One of the solutions to this challenge comes from somewhere that may at first seem unlikely: the steel industry. Blast furnace slag, one of its valuable by-products, can be transformed into low-carbon cement with the Ecocem process, which creates Ground Granulated Blast Furnace Slag (GGBS). This high-quality cement substitute has a carbon footprint substantially lower than traditional cement, emits virtually no toxic pollutants (such as NOx, SOx and particulates) and has numerous technical and architectural advantages over traditional cement. GGBS is also price competitive and likely to become more so as the cost of carbon is factored into the price of traditional cement.
There is huge demand around the world for concrete, whose prized durability and strength as a building material come from cement. But the traditional way of making this material is highly energy-intensive – so much so that its production accounts for 8% of global greenhouse gas emissions. There’s no easy way for the cement industry to decarbonise. Because cement is made in many plants around the world, installing carbon capture and storage (CCS) to deal with its emissions is complex and costly.
This initiative is a perfect illustration of the circular economy in action
Ecocem GGBS: the advantages:
- Substantial reductions in CO2 emissions compared with conventional cement
- Higher strength can double the lifespan of concrete structures
- No primary natural resources used specifically for the production of slag
- Superior technical characteristics
- Environmental certifications, including BREEAM and LEED
Circular economy in action
This innovative technology is a perfect illustration of ‘circular economy’ principles in action: by-products from one process are repurposed to make valuable new materials, saving significant energy and emissions. It is also part of ArcelorMittal’s journey to becoming a zero-waste company by transforming the way it does business.
To put GGBS into production, in 2007 ArcelorMittal Méditerranée and Ecocem Materials established the Ecocem France joint venture. Ecocem France makes GGBS in facilities close to ArcelorMittal’s blast furnaces at Fos-sur-Mer, where production started in 2009, and Dunkerque in France, which was commissioned in 2018. To date, Ecocem France has avoided over 4.5 million tonnes of CO2 emissions in the cement industry* and is targeting a further reduction of more than 1 million tonnes of CO2 in 2020.
4.5 million tonnes of CO2 avoided to date*
Ecocem GGBS has been used in a number of high-profile building projects, where it was chosen for its technical and environmental performance.
ITER fusion reactor
- Specified for the reactor floor
- Chosen for mechanical resistance, strength, low heat of hydration and durability
Belle Ombre Clermont-Ferrand, Rainwater Retention Basins
- 50% Ecocem GGBS
- Specified for performance, durability and impermeability
Odeon Tower, Monaco
- 4000 tonnes of CO2 avoided
- Specified for performance, strength, durability and resistance to chloride
- Improved the workability of the concrete and decreased heat hydration
La Marseillaise Tower, Marseille
- Specified for performance and durability
- LEED and HQE accredited
The Grand Paris project
- Europe’s largest transport project
- For new Metro lines/200km tunnels
- Ecocem GGBS to be used in a number of applications for strength, durability and resistance to aggressive environments
As the landmark building projects show, Ecocem GGBS is becoming a material of choice for designers, architects and engineering consultants and contractors. The leading low-CO2 cement technology based on GGBS in France, it is reducing the carbon footprint of an energy-intensive industry while extending what’s possible in construction. And as the demand for low-carbon building materials grows, there’s an exciting future for this innovative circular economy process.
Materials experts are developing solutions that extend the technical and environmental performance of Ecocem GGBS:
- Self-levelling flooring – major advance in concrete flooring
- Sprayed concrete – highly demanded for tunnels and mines
- Ultra-low carbon cements – new formulations for added durability and environmental performance
*Calculated on the basis of volumes of GGBS produced over the period 2010 – 2019; GGBS Global Warming Potential of 16kgCO2/tonne (MRPI) compared to CEM I cement Global Warming Potential of 898kgCO2/tonne (Cembureau 2015)