Bitumen 70/100 — Specification, Production & Applications
Bitumen 70/100 is a soft penetration grade for cooler climates, lower traffic volumes and applications where flexibility matters more than deformation resistance.
Where Bitumen 70/100 sits among the penetration grades
Penetration is measured as the depth in tenths of a millimetre that a standard needle penetrates the binder in five seconds at 25 °C under a 100 g load, to ASTM D5. A lower number means a harder binder. The scale above runs from hard on the left to very soft on the right.
What defines Bitumen 70/100
At 70 to 100 tenths of a millimetre penetration and a softening point minimum of only 42 °C, this is a markedly softer binder than the 50/70 and 60/70 grades that dominate warm-climate paving. It is chosen where the pavement will not reach the surface temperatures that would cause a soft binder to rut.
The values that matter
Two of its specification limits are notably looser than the harder grades: loss on heating is permitted up to 1.5 per cent and retained penetration only 40 per cent, against 0.8 and 58 for 50/70. Those wider allowances reflect the higher volatile content that comes with a shallower cut, and they are a reason to check the certificate carefully rather than assume equivalence with a harder grade.
How Bitumen 70/100 is produced
Refining route
Bitumen 70/100 comes from a shallower vacuum cut than the harder paving grades. Less of the oily and resinous maltene fraction is removed from the residue, which is what leaves the binder soft and gives it its lower softening point. In some refineries the grade is reached by fluxing a harder residue with a compatible distillate rather than by adjusting cut depth, since a very shallow cut sacrifices distillate yield.
Blend and release control
The production risk with a soft grade is the opposite of the one that governs hard grades: the binder can end up too soft rather than too stiff. Release testing therefore concentrates on the lower end of the penetration window and on the 42 °C softening point minimum, which is the value most likely to fail on a marginal batch.
Bitumen 70/100 specification
| Property | Test method | Unit | Requirement |
|---|---|---|---|
| Density @ 25 °C | ASTM D70 | g/cm³ | 1.01–1.06 |
| Penetration @ 25 °C, 100 g, 5 s | ASTM D5 | ×0.1 mm | 70–100 |
| Softening point, ring and ball | ASTM D36 | °C | min 42 |
| Ductility @ 25 °C | ASTM D113 | cm | min 100 |
| Loss on heating | ASTM D6 | wt % | max 1.5 |
| Retained penetration after heating | EN 1426 | % | min 40 |
| Solubility in trichloroethylene | ASTM D2042 | wt % | min 99 |
| Flash point, Cleveland open cup | ASTM D92 | °C | min 200 |
| Spot test | AASHTO T102 | — | negative |
A certificate of analysis accompanies every shipment. Independent inspection by SGS, Intertek or an equivalent surveyor can be arranged at the buyer instruction and account.
Where Bitumen 70/100 is used
Cool climate road works
Surfacing in temperate and cool regions where summer pavement temperatures stay moderate.
Cold mix and emulsion base
Feedstock for bitumen emulsions and cold-applied mixtures where a softer base binder is required.
Surface dressing in cool regions
Chip seals applied at lower ambient temperatures, where a harder binder would not wet the aggregate.
Low volume rural roads
District and rural networks with light traffic and long design lives governed by weathering.
Crack sealing and patching
Maintenance applications where flexibility and adhesion matter more than modulus.
Lower pavement layers
Base courses insulated from surface temperature extremes.
Handling and application temperatures
Working temperatures follow the binder viscosity rather than the grade designation alone. The ranges below are typical starting points for Bitumen 70/100 and should be confirmed against the mix design.
| Operation | Typical range | Control note |
|---|---|---|
| Bulk storage | 145–165 °C | Circulate to avoid local overheating at the coils |
| Pumping and transfer | 145–165 °C | Confirm line tracing before transfer begins |
| Hot mix asphalt mixing | 145–160 °C | Per mix design, not per binder alone |
| Compaction | 125–145 °C | Cease rolling below the lower figure |
| Maximum sustained heating | below 180 °C | Above this, oxidative hardening accelerates sharply |
Drummed material should be reheated in a controlled oven or hot room rather than by direct flame. Localised overheating hardens the binder at the drum wall and can take a compliant parcel out of specification before it reaches the mixer.
Available packing for Bitumen 70/100
| Packing | Net weight | Loading per 20 ft FCL | Typical use |
|---|---|---|---|
| New steel drum | 150 / 180 / 185 / 200 kg | 110 drums, 20.35 MT at 185 kg | Smaller parcels, sites without bulk storage |
| Jumbo bag | 1 MT | 20 MT | Lower packing cost, requires melting facility |
| Flexitank / bitutainer | 20–22 MT | 1 unit | Bulk economics without a bulk vessel |
| Bulk vessel | by parcel | heated tanker | Terminal to terminal, largest volumes |
As a Bitumen 70/100 supplier Bitumen Asphaltive ships on CFR, CIF and FOB terms with commercial invoice, packing list, bill of lading, certificate of origin and certificate of analysis.
Questions about Bitumen 70/100
Why is loss on heating allowed up to 1.5 per cent for 70/100?
Because a softer binder produced from a shallower cut retains more volatile material by nature. The limit is set relative to what is achievable for the grade rather than as an absolute quality measure. It does mean the binder will change consistency more between tank and road than a harder grade, which the mix design should account for.
Can 70/100 be used in a hot climate?
Only in layers protected from surface heat, or in applications where deformation is not a failure mode. On a trafficked wearing course in a hot region it will rut. If the climate is hot but a soft binder is wanted for workability, the correct answer is usually a modified binder rather than a softer penetration grade.
How does 70/100 compare with 85/100?
The windows overlap across 85 to 100, but 85/100 carries tighter ageing limits, 0.8 per cent loss on heating against 1.5, and 52 per cent retained penetration against 40. Where both are offered, 85/100 is the more constrained specification even though the two look similar on penetration alone.
What flash point applies?
A minimum of 200 °C by ASTM D92. That is lower than the harder grades, again reflecting higher volatile content, and it narrows the safe heating margin. Storage temperature control matters correspondingly more.
The penetration grade range
Penetration windows overlap between adjacent grades, so a single parcel can sometimes satisfy two specifications. Ageing limits and softening point are what separate them.
| Grade | Penetration @ 25 °C | Character |
|---|---|---|
| Bitumen 20/30 | 20–30 × 0.1 mm | Hard |
| Bitumen 30/40 | 30–40 × 0.1 mm | Hard |
| Bitumen 40/50 | 40–50 × 0.1 mm | Medium hard |
| Bitumen 50/70 | 50–70 × 0.1 mm | Medium hard |
| Bitumen 60/70 | 60–70 × 0.1 mm | Medium hard |
| Bitumen 70/100 | 70–100 × 0.1 mm | Medium soft |
| Bitumen 80/100 | 80–100 × 0.1 mm | Medium soft |
| Bitumen 85/100 | 85–100 × 0.1 mm | Medium soft |
| Bitumen 120/150 | 120–150 × 0.1 mm | Soft |
| Bitumen 200/300 | 200–300 × 0.1 mm | Very soft |
Speak to a Bitumen 70/100 supplier
Send quantity in metric tonnes, required packing, destination port and preferred Incoterm. Offers are normally returned within one working day.