Description
Bitumen rubber is globally known to be the best modified binder from a rheological and a durability perspective. Due to its visco-elastic properties, the product must be handled at very high temperatures (relative to other binders used in similar applications) and it has a limited shelf-life at these elevated temperatures. Despite the excellent performance of the bitumen rubber product, it is often disregarded as a result of the complexity of the operation and the risk associated with the product. These concerns can be addressed by lowering the handling and application temperatures. The integration of a warm mix wax additive in bitumen rubber manufacturing, allows for lower handling and application temperatures. This is aligned with the global focus on the reduction of temperatures during asphalt manufacturing and paving, to improve worker health and safety, while reducing the carbon footprint. A “stabilized warm mix rubber asphalt binder” that can be produced at reduced temperatures with an increased stability over time is now possible with the use of innovative compounds of ground tyre rubber, swelling agents and warm mix wax additives. The combination of a Fischer-Tropsch wax additive and a swelling agent decreases the viscosity of the reacted binder significantly and improves the handling and compaction behaviour of the asphalt mixes. It further allows lowering the production and paving temperatures from ~200°C to ~160°C. This rubber compound technology overcomes current drawbacks of rubber modified asphalt enabling the use of this technological to deliver environmentally beneficial pavements.
