Bitumen-C600

Under AS 2008:1997, C600 is a Class 600 bitumen with a dynamic viscosity at 60°C of 500–600 Pa·s and a nominal kinematic viscosity of 600 mm²/s — the highest of the five standard AS 2008 classes. This extremely stiff binder has a softening point of 51–61°C and a penetration of only 30–60 dmm at 25°C, reflecting a hard, rigid binder comparable to the upper end of penetration grade bitumens or the AASHTO AC-40 / VG-40 IS 73:2013 specification in other systems. C600 is not a widely used general-purpose grade — its stiffness makes it challenging to mix and compact in cool conditions, requiring higher plant temperatures and tighter quality control. It is reserved specifically for applications where no softer grade can provide adequate performance: extreme heat, ultra-heavy traffic, or both combined. When properly specified and applied, C600 dramatically extends pavement service life and reduces whole-of-life maintenance costs in these demanding environments. C600 is also the standard base binder for producing the stiffest Austroads PMB grades (A60E equivalent) for the most demanding pavement wearing courses in Australia.