
Where Oxidized Bitumen 115/15 is used
Electrical insulation
Cable compounds and jointing material. Bitumen is non-conductive, and 115/15 holds its form at the temperatures electrical plant reaches in service.
Pipe coating
Hot-applied corrosion protection for buried and above-ground steel pipelines, where the coating must not sag or flow in sun.
Roofing felt and membranes
The base bitumen in felts and roll sheets destined for the hottest climates, where a softer grade would creep on a slope.
Industrial waterproofing
Tanking of concrete structures, bridges, tunnels and basements, where the substrate is rigid and permanent.
Paints and protective coatings
A raw material in bituminous paints, primers and anti-corrosion coatings for steel and concrete.
Asphalt modification
Added to paving mixes to raise the high-temperature performance of the binder in extreme heat.
Application temperature is roughly 230 °C — about twice the softening point — and surfaces must be clean, dry and free of loose material before application. If the product is supplied in meltable bags, allow a further 50 °C so the packaging melts into the batch rather than sitting in it.
115/15 compared with the other oxidized grades
Across the oxidized range the trade-off is constant: higher softening point buys heat resistance and costs flexibility. 115/15 is at the far end of that line.
| Grade | Softening point | Penetration | Ductility | Typical use |
|---|---|---|---|---|
| 85/25 | 80–90 °C | 20–30 dmm | 3 cm min | Roofing felt, pipe coating, hot climates |
| 85/35 | 80–90 °C | 30–40 dmm | Higher | General waterproofing and membranes |
| 90/40 | 85–95 °C | 35–45 dmm | 5.5 cm min | Membranes and sealants where the substrate moves |
| 90/10 | 85–95 °C | 10–20 dmm | Low | Rigid industrial coatings |
| 115/15 | 110–120 °C | 10–20 dmm | 1.5 cm min | Electrical insulation, extreme heat, rigid substrates |
115/15 or 85/25?
This is the comparison buyers ask for most often. 85/25 softens at 80 to 90 °C with a penetration of 20 to 30 dmm; 115/15 softens 30 °C higher and is roughly twice as hard.
Choose 115/15 when the service temperature is genuinely extreme, when the coating must not sag or flow, or when the requirement is electrical insulation. Choose 85/25 for general waterproofing in warm to hot climates, where some tolerance for movement is worth more than the last 30 °C of heat resistance.
A caution worth stating plainly. 115/15 is brittle. On a substrate that expands, contracts or settles, that hardness becomes a liability rather than an asset, and the coating cracks. If anything in the assembly moves, 90/40 is the grade to look at instead. Send us the application rather than the grade name and we will tell you which one the job needs.
Packing and container loading
Oxidized bitumen is solid at ambient temperature, so it ships as cast blocks in bags or cartons rather than in bulk. Blocks are delivered solid and melted on site.
| Packing | Unit | 20′ container | Notes |
|---|---|---|---|
| PP bag, palletised and shrink-wrapped | 25 kg | 22–23 MT | Most common export format; stacks and handles well |
| Kraft paper bag, palletised and shrink-wrapped | 25 kg | 22–23 MT | Recyclable, with an inner coating so the block releases cleanly |
| Carton box, palletised and shrink-wrapped | 25 kg | 22–23 MT | Removable mould, easiest to strip at destination |
All three formats are palletised and shrink-wrapped as standard, which is what stops blocks fusing in transit through a hot climate. Meltable bags that go into the melt with the material can be quoted on request — tell us at enquiry stage, because the melting procedure and the per-tonne figure both change.
Our minimum order is two 20′ containers, roughly 45 MT at 22 to 23 MT per container. Mixed oxidized grades within one shipment are accepted provided each grade reaches a full container.
Storage, handling and safety
Stored under shelter, out of direct sun and rain, in a dry ventilated space, in its original packing and not over-stacked, Oxidized Bitumen 115/15 holds its properties for years. The datasheet figure is a minimum of 12 months, and in practice the limiting factor is packaging damage rather than the material ageing. Prolonged exposure to rain or direct sunlight in open storage is what degrades it.
Heating. Use indirect heat — an oil-jacketed kettle or a thermostatically controlled melter. Because the working temperature is high, around 230 °C, the margin to the 250 °C flash point is narrower than for softer grades, so thermostat control is not optional. Direct flame on the vessel wall overheats the material at the contact point and drives off fume before the bulk has melted.
Safety. Hot bitumen causes severe burns and adheres to skin. Heat-resistant gloves, face protection, long sleeves and closed footwear are required wherever the material is handled hot, and heating areas need ventilation to stop vapour accumulating. Do not use water on a bitumen fire — it flashes to steam and ejects burning material; dry powder and foam are the correct media. Full handling, exposure and first-aid guidance is in the material safety data sheet, which we also issue with every shipment.
Payment, inspection and documentation
Our standard terms are 50% by TT in advance, balance against a copy of the Bill of Lading. The advance secures production and loading; the balance falls due once the cargo is demonstrably on the water and documented. We do not work on letters of credit — bank charges and discrepancy risk end up in the per-tonne figure, and saying so plainly saves a week of negotiation.
Every shipment travels with a commercial invoice, packing list, bill of lading, certificate of origin, safety data sheet and the batch certificate of analysis. SGS, Bureau Veritas, Intertek or the surveyor named in your contract can attend loading for quality and quantity. Shipping documents are issued within three days of vessel departure. The export documentation guide sets out what each document does and where presentations usually fail.
We load from Jebel Ali, Mersin and Iskenderun, and the port we quote from depends on the destination and the packing you choose. The exact port and sailing are confirmed with the quotation.
Frequently asked questions about Oxidized Bitumen 115/15
What are the specifications of Oxidized Bitumen 115/15?
Softening point 110–120 °C (ASTM D36), penetration 10–20 dmm at 25 °C (ASTM D5), specific gravity about 1.05 (ASTM D70), ductility 1.5 cm minimum (ASTM D113), flash point 250 °C minimum (ASTM D92), loss on heating 0.2% maximum (ASTM D6), solubility in CS₂ 99.5% minimum (ASTM D4), spot test negative. The full sheet is a downloadable PDF.
What do the numbers 115 and 15 mean?
In oxidized grades the first number is the softening point in °C and the second is the penetration in dmm. So 115/15 softens at about 115 °C and has a penetration of about 15. This is the opposite convention to penetration grades such as 60/70, where both numbers describe penetration.
What is the difference between 115/15 and 85/25?
115/15 softens about 30 °C higher and is roughly twice as hard. Choose it for extreme service temperature, rigid substrates and electrical insulation. Choose 85/25 for general waterproofing in warm to hot climates, where some tolerance for movement matters more than the last 30 °C of heat resistance.
Is Oxidized Bitumen 115/15 the same as blown asphalt?
Yes. Blown asphalt, blown bitumen and oxidized bitumen are the same product under different names, from the air-blowing process used to make it. Suppliers and specifications use the terms interchangeably.
At what temperature is it applied?
Around 230 °C, roughly twice the softening point. Surfaces must be clean, dry and free of loose material. If the product is supplied in meltable bags, allow a further 50 °C so the packaging melts into the batch. Keep a clear margin below the 250 °C flash point and use thermostatically controlled indirect heat.
Can it be used where the structure moves?
No — that is the one case where this grade is the wrong choice. Its ductility is 1.5 cm minimum, so on a substrate that expands, contracts or settles it will crack. For assemblies with movement, use 90/40, which has about four times the extensibility.
Why is it used for electrical insulation?
Bitumen is non-conductive, chemically stable and water-resistant, and 115/15 adds a softening point high enough that it holds its form at the temperatures electrical plant reaches in service. That combination is what makes it a cable compound and jointing material rather than a general-purpose coating.
What is the minimum order quantity?
Two 20′ containers, roughly 45 MT in total at 22 to 23 MT per container. Mixed oxidized grades in one shipment are accepted provided each grade reaches a full container.
What are your payment terms?
50% by TT in advance with the balance settled against a copy of the Bill of Lading. We do not work on letters of credit. The balance falls due only once the cargo is on the water and documented.
Is a certificate of analysis provided?
Yes, with every shipment. It carries the lot number and production date and reports the actual test results for softening point, penetration, specific gravity, ductility, flash point, loss on heating and solubility — not generic typical values.
How long does it keep in storage?
A minimum of 12 months under correct storage, and considerably longer in practice. Keep it sheltered, dry, out of direct sunlight, in its original packing and not over-stacked. Prolonged exposure to rain or sun in open storage is the usual cause of loss, not the material ageing.
What is the price of Oxidized Bitumen 115/15?
It moves with feedstock cost, ocean freight, packing choice and destination, so a flat published number would not hold. Indicative levels are on our bitumen price page. Send quantity, packing, destination port and Incoterm and we issue a firm FOB, CFR or CIF quotation within one business day.
Related grades and products
All oxidized grades
The full range, the naming convention and how to choose between grades is on the oxidized bitumen overview.
Oxidized Bitumen 85/25
85/25 is the standard roofing felt and pipe coating grade, softer and more forgiving than 115/15.
Oxidized Bitumen 90/40
90/40 pairs a high softening point with real extensibility, for assemblies that move.
Oxidized Bitumen 90/10
90/10 is similarly hard but softens 25 °C lower, for rigid coatings in less extreme heat.
Bitumen roll sheet
Finished SBS and APP membranes, if you are buying the product rather than the raw material.
Penetration grades
60/70 is the feedstock oxidized grades are blown from, and the standard paving binder in warm climates.
Request a quotation for Oxidized Bitumen 115/15
Send us the quantity in MT, the packing format, the destination port and the Incoterm. We come back with a firm price, a production schedule and the documentation list for clearance within one business day. If you have a softening point and penetration requirement but no grade name, send the specification instead and we will match it.
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