Asphalt industry must deliver on sustainability promise

In view of the Paris climate agreement, the originally conservative asphalt industry is now developing rapidly. Since January 1, hot-mix asphalt has been the norm, machinery is evolving towards emission-free, and experiments with sustainable mix compositions are in full swing. Nevertheless, there are still challenges to overcome. 

As an industry, we took on the challenge of slowly phasing out Hot Mix Asphalt. To gain experience, Mourik started replacing some 10-25% regular asphalt with Warm Mix Asphalt two years ago. The big challenge of Warm Mix Asphalt is its life expectancy. For base and intermediate layers, everyone believes in it, but it is also a matter of securing quality for the more critical mixtures. This requires a bit of trust. What is very important is that everyone goes along with this development. Fortunately, all asphalt producers have agreed to it, but it is precisely for those few critical mixtures that we still have some work to do as a sector.

Further development of asphalt mixtures is an ongoing process. In early 2025, we got a new mixture certified at TRL 9. A good start to the new year. This is the Warm Mix asphalt mixture SMA GRA 8 COLT® developed in cooperation with the Asphalt Knowledge Center. The mixture dates back to 2012 and was actually ahead of its time. In the meantime, we have completed all certifications and now make the mixture perfect for Warm Mix. We have already applied 90,000 tons of it, demonstrating its proven ability to withstand heavy loads, extreme weather conditions and daily traffic. COLT® is a great example of what you can achieve together as an industry by linking innovation to sustainability. 

When calculating the Environmental Cost Indicator (EQI) of asphalt, there is still a world to be gained. The MKI figures of the most favorable asphalt plant are always assumed. And that is not necessarily the plant closest to a project. We are happy to make a detour for that. After all, transport kilometers are only a limited factor in the MKI calculation. That should be changed. Moreover, there should also be more focus on the life expectancy of a particular asphalt composition. A 2-centimeter thicker construction, for example, could potentially stretch the life of the road by many years. That's real sustainability, and current calculation methodologies take little to no account of that. We also have to ask ourselves, is ZOAB still the most sustainable product? After all, it is an overlay that only lasts about ten years....

The asphalt industry is among the frontrunners in making its machinery more sustainable. At Mourik, too, we are investing heavily in expanding an emission-free fleet of equipment. A mobile electric excavator was delivered in November 2024 and this year we will conduct a pilot with an electric asphalt spreader. We also have two hydrogen-powered crawler cranes that we developed and built in-house, and an electric three-roller roller is in the works. We are also doing that ourselves, making the necessary improvements over the first model. For example, more power is available directly at the wheels, and that in turn leads to less loss and thus higher efficiency. Furthermore, the asphalt plant in which we have a stake was made more sustainable two years ago and is completely up to date.

Bitumen is made from petroleum. By 2050, we want to be fossil-free. Together with other contractors within the Asphalt Knowledge Center, we are developing fossil-free asphalt. Some twenty trial sections in the Netherlands have already been laid with fossil-free asphalt. It is performing above expectations, although we do see a spread in the results. In the coming years we will continue to work on this, so that we as a sector can fulfill our sustainability promise.

The Pen - Bram Lommers – Asphalt plant manager at Mourik