On the road to more sustainable asphalt | foresight.skanska.com
Decarbonizing construction

On the road to more sustainable asphalt

Well-built roads keep society functioning, allowing us to travel across town – or across the nation. Unfortunately, the construction of asphalt roads has traditionally relied on fossil-fuel products and produced significant carbon emissions. Now, a new approach to producing asphalt is cutting its climate impact.

Most people recognize the sulfurous, oily smell of hot asphalt being prepared for use on a road. But if you walk past asphalt being laid on certain Skanska projects in Sweden, your nose will detect something different – a warm pine smell a little like a sauna. Skanska’s Christopher Elofsson explains that’s because the binding agent in the asphalt on some projects is a mix of pine oil pitch and bitumen – as opposed to just plain bitumen in regular asphalt. As well as smelling better, this road covering, known as Asfalt Zero (link in Swedish), reduces the use of fossil fuels in road projects and helps lower CO2 emissions.  
In the latest episode of our Shaping Sustainable Places podcast, we learn how some parts of the construction sector are reassessing the way that asphalt is both produced and used, with the goal of improving sustainability. In addition to Christopher, we speak with Abubeker Ahmed and Jiqing Zhu, who are both senior researchers working for the Swedish National Road and Transport Research Institute

Recyclable like aluminum

Christopher is the project manager at Vällsta Asphalt Plant near Stockholm which was upgraded two years ago to be more sustainable. He explains that, like aluminum, asphalt can be used again and again. Recycling old asphalt reduces CO2 emissions in the production of new asphalt by up to 50 percent. Our Vällsta plant is designed to use up to 100-percent recycled asphalt when making new asphalt. It’s also powered with pine oil pitch, a byproduct of paper manufacturing which can be used as a biofuel. 

The new black gold 

Abubeker Ahmed and Jiqing Zhu from the Swedish National Road and Transport Research Institute see a big future for bio-asphalts that replace traditional bitumen with non-petroleum-based renewable resources. However, they say a challenge lies in determining what properties different types of bio-asphalts have and developing regulations for their use. Jiqing Zhu says researchers need to assist policymakers by exploring the properties of such materials and sharing their findings. 
Abubeker is encouraged to see authorities across Europe trialing roads made with bio-based binders in asphalt. He says there have been early signs that bio-based asphalt can be as durable – or more durable – than traditional versions, but more research is needed.  
Jiqing says that with uncertainty around future petrochemical supplies, recycling of existing asphalt into new asphalt may become increasingly important. He describes the asphalt in today’s roads as tomorrow’s ‘black gold’.  
You can tune in, listen and subscribe to the podcast on Spotify and Apple Podcasts.