Sustainable road construction for safe driving
The road of the future already exists. Currently it's a small stretch of public road 1134 near Mühlacker in Baden-Württemberg, Germany. Measuring 120 meters long and 3.50 meters wide, what makes this test section special is its asphalt – a mixture containing bitumen and rubber from old tires. Bitumen is a black viscous mixture of hydrocarbons obtained naturally or as a residue from petroleum distillation. A new type of LANXESS additive makes the mixture work.
Bitumen, asphalt mixtures magic ingredient
Asphalt’s core ingredients are aggregate, bitumen, additives, and air. Bitumen is produced in various grades of hardness. Depending on the mix and grade of bitumen used, it is possible to lay road surfaces to meet a wide variety of requirements. Regional and climatic conditions play a key role in defining these.
- Bitumen, and consequently the asphalt mixture is hard at normal temperatures. During hot summers, however, it can deform, when, for example, heavy trucks drive over it.
- Harder grades of bitumen offer more dimensional stability. But asphalt mixtures containing a hard bitumen is more difficult to compact.
- Low noise asphalt pavement is particularly open-pored, absorbs tire noise and drains rain quickly.
- Colored asphalt pavement can be used to differentiate bike paths from roads and direct traffic. It is also ideally suited to highlighting dangerous points or making areas attractive.
Mixtures vary depending on the type of asphalt pavement that is required. Ensuring a good bond between the bitumen and old rubber, the additive recipe is adjusted in accordance with this.
Bitumen with a bounce
Rubber is a polymer. Polymers help modify bitumen. They
- lend elasticity to the bitumen,
- indirectly improve drainage and, thus, prevent aquaplaning,
- improve the durability of the surface, thereby reducing the need for maintenance and roadworks, and
- allow fewer ruts and cracks to form.
Huge energy and time savings
Designed to advance the use of recycled materials in road construction, the test section has already proven that bitumen, rubber from old tires, the LANXESS BA CR 36 additive, and aggregates combine well. In December 2020, The Institute for Road and Railway Engineering of the Karlsruhe Institute of Technology (KIT) confirmed that the asphalt mixture meets its requirements for use in road construction. The BA CR 36 additive is already patented in Europe and the USA.
Our additive offers the following benefits:
- It ensures that rubber from old tires mixes well with bitumen. This means it is no longer necessary to produce rubber-modified bitumen as part of a separate process. This keeps costs low.
- At the same time, it retains the elasticity achieved by adding rubber, and helps the road surface to reform when, for example, heavy trucks drive over it during hot weather.
“Lots of asphalt mixing plants have shown an interest in our additive,” says Dr. Thomas Klein.
Intelligent roads are the future
Emphasizing recycled materials and reducing the amount of energy required to produce asphalt are trends shaping road construction. Low-temperature asphalt is one outcome of these developments. But there are lots of other ways to make road building more sustainable and LANXESS is driving them. For example, LANXESS specialists in collaboration with KIT recently presented work on rubber-modified asphalt at the “Eurobitume and Euroasphalt” congress. The reuse of old asphalt in new road construction was also a key topic.
We want to know what the road of the future will look like! You too? Join us!