AR Bitumen

Viscosity test (AR) is based on ancient remains of rolling thin film oven test. AR system is designed to simulate the adhesion property of asphalt. So, it should be more representative of how asphalt binder behaves in HMA pavements.

Softening at high temperature and hardening at low temperature due to thermoplastic property are characteristic of viscosity grade. The temperature/viscosity relationship should be used to determine properties such as adhesion, rheology, temperature, durability. The ductility of the bitumen is emphasized by the VG Bitumen spec.

RTFOT Viscosity Grade Bitumen Binders (AR Bitumen) include:

Viscosity grade Bitumen AR-1000, 2000, 4000, 8000 and 16000.

The Viscosity of bitumen (asphalt) is measured at 60 degrees C (140 degrees F) after the roll on thin film oven test, is called RTFOT Viscosity Grade Bitumen (AR-Grades). It has thermoplastic properties which gets softer with heating and hardens when cooled.

Asphalt-Rubber (A-R) Binder specification:

Binder materials modify at least 15% of crumb rubber modifier (CRM) and are in accordance with the requirements of Item 300, Table 16. (These new tires are made from the remnants of recycled passenger and truck tires. The requirements for CRM are in Section 300.2.G. and Table 13.) To make this type of tires, we have to mix the asphalt with the rubber in specialized tanks and left it cook (digest) for an hour or more. It is classified into three types:  Types I, II, and III. As the number increase, the material gets softer for A-R Binders (opposite other designation nomenclatures).

American Society for Testing and Materials (ASTM) has defined Asphalt rubber (AR)   as a blend of hot paving grade asphalt cement, reclaimed tire rubber and additives. At least 15% of the liquid asphalt binder and has reacted to cause swelling of the rubber types.