Performance Grade (PG 58-16)
WHAT IS PG BITUMEN?
Performance Grade (PG) Bitumen is a type of bitumen classified based on its performance under specific temperature ranges, ensuring suitability for diverse climate conditions. This grading system helps in selecting bitumen that can withstand both extreme heat and cold without compromising its durability or flexibility. PG Bitumen is produced in compliance with international standards, including AASHTO M 320-10 and ASTM D6373-1, which set benchmarks for quality and performance.
INTRODUCTION OF BITUMEN PERFORMANCE GRADE
Traditionally, bitumen has been classified based on two primary parameters: penetration degree, indicating its hardness, and viscosity, which reflects its flow characteristics. Penetration is measured at 25°C, while viscosity is assessed at 60°C and 135°C, showcasing the material’s behavior under different conditions.
However, over time, the Strategic Highway Research Program (SHRP) identified a critical limitation in these methods. They realized that temperature was not adequately considered in traditional classifications, despite being a key factor in bitumen’s performance. Since bitumen’s behavior and durability are significantly influenced by temperature extremes, engineers introduced Performance Grade (PG) classification, which directly correlates bitumen properties to its performance in specific temperature ranges.
PG 58-16: APPLICATIONS AND SIGNIFICANCE
Performance Grade (PG) 58-16 bitumen is a versatile paving material tailored for regions with moderate climatic conditions. Its temperature range of 58°C maximum and -16°C minimum makes it suitable for areas experiencing neither extreme heat nor severe cold.
This grade is widely used in road construction, including highways, urban streets, and rural pathways, offering balanced performance against rutting and cracking. It is especially effective in climates where the pavement temperature does not exceed its high or low thresholds. Performance Grade (PG) 58-16 is also used in asphalt mixes for parking lots and driveways, delivering durability and longevity.
The bitumen’s moderate temperature sensitivity ensures effective performance in road maintenance projects like overlays and patching. Its cost-effectiveness and adaptability make it a preferred choice for regions with stable climate conditions, contributing to sustainable infrastructure development.
UNDERSTANDING PG GRADES IN BITUMEN
The Performance Grade (PG) system categorizes bitumen based on its performance under specific temperature conditions. Each PG grade represents the high and low pavement service temperatures it can withstand.
- High-Temperature Grade: Measured as the average pavement temperature over 7 consecutive days, ensuring the bitumen resists rutting, which develops gradually.
- Low-Temperature Grade: Determined by the minimum pavement temperature, addressing thermal cracking in cold conditions.
KEY DETAILS:
- PG grades are defined in 6°C increments (e.g., PG 64-10).
- A binder labeled as PG 64-10 is designed to perform at 64°C (high) and -10°C (low) pavement temperatures with 98% reliability.
- Maximum pavement temperatures are typically 20°C higher than air temperatures, measured about 1 inch below the surface.
PRACTICAL APPLICATION:
- Stiffer grades (e.g., polymer-modified binders) are used in high-traffic areas like highways, intersections, and bus stops to resist rutting and cracking.
- Polymer modification is essential when both high-temperature rutting resistance and low-temperature cracking resistance are needed.
For specific requirements and queries, consult experienced bitumen suppliers to select the right grade for your application.
PERFORMACE GRADE BITUMEN TESTS
The PG bitumen is tested based on the different methods of the AASHTO standard. For PG bitumen, 3 parameters which are related to rutting, fatigue and thermal cracking should be tested.
For PG bitumen, besides the solubility test, flash point test, specific gravity and softening point tests, there are new test methods including:
- Viscosity Determination of Bitumen Using Rotational Viscometer (RV)- AASHTO T 316
- Determining the Rheological Properties of Bitumen Using a Dynamic Shear Rheometer (DSR)-AASHTO T 315
- Determining the Fracture Properties of Bitumen in Direct Tension (DT) – AASHTO T314
- Determining the Flexural Creep Stiffness of Bitumen Using the Bending Beam Rheometer (BBR)-AASHTO T 313
- Test for Effect of Heat and Air on a Moving Film of Bitumen (Rolling Thin-Film Oven Test)-AASHTO T 240
- Accelerated Aging of Bitumen Using a Pressurized Aging Vessel (PAV)-AASHTO R 28
- Elastic Recovery Test- AASHTO T301
- Determining the Separation Tendency of Polymer from Polymer -Modified Bitumen – ASTM D7173
PACKAGING
Performance Grade (PG) 58-16 is available in 0.6 mm thickness, 180 kg net weight drums, 95 cm height and 45 cm diameter (+/- 3 kg operational tolerance).
TECHNICAL DATASHEET OF SBS MODIFID BITUMEN PG 58-16
| Specification | Unit | Value | Method |
|---|---|---|---|
| Average 7-Day Maximum Pavement Design Temperature | °C | <58 | – |
| Minimum Pavement Design Temperature | °C | > -16 | – |
| Flash Point Temperature | °C | MIN230 | AASHTO T48 |
| Viscosity Maximum 3 Pa.s, Test Temperature | °C | 135 | AASHTO T316 |
| Dynamic Shear G*/sin Minimum 2.2 KPa Test Temperature | °C | 58 | AASHTO T315 |
| Rolling Thin Film Oven Test (T 240) | |||
| Mass Change | % | MAX1.00 | AASHTO T240 |
| Dynamic Shear G*/sin Minimum 2.2 KPa Test Temperature, @10 rad/s | °C | 58 | AASHTO T315 |
| Pressure Aging Vessel (PAV) Test (AASHTO R28) | |||
| PAV Aging Temperature | °C | 100 | AASHTO R28 |
| Dynamic Shear G*/sin Maximum 5000 KPa Test Temperature, @10 rad/s | °C | 31 | AASHTO T315 |
| Creep Stuffiness S Maximum 300 Mpa M-Value Minimum 0.300 Test Temp,@60s | °C | -6 | AASHTO T313 |
| Direct Tension Failure Strain Minimum 1 % Test Temp@1mm/min, | °C | -6 | AASHTO T314 |
| Critical Low Cracking Temperature Critical Cracking Determined by PP42 Test Temp | – | -6 | AASHTO PP42 |
For more information or to inquire about specific grades, feel free to contact our team of bitumen experts.
