Most modern flexible pavements use paving-grade bitumen, typically penetration grades such as 50/70 or 60/70, viscosity grades like VG-30 or VG-40, or performance-graded binders such as PG 64-22. In practice, the bitumen is used in road construction in different grades selected according to climate, traffic loading, and national specifications.
Highlights & Key Sections
Understanding what “road bitumen” actually is
Before choosing a grade, it helps to clarify what we mean by “bitumen” in roads.
Bitumen = the black, sticky binder from crude oil that glues mineral aggregates together.
Asphalt (asphalt concrete) = bitumen + aggregates (and sometimes additives).
Flexible pavements (most highways and city streets) rely on bitumen as the primary binder.
In a typical asphalt pavement structure, bitumen appears in:
Prime and tack coats (very fluid binders, often cutbacks or emulsions).
Binder and surface course mixes (paving-grade or modified bitumen).
Seals and maintenance layers (emulsions, polymer-modified surface treatments).
So when engineers ask which bitumen is used in road construction, they usually mean:
“Which paving-grade or modified bitumen should be used in the asphalt layers of a specific road?”
Which bitumen is used in road construction for typical highways?
There is no single universal grade. Instead, families of paving-grade binders are used, with specific grades chosen to suit climate and traffic. In most national standards, the bitumen is used in road construction in one of these groups:
Penetration grades – e.g., 40/50, 50/70, 60/70, 80/100. Classic “paving bitumen” widely used worldwide.
Viscosity grades (VG) – e.g., VG-10, VG-20, VG-30, VG-40, now standard in India and many Asian/African markets.
Performance grades (PG) – e.g., PG 58-28, PG 64-22, PG 70-22, PG 76-22, used under Superpave-type systems in the US and many other countries.
Polymer-modified and rubber-modified binders – PMB, SBS-modified, crumb-rubber modified bitumen for heavy traffic and harsh climates.
Quick comparison of common road bitumen types
| Bitumen type | Typical grades | Where it’s common | Main use in roads |
|---|---|---|---|
| Penetration grade | 40/50, 50/70, 60/70, 80/100 | Europe, Middle East, parts of Asia | General highways, city roads, surface courses |
| Viscosity grade (VG) | VG-10, VG-20, VG-30, VG-40 | India, Middle East, Africa | Binder/surface course, hot regions, heavy traffic |
| Performance grade (PG) | PG 58-28, 64-22, 70-22, 76-22 | North America, many modern specs | Climate-specific, high-performance pavements |
| Polymer-modified (PMB) | e.g., PG 76-22 PM, PMB 40 | High-volume and urban networks | Rutting/fatigue resistance, bridges, bus lanes |
| Bitumen emulsions/cutbacks | CSS-1, CRS-2, MC-30, etc. | Global | Prime/tack coats, cold or maintenance works |
A very typical pattern in many countries today:
Standard highways → VG-30 or 60/70 pen (or PG 64-22 under PG systems).
Very heavy traffic or hot deserts → VG-40, 40/50 pen, or PG 70-22 / PG 76-22, often polymer-modified.
Cold regions → softer penetration grades (80/100) or PG binders with lower temperature ratings such as PG 58-34.
How bitumen grades are classified in practice
Globally, three main grading systems coexist: penetration, viscosity and performance grading. Understanding them helps you “translate” between countries and suppliers.
1. Penetration grading
Older but still widely used (e.g., 50/70, 60/70).
Grade reflects the needle penetration in tenths of a millimetre at 25 °C
Lower penetration number = stiffer bitumen.
Typical practice:
60/70 → moderate climates and traffic.
40/50 or 50/70 → hotter regions and/or higher traffic loading.
2. Viscosity grading (VG system)
Many authorities have moved from penetration to viscosity grading to better control performance at high temperatures. India’s IS 73:2013 explicitly grades paving bitumen by viscosity at 60 °C and links grade to the 7-day average maximum air temperature.
Example (IS 73:2013):
| Grade | 7-day average max air temp (°C) | Typical use in roads |
|---|---|---|
| VG-10 | < 30 | Cold regions, spray applications, emulsions |
| VG-20 | 30–38 | Cool–warm climates, medium traffic |
| VG-30 | 38–45 | Hot regions, standard highways and expressways |
| VG-40 | > 45 | Very hot climates, heavy/slow traffic areas |
3. Performance grading (PG system – Superpave)
The PG system classifies binders by the pavement temperatures they must withstand, not just lab penetration or viscosity. The designation, for example PG 64-22, means:
64 → high pavement design temperature (°C)
-22 → low pavement design temperature (°C)
Key points:
Grades chosen using long-term climate data (often 100-year climate record).
Heavier traffic or slow-moving traffic may need one or two grades stiffer than climate alone suggests.
Mini tutorial: choosing which bitumen is used in road construction
Here’s a practical 5-step method that pavement designers and buyers can use almost anywhere.
Step 1 – Define the project
New highway, rehabilitation, urban street, or industrial yard?
Design traffic (ESALs or heavy truck %)?
Design life (often 15–25 years for major roads)?
Step 2 – Characterize climate
Obtain 7-day max pavement temperature and minimum pavement temperature – from local codes or tools.
In hot, sunny climates, remember pavement can be 20 °C hotter than air.
Step 3 – Choose base grade
Use national guidance where available (e.g., IS 73, AASHTO, local road agency manuals).
Illustrative mapping (conceptual):
| Climate / traffic | Pen or VG example | PG example |
|---|---|---|
| Mild climate, light traffic | 80/100 pen or VG-10 | PG 58-22 |
| Mild climate, heavy traffic | 60/70 pen or VG-20 | PG 64-22 |
| Hot climate, heavy traffic | 40/50 pen or VG-30/VG-40 | PG 70-22 or PG 76-22 |
| Very cold climate | 80/100 pen, softer PG | PG 58-34 or PG 52-40 |
Step 4 – Decide on modification
Choose polymer-modified or rubber-modified bitumen when you need:
High resistance to rutting in wheel-paths.
Better fatigue life on thin or heavily-loaded pavements.
Improved low-temperature cracking resistance.
Step 5 – Align with mix design and specs
Confirm the binder grade is compatible with mix design (aggregate gradation, RAP/RAS content).
Check project specifications for allowed binder families (PG vs VG vs pen).
Lock in test requirements (DSR, BBR, MSCR, etc.) with the supplier.
Real-world examples of which bitumen is used
Example 1 – Four-lane expressway in a hot region
Climate: 7-day max air temperature ~42 °C, surface temperatures around 70 °C.
Traffic: High truck percentage, slow sections near toll plazas.
Typical binder choices:
Base option: VG-30 or 40/50 pen.
Enhanced option: PG 76-22 PMB or equivalent polymer-modified grade to control rutting at slow speeds.
Example 2 – Urban arterial with many intersections
Frequent braking and turning → high strain in the top 50 mm.
Good candidates: stiffer and modified binders in the wearing course, such as VG-40 or PMB/CRMB in a PG 70-22 or PG 76-22 class.
Example 3 – Low-volume rural road in a cold climate
Low traffic but repeated freeze–thaw cycles.
Softer binders (e.g., 80/100 pen, PG 58-34) help avoid thermal cracking; emulsions are used for surface treatments and cold mixes.
These examples show how one project might legitimately use different bitumen grades in prime coat, binder course, and surface course, even though they all belong to the same overall road.
Industry trends: from conventional bitumen to high-performance binders
Two big trends are reshaping which bitumen is used in road construction worldwide.
1. Shift to performance and modified binders
Many agencies have migrated from pure penetration grades to viscosity and PG systems to reduce premature rutting and cracking.
Polymer-modified bitumen (PMB) is now standard on many high-volume corridors, improving fatigue and thermal cracking resistance.
Crumb rubber–modified binders also show strong fatigue resistance while recycling waste tires.
2. Sustainability, AI and advanced testing
Recent work combines advanced rheological testing with machine learning to optimize modified binders for hotter climates and heavier loads, helping agencies adapt to climate change.
Wider use of RAP/RAS pushes agencies to control effective binder grade more precisely.
New additives and PMB systems aim to balance lower production temperatures, lower emissions, and equal or better rutting and fatigue performance.
For buyers and engineers, this means the “default” answer to which bitumen is used in road construction is increasingly:
“A PG or VG grade, often polymer-modified, tailored to local climate, traffic and sustainability targets.”
Buyer’s guide: turning specifications into a purchase order
When you move from design to procurement, focus on translating the technical grade into a clear, enforceable order.
1. What to specify
Include at least:
Binder family – Pen, VG, PG, PMB, CRMB, emulsion, etc.
Exact grade – e.g., VG-30, PG 64-22, PMB 40, CRS-2.
Relevant standards – national (e.g., IS 73, EN 12591, AASHTO M320) and any local modifications.
Test limits – penetration/viscosity, softening point, DSR/BBR, MSCR where applicable.
2. Quality control and documentation
Request from the supplier:
Certificate of Analysis (CoA) for each batch.
Sampling and testing plan tied to project stages (plant, site storage, paving).
Confirmation of storage stability for modified binders (no phase separation, proper mixing instructions).
3. Handling and storage checklist
Match storage temperature to binder type; avoid overheating PG and PMB grades.
Ensure insulated tanks and proper circulation for PMB and CRMB.
Keep emulsions below boiling, protected from freezing, and avoid contamination with other binders.
Good procurement practice ensures the bitumen delivered to site actually matches the grade assumed in your pavement design.
Executive summary & practical checklist
In daily practice, bitumen is used in road construction mainly as standardized paving and modified grades. Choosing correctly can add years of life to a pavement and significantly reduce whole-life cost.
Executive summary
For most flexible pavements, you’ll use paving-grade bitumen (pen, VG or PG), sometimes polymer- or rubber-modified.
Grade selection must consider climate, traffic, and national standards, not just price.
Performance-based systems (PG + PMB, CRMB) are gaining ground due to better rutting and cracking control.
On-site checklist
Use this quick checklist before finalizing which bitumen is used in road construction for your project:
Have we defined climate and traffic clearly?
Is there an official local guideline (VG/PG/pen) we must follow?
Does the chosen grade match our mix design and RAP/RAS content?
Do we need PMB or CRMB for rutting or fatigue control?
Are QC tests and acceptance criteria clearly written in the contract?
Have storage, transport and heating conditions been agreed in writing?
Is the supplier able to provide consistent batches at the required volume?
If you can confidently tick each item, the chances are high that your selected bitumen grade will perform as designed on the road.
FAQ: bitumen for road construction
1. Which bitumen grade is most commonly used for road construction?
In many markets, standard highways and city streets use 60/70 penetration grade, VG-30 or PG 64-22 class binders. These grades balance stiffness at high temperatures with enough flexibility to resist cracking under typical traffic and climate conditions.
2. Why do some specifications still use penetration grade while others use VG or PG?
Penetration grading is simple and familiar, but it doesn’t fully capture performance at high and low temperatures. Viscosity and PG systems better correlate binder properties with field conditions, so many agencies are gradually moving from pen to VG and PG while still allowing pen grades for less demanding applications.
3. Is polymer-modified bitumen always better for roads?
Not always. Polymer-modified bitumen usually offers better rutting, fatigue and crack resistance, but it costs more and needs careful handling. It is most cost-effective on heavily loaded, strategic, or urban roads where conventional binders would deteriorate too quickly. For low-volume rural roads, unmodified grades are often adequate.
4. What grade of bitumen is preferred in very hot climates?
In hot climates, engineers usually choose stiffer binders: lower-penetration grades (e.g., 40/50), higher VG grades (VG-30, VG-40) or PG grades like PG 70-22 or PG 76-22. These binders resist rutting and bleeding at elevated pavement temperatures while still providing workable mixes.
5. Which bitumen is used in road construction for cold regions?
Cold regions use softer binders (higher penetration values or PG grades with very low temperature ratings, such as PG 58-34). Softer binders tolerate thermal contraction without cracking and help pavements survive freeze–thaw cycles and low-temperature stresses.
6. What is the role of bitumen emulsions in road construction?
Bitumen emulsions are used mainly for prime coats, tack coats, cold mixes and surface treatments. They allow application at lower temperatures than hot bitumen, reduce energy consumption, and are especially useful for maintenance, rural roads, or where rapid opening to traffic is needed.
7. How do reclaimed asphalt (RAP) and recycled shingles (RAS) affect binder selection?
RAP and RAS bring aged, stiff binder back into the mix. Designers must adjust the virgin binder grade to achieve the desired overall stiffness. That often means selecting a slightly softer virgin grade or using rejuvenators and advanced PG/MSCR testing to ensure long-term performance.
8. When should crumb rubber–modified bitumen be used?
Crumb rubber–modified binders are chosen when agencies want improved fatigue resistance, noise reduction, and recycling of waste tires. They are popular in surface courses for highways and urban arterials where both performance and sustainability are priorities, but they require compatible plant equipment and handling procedures.
9. Are cutback bitumens still used for roads?
Cutbacks (bitumen diluted with solvents) are still used in some regions for prime coats and cold-weather work, but many agencies are phasing them out due to VOC emissions and environmental concerns. Emulsions are increasingly preferred as a safer, more sustainable alternative.
10. How often should specifications for road bitumen be updated?
Because traffic patterns, climate data, and testing technologies evolve, many road agencies review their binder specifications every 5–10 years. Regular updates allow them to incorporate new performance tests, climate projections and sustainability requirements, ensuring that selected grades remain fit for purpose.
References
Emperador
Types of Bitumen Used in Road Construction – A practical overview of various bitumen types by road layer (prime, binder, tack, surface, seal).
https://emperador-ae.com/types-of-bitumen-used-in-road-construction/Bureau of Indian Standards
IS 73:2013 – Paving Bitumen – Specification – Defines viscosity-based VG grades related to climatic conditions and mandatory test requirements.
https://law.resource.org/pub/in/bis/S11/is.73.2013.pdfGabbert, C., Missouri Asphalt Pavement Association
The Basics of Asphalt Binders – Training document explaining penetration grading, viscosity grading, and the PG system.
https://moasphalt.org/wp-content/uploads/2023/03/chase-THE-BASICS-OF-ASPHALT-BINDERS.pdfTutu, K.A., et al.
Superpave Performance Graded Asphalt Binder Selection for Asphalt Mixture Design in Ghana, Scientific African, 2022 – Climate-based PG grade selection methodology.
https://www.sciencedirect.com/science/article/pii/S2468227622002551Yang, Q., et al.
A Review of Polymer-Modified Asphalt Binder: Modification Mechanism, Properties and Performance, 2024 – Comprehensive review of PMB advantages and testing methods.
https://www.sciencedirect.com/science/article/pii/S277239762400039X
2 Responses
Dear Sir
One of our Pokhara-Mugling road contractor Chinese Construction company required the following grade and quantity bitumen for Nepal. If you can supply then kindly quote your best price along with payment terms.
Bitumen : Quantity
VG30 10041MT
VG 10 1730MT
Port Name: Sirsiya Dry Port Birgunj Nepal Via Visakhapatnam Port India
Hello,
Please send your request to the following email:
sales@petronaftco.com