Amsterdam inaugurates bridge with cementless concrete

If it is up to the City of Amsterdam, then the most important question of the moment will have to be asked during the design phase of concrete and steel challenges in the infrastructure: how do you design in such a way that on the one hand the social goal is well served and on the other hand a minimal climate and environmental impact is generated? In other words: if 'circular' is the goal, how do you execute the work in practice?

A project using cementless concrete was delivered in Amsterdam this spring: the Galgenveld Bridge in Amsterdam North. It involved a Framework Agreement for Major Maintenance (ROGO). It seems to become a representative reference project on the use of sustainable concrete. We are talking with Desirée Bernhardt, Sr. Policy Advisor on Sustainability at the Directorate of Space and Sustainability at the City of Amsterdam and Tessa Lievestro, structural engineer and design leader at the Ingenieursbureau Amsterdam. And, we're talking about geopolymer concrete, which was used for the intermediate piers on which the bridge deck of the Galgenveld Bridge rests. 

In geopolymer concrete, the binder has been replaced by selected industrial mineral residues, alkalis and patented additives. Thus, a CO2 reduction of 50% can be achieved. Geopolymer concrete can later be ground back into a powder, which can serve as a raw material for new concrete. But it can also be easily combined with cementitious concrete in the future. In short: sustainability and circularity! Bernhardt says: "When you talk about striving for a circular economy, in Amsterdam we start from the credo 'learning by doing'. It is a clear policy choice of the city council: money has been made available for it and together with a wide variety of stakeholders in the city we are trying to give substance to it. These parties contributed - both internally and externally - to the drafting of the Amsterdam Circular Strategy 2020-2026. Moreover, I see that the pursuit of sustainability based on good innovations is supported by most of our colleagues at the municipality. There is an incredible will to get something off the ground to achieve a livable and future-proof city."

"Still, it is sometimes difficult to give a concrete meaning to the circular economy, because in the end it also involves technical developments and innovations of which you are not always 100% sure how they will ultimately turn out. Especially in tenders, it is therefore a matter of asking better and sharper questions of market players. After all, you want to know as much as possible whether the process, which a party proposes, creates a positive environmental impact. The why of this - as I said - is no longer really up for discussion. So it's about the 'how'."

"By the way, I will say right away that market parties also have a lot of motivation to offer circular solutions and work with us - as a government organization - to make the world a little more sustainable. I see in them a lot of expertise and quite a lot of innovativeness. That makes it easier for us - so we have excellent interlocutors in this - to be able to continually examine well how we can really make concrete in the infra a sustainable product and take another step towards achieving the circular policy goals."

Lievestro explains that with the Galgenveld Bridge, it was indeed the contractor who came up with the solution: geopolymer concrete. "At the same time, we had to be critical at that point because we don't yet know everything about geopolymer concrete, and certainly not for the long term. That sometimes makes it difficult in the permit process, but in this case we fortunately got approval on the application for the environmental permit. However, there was one condition: there had to be strict monitoring. So we literally "poured a wire" into the Galgenveld bridge to keep watching. Because, measuring is knowing. And that's important for the future!"

Lievestro and Bernhardt hope that the acceleration begun on the road to even more "CO2 hits" can continue. "Of course, this will not happen automatically," says Lievestro. "What is important is that parties, from government to the market, continue to share their knowledge so that others can benefit. In that sense, then, it is really my appeal: show how your processes work." Bernhardt adds, "It is also important that we show more of the successes we achieve. After all, the management of public space is our responsibility, but we desperately need the knowledge of the market in order to initiate changes. The same goes for the market: if a producer has a good product, tell us about it. Then we will also investigate whether it is practical. So let's keep designing with a focus on future-proofing. Prevent, extend, value and replace is what we really want. That's good for our earth and our city of the future."