Polymer technology: An adhesive for long-lasting roads

Road construction with polymer technology - machines prepare road surfaces © Gert Beer
© Gert Beer

How polymer technology makes roads more resistant

Increasing heavy goods traffic and heavy rainfall are taking their toll on our roads. Many roads show recurring damage such as cracks and potholes. In Germany alone, every tenth kilometer of municipal road is now in poor condition. At STRABAG, we use polymer binders and an innovative construction method to rehabilitate roads from the ground up, permanently and economically.

Cracked and damaged asphalt road before renovation © Gert Beer

How do polymer binders strengthen our roads?

In road construction, polymers act like a flexible adhesive that bonds cement and soil particles together while remaining elastic. The result is a road that is significantly more stable, water-repellent and less susceptible to cracking. In many cases of road damage, it is not enough to simply renew the asphalt surface, as the damage extends deep into the lower layers. The road surface has then lost its load-bearing capacity and no longer provides adequate protection against water and frost penetration. The polymer binder is used to consolidate the road and strengthen the entire road structure.

How does the innovative construction method reduce CO₂ and costs?

Road construction using polymer technology conserves the use of primary raw materials, reduces CO₂ emissions and cuts costs by up to 50 percent. Compared to conventional consolidation, we build slimmer roads because the polymers enable thinner road layers.

The construction material mixture does not have to be removed during the renovation, but is processed on site with the polymer and cement. Road material that is not normally suitable for recycling can also be reused in this way.

Close-up of a roller compacting the road surface © Gert Beer

A layer consolidated with polymers can be covered with a new road surface after a short time - and does not have to rest for several days until the layers have set and are load-bearing.

  • We were able to reduce the construction costs in Windorf by 43% compared to the full expansion and improve the carbon footprint at the same time. The project is an example of how polymers can fundamentally change construction methods and thus open up new possibilities for renewing traffic routes in an economical and resource-saving way.

    Andreas Fuchs
    R&D Representative STRABAG

What potential does polymer technology have in road construction?

The use of polymers in road construction opens up new prospects for resilient and sustainable infrastructure. Thanks to the more flexible construction method, even soils that are difficult to work with - such as fine-grained desert soils - can be turned into load-bearing roads that are less susceptible to damage and cracking. We also use ROADFLEX RF® to rehabilitate road verges - the areas to the side of the road - without having to replace the material. The approach offers road authorities the opportunity to rehabilitate roads faster, with a longer service life and lower emissions - a modern alternative in view of the high need for rehabilitation in the European transport network.

Windorf community project

In the municipality of Windorf near Passau, we rehabilitated a road around two kilometers long with ROADFLEX RF®. The existing municipal road was no longer frost-proof, the asphalt was cracked and the subsoil was severely deformed - it was therefore not possible to repair it with asphalt. For the renovation, the STRABAG team mixed the polymer binder together with cement under the previously milled road surface and then compacted it. The new asphalt surface could then be laid after just 24 hours. The innovative process shortened the construction time by around four weeks and reduced CO₂ emissions by around 20 percent by eliminating the need for transportation.

Liquid polymer binder is dosed into mixing container © Gert Beer

Polymers in road construction

  • Polymers are chemical compounds that consist of long, chain-like molecules. Similar to polymer-modified mortar in building construction, polymer binders create a robust yet elastic structure in road construction.
  • ROADFLEX RF® is a joint development of STRABAG, Wacker Chemie AG and H2BQ. The binder is harmless to soil and groundwater in accordance with the guidelines of the German Institute for Building Technology (DIBt). The polymer content in the cement-bound mixture is less than one percent and is therefore not classified as microplastic.