Bitumen PG 70-10 — Production, Specification & Applications
PG 70-10 is the stiffest binder in the standard Superpave range supplied here, written for sustained surface heat combined with heavy axle loading.
Where PG 70-10 sits on the temperature scale
Performance grading ties the binder to the climate of the road rather than to a refinery output slate. The shaded band is the range PG 70-10 is certified to serve, a useful span of 80 degrees.
What distinguishes PG 70-10
The step from a 64 to a 70 upper grade is larger in production terms than the six-degree gap suggests. Meeting a minimum G*/sinδ of 1.00 kPa at 70 °C on unaged binder, and 2.20 kPa after RTFOT, usually rules out a straight-run product from an ordinary crude slate.
What buyers should know
PG 70-10 also occupies a useful position in the AASHTO M323 traffic adjustment scheme. A site whose climate calls for PG 64 but which carries slow transient traffic is bumped one grade, to PG 70. A large share of PG 70-10 demand is therefore not extreme-climate demand at all; it is ordinary hot-climate demand adjusted upward for traffic.
How Bitumen PG 70-10 is produced
Understanding the refining route explains why some grades are readily available and others are not, and why two binders that look similar on a datasheet can behave differently in service.
From crude oil to vacuum residue
Production begins the same way as any paving binder. Crude oil is fractionated in an atmospheric column, and the long residue that leaves the base of that column is fed to a vacuum unit where the remaining distillates are stripped under reduced pressure. What remains is vacuum residue, and its stiffness is governed by how deep that cut was taken and by the asphaltene content of the crude itself.
Reaching the PG 70-10 envelope
For a 70 °C upper grade the residue has to be considerably stiffer than the one that yields PG 64. Three routes are used. The first is crude selection: naphthenic and asphaltic crudes with high native asphaltene content produce a harder residue at the same cut depth. The second is a deeper vacuum cut, which removes more of the softening oil fraction but reduces yield and can push the binder past its low-temperature limit. The third, and the most common for reliable PG 70 production, is polymer modification with styrene-butadiene-styrene elastomer at roughly two to three and a half per cent by mass, blended in a high-shear mill and then held under agitation to develop a stable polymer network.
Production control
Air blowing is a fourth route but is not appropriate here. Partial oxidation raises the softening point efficiently, which is why it is used for oxidized and industrial grades, but it does so by hardening the binder in a way that damages low-temperature relaxation. A blown binder will usually fail the bending beam m-value criterion, so it cannot be used to reach a paving performance grade.
Derived test temperatures you can check
The two intermediate temperatures on a PG 70-10 certificate follow arithmetically from the grade, so a buyer can verify the document without reference to any other source.
| Test | Derivation | Result for PG 70-10 |
|---|---|---|
| PAV dynamic shear (fatigue) | (70 + −10) ÷ 2 + 4 | 34 °C |
| Bending beam (stiffness, m-value) | −10 + 10 | 0 °C |
Bitumen PG 70-10 specification
| Property | Test method | Requirement |
|---|---|---|
| Average 7-day max pavement design temperature | AASHTO M323 | 70 °C |
| Minimum pavement design temperature | AASHTO M323 | −10 °C |
| Original binder | ||
| Flash point, Cleveland open cup | AASHTO T48 | min 230 °C |
| Rotational viscosity @ 135 °C | AASHTO T316 | max 3 Pa·s |
| Dynamic shear G*/sinδ @ 70 °C | AASHTO T315 | min 1.00 kPa |
| After RTFOT (short-term ageing) | ||
| Change of mass | AASHTO T240 | max 1.00 % |
| Dynamic shear G*/sinδ @ 70 °C | AASHTO T315 | min 2.20 kPa |
| After PAV @ 100 °C (long-term ageing) | ||
| Dynamic shear G*·sinδ @ 34 °C | AASHTO T315 | max 5000 kPa |
| Creep stiffness S @ 0 °C | AASHTO T313 | max 300 MPa |
| m-value @ 0 °C | AASHTO T313 | min 0.300 |
The full PG 70-10 specification is tested to AASHTO M320 and reported on the certificate of analysis for every parcel. Nearest indicative equivalents: penetration grade 40/50, viscosity grade VG-40. These are reference points for discussion, not substitutions. A certificate of analysis accompanies every shipment; third-party inspection by SGS, Intertek or an equivalent surveyor can be arranged at the buyer instruction and account.
Where Bitumen PG 70-10 is used
Tropical trunk highways
Dense-graded wearing courses on high-volume routes in tropical and desert climates. Surface temperatures on dark pavement in these regions routinely exceed 60 °C in the afternoon, and the binder has to hold aggregate structure under repeated heavy loading at that temperature.
Container terminals and ports
Aprons and stacking yards where reach stackers and loaded terminal tractors apply near-static loading. Load duration rather than load magnitude drives deformation here, which is exactly the condition the upper grade addresses.
Toll plazas and bus lanes
Queuing and approach areas where vehicles stand or crawl. AASHTO M323 treats standing traffic as a two-grade bump, so a PG 64 climate with a toll plaza becomes a PG 76 requirement; PG 70-10 covers the intermediate slow-transient case.
Mining and quarry haul roads
Industrial access roads carrying very heavy axle loads at low speed over long service periods, where surface deformation directly affects haul cycle times.
Airport aprons and stands
Aircraft parking positions where static loading over long dwell times drives deformation rather than fatigue, and where surface deformation has operational consequences.
Heavy industrial hardstanding
Plant yards and laydown areas subject to concentrated wheel loads and point loading in high ambient temperatures.
Mix design and handling temperatures
Mixing and compaction temperatures are set from the binder viscosity–temperature relationship rather than from the grade designation alone. The ranges below are typical starting points for PG 70-10 and should be confirmed against the rotational viscosity figure on the delivered certificate.
| Operation | Typical range for PG 70-10 | Control note |
|---|---|---|
| Bulk storage | 160–180 °C | Circulate to prevent local overheating at the heating coils |
| Pumping and transfer | 160–180 °C | Confirm line tracing is operating before transfer begins |
| Hot mix asphalt mixing | 160–175 °C | Target viscosity approximately 0.17 Pa·s |
| Compaction | 145–160 °C | Target viscosity approximately 0.28 Pa·s; 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.
What happens when PG 70-10 is mis-specified
Where PG 70-10 is specified for a climate whose winter minimum falls below minus 10 °C, the failure is transverse thermal cracking: regularly spaced cracks running across the carriageway, typically appearing within two or three winters and then propagating. The reverse error, specifying a softer grade where PG 70-10 was required, produces rutting and shoving in the wheel paths within the first hot season, most visibly at intersections and on gradients where traffic slows.
Available packing for PG 70-10
| 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 PG 70-10 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 specific to PG 70-10
Is PG 70-10 always a modified binder?
Not necessarily. Some crude slates yield a base binder stiff enough to meet the 70 °C criteria without polymer, particularly asphaltic crudes processed at a deep vacuum cut. Where the refinery cannot reach the grade straight-run, styrene-butadiene-styrene modification is the usual route. The certificate of analysis does not distinguish the two, so if the contract requires an unmodified or a modified binder specifically, that must be stated separately in the enquiry.
Our climate calls for PG 64 but the road carries slow traffic. Should we order PG 70-10 or PG 64-10?
AASHTO M323 adjusts the upper grade for traffic, not the lower. Slow transient traffic between 20 and 70 km/h raises PG 64-10 to PG 70-10. Ordering PG 64-10 for that site meets the climate requirement but not the traffic requirement, and rutting is the likely outcome.
Can PG 70-10 be used where winters reach minus 15 degrees?
No. The lower grade is a design limit, not a guideline. A pavement built with PG 70-10 in a minus 15 °C climate is expected to develop transverse thermal cracking. PG 70-22 or a modified equivalent would be required, and availability should be confirmed before the specification is issued.
Why can oxidized bitumen not be used to reach PG 70?
Air blowing raises the softening point by hardening the binder through partial oxidation, which simultaneously degrades its ability to relax stress at low temperature. A blown binder will normally fail the bending beam m-value requirement of 0.300, so it cannot satisfy a paving performance grade regardless of how well it performs at the upper temperature.
Does a modified PG 70-10 need different storage arrangements?
Yes. Polymer-modified binder should be kept under gentle agitation or circulation during storage to prevent phase separation, and prolonged storage at elevated temperature without agitation should be avoided. Confirm whether the delivered product is modified so that site storage can be arranged accordingly.
The performance grade range
Intermediate temperatures below are derived from each grade, not selected by the supplier.
| Grade | Upper | Lower | Span | PAV DSR | Bending beam | Pen equiv. |
|---|---|---|---|---|---|---|
| PG 70-10 | 70 °C | −10 °C | 80 °C | 34 °C | 0 °C | 40/50 |
| PG 64-22 | 64 °C | −22 °C | 86 °C | 25 °C | −12 °C | 60/70 |
| PG 64-16 | 64 °C | −16 °C | 80 °C | 28 °C | −6 °C | 60/70 |
| PG 64-10 | 64 °C | −10 °C | 74 °C | 31 °C | 0 °C | 60/70 |
| PG 58-22 | 58 °C | −22 °C | 80 °C | 22 °C | −12 °C | 85/100 |
| PG 58-16 | 58 °C | −16 °C | 74 °C | 25 °C | −6 °C | 85/100 |
| PG 58-10 | 58 °C | −10 °C | 68 °C | 28 °C | 0 °C | 85/100 |
| PG 52-10 | 52 °C | −10 °C | 62 °C | 25 °C | 0 °C | 120/150 |
Speak to a Bitumen PG 70-10 supplier
Send quantity in metric tonnes, required packing, destination port and preferred Incoterm. Offers are normally returned within one working day.