FAQ: What is AC Grade Bitumen?

❓ What is AC Grade Bitumen?

🛢️ AC Grade Bitumen stands for Asphalt Cement Grade Bitumen. It’s classified based on viscosity at 60°C, measured in poises. For example, AC-10 or AC-20 indicate viscosity values of 1000 and 2000 poises, respectively. This grading system ensures better temperature control and performance in asphalt mixtures.

❓ How is AC Bitumen different from VG Bitumen?

🔍 Although both grades are viscosity-based, AC Bitumen follows the American (ASTM) system, while VG Bitumen follows the Indian standard (IS:73). AC grading focuses strictly on viscosity at one temperature, which helps in regions that use Superpave mix designs. This makes AC Bitumen highly preferred in North America.

❓ Where is AC Grade Bitumen typically used?

🛣️ Engineers use it in hot mix asphalt, highways, expressways, and airport pavements. Because AC grades offer precise control over flow characteristics, they are excellent for temperature-sensitive regions. They also help reduce rutting and cracking under heavy traffic.

❓ What are the common AC Bitumen grades?

📊 The most used types include AC-2.5, AC-5, AC-10, AC-20, AC-30, and AC-40. The higher the number, the thicker and more viscous the bitumen. For instance, AC-30 is commonly used for high-traffic roads, while AC-2.5 suits cold climates or surface dressing.

❓ How do experts test the quality of AC Bitumen?

🧪 Quality is verified through viscosity testing at 60°C, softening point analysis, ductility tests, and flash point evaluation. These tests follow ASTM D3381 and other related standards. Testing ensures that each batch meets performance requirements for modern paving applications.