Questions about circular concrete

Here, you will find answers in advance to all the questions we could think of. If you have a question that we have overlooked, do be sure to let us know using the button at the bottom of the page.

General questions about circular concrete

What is circular concrete?

Concrete – as we still largely know it today – has a very large ecological footprint: we do not have an endless supply of (suitable) sand, the production of cement emits a great deal of CO2, and for the granulates, we need to mine. Very briefly, circular concrete addresses these three issues: for the granulates and sand, we look at secondary raw materials, and the cement we replace with an alternative binder with a lower footprint.

As a manufacturer, why should I develop circular concrete?

A few reasons:

  • We all bear responsibility for keeping our planet liveable. The construction industry plays a crucial role in this.
  • Innovators are always one step ahead. The sooner you engage with it, the sooner you will have a market-ready product. We are, of course, here to guide you in this.
  • After all, our emissions need to go down. In the coming years, emissions standards will become stricter and stricter.

As a contractor, why should I work with circular concrete?

A few reasons:

  • We all bear responsibility for keeping our planet liveable. The construction industry plays a crucial role in this.
  • Innovators are always one step ahead. We are, of course, here to guide you in this. With our knowledge partners and our lab, we can demonstrate that circular concrete is equally safe to work with. So you will not need to worry about your liability.
  • After all, our emissions need to go down. After all, in the coming years, emissions standards will become stricter and stricter.

Circular concrete is mostly outside the norm, so why would I work with it?

It is true that many circular concrete mixtures are (currently) outside the norm. It is important to note here that this is not because they are not high-quality, but rather because they are not eligible owing to their different composition. There is an ongoing trend towards standardising mixtures that can demonstrate equal quality.

This is what we are very committed to with the Circular Concrete Centre: removing all doubt by testing the mixtures at our lab and objectively demonstrating that these mixtures are (at least) as good and as safe to work with.

What is the Circular Concrete Center?

The Circular Concrete Centre is a consulting, testing and demonstration centre for circular concrete. We want to accelerate the transition from classical concrete to circular concrete, and offer advice on this to anyone who comes into contact with concrete.

You can come to us for advice ranging from 'How can I engage with circular concrete?' to 'How do I get my concrete mix certified?'

What can the Circular Concrete Center offer me?

The Circular Concrete Centre offers several work packages:

  1. General advice on circular concrete mixtures and applications (everything you can find on this website).
  2. Advice on a specific concrete mix or application.
  3. Advice and accompanying tests at our concrete lab (e.g. feasibility studies).
  4. Full guidance towards the certification of your concrete mix.
As an individual, can I turn to the Circular Concrete Center?

Yes, of course! Our advice is there for anyone who comes into contact with concrete.

How do I or my organisation become a member of the Circular Concrete Center?

Glad to hear you are jumping on the bandwagon! Contact our staff and we will take care of that!

I am a principal and would like to commit to circular concrete in my project. How do I go about this?

Depending on the concrete application, there are various ways to commit to circular concrete. Besides ambitions and objectives, the Flemish Circular Concrete Agreement also provides some practical pieces of specifications text that you can adopt in order to commit to circular solutions in your contract, without having to compromise on quality.

As an authority or principal, can I turn to the Circular Concrete Center?

Definitely! We want to provide advice to everyone who comes into contact with construction and concrete.

Technical questions about circular concrete

Who will deal with my question?

Your question will reach a Circular Concrete Centre staff member. Depending on the type of question, the staff member will either handle your question themselves or will go and ask an expert from a knowledge institution. In doing so, this staff member will always ensure that the question is anonymised.

Are you having any tests performed at our lab? Then our staff member will make sure your question is anonymised as well. The lab technician will not know who or what company the question comes from. This is how we guarantee the proper handling of your question.

How much does Circular Concrete Center advice cost?

The service of this advice desk is part of the ERDF Concrete Circularity Centre project and falls under de minimis support. After you send in your question, the value of the de minimis support will be calculated and transmitted. After that, you can decide whether to accept the guidance and a de minimis form will be prepared and signed.

What tests can I have performed at the Circular Concrete Center?

You can come to our lab for granulate testing and testing for the mechanical and durability properties of fresh and hardened concrete. You can see in more detail here what devices we have at our concrete lab, and what tests we can perform with them. Tests that we cannot perform at our lab, we can often perform at one of our partners' labs. So don't let that stop you from contacting the Circular Concrete Centre.

I am a concrete producer. How can I make my product more sustainable?

To make your product more sustainable, you can focus on several things: the granules, the sand, and/or the cement. In short, there are many roads that lead to sustainable concrete. Hopefully, they will soon consist of sustainable concrete as well.

Please contact us through our advice desk and we will look at the options for your specific situation.

What should I consider when choosing alternative and sustainable binders?

If you choose to use alternative and sustainable binders in concrete, there are several aspects to consider. Here are some important considerations:

  1. Environmental friendliness and sustainability of raw materials: Choose binders that have minimal impact on the environment. Check that the raw materials used to produce the binders are sustainable.
  2. Performance and functionality: Ensure that the alternative binders are suitable for the intended use. They should offer the same or similar performance as traditional binders.
  3. Compatibility: Consider whether the alternative binders are compatible with the other materials with which they are to be used. They must be able to interact well with, for example, additives, fillers and other additives that may be needed in the production process.
  4. Certifications and standards: Check that the alternative binders meet relevant certifications and standards in terms of sustainability and environmental performance. This can help ensure the quality and reliability of binders.
  5. Availability: Make sure the alternative binders are sufficiently available for your specific application. Check that there is sufficient production capacity and that suppliers are able to meet your demand.

The specific influence of using alternative and sustainable binders is different in each concrete composition. Therefore, it is advisable to contact the Circular Concrete Centre staff to review your specific case.

What should I consider when using recycled granulates in concrete?

If you want to use recycled granulates in concrete, there are some important technical considerations to take into account:

  1. Grain distribution: Check the grain distribution of the recycled granules. The grain size can affect the workability, strength and durability of the concrete. Ensure that the grain distribution meets the application's requirements.
  2. Replacement percentage: Determine the percentage of recycled granulates that you want to use as a replacement for primary granulates in the concrete mix. The replacement rate may vary depending on the specifications and desired properties of the concrete. Conduct some trials and tests to determine the optimum replacement rate that meets the required technical performance.
  3. Concrete strength: Consider the influence of recycled granulates on the strength of the concrete. In some cases, the use of recycled granulates may result in lower concrete strength compared to using only primary granulates. It is important to specify the desired strength requirements and adjust the concrete mixtures accordingly.
  4. Sustainability: Analyse the impact of recycled granulates on concrete durability. Recycled granulates can affect certain properties of the concrete, such as resistance to freeze-thaw cycles, resistance to chemical attack and long-term durability. Ensure that recycled granulates do not adversely affect the durability of the concrete.
  5. Water-cement factor: Adjust the water-cement factor of the concrete based on the properties of the recycled granulates. Some recycled granulates may have higher water absorption than primary granulates, which may affect the water requirements for the concrete mix. Ensure that the concrete mix has an appropriate water-cement factor to achieve the desired strength and durability.
  6. Consistency: Ensure a proper mixing process to guarantee proper distribution of recycled granulates in the concrete mix. Check the consistency of the concrete to ensure that the mixture is properly workable and has the desired properties. If necessary, adjust the proportions of other components of the concrete to achieve the desired consistency.
  7. Quality control: Implement thorough quality control to ensure that the concrete mix with recycled granulates meets the required specifications. Perform regular testing and analysis to check the properties of the concrete, such as its strength, durability and consistency.

It is advisable to work with experienced Circular Concrete Centre staff. They can help develop suitable concrete mixtures and optimise the technical performance of concrete with recycled granulates.

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