International Airport Rejuvenates RAP Use
The reuse of asphalt is a long tradition in the Netherlands, where no stone quarries exist. This geology means expensive aggregates must be imported, necessitating the reuse of asphalt across the country. Dutch company Heijmans is no stranger to reclaiming asphalt for its applications, with a long history of expertise in innovative and sustainable asphalt solutions.
Recently, Heijmans was able to put its experience to good use, partnering with the bustling Amsterdam Airport Schiphol, the main international airport of the Netherlands. Heijmans has worked closely with Schiphol for over 7 years, with Schiphol relying on Heijmans’ expertise as their asset management partner in keeping their runways and taxiways available for takeoff and landing. The role of Heijmans is to optimize maintenance in costs and availability.
Schiphol Group aims to operate the most sustainable airport in the world with a focus on sustainable aviation, energy positive operations and a circular economy—with an ultimate goal of moving toward 100% reclaimed asphalt pavement (RAP) and bio-based materials in its lanes and runways. To achieve this, Heijmans has been a key collaborator, and recently started integrating the use of Anova® asphalt rejuvenator from Cargill into its asphalt revitalization initiatives for the airport.
Schiphol tasked Heijmans with the repaving of a significant landing and takeoff lane. The Schiphol technical teams desired to make the intermediate asphalt layers more sustainable. The requirement of this project was to maintain the same technical performance specifications as the existing asphalt mix for this application, while increasing the percentage of recycled ingredients from zero to 60% making the mix more sustainable.
According to Maarten van Santvoort, innovation manager at Heijmans, to arrive at a solution the team started with the design objective—maintain the same functional and technical specifications as the existing asphalt solution while increasing RAP usage. This is where Cargill’s Anova rejuvenator came in.
Then they began mix design, which van Santvoort described as, “like making a new recipe for an asphalt mix.” This process is straightforward for Heijmans as they have extensive experience designing mixes with reclaimed asphalt and/or secondary raw materials while maintaining the technical properties and expected service life. Because of Anova they enabled the use of a high percentage of RAP, while still achieving the desired high-performance properties. The results came through a combination of exactly the right dose of Anova and an innovative and clever mixing process, according to Van Santvoort.
After the mix was designed including aggregates, fillers, polymers, RAP and Cargill’s Anova rejuvenator, the Heijmans experts tested it on all possible functionalities—including cracking and rutting resistance—in the laboratory environment to predict the technical performance and properties of the mix. In the end, after rigorous testing, all teams approved of the results. Heijmans got the greenlight to use the mix and the paving project commenced at Schiphol.
During the renovation project, Heijmans paved 225,000 square meters, the equivalent to 45 soccer fields. This is approximately 30,000 tons and roughly 1,200 truck loads. The Polderbaan runway was closed from the end of January 2021 through mid-May 2021.
Ultimately with the help of Cargill’s Anova rejuvenator and the skilled team at Heijmans, both the performance and sustainability goals were achieved.
“Although it’s only a small percentage in the mixture, the rejuvenator enables us to increase sustainability of the mixtures and increase the percentage of RAP from zero up to 60%. Without Anova rejuvenator, we wouldn’t have been able to do this,” van Santvoort said.
Jan Struik, business development manager at Cargill, said the Schiphol project was again a valuable collaboration with Heijmans. “Heijmans and Cargill are on the same page when it comes to innovation and sustainability. We know that the maintenance program at Schiphol is not over yet. In 2022 a second runway will be renovated by Heijmans as well and we’re looking forward to a continuation of our successful collaboration in this area.”