VG bitumen application is decided by two things: the air temperature the pavement will live in, and the traffic it will carry. Everything else follows from those. This guide gives the full IS 73:2013 specification for all four grades, the selection matrix Indian and South Asian engineers actually use, the mixing and compaction temperatures for each grade, and what goes wrong when the grade is chosen on price rather than on climate.
What VG bitumen is and why the grading changed
VG stands for viscosity graded. The grade number is the target absolute viscosity in hundreds of poise measured at 60 °C, so VG-30 targets roughly 3,000 poise. That single temperature was chosen deliberately: 60 °C approximates the maximum pavement temperature in a hot climate, which is the condition under which a binder either resists rutting or does not.
India moved from penetration grading to viscosity grading in 2006 with the revision of IS 73, and the current version is IS 73:2013. The reason for the change matters to anyone specifying VG bitumen application today. Penetration grading measures consistency at 25 °C, which tells you very little about how a binder behaves at road surface temperature. Two binders can both meet 60/70 at 25 °C and behave completely differently at 60 °C, because penetration says nothing about temperature susceptibility. Viscosity grading closed that gap.
IS 73:2013 also grades on the aged binder rather than only the fresh one. Every grade carries a viscosity ratio limit after RTFOT ageing and a ductility requirement on the aged residue. That is what separates viscosity grading from the older systems: it tests the binder in something closer to its service condition.
Where VG grades are specified
India is the primary market, under IS 73 and the MoRTH Specifications for Road and Bridge Works. Bangladesh, Nepal and Sri Lanka use the same system. Beyond South Asia, VG grades appear in tenders across East and West Africa and parts of the Middle East, usually where Indian contractors or Indian-trained engineers are running the project. If you are quoting into those markets, expect VG rather than penetration grade.
VG bitumen specification: IS 73:2013
These are the requirements every grade must meet. Any certificate of analysis that does not show these tests against these limits is not certifying to IS 73.
| Property | VG-10 | VG-20 | VG-30 | VG-40 |
|---|---|---|---|---|
| Absolute viscosity @60 °C, poise | 800–1200 | 1600–2400 | 2400–3600 | 3200–4800 |
| Kinematic viscosity @135 °C, cSt, min | 250 | 300 | 350 | 400 |
| Penetration @25 °C, dmm, min | 80 | 60 | 45 | 35 |
| Softening point, °C, min | 40 | 45 | 47 | 50 |
| Flash point (Cleveland), °C, min | 220 | 220 | 220 | 220 |
| Solubility in trichloroethylene, %, min | 99.0 | 99.0 | 99.0 | 99.0 |
| Viscosity ratio @60 °C after RTFOT, max | 4.0 | 4.0 | 4.0 | 4.0 |
| Ductility @25 °C after RTFOT, cm, min | 75 | 50 | 40 | 25 |
Test methods are those referenced in IS 73:2013, published by the Bureau of Indian Standards. Absolute viscosity follows IS 1206 (Part 2), kinematic viscosity IS 1206 (Part 3), penetration IS 1203, softening point IS 1205 and ductility IS 1208. Where a project cites ASTM equivalents instead, the corresponding methods are ASTM D2171, D2170, D5, D36 and D113.
The two limits most people ignore
The viscosity ratio after RTFOT is the most useful number on the certificate and the one buyers most often skip. It tells you how much the binder hardens during mixing and laying. A ratio close to 4.0 means the binder is already near its ageing limit before the road has seen any traffic. A ratio around 2.5 to 3.0 leaves headroom for the pavement’s service life.
The ductility on the aged residue is the second. VG-40 only has to reach 25 cm, which sounds low until you realise it is measured after ageing. A binder that fails this is brittle before it ever goes down, and brittleness is what produces cracking two winters later.
Selecting the right grade: climate and traffic
This is the part that decides whether a VG bitumen application succeeds. IS 73:2013 sets out a selection framework based on air temperature, and IRC:37 layers traffic loading on top of it.
Selection by air temperature
| Highest daily mean air temperature | Lowest daily mean air temperature | Recommended grade | Typical regions |
|---|---|---|---|
| Below 20 °C | Below −10 °C | VG-10 | Himalayan states, high altitude, temperate uplands |
| 20 to 30 °C | Above −10 °C | VG-10 or VG-20 | Coastal temperate zones, hill regions |
| 30 to 37 °C | Above −10 °C | VG-30 | Most of the Indian plains, Bangladesh, Sri Lanka |
| Above 37 °C | Above −10 °C | VG-30 or VG-40 | Rajasthan, Gulf, Sahel, arid interiors |
Selection by traffic loading
Climate sets the floor; traffic can push you a grade harder. Design traffic is expressed in million standard axles (MSA) over the design life.
| Design traffic | Road type | Grade | Note |
|---|---|---|---|
| Below 10 MSA | Rural roads, low-volume district roads | VG-10 / VG-20 | Climate governs. Softer binder gives better workability on small jobs |
| 10 to 30 MSA | State highways, urban arterials | VG-30 | The default across most of South Asia |
| Above 30 MSA | National highways, expressways | VG-40 | Or a modified binder where the temperature range is wide |
| Any, with slow or standing loads | Intersections, toll plazas, bus bays, ports | VG-40 | Slow loading is more damaging than fast loading at the same axle weight |
Where climate and traffic point to different grades, take the harder one — but check that the low-temperature end still works. A pavement in a location with 42 °C summers and 2 °C winters carrying 40 MSA is asking a single unmodified binder to cover a very wide range. That is the point at which polymer modified bitumen becomes the correct answer rather than a more expensive one.
What happens when the grade is wrong
Grade selection errors do not show up at handover. They show up in the second or third year, and by then the cause is hard to prove. These are the two failure directions.
| Error | What you see | When it appears | Why it happens |
|---|---|---|---|
| Binder too soft for the climate | Rutting in the wheel paths, shoving at intersections, bleeding and fatty patches in summer | First or second hot season | At 60 °C the binder viscosity is too low to resist shear under load |
| Binder too hard for the climate | Transverse and block cracking, ravelling, aggregate loss, poor chip retention | Second or third winter | Insufficient flexibility at low temperature; the binder cannot accommodate thermal contraction |
| Grade correct, viscosity ratio high | Premature ageing, surface cracking earlier than design life | Years two to four | Binder was already near its ageing limit on delivery |
| Overheated during mixing | Same as too hard, plus fume and smoke during laying | Immediate to first winter | Mixing above the recommended range hardens the binder before it reaches the road |
The last row is worth dwelling on, because it is the one failure that is entirely within the contractor’s control. A correctly specified VG-30 mixed at 190 °C arrives on the road behaving like VG-40. The specification was right; the execution destroyed it.
Mixing, laying and compaction temperatures
These ranges follow the MoRTH Specifications for Road and Bridge Works. They are not suggestions — the viscosity ratio limit in IS 73 assumes the binder is handled inside them.
| Grade | Binder temperature | Aggregate temperature | Mixed material | Laying, min | Rolling, min |
|---|---|---|---|---|---|
| VG-10 | 140–160 °C | 140–165 °C | 140–160 °C | 120 °C | 90 °C |
| VG-20 | 150–170 °C | 150–175 °C | 150–170 °C | 130 °C | 100 °C |
| VG-30 | 150–170 °C | 150–175 °C | 150–170 °C | 130 °C | 100 °C |
| VG-40 | 160–180 °C | 160–185 °C | 160–180 °C | 140 °C | 110 °C |
Storage temperature is a separate question
Mixing temperature and storage temperature are not the same thing, and confusing them is expensive. A tank of VG-30 held at mixing temperature over a weekend loses penetration measurably. For holds longer than a few days, drop to 110–125 °C with circulation running and bring the temperature back up shortly before use. Our bitumen shelf life and storage guide covers the full picture, including how long each product stays on specification and how to retest material that has been sitting.
VG bitumen application by work type
Dense bituminous macadam and bituminous concrete
The main structural application and where most VG tonnage goes. VG-30 is the default for DBM and BC across the Indian plains. VG-40 replaces it on expressways, on approaches to toll plazas and anywhere the traffic is heavy and slow. Binder content typically runs 4.5 to 5.5 percent by weight of total mix, set by the Marshall mix design rather than by the grade.
Bituminous macadam and built-up spray grout
Coarser, more open mixes used as base and binder courses. VG-30 in hot regions, VG-10 or VG-20 in cooler ones. The open grading means the binder film is exposed to more air, so the viscosity ratio matters more here than in a dense mix.
Surface dressing and penetration macadam
Chip seals and surface dressing need a binder that wets the aggregate and holds the chip. VG-10 is the usual choice because low viscosity at spraying temperature gives better coverage. Aged or over-hard binder is the most common cause of chip loss in the first winter.
Micro surfacing and slurry seal
These use bitumen emulsion rather than hot binder directly, but VG-10 is the typical base for producing the emulsion. Softer base bitumen gives a more stable emulsion and better early-strength development.
Prime and tack coats
VG-10 is the base for cutback bitumen prime coats and for tack coat emulsions. Nothing harder is appropriate — a prime coat has to penetrate the granular base, and a viscous binder sits on the surface instead of soaking in.
Waterproofing and roofing
VG grades appear in waterproofing specifications in South Asia, though oxidized grades and SBS and APP membrane are the technically better answer for most roofing work. Where a VG grade is specified for damp proofing or protective coating, VG-10 in temperate conditions and VG-30 where the surface will see high temperatures.
VG grades and their penetration grade equivalents
Buyers moving between markets ask for this constantly. The correspondence is real but it is not an equivalence, and treating it as one causes tender problems.
| VG grade | Typical penetration match | Typical PG match | Typical AC match |
|---|---|---|---|
| VG-10 | 80/100 | PG 58-16 | AC-10 |
| VG-20 | 70/100 | PG 58-22 to PG 64-22 | AC-20 |
| VG-30 | 60/70 | PG 64-22 | AC-20 to AC-30 |
| VG-40 | 40/50 | PG 70-10 | AC-40 |
A binder meeting 60/70 does not automatically pass VG-30. Penetration grading measures consistency at 25 °C on unaged binder; VG grading measures viscosity at 60 °C and also imposes limits on the aged residue. If your contract names VG-30 to IS 73, the certificate of analysis has to show VG-30 tested to IS 73. A certificate showing 60/70 to EN 12591 does not satisfy it, however close the material actually is. Our bitumen grade equivalence chart sets out the full cross-reference and explains where each correspondence breaks down.
What to check before you accept a VG bitumen cargo
- The standard named on the certificate. It must say IS 73:2013, not “equivalent to” or “conforming to Indian standards”.
- A batch number and production date. A certificate showing only typical values describes a grade, not the cargo in front of you.
- Absolute viscosity as a measured figure, not a range copied from the specification table.
- The viscosity ratio after RTFOT. If it is missing, the binder has not been tested to IS 73 properly.
- Ductility on the aged residue, not on the fresh binder. The distinction matters.
- Third-party inspection where the value justifies it. Sampling follows ASTM D140 or IS 1201.
Frequently asked questions about VG bitumen application
What does VG stand for in bitumen?
Viscosity graded. The number is the target absolute viscosity in hundreds of poise at 60 °C, so VG-30 targets around 3,000 poise. The 60 °C test temperature approximates maximum pavement temperature in a hot climate, which is the condition that governs rutting resistance.
Which VG grade should I use for hot climates?
VG-30 where the highest daily mean air temperature is 30 to 37 °C, and VG-40 above 37 °C or wherever traffic exceeds 30 MSA. VG-40 is also the correct grade at intersections, toll plazas and bus bays regardless of the general climate, because slow and standing loads are more damaging than fast ones at the same axle weight.
Which VG grade is used for cold climates?
VG-10 where the highest daily mean air temperature stays below 20 °C or the lowest falls below −10 °C. VG-10 or VG-20 in the 20 to 30 °C band. Using a harder grade in a cold climate produces transverse cracking and ravelling in the second or third winter.
Is VG-30 the same as 60/70 bitumen?
They usually correspond in practice but they are not the same specification. VG-30 is defined by absolute viscosity of 2,400 to 3,600 poise at 60 °C under IS 73:2013, plus limits on the aged residue. 60/70 is defined by penetration of 60 to 70 dmm at 25 °C on unaged binder. If your contract names VG-30, the certificate must show VG-30 tested to IS 73.
What is the difference between VG-30 and VG-40?
VG-40 is harder and more viscous — 3,200 to 4,800 poise at 60 °C against 2,400 to 3,600 for VG-30 — with a higher softening point and a lower minimum penetration. VG-40 resists rutting better under heavy and slow traffic, but it is less forgiving at low temperature and needs higher mixing and compaction temperatures.
What is the mixing temperature for VG-30?
Binder at 150 to 170 °C, aggregate at 150 to 175 °C, mixed material at 150 to 170 °C, laying at 130 °C minimum and rolling at 100 °C minimum. Mixing above the range hardens the binder before it reaches the road, which produces the same failures as specifying a grade that is too hard.
What is the viscosity ratio and why does it matter?
It is the ratio of absolute viscosity at 60 °C after RTFOT ageing to the viscosity before ageing, and IS 73 caps it at 4.0 for every grade. It measures how much the binder hardens during mixing and laying. A binder arriving with a ratio close to the limit has little headroom left for its service life, so a figure around 2.5 to 3.0 is materially better than one at 3.9 even though both pass.
Can VG bitumen be used for waterproofing?
It can, and VG grades appear in South Asian damp proofing and protective coating specifications. However, oxidized grades and SBS or APP modified membrane are technically better suited to roofing work because they hold a much higher softening point without flowing. Where a VG grade is specified, use VG-10 in temperate conditions and VG-30 where the surface will get hot.
Which countries specify VG bitumen?
India under IS 73 and the MoRTH specifications, plus Bangladesh, Nepal and Sri Lanka. VG grades also appear in tenders across East and West Africa and parts of the Middle East, generally where Indian contractors or Indian-trained engineers are running the project.
How long does VG bitumen stay on specification in storage?
Around 24 months in sealed drums stored upright, on pallets and under cover. In bulk hot storage the useful window is three to five days at working temperature; beyond that, drop to a holding temperature of 110 to 125 °C with circulation. Retest absolute viscosity and penetration against the batch certificate before using material older than a year.
What is the minimum order quantity and how is it packed?
100 MT, which is roughly seven 20-foot containers of drummed product or five bulk bitutainers. Packing options are 180 kg and 200 kg new steel drums, 300 kg jumbo bags and bulk bitutainers. Mixed grades in one shipment are accepted provided each grade reaches one full container.
Can you certify against IS 73:2013?
Yes. Every shipment carries a batch certificate of analysis stating the lot number, the production date and each test with its method and measured result against IS 73:2013. We also accept third-party inspection at loading by SGS, Bureau Veritas, Intertek or the surveyor named in your contract.
Reference standards
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IS 73:2013
Paving bitumen specification, published by the Bureau of Indian Standards. Defines all four VG grades and the test requirements.
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MoRTH Specifications
Specifications for Road and Bridge Works from the Ministry of Road Transport and Highways. Sets mixing, laying and compaction temperatures.
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IRC:37
Guidelines for the design of flexible pavements from the Indian Roads Congress. Traffic-based binder selection.
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ASTM equivalents
Where a project cites ASTM rather than IS methods, the corresponding standards are maintained by ASTM International.
Related product and technical pages
Grade-level specifications and typical test values: VG-10, VG-20, VG-30 and VG-40. For cross-referencing against other grading systems, see the bitumen grade equivalence chart. For penetration grades, see penetration grade bitumen. For storage limits and retesting, see the bitumen shelf life and storage guide. Country-level supply detail is on the global bitumen supply guide.
Send us the specification, not just the grade name
Tell us the destination climate, the design traffic and the standard your contract names. We will confirm which VG grade fits, tell you whether a modified binder would serve you better, and issue a batch certificate of analysis against IS 73:2013. If two grades would both work and one is cheaper, we will say which.
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