Circular sulphur concrete from De Bonte

Posted on 29 Oct 2020

A smaller CO2 footprint and less waste

An increasing number of companies and organisations are endorsing the demand for sustainability, and that includes the concrete company Beton De Bonte. De Bonte is focusing on sustainability and the development of new products made from sustainable concrete. In doing so, they will launch an innovative circular sulphur concrete at the end of this year. With this activity they will contribute to the European Green Deal: Europe aims to be the first continent in the world to be climate neutral by 2050. This will greatly affect the building and infrastructure industry. Less CO2 emissions are produced when making circular sulphur concrete, which contains no Portland cement. This also means that Beton De Bonte is contributing to EU objectives to recycle 70% of building and demolition waste by 2020.

Could you tell us a little more about De Bonte?

“We are a 3rd generation family business with years of experience in producing prefab concrete products for the railway, sewerage and traffic infrastructure. We have five production sites in Belgium, as well as sites in France, Turkey and Poland. We also sell machines and moulds that are developed in house.”

You have developed circular concrete?

“That's right. We'll soon be the first in the world to launch our so-called ‘circular sulphur concrete’. This is a type of concrete that is 100 per cent recyclable. That was impossible until now. Old concrete can be recycled but is seldom of the same quality. Old concrete is usually crushed and re-used in foundations. 

How did these circular concrete products come about?

“In 2012, we teamed up with Shell in a large innovation project. Sulphur is released as a by-product in crude-oil refinement. Although this can be used as artificial fertiliser, this was not sufficient for Shell to use up its entire sulphur residue. Therefore, Shell was looking for another solution to use its sulphur and ways to turn it into something new. They developed sulphur concrete, in which sulphur replaces the Portland cement and water in concrete. They came to De Bonte to develop some appropriate applications. During the project, Shell decided to award exclusive rights for the fully-patented technology to De Bonte. 

How does it differ from standard concrete?

There are several differences compared to standard concrete. However, when it comes to sustainability, the lower carbon emissions are a big difference. “The production of Portland cement, as the traditional binding agent for concrete, is what you would call eco-friendly. Indeed, during the heating process immense quantities of CO2 are released, which is not the case with sulphur as a waste product. So, replacing Portland cement with sulphur is a tremendous step forward for the carbon footprint of these products.”

What are the advantages?

“Sulphur-concrete products have a lower CO2 footprint than cement concrete. Not only that, they are also acid-resistant and waterproof, which is a great advantage in the sewerage market. The sewerage network must be strictly divided between waste water (dry-weather flow) and rainwater. Over time, traditional concrete pipes start reacting to the acidity in separated waste water, and this is a global concern. Ceramic pipes are acid-resistant, but they are also very fragile. Our sewerage pipes made of sulphur concrete are the solution: they are acid-resistant, stronger, competitively priced and also 100% circular.”

In which products do you use sulphur concrete?

“We have global exclusivity to use sulphur concrete in a number of products. So far we have already developed sulphur concrete sleepers for use in the railway network. These have already been homologated in Belgium, France and the Netherlands. It is now a matter of launching the products, pointing out the sustainable benefits to railway constructors and getting ourselves ready for sustainable tenders. We are also using sulphur concrete in sewerage pipes: we have the COPRO mark and the products are ready for certification. We will launch the sleepers and pipes worldwide.”

Are there any other advantages?

“Actually, the greatest difference lies in the circularity. When using cement concrete it is very difficult to reactivate the binding agent. Cement concrete can therefore be broken and those granulates reused, but rarely to make the same product. However, it's the opposite with sulphur concrete. This turns to liquid as from 120° C. To explain it simply, a broken sewerage pipe can be melted and turned into a new pipe of a similar quality.”

What is the result?

“The most important result is that, by using circular sulphur concrete in our products, we help to decrease the mountain of industrial waste and drastically reduce the carbon footprint.”

You probably plan to make this the foundation of your business model? 

“Absolutely. That is what we are now busy researching. Complete circularity is only achieved if you also take back the products that you have sold as circular. Our sleepers and sewerage pipes are easily traceable, which makes it easier to establish such a circular model. From our customers, we know the whereabouts of every one of our sleepers and sewerage pipes. Whenever these need replacing, the intention is that they come back to us and that we recycle them. In fact, real-life tests have already been carried out to melt sleepers and turn them into new ones. Their properties remained the same and we can confirm our success in recycling them.”

That sounds pretty promising!

“Indeed, we are seeing plenty of opportunities, worldwide. However, this also requires a new mindset among sewerage authorities and railway companies, as our current customers. These are actually rather conservative markets. Discussion and collaboration are fundamental to success. 
In fact we have been working on this for many years and, as an SME, we would never have been able to achieve this alone. We have worked closely with research centres, universities, research institutions to get where we are today. The IWT (editor's note: in 2016, IWT joined forces with the Enterprise Agency to become VLAIO) gave us guidance in finding research partners and (European) subsidies.”


What stage are you at in the production of these sulphur concrete products?

“At the end of this year, we will launch a dedicated production line to manufacture sewerage pipes with a diameter of 250-500 mm at our site in Mons. Next year, we will normally set up a production line with the capacity to produce 125,000 sleepers a year.”

Why is innovation and sustainability important to you?

“Sustainability has been a key focus in our company over the last ten years. Sustainability is the future for every company. We have seen this in every channel. You can no longer ignore the need for sustainability. If you wish to continue growing, you must remain alert and creative, and invest in sustainable innovation. Otherwise you are bound to disappear in the short or long term.”

What is your approach?

“There are so many ways to be sustainable. We do not limit sustainability to ecological initiatives. It can also affect the way you recruit, train and invest in employees. Of course, we also consider how we can produce in a more energy-friendly way, on the one hand, by consuming less energy and, on the other, by making greater use of green energy, for example, with the installation of solar panels or wind turbines. We also make much use of waterways to transport the required raw materials to our sites, but also in transporting our finished goods. Sustainability is also a standard element in our product-development process. We design our products so that they can be installed more efficiently, we integrate draining elements, etc. So you can see that sustainable innovation is not limited to the R&D department. It is truly embedded throughout the company.”

What is your ambition? How do you see the future of Beton De Bonte?

“Our ambition in the short term is the further realisation of our products with sulphur concrete: the launch of our first production line this year in Wallonia and the search for partners with which to launch sulphur concrete products internationally. As a medium-sized local company we recognise that we lack the market knowledge in house, for example, to roll out in America. Yet, working with the right partners we believe that the world is our oyster.”

Do you plan on going circular or developing your sustainable initiatives (further)? Looking for a cleantech solution? Or do you have your own cleantech application? Become a partner of Cleantech Flanders: www.cleantechflanders.be

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