Utrecht used recycled asphalt for the Cremerstraat cycle lane to reduce resource input
The sustainable goals of the Dutch city Utrecht are all reflected in the Cremerstraat cycle lane, which was finalised in 2017. This project involved the transformation of an existing brick road into a 900-metre cycle lane.
This project aims at developing a cycle lane to be part of a longer cycling highway between the centre and the suburbs. Utrecht challenged the contractors to submit a circular solution for the asphalt that was to be used in building the road. The selected contractor KWS submitted a bid that contained two innovative elements:
- less asphalt: two instead of three layers of asphalt
- 100% recycled asphalt for the lower layer.
The main challenge in this project was to convince the internal decision makers to depart from the standard procurement procedures and from the standard specifications as defined in Utrecht’s public space manual. In order to stimulate innovation, the procurement team wanted to include functional specifications instead of technical specifications in the tender documents. The team also asked the potential contractors to provide a life cycle analysis to prove that their proposed solution was the most sustainable.
The solution of the contractor was to increase the thickness of the foundation enabling them to reduce the amount of asphalt to 2 layers. Reducing the total amount of asphalt minimises the environmental impact.
The second sustainable solution in this project is the use of 100% recycled asphalt in the lower asphalt layer. The overall project required 69% less new asphalt than for standard construction.
The overall environmental cost indicator value of the cycle lane is 68% lower than in a design with regular asphalt.
Applying functional specifications instead of technical specifications in the tender document prompts the supplier to deliver new solutions.