PMB with biogenic material reduces climate impact

An important aspect of the work to reduce a product’s environmental impact is to increase its service life. And if you can improve the opportunity for circularity, i.e. reusing or recycling the product, that is another benefit. Both of these properties are characteristics of bitumen in road applications; in addition to the long service life, asphalt is 100% reusable.

“By adding polymers, you can further extend the service life of a road,” says Jenny-Ann Östlund, Nynas Bitumen Technology Manager. ”One downside is that a PMB in itself has a larger climate impact due to the relatively large contribution of the polymers to its carbon footprint. This is in a way compensated by the longer service life.”

To reduce the climate impact even further, Nynas has developed the Nypol RE range – PMBs that contain material with biogenic carbon, which compensates for the increased footprint from polymers without affecting the extended service life that they provide.

“Viewed over a life cycle perspective, that’s the whole service life of the product, this results in a significantly reduced climate impact,” confirms Jenny-Ann Östlund.

There is a high level of interest in Nypol RE among road authorities and contractors. The product has already been used in asphalt surfaces on heavily trafficked roads in Sweden and the UK, where there have been very strict demands in terms of both sustainability and a reduced carbon footprint.

The use of biogenic material in the binder is in line with leading construction materials group Breedon’s objective to continuously reduce the impact of their operations on people and the environment. This explains why they chose Nypol RE for a car park in Nottinghamshire, where the typical tight turning circles and heavy abrasion are often problematic.

“We are proud to be the first asphalt manufacturer and contractor in the UK to produce and lay an asphalt using a polymer modified bitumen containing a biogenic component,” says Tony Wilson, Technical Director at Breedon.

The analyses and evaluations performed by Breedon before work could commence produced only positive answers. “The properties of the asphalt and test results clearly demonstrate there is very little difference in performance between Nypol RE 103, the PMB with biogenic material, and Nypol 103,” explains Tony Wilson.

The experiences from Nottinghamshire illustrate the importance of innovative development work and how Nynas, together with its customers, can boost work on sustainability in the industry.

“This new binder is a major change for the industry, with the ability to now offer a PMB performing asphalt with a lower CO2 footprint, which will significantly reduce a pavement’s environmental impact,” confirms Tony Wilson.

We can look at another current example from Sweden and the construction group Skanska, whose goal is to gradually reduce the climate impact from their asphalt products, so they can be climate-neutral by 2045.

One important step in this direction was taken last autumn, when they installed a new pavement, with a total area of 35,000 m2, on a section of road with heavy traffic in Malmö in Southern Sweden. Nypol RE was used for some of this surface, as the client wanted a solution with the smallest possible carbon footprint.

Before surfacing work started, Skanska conducted laboratory studies in order to assess and compare functional properties in the asphalt mixture made with Nypol RE with a reference using conventional PMB.

“We were unable to identify any differences between the two types,” says Kenneth Olsson, Skanska’s asphalt specialist.

The paving team could also confirm that the new binder flows more freely when discharging compared with a regular PMB, and that the asphalt mixture has really good workability.

In summary, the two projects in the UK and Sweden are excellent examples of how actors in the industry can work together to develop quality products that provide both a long useful life and reduced climate impact.