How do you come up with a new asphalt mix?
‘If we’re developing a new mix, we look at the functional requirements and lifespan of the intended mix. As soon as we know what properties the mix must offer, we get together with our team of experts and examine the options. When it comes to innovations, and new mixes beyond the framework of the standard RAW provisions, we involve Rijkswaterstaat in the development process. Everyone thus works together to supply a decent product.’
‘Sustainability is an important motive. Heijmans is encountering more and more DBFM contracts, where we are responsible for the long-term maintenance of (motorway) roads. For example, we are responsible for maintaining the A12 Veenendaal – Ede – Grijsoord for 16 years. And this responsibility extends to 25 years for 3Angle: A27/A1 Utrecht – Eemnes – Amersfoort. During this period, asphalt quality must be sustained and lifespan plays a decisive role. Heijmans cannot afford to be confronted by unexpected damage.’
maintenance A12 Veenendaal - Ede - Grijsoord16 years to deliver
Were you involved in the invention of porous asphalt?
‘No, that was before my time. However, I was involved in recycling double-layered porous asphalt. It features a substrate of coarse grit and a thinner top layer of fine grit. This enables us to drastically reduce noise and ensure good water drainage.’