Make room for sustainable concrete

Sustainable concrete requires a change in the sector: from large-scale use of primary raw materials such as sand and gravel to large-scale use of secondary material flows such as rubble and demolition waste. Until now, this has not been possible due to the great variation in these waste streams, both in size and composition. Our new approach helps accelerate this sustainable transition and take the step towards more sustainable concrete. Introducing Material-Driven Multi-Criteria Design Optimization, or MIMO.

MIMO approach as a solution for sustainable concrete

MIMO is a complete approach to the transition to sustainable concrete. The idea: Take as a starting point the data and material properties of available raw materials, (new) material flows and elements. And ensure ongoing flexible processing of new data instead of long-term established standards and calculation rules.

Until now, this has hardly been the case, because traditional concrete formed the starting point in the design process of concrete structures. The great diversity and size of the material flows, e.g. from demolition waste and rubble, making concrete more sustainable and therefore difficult to implement. But the technological development now makes it possible for the concrete sector to take the step towards more sustainable concrete. Three elements play an important role in the MIMO approach:

  • Specific and measurable data on the properties of the material available;
  • Advanced material models that, fed with this data, predict the effect the material used has on a concrete structure;
  • Smart optimization software to generate sustainable and integrated design solutions that meet the requirements: environmentally friendly, constructively safe and affordable.

We call this node of data, models and optimization software MIMO.

This is how MIMO works

  1. The data: early in the design process of a new concrete structure, you collect data from the new project. These data form wants and requirements (criteria) in the MIMO approach. This step also includes all available data from all available sustainability methods as well as data from recycled raw materials, materials and elements;
  2. Validated calculation models: a chain of validated calculation models is ready in MIMO to process all data, such as data on material properties, costs and quantities, into information that helps the designers in the design of the concrete structure. The calculation models are tailored to the materials and sustainability methods and come from current regulations, state-of-the-art knowledge and research in concrete and safety. Missing models are developed and added to MIMO;
  3. Optimization software: the computing power in multi-criteria optimization software performs a complex balancing process between the entered data, the requirements/criteria that the design must meet and the calculation models.

The result of MIMO

After going through these steps, MIMO provides different design solutions for a concrete structure that is safe, making optimal use of the available preservation methods, and which fits in with the architect’s and constructor’s design. MIMO indicates how well a variant meets the wants and requirements specified in step 1. Watch this calculation example to see how MIMO works in practice.

It is also possible to prioritize the requirements. This gives you a good insight into which design variant, based on available material flows and compared to requirements and priorities, best suits your wishes. And take the best step towards sustainable concrete!

5 frequently asked questions about MIMO:

What can MIMO do for my business?

In addition to the benefits of the (early) design process, MIMO can also pave the way for better collaboration in the sector:

  • Customers, for example, get design solutions that measurably meet their requirements and which they can transparently compare with each other
  • Contractors and demolition companies gain better insight into the costs and benefits of smart dismantling and storage of materials;
  • Material-specific information that demolition companies can provide becomes valuable to construction and engineering firms;
  • For recycling companies, the demand for, for example, concrete aggregates and brick powders will increase. They can add value by providing information about material properties in advance that can be used for calculations in the design.

I would like to use MIMO. What should I do?

MIMO is specialist work and is currently still in the development stage. We are looking for companies to grow MIMO with! We do this by providing MIMO with more information together with companies from the sector. The more information included in MIMO, the better the sustainable solutions.

Where is the surplus for the construction sector?

Design process
With MIMO, designers gain near-real-time insight into the effect new data about (available) materials, raw materials and elements has on the performance of their designs. This allows them to make well-founded and objective assessments with customers. The MIMO approach removes uncertainties and issues around new (secondary) material flows: a design that is sustainable but also meets the requirements for structural safety and remains affordable.

Increased use of secondary material flows and scarcity of primary raw materials
MIMO allows for a wider use of available secondary material streams. In addition, this approach also makes it possible to reuse more diverse secondary material streams than is currently possible with the traditional design approach – also when using different materials and raw materials within a project. Especially in light of the (coming) shortage of raw materials, recycling of raw materials, materials and elements is becoming increasingly important.

What does sustainable concrete (the sector) provide?

Secondary concrete and masonry now together make up almost half of the annual Dutch waste. If these material flows can be used on a larger scale or even completely for new, sustainable concrete, then it will lead to at least ten times as much recycling in concrete as now. And up to at least 50% less use of primary raw materials in concrete. We estimate that effect at a reduction of 20% of the current CO2 emissions from concrete and a third of the objective in the Concrete Agreement in 2030.

Why is this new approach to sustainable concrete necessary?

Although there are various innovations to make concrete more sustainable, these hardly find their way into practice. This is due to a number of factors:

  • in the construction sector, everything is laid down in standards and regulations, which are not yet suitable for innovative concrete types (of secondary material flows, for example);
  • ‘Counting back’ to traditional concrete or creating new standards and calculation rules is not a sustainable solution either. This inhibits the use of more sustainable raw materials and leads to designs that are less sustainable than possible;
  • the complex design process: on the one hand the arrival of more sustainable but variable material flows and on the other hand an increasing number of requirements for e.g. constructive safety, environment and costs.

The entire concrete sector has a role to play in realizing sustainable, affordable and safe concrete structures now and in the future. So don’t wait any longer and get started with TNO!


Wouter Moorlag
Location Delft
088 86 60 674

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