**Viscosity Graded Bitumen**

Viscosity graded bitumen is a classification of asphalt based on the viscosity at a specific temperature. This grading system assesses the material’s resistance to flow under carefully controlled temperature conditions, which corresponds to its performance characteristics in terms of handling, application, and compaction. The viscosity of the bitumen plays a significant role in determining how well it will perform as a binder in road construction, influencing factors such as rutting, fatigue cracking, and the pavement’s ability to withstand various loading conditions.

The primary advantage of viscosity graded bitumen is that it gives a better description of the material’s behavior over a range of temperatures compared to the older penetration grade system. The specification involves measuring the viscosity of the bitumen at two different temperatures: 60°C, which approximates the maximum pavement temperature during summer, and 135°C, which is representative of the mixing and compaction temperatures during road construction. Based on the measurements, bitumen is classified under various grades such as VG-10, VG-20, VG-30, and VG-40, where the number indicates the viscosity range of the bitumen at 60°C.

For more detailed information on viscosity graded bitumen, you can visit the following websites:

1. **Asphalt Institute**: The Asphalt Institute is one of the premier sources of knowledge on asphalt technology. You can explore detailed expert resources on viscosity graded bitumen and its applications in modern road construction.

(https://asphaltinstitute.org/)

2. **The Association of Modified Asphalt Producers (AMAP)**: AMAP devotes significant resources to the understanding and advancement of modified asphalts, and their website provides comprehensive material on viscosity graded bitumen and related technologies.

(https://www.modifiedasphalt.org/)

Please note that websites may update their content or structure, so it is always a good idea to use their search function if the homepage does not provide direct links to the information you require on viscosity graded bitumen.