Polymer Modified Bitumen grades are not a single product. They form a family of binders that differ by a defined set of properties rather than one number. Understanding how polymer modified bitumen grades are classified, what each property measures, and how a project specification determines the applicable grade is essential before comparing offers or reviewing a technical data sheet.
This article explains the overall PMB grading system. It covers classification, the nine nominal penetration ranges, the other properties that matter, and how grade selection connects to project requirements without becoming a product catalogue.
For technical details about the governing standard, see our companion article, EN 14023: Polymer Modified Bitumen (PMB) Classification Explained.
What Are PMB Grades?
A PMB grade is a specific combination of declared properties, not just a hardness value. Ordinary, unmodified bitumen typically uses penetration to classify its consistency. Penetration indicates how hard or soft the binder is at a reference temperature.
PMB classification is broader because polymer modification can affect more than hardness. It can also influence high-temperature behavior, low-temperature behavior, elastic recovery, and storage stability.
Therefore, polymer modified bitumen grades cannot be reduced to a single figure. A complete grade reflects a combination of properties selected to suit the project’s climate, traffic, and application requirements.
How EN 14023 Classifies Polymer Modified Bitumen Grades
EN 14023 provides a European framework for specifying polymer modified bitumens for roads, airfields, and other paved areas. Buyers working to another system, such as IS 15462 or an AASHTO Performance Grade classification, should confirm the standard and edition specified for their project.
Nominal Penetration Range
EN 14023 defines nominal penetration ranges measured in tenths of a millimeter (0.1 mm). These ranges describe the binder’s consistency at a standard intermediate temperature.
Minimum Softening Point
Alongside the penetration range, the framework defines minimum softening-point classes. Softening point describes how the binder behaves as temperature rises. This property relates to resistance to flow and deformation in hot conditions.
Why a Penetration Range Alone Isn’t a Complete Grade
A complete PMB designation combines the nominal penetration range with the applicable minimum softening-point class. For example, the standard’s informative example combines the 45/80 penetration range with a softening-point class of 60, written as PMB 45/80 60.
The range “45/80” identifies only one part of the classification. The complete grade and the full set of declared properties must match the applicable project specification.
For a detailed explanation of this classification system, see our EN 14023 classification article.
The Nine Nominal Penetration Ranges
EN 14023 recognizes nine nominal penetration ranges. These are ranges rather than complete grades. Each range becomes part of a full designation when combined with the applicable softening-point class.
As a general pattern, lower ranges such as 10/40 describe stiffer binders, while higher ranges such as 200/300 describe softer binders. However, this is only a general tendency. The governing project specification determines the applicable range.
What Penetration Tells You About Polymer Modified Bitumen Grades
Penetration measures how far a standard needle sinks into the binder under controlled load, time, and temperature. A lower value indicates a harder, stiffer binder, while a higher value indicates a softer binder.
For PMB, penetration describes consistency at intermediate temperatures. However, it represents only one part of the performance picture. Two binders with the same penetration range can still behave differently at high and low temperatures because of differences in softening point, elastic recovery, and other declared properties.
Why Softening Point Matters in PMB Grades
Softening point indicates the temperature at which the binder moves from a stiff, solid-like state toward a softer and more fluid state. The property helps describe binder behavior at elevated service temperatures.
Because projects require different performance characteristics, EN 14023 defines multiple softening-point classes rather than one fixed value.
The project specification determines which class applies. Buyers should not infer the softening-point class from the penetration range or assume that one class automatically suits a particular climate or traffic condition.
Other Properties That Define Polymer Modified Bitumen Grades
Elastic (Strain) Recovery
Elastic recovery measures the binder’s ability to return toward its original shape after stretching and release. This property relates closely to polymer modification, particularly elastomeric modification.
The applicable minimum value for elastic recovery depends on the project specification and complete grade designation. The penetration range alone does not determine it.
Storage Stability
In some PMB formulations, the polymer remains dispersed through the bitumen rather than forming a chemical bond with it. During prolonged hot storage, poor formulation or handling can allow separation.
Storage stability testing checks for this separation. As a result, storage stability forms an important part of the characteristics that buyers may need to review for PMB.
Durability and Low Temperature Behavior
PMB evaluation also considers changes in properties after simulated short-term ageing and the temperature at which the binder becomes brittle in cold conditions.
Together, these characteristics help describe expected binder behavior during production, application, and service across different temperature conditions.
How Project Specifications Determine the Right PMB Grade
EN 14023 provides selectable classes for different characteristics rather than one fixed specification. Therefore, the project specification determines the actual grade required.
Typical factors include:
- Traffic loading: volume, speed, and whether traffic flows freely or remains slow and standing.
- Pavement and climate conditions: the temperature range and environmental conditions the binder will experience.
- Application: wearing course, binder course, gap-graded mix, or a specialized use such as an airport or bridge deck surface.
- Required performance characteristics: elastic recovery, storage stability, durability, or low-temperature behavior.
- Governing standard or specification: EN 14023, IS 15462, AASHTO PG, or a national annex or project-specific document.
For project-level guidance, see our guide to choosing the right bitumen grade.
General Application Patterns Across the PMB Range
Polymer Modified Bitumen is generally specified where project requirements exceed what a conventional, unmodified binder can reliably deliver. However, the complete project specification determines the applicable PMB grade.
A project specification typically considers:
- Traffic loading.
- Pavement and climate conditions.
- Application, such as wearing course, binder course, gap-graded mix, airport surface, or bridge deck surface.
- Required performance characteristics, such as elastic recovery, storage stability, or low-temperature behavior.
- The governing standard or specification document.
Different PMB ranges may suit different project requirements. However, the applicable grade should always come from the complete project specification rather than the penetration range alone.
No penetration range is inherently suited to a particular traffic level, climate, or application in isolation. The complete designation combines the penetration range with the applicable softening-point class and other required properties.
Buyers and specifiers should use this article to understand how polymer modified bitumen grades work. They should then use the project specification, rather than a general hardness or softness rule, to determine the applicable grade.
How to Read a PMB Technical Data Sheet
When reviewing a PMB technical data sheet, check the information in a consistent order:
- Identify the stated nominal penetration range.
- Check the applicable minimum softening-point class together with the range. These values form the complete designation.
- Review the declared properties, including elastic recovery, storage stability, durability, and low-temperature behavior, together with the relevant test methods.
- Confirm the standard and edition that the data sheet quotes.
- Compare the data sheet with your project specification, rather than comparing it only with the standard in general.
Tiger Bitumen’s PMB Range: From Classification to Product
Tiger Bitumen supplies PMB across the nominal penetration ranges described above. The complete designation and applicable standard should be confirmed against each project’s specification.
Each range has a dedicated specification page:
Visit the Polymer Modified Bitumen (PMB) category to review the range and request a quotation.
Explore Tiger Bitumen’s Polymer Modified Bitumen Range
To request a quotation or technical documentation for a specific PMB grade, visit the bitumen quotation page and include your project specification.
Frequently Asked Questions
What is a PMB grade?
A PMB grade is a complete classification combining a nominal penetration range with an applicable minimum softening-point class, along with other declared properties such as elastic recovery and storage stability, as set by the governing standard and project specification.
How many PMB penetration ranges are there?
Under EN 14023, nine nominal penetration ranges are defined, from 10/40 up to 200/300.
Is a penetration range like 45/80 a complete PMB grade?
No. A penetration range identifies one part of the classification. The complete grade also requires the applicable minimum softening-point class, confirmed against the project specification.
What's the difference between penetration and softening point?
Penetration measures consistency at a standard intermediate temperature; softening point measures the temperature at which the binder begins to transition toward a softer, more fluid state relevant to performance at elevated temperatures.
Does a harder PMB grade always mean better performance?
No. Neither a harder nor a softer PMB grade is inherently “better.” The applicable PMB classification including the penetration range, the softening-point class, and any other required properties should always be determined by the complete project specification, not by hardness or softness considered on its own.
How is this different from the EN 14023 article?
This article covers the overall PMB grading system properties, the nine ranges, and how selection works. Our EN 14023 classification article covers the governing standard itself in technical depth, including test methods and the standard’s current edition status.
