Performance of Bitumen 60/70 in Different Climatic and Traffic Conditions — A Comparative Study of Turkey, Dubai, and India
Introduction
Bitumen 60/70 is one of the most widely used penetration-grade bitumens in road construction and pavement maintenance worldwide. Classified under ASTM D5, the designation “60/70” indicates its penetration range (60–70 dmm) at 25°C. Despite its popularity and cost-effectiveness, the performance of this bitumen varies significantly under different climatic conditions, traffic loads, and environmental stresses. This article evaluates the performance of 60/70 bitumen in cold versus hot climates, high-traffic versus low-traffic roads, and high-stress versus low-stress conditions. Furthermore, it presents a comparative analysis across three distinct countries—Turkey (temperate to cold), Dubai, UAE (hot and arid), and India (hot and humid)—and offers tailored recommendations for optimal bitumen selection in each region.
1. Technical Characteristics of Bitumen 60/70
- Penetration (25°C): 60–70 dmm
- Softening Point (Ring & Ball): Typically 48–52°C
- Viscosity: Suitable for mixing at 150–160°C
- Adhesion: Generally good, but may degrade under moisture and heavy loading
- Fatigue and Thermal Cracking Resistance: Moderate
Bitumen 60/70 is designed for moderate temperature zones. Its performance deteriorates in extreme cold (leading to brittleness) or extreme heat (causing softening and rutting).
2. Performance in Different Climatic Zones
2.1. Cold Climates (e.g., Northern Turkey)
In cold regions, low temperatures increase bitumen stiffness, reducing flexibility and promoting thermal cracking during winter months. Bitumen 60/70, being relatively hard at low temperatures, exhibits poor performance in such environments.
- Key Issues: Surface cracking, reduced service life
- Recommendation: Use softer grades (e.g., 80/100) or polymer-modified bitumen (PMB) with low-temperature performance grading (e.g., PG 58-28 or PG 64-22)
2.2. Hot Climates (e.g., Dubai and much of India)
In hot climates, pavement surface temperatures can exceed 65–70°C. Under these conditions, 60/70 bitumen softens excessively, leading to permanent deformation (rutting) under traffic loads.
- Key Issues: Rutting, shear failure, bleeding
- Recommendation: Use harder grades (e.g., 40/50) or high-performance PMB with elevated high-temperature grading (e.g., PG 76-22 or PG 82-10)
3. Performance Under Different Traffic Conditions
3.1. High-Traffic and High-Stress Roads
On urban highways, freight corridors, or heavily loaded intersections, repeated heavy axle loads demand high rutting and fatigue resistance. Bitumen 60/70 often lacks sufficient elasticity and shear strength under such stress.
- Recommendation: Polymer-modified bitumen (PMB), high-viscosity bitumen (HVB), or crumb rubber-modified bitumen (CRMB)
3.2. Low-Traffic and Low-Stress Roads
In residential streets, rural roads, or areas with light vehicle usage, 60/70 bitumen performs adequately. Its ease of handling, workability, and lower cost make it economically favorable.
- Recommendation: Standard 60/70 bitumen is suitable without modification
4. Comparative Performance in Turkey, Dubai, and India
| Dominant Climate | Temperate to cold (north); hot & dry (south) | Hot & arid (pavement temps >70°C) | Hot & humid (high temp + high moisture) |
| Traffic Intensity | Moderate to high in cities | Very high in urban centers | Extremely high and mixed (including heavy vehicles) |
| 60/70 Performance | North: Poor (thermal cracking); South: Acceptable | Poor (severe rutting in summer) | Poor to moderate (rutting + moisture-induced stripping) |
| Key Challenges | Seasonal temperature swings | Extreme heat + UV radiation | Heat + moisture + overloaded vehicles |
| Optimal Bitumen Type | North: 80/100 or PMB (PG 58-28); South: 40/50 or PMB (PG 70-22) | PMB (PG 76-22 or higher) or oxidized bitumen | PMB with anti-stripping additives (e.g., PG 76-22 or PG 82-10) |
5. Country-Specific Recommendations
Turkey
- Northern Regions (Cold): Use softer bitumen (80/100) or low-temperature PMB (e.g., PG 58-28)
- Southern Regions (Hot): Use harder grades (40/50) or high-temperature PMB (e.g., PG 70-22)
- Note: Regional zoning in bitumen specification is essential due to climatic diversity
Dubai (UAE)
- Bitumen 60/70 is not recommended due to extreme summer temperatures and intense solar radiation
- Recommended: Polymer-modified bitumen (PMB 76-22 or higher) or specially formulated high-performance binders with UV stabilizers
India
- High ambient temperatures, monsoon moisture, and overloading create a complex stress environment
- Recommended: PMB with anti-stripping additives (e.g., hydrated lime or liquid anti-stripping agents) and high-temperature performance grading (PG 76-22 for most regions; PG 82-10 for southern/coastal zones)
6. Conclusion
Bitumen 60/70 remains a practical and economical choice for moderate climates and low-traffic applications. However, its limitations become evident under climatic extremes or heavy loading conditions.
- In Turkey, a region-specific approach is critical due to its climatic gradient.
- In Dubai, the extreme heat renders 60/70 unsuitable; high-performance modified binders are necessary.
- In India, the combination of heat, moisture, and traffic overload demands advanced bitumen formulations with enhanced durability and moisture resistance.
Therefore, bitumen selection should be based on local performance requirements, ideally using the Performance Grading (PG) system (AASHTO M 320), which accounts for both high- and low-temperature performance. Moving beyond traditional penetration grading toward performance-based specifications will significantly enhance pavement longevity and reduce lifecycle costs.
Suggested References
- ASTM D5 – Standard Test Method for Penetration of Bituminous Materials
- AASHTO M 320 – Performance-Graded Asphalt Binder Standard
- Ministry of Road Transport and Highways (MoRTH), India – Specifications for Bitumen and Mixes
- Turkish General Directorate of Highways (KGM) – Technical Guidelines for Pavement Materials
- Dubai Municipality – Road Construction and Materials Specifications (2023 Edition)
- Asphalt Institute Manual Series (MS-2, MS-22)
Author: Civil Engineer – Pavement Specialist
Date: October 30, 2025