Bitumen 60/70 or VG-30? How to Read Bitumen Grades Before You Ask for a Quote

01 · Why it matters

A grade without its standard cannot be priced, inspected or enforced

The most common first line in a bitumen enquiry is “What is your price per ton for 60/70?” The seller reads that line against its own refinery standard. The buyer reads it against the road authority's standard back home. When the two differ, the problems arrive in a predictable order.

That is why the work starts not with the grade, but with agreeing three things: which standard, which edition and which test methods. Everything else in the contract — the price basis, the inspection scope, the acceptance criteria — hangs on that line.

1. At the quote stage, prices for different specifications are compared as if they were the same product. The cheapest offer may simply be the loosest specification.
2. At pre-shipment inspection, nobody has told the surveyor which standard's methods and limits to judge against, so the certificate can be read two ways.
3. After arrival, if the site laboratory finds the softening point or aged penetration outside the road authority's limits, a contract that never named a standard leaves responsibility unclear.

Sources [1][5]

02 · Penetration grades

60/70 means a standard needle sinks 6 to 7 mm at 25 °C — and little else is shared between standards

Penetration is the depth, in tenths of a millimetre, that a standard needle loaded with 100 g sinks into a sample held at 25 °C for 5 seconds (ASTM D5, EN 1426). A 60/70 grade reads 60 to 70, that is 6.0 to 7.0 mm. Higher numbers mean softer bitumen.

In practice, 60/70 is the usual choice for regions with heavy rainfall and the softer 80/100 for cold regions, while the harder 40/50 leans toward hot climates and heavy traffic. Outside special applications, most offers from Iraq and other Middle Eastern origins are 60/70 or 80/100.

The catch is that “60/70” exists in more than one standard, and every property other than penetration can differ. The table puts the same or nearest grade side by side.

Three things follow. First, the European standard has no 60/70: a European-style 50/70 allows penetration down to 50, so a harder product can arrive. Second, ASTM D946 does not require a softening point at all; if your site depends on it, write it into the contract. Third, ageing limits differ by standard, so the same material can pass under one and fail under another.

Sources [1][2][3][4]

03 · Viscosity grades

VG-30 means 2,400 to 3,600 poise at 60 °C — and only 45 minimum penetration

Viscosity grading was introduced by the Indian standard IS 73 in its 2006 revision, replacing penetration grading. It classifies bitumen by absolute viscosity at 60 °C, close to peak summer pavement temperature, and checks kinematic viscosity at 135 °C, close to mixing and compaction temperature. The argument for the change was that two temperatures describe field behaviour better than a single reading at 25 °C.

The line that matters most is minimum penetration. VG-30 requires only 45. A VG-30 that passes is therefore not guaranteed to fall inside 60–70. “VG-30 equals 60/70” means the two serve similar roads, not that they test the same.

Units trip people up too. Indian certificates report poise; European ones report Pa·s. One Pa·s equals 10 poise, so a reported viscosity of “300” is inside VG-30 only if the unit is Pa·s. In poise, it would not even reach VG-10.

Sources [5][6][7][8]

04 · Performance grades

PG 64-22 means no rutting at 64 °C and no cracking at −22 °C

Performance grading came out of the US Strategic Highway Research Program's Superpave system and was standardised as AASHTO M320. In PG 64-22, 64 is the highest pavement temperature at which the binder should resist rutting and −22 the lowest at which it should resist cracking. Both are tested directly at those temperatures with a dynamic shear rheometer and a bending beam rheometer. Some agencies have moved on to AASHTO M332, which adds a traffic letter, for example PG 64S-22 or 64E-22.

Korean road paving uses this system through KS F 2389. Bitumen bought on a penetration or VG certificate may therefore need separate PG test results before it can be supplied to a Korean road project.

Because the three systems test at different temperatures and by different methods, there is no conversion table between them. Whether a product that passes one system meets a given grade in another can only be known by running the other system's tests.

Sources [9][10][11][12]

05 · Certificate review

Read the certificate's header before its numbers

If the standard, the sample or the testing party is wrong, numbers that are all within limits are still unusable. A certificate of analysis answers three questions before any value matters: judged against what, tested on which material, and by whom.

When you appoint a pre-shipment inspector, state “judge against Table X of standard Y”. Surveyors judge only against the criteria they are given.

Sources [1][5]

06 · From the field

Six misconceptions that sit outside the specification sheet

Getting the grade right is only the starting point. Working on bitumen and petroleum product deals from Middle Eastern origins, we found that most misunderstandings sit outside the specification. Some of these experiences are told at greater length in PentaBay's Korean field-notes blog (see sources).

Sources [13][14][15]

07 · Common errors

Six specification and inspection mistakes we see often

Each of these is cheap to prevent at the enquiry stage and expensive to argue about after arrival.

1. Grade without standard. Write “Penetration grade 60/70 per ASTM D946, softening point 48–56 °C additionally required” rather than “Bitumen 60/70”.
2. Judging a drum cargo on a tank sample. Certificates are often from a tank sample taken before filling. For drums, include random sampling from filled drums in the inspection scope. IS 73:2013 offers a reference: from containers of the same batch, select 3 for lots up to 50, 5 for 51–150, 7 for 151–500 and 10 for 501 or more.
3. Mixing net and gross weight. Drums and jumbo bags add packaging weight. State in the contract whether the price per ton is on net product or gross packed weight.
4. Confusing flash point units. The “450” in an ASTM-based specification is °F. Read as °C it becomes absurd; read the other way, a °C limit becomes far too loose.
5. Checking the destination standard too late. Korean road bitumen, for example, is managed by PG grade (KS F 2389) and KS M 2201. Product bought on penetration or VG grade may need separate PG results for a Korean road job, so obtain the end user's specification before signing.
6. Accepting a certificate without ageing tests. TFOT and RTFOT take time and are easy to skip, but they are the only results that show how quickly the binder will harden after paving.

Sources [1][5][12]

08 · Before you send an enquiry

A six-point checklist that makes quotes comparable

If every line below is answered, two quotes can be compared on the same product, the same weight basis and the same acceptance test. If any line is open, the cheaper quote may simply be answering a different question.

• Grade and standard written together, with edition (e.g. 60/70 per ASTM D946, VG-30 per IS 73:2013, PG 64-22 per AASHTO M320).
• Requirements beyond the standard listed separately (softening point, ageing limits).
• End user's specification — road authority or site — in hand.
• Packing (bulk, drums, jumbo bags) and weight basis (net or gross) decided.
• Inspection company, sampling point (tank or drums) and acceptance table agreed.
• Certificate units (P, Pa·s, °F, °C) aligned with the contract.

Sources [1][5]