B2Last® - Questions and Answers
At room temperature, B2Last is a low viscosity, black liquid. The additive neither contains water nor solvents.
As a reactive bitumen additive, B2Last crosslinks bitumen components to form a network. Thanks to its low viscosity and the addition of B2Last during processing at the mixing plant, lower mixture temperatures (WMA - warm mix asphalt) can be achieved.
This is in contrast to PmB in which an existing polymer is incorporated into the bitumen.
The dosage of B2Last can be selected depending on the desired properties and the bitumen used. Previously, a B2Last content of 1% to 3% with regard to the total binding agent has proven to be practical (equal to approx. 0.8 to 1.5kg per metric ton of mixture).
B2Last can easily be combined with other bitumen additives. The reaction modification of a polymer-modified bitumen (PmB), in particular, delivers excellent results, and the combined use with other additives, such as rejuvenators or waxes can create other positive properties. Generally, the compatibility of multiple components must be checked before they are used.
At storage temperatures of between 20 °C and 25 °C and excluding moisture, the shelf life of B2Last is at least 12 months. Storage is possible at temperatures of 0°C to 70°C, but this may reduce the storage period. Collecting troughs can also be used to protect against leakages.
A supply terminal for B2Last must be installed in the asphalt mixing plant in order to add the bitumen to the asphalt via pumping technology before it is processed. Other processes, such as batch times, storage or transport conditions, remain unchanged by the use of B2Last.
B2Last can be used in all asphalt layers (load-bearing, binder and top layers). The most experience gained with B2Last is based on stone mastic asphalt (SMA) and asphalt concrete (AC), however, use in other systems is conceivable. For example, use in mastic asphalt is currently being developed.
Despite the high content of asphalt granulate, mixtures modified with B2Last can be processed easily. This is due to the low viscosity of the binding agent and the resulting improved flow behavior. This also improves the behavior when tipping the mixture. As such, minimal cleaning is required for systems modified with B2Last.