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The Vereniging van Ondernemers van Betonmortelfabrikanten in Nederland unites 110 concrete plants, which register the use of secondary and recycled materials as well as the CO2 footprint in a benchmark. This benchmark is part of the certification of the Concrete Sustainability Council (CSC). It is a certification system for sustainable production of concrete and responsible sourcing of raw materials that provides assurance to buyers. Paul Ewalds is coordinator of Policy & Regulation at Concrete House, we speak to him about the 2018-2019 sustainability reporting of the Concrete Mortar sector.
The benchmark shows that concrete has increased in volume, but the supply of raw materials with limited CO2 emissions has decreased. What does that mean? Ewalds: "Due to the limited availability of raw materials with limited CO2 emissions, more CEM1 has been used, resulting in more CO2 emissions. That problem is mainly on the binder side. Is that a problem? For the concrete industry, yes, but not for the Netherlands. It means that other industries have started to produce less waste. That does mean that we have to look at alternatives that reduce CO2 emissions in our industry again. Calcined clay could be a solution."
The Concrete Agreement points the way to sustainable operations and the bar is high. "The Concrete Mortar sector even wants to achieve 55% CO2 reduction by 2030 (compared to 1990). By 2050, we want to have 100% CO2-neutral concrete. We can't achieve this ambition alone, for that we are also looking in the direction of the other parties in the construction chain," explained Ewalds. "The concrete industry often delivers what is demanded. If our industry proposes sustainable solutions, it may mean that clients have to abandon plans or actually invest more money for certain things. But also that builders and designers will have to hold their methods and plans up to the light, arrange waiting times differently, adjust structures, reuse or construct more leanly. So there will have to be sustainable ordering and more collaboration. The ordering party must indicate how much environmental impact it wants to make. So less CO2 emissions means processing less CEM1 and more CEM3, applying more blast furnace slag and so on. We as a concrete industry will have to consult with our clients. When public clients are awarded contracts, for them the MKI value often counts, but these are not real costs. Non-public clients can work with the CSC label, with the secondary material module. A CO2 module is also planned for 2022. Then you can order concrete with a sustainability factor, expressed in 1 to 5 stars. That works internationally, in the Netherlands we will most likely give those stars an MKI reference (abroad they do not know MKI)."
In Europe, calculations are made using the EU ETS, European Emissions Trading System. "The current ETS system needs to be adjusted. It is getting stricter in terms of free allowances, but it must remain a fair playing field. If we pay ETS allowances on all CO2 emissions, then it becomes a European matter and CO2 emissions caused by imports are also taxed."
Something else is at play on the sidelines, according to Ewalds: "A report called 'Carbon Based Design' has just come out, from TNO/RVO. We already try to build with as few CO2 emissions as possible, but the report indicates that where the CO2 emissions from materials is a factor of 1, the use of the building is a factor of 7. Using fewer materials means fewer CO2 emissions, but involves more heating and cooling. What I mean by that is that materials are not solo sources of CO2 emissions. Much of the emissions are on the side of the client, developers and constructors, in a non-material way. So on the building value model side, on the life cycle and circular design side. Then you can tighten the thumbscrews on the MKI more and more in the concrete industry, but the non-material side should also be looked at. However, that is not defined anywhere."
The conclusion we can draw is that the benchmark doesn't say everything, because the results are based on cubic meters of concrete. "However, it is about the whole," says Ewalds. "The current benchmark fits into the zeitgeist of 2014, as a driver for sustainability. Now that the Concrete Agreement is in place, we can monitor in a completely different way. Broader, more complete. A piece of evolution."
Key conclusions reporting
– The increased demand for concrete is due to the increase in major infra works in 2019, such as IJmuiden Lock and Afsluitdijk. Moreover, such infra works require a lot of cement of a quality that is resistant to seawater, which means higher environmental classes that provide more CO2.
- Due to the growing market, proportionally less (CO2-neutral) secondary raw materials were used per m3 and at the same time there was less supply of CO2-neutral materials such as fly ash and H slag.
- There has been a relatively large amount of high-rise construction and thus more demand for higher strengths. This requires higher percentages of cement in the concrete which contributes to a higher volume of CO2.
