Sustainable Road Construction


Use of Renewable, Modified or Recycled Raw Materials

Graphic: City view with buildings, street and construction vehicles Copyright: © ISAC

Conventional traffic surface structures mostly consist of asphalt. The basic building materials of asphalt (rocks, bitumen) are not renewable raw materials. The availability of bitumen is linked to crude oil production. The use of renewable raw materials in traffic surface construction succeeds, for example, through the use of plant-based or partially plant-based binders, such as polyurethane. However, studies and test methods for performance characterization still need to be developed in some cases for renewable raw materials for road construction.

An alternative approach results from the chemical modification of bitumen. In the manufacturing process, the fluidity of the bitumen is increased by adding this liquid, so that asphalt can be manufactured, laid and compacted at temperatures that have been lowered by up to 30 °C. During the cooling of the asphalt, the fluidity of the bitumen is increased. While the asphalt is cooling, a second reaction phase takes place in which the functional groups in the bitumen are crosslinked. The resulting chemical network improves the performance properties of the bitumen/asphalt (deformation stability, fatigue, adhesion) without negatively affecting the low-temperature behavior. Therefore, this bitumen additive promotes the use of asphalt granules and thus the safe and level use of recycled construction materials.


Sample Projects

AZwiSuB - Investigation of asphalt interlayers underneath concrete pavements

B2Last® - Improving bitumen performance through chemical modification

Durability of Layer Bond - Influence on the effectiveness and durability of layer composites when using viscosity-changing organic additives in asphalt