Sustainable road construction with B2Last^®

Reactive modification of bitumen

B2Last crosslinks bitumen components to form a polymeric network with strong elastic properties and excellent durability and crack resistance across a wide range of temperatures. B2Last is integrated into the polymeric network and is fully consumed during the reactive modification. 

The dosage amount for B2Last increases the elasticity and softening point, while the low-temperature behavior remains unchanged. The selection of the virgin bitumen enables the temperature properties to be adapted. This makes it possible to flexibly vary the performance of the binding agent across a wide range. 

Temperature-reduced installation through reactive modification  

B2Last is homogenized with bitumen during the manufacturing process of asphalt. The flow capability of the binding agent is initially increased through B2Last as a low-viscosity liquid. This enables the manufacturing and processing temperatures of the mixed product to be reduced without negatively affecting the compactability.

Throughout the transport and installation processes, reactive modification causes B2Last and bitumen to form a polymer network. Here, reactive groups in the bitumen components act as anchors for B2Last. In particular bitumen from asphalt granulate (AG) displays a high content of reactive groups, enabling high connectivity of virgin bitumen to recycled bitumen. This guarantees excellent workability of the mixed product, as well as enabling the use of high AG content. Following the complete compacting process and cooling of the asphalt, the reactive modification is complete and the asphalt displays its maximum stability.

The chemistry behind reactive modification

The components in bitumen form an interconnected network following reactive modification. This chemical networking primarily takes place between the contained resin and asphalt components. This is due to the fact that they possess a particularly high content of what are known as functional groups. It is on these groups that B2Last docks during the production and processing of the asphalt. 

Interaction with aged bitumen from asphalt granulate (AG)

The bitumen from recycled asphalt granulate displays a high content of asphalts and increased functionality. This aspect also has a positive effect on the reactive modification. B2Last can use this bitumen to establish an especially dense network and also establish good crosslinking of the different bitumen types. The binding agent becomes more homogeneous and allows excellent workability of the produced asphalt mix, even when it contains a high content of recycled asphalt.

Bitumen aerosols and vapors

B2Last enables asphalt mix production and laydown temperatures below 140 °C (warm mix asphalt) and thereby reduces bitumen aerosols and vapors. For asphalt applications, a reduction in emissions on the site of up to 65% can be achieved compared to a reference project performed at around 170 °C (hot mix asphalt). B2Last can therefore make an important contribution to complying with the limit value of 1.5 mg/m³ which will apply in Germany from 2025. 

Product safety

We value the health and safety of people above all else – in all plant trials, we instruct our customers on safe processing and handling the product. The product emissions are also recorded during the manufacturing and processing steps of B2Last modified mixtures. Here, the numerous measurements in practice confirm that the emissions produced during the manufacturing of modified mixtures with B2Last are significantly below those of the maximum permitted workplace concentrations.