'Concrete offers huge potential in circular economy'

Concrete is the second most widely used raw material in the world after water and has enormous potential in the circular economy, according to Betonhuis. For example, concrete can be 100% reused without loss of quality, provided a number of conditions are met. The concrete sector is working hard to achieve the circular goals for 2030. As a knowledge center, Betonhuis is constantly looking for new ways to contribute to a better world. It focuses on even safer working practices, but also on nature-inclusive and climate-adaptive building, energy-efficient designs, leaner constructions and adaptive and remountable concrete elements. 

Circular Construction Economy Transition Team

Currently, only 5% of the ingredients in new concrete consist of recycled materials. "A lot of concrete residual streams are currently used in other applications, such as for foundation material in roads. In contrast, the Concrete Agreement states that concrete residual streams from the built environment should be reused in new concrete. This means that demolishers and recyclers must be instructed to demolish selectively. Unfortunately, this is still (far) from happening in all cases." Speaking is Paul Ewalds, sector manager of concrete mortar & coordinator of policy and regulations at Betonhuis. "From Betonhuis we are actively informing the entire chain to give direction on this. Moreover, from TU Delft we are working on a methodology to be able to assess the quality of concrete before it is demolished, so that high quality concrete can also be reused in high quality instead of in low quality applications. Only then do we really come full circle. Fortunately, this vision is widely shared. For example, the Circular Construction Economy Transition Team is taking the construction industry by storm. In its report "advisory route to a circular construction economy" an advice has been drawn up to the government to achieve the raw material reduction goals. In it there is also extensive attention to concrete. A good thing, especially because of the approach to include the entire chain in the objective."

Photos 1-3: 

Amsterdam live/work building with roof garden. In 2016, the building was transformed by Van Heeswijk Architects. On the second floor, client Vesteda established its headquarters. The architect recommended stripping the building entirely, revealing the concrete building skeleton. On top of the building a 700 m2 communal roof garden was realized with panoramic views. This was made possible by adding a reinforced concrete compression layer to the roof structure.

Building Value Model

As the Concrete Agreement also states, only part of concrete's performance on the themes of circularity and sustainability comes from the material itself. "The vast majority of the circular goals to be achieved lie in the design phase," Ewalds emphasizes. "There has to be a focus on circular design. The Building Value Model is a good tool for this. One of the most important aspects in it is lifespan and thus circular design. We still design linearly now. That is, the concrete structure is designed for the first user and application, while it is much more sustainable to already look beyond the current task in the design. We are building for more than 100 years. How can the building be used when it loses its intended function? The Building Value Model advocates adaptive and remountable design, where the concrete structure can also be adapted and/or dismantled to suit other user needs and functions. In the current system, buildings are depreciated after 50 years. Absolutely unnecessary! A building and certainly the concrete structure is still worth a lot after that period, because it can easily last 100 to 150 years. That's three times as long and provides a lot of sustainability and circularity benefits."

Ewalds: "The temporary Rechtbank Amsterdam, for example, shows the future of construction. Ideally, within 30 years, all structures should be designed to be easily adapted or rebuilt elsewhere, and concrete and concrete structures should last 150 years, for example. But before that happens, a lot of water has to pass through the Rhine. And for that we need the whole chain. We have taken the first steps in that direction. Concrete has enormous potential in the circular economy."

Netherlands as frontrunner

By the way, the Netherlands leads Europe in the use of concrete residue streams in new concrete. Admittedly, it is only 5%, but that is still more than in the countries around us. We also lead the way in terms of the total CO2 impact of concrete. In the Netherlands, concrete is responsible for 1.6% of total CO2 emissions. On average in Europe it is 6% and worldwide it is even 9%. That's because we all use secondary materials in the Netherlands, such as fly ash and blast furnace slag, according to Ewalds. "The Concrete Agreement still offers a lot of scope for action to further reduce CO2 emissions, because ultimately we want to go to zero emissions. For example, the cement industry is intensively engaged in CO2 capture and reuse in other materials, even outside its own chain. The concrete industry is miles ahead of other industries in this respect with the Concrete Agreement in the Netherlands." This is presumably also the reason that Betonhuis has been asked to chair the circular economy working group at the European umbrella. Because Europe and even the rest of the world can safely take an example of how the concrete industry manifests itself in the Netherlands as a chain to achieve the intended climate goals.

First Circularity Economic Package 

Yet there are also positive developments from a European perspective. Ewalds mentions, among other things, the First Circularity Economic Package in which it was announced at the European level that the Construction Products Regulation will be repaired. "There will be a CE mark on cement as well as concrete mortar. That has quite an impact, because it means that products made on the construction site, such as concrete mortar, will also fall under the CPR. The contracting industry must realize that it will soon also have an essential share in this; it must issue a Declaration of Performance. Furthermore, a new sustainability and circularity system has been announced. It replaces the current system that is not harmonized in all countries. The new ecosystem is planned to be part of the Ecodesign Directive. It may just have a major impact on local determination methods, such as the MPG. The goal behind it is to assess not just at the material level, but the environmental impact of the overall project. In short, a lot of things are still hanging over our heads."

Suppose we are 100 years down the road and as much is built in the Netherlands as is demolished. Could we then make new concrete from 100% recycled concrete residual streams? "Yes indeed," Ewalds says firmly. "The concrete industry has long stood for high-quality recycling, but circularity goes much further than that. And we need the whole chain for that. But the first steps have already been taken, and any concrete residual steam that becomes available now can already be used in new concrete." Clients at the CSC-certified companies can also specify how much circular material can be used in new concrete through Betonhuis' CSC-R module. And for those interested, through the CO2 module, the maximum climate impact of the concrete ordered is revealed. Concrete also has enormous potential in a sustainable and circular economy.