Cement production is one of the most polluting industries in the world. It accounts for almost 3% of France’s greenhouse gas emissions and 8% worldwide. Cement is also the most used material in the world: 15 billion cubic meters of concrete are poured every year.
Even if the French cement industry claims to have reduced its emissions by 40% since the 1990s, the fact remains that 650 kilograms of CO2 are emitted at 1 tonne of cement at best. Moreover, according to a recent report by The Shift Project, the decarbonisation of cement since 1990 has been more linked to declining consumption and production than to voluntary action.
If the technical aspects of the material have been able to evolve, its formulation and production have made little progress in recent decades, while still remaining highly emitting.
The main component of concrete, cement, which is a binder that connects pebbles and sand, is clinker. The product of burning limestone and clay in a rotary kiln heated to 1450 ° C requires a lot of energy from oil, the only one capable of rising to such a temperature to obtain it, emitting a huge amount of carbon dioxide.
Cement production requires heavy infrastructure and large investments, so there are only a few players in this sector.
According to INSEE, the cement industry in France remains highly concentrated. Thirty-five of the country’s 43 cement plants are owned by five companies, which own about 95% of the market. Concentration, which is not conducive to change, and France, the second European cement producer, is slowly implementing the necessary innovations in environmental issues.
However, the cement industry will have to work twice as hard to achieve the goals set by the National Low Carbon Strategy. In its roadmap published last year, it plans to reduce emissions by 24% in 2030 and then by 80% in 2050 compared to 2015.
To achieve this, the sector will rely on levers such as reducing the clinker content of the cements it produces, replacing fossil fuels with alternative fuels such as waste and biomass. The sector also relies heavily on the deployment of future carbon capture and storage technologies.
Of course, the cement sector will also have to process concrete.
As new construction causes significant carbon emissions, remember that the new environmental standards for buildings applicable from 1 January 2022, RE2020 also apply to emissions associated with its construction, including materials that are considered throughout their life cycle.
The dream of “green concrete”
So-called “low-carbon” or “green concrete” has recently appeared on the shelves of building materials stores and on public works carried out by large industrialists.
These concretes are obtained by adding to the cement waste from other industries, including a by-product of the metallurgical industry – blast furnace slag, which replaces part of the clinker with high emissions. Slag, an admixture in iron ore, will have a low carbon footprint, 17 kg per ton, or 45 times less than traditional cement.
According to the newspaper Les Echos, what could be good news for the environment is really just a trick of the hands due to the inaccuracy of the standard NF 15 804 on the contribution of construction to sustainable development, which does not take into account the share of CO2 emitted by blast furnaces. Experts have called for an excellent “green laundering” operation, calling on the authorities to eliminate this legal vacuum as soon as possible.
An update is needed to not discredit real innovation and to allow ongoing research into low-carbon concrete on a more reliable basis, ie with real, recognized and proven environmental impact.
Because today it is still difficult to find the right formula for “green concrete”. Many teams of researchers and startups are trying this around the world with more or less success.
Raw clay cement without firing
In this race for “low-carbon concrete”, young French filmmakers are hoping for French innovation. Materrup, founded in 2018 by Mathieu Neville, PhD in Physics of Materials and Binders, is a pioneer in the production of cement based on raw clay. Working in the research and development departments of Lafarges and Total, the young entrepreneur knows from experience that a radical transformation of the production of building materials must take place as soon as possible.
The technology he developed, called Crosslinked Clay Cement, involves the introduction of up to 70% of raw clay into cement without firing. The rest of the formula focuses on minerals, says Mathieu Neville without further details, seeking to protect trade secrets.
We appreciate clay, not calcined. It is mixed with the activator and precursor to provide a cold reaction and provide the desired mechanical properties
This cement reduces CO2 emissions by at least half without compromising the performance or quality of the concrete. The founders, who are working on zero-carbon formulations in their lab, believe Materrup technology, which they already consider destructive, can still be improved.
The study is also one of the pillars of the company, which in 2021 participated in the creation of a new industrial department at the University of Po and Pey de l’Adour in Anglet. This chair works on the properties of new generations of concrete in terms of hygrothermal comfort and air quality, recyclability and modeling. He is also beginning research on mixed building systems made of clay concrete and natural materials such as straw or hemp, and bio-insulating materials.
Materrup has also just signed an exclusive partnership with the Office of Geological and Mining Research (BRGM) in Orleans to restore the extracted soil.
Local production in conditions of short circuit
Materrup, selected by the Ministry of Environment’s GreenTech program for its environmental impact and large-scale deployment, set up its pilot plant in Saint-Georges-de-Maremne, earlier this year.
The first Materrup cement plant, which has an investment of more than 7 million euros, is equipped with solar panels to reduce the impact of drying, capable of producing 50,000 tons of clay cement from extracted land and quarries nearby. At the marketing stage, it already offers a wide range of materials for building and building cities: concrete blocks, parking slabs and even public benches.
With 17 employees and about ten recruits, the management team has expanded. The adventure was joined by his twin brother and his wife, Julie and Charles Neville from the financial part, as well as his childhood friend Manuel Mercy, a chemist by education, the founder of Materrup puts the company to rapid development.
The company aims to build plants locally, using available clay and distributing its solution in the neighborhood, explains Charles Neville, CFO.
“The goal is to develop small cement plants with an area of approximately 2,000 square meters in the regions, with the advantage of being able to produce materials near workplaces, and thus limit the economic and environmental costs of transporting them.
The project of the new factory may also see the light of day next year in the region of New Aquitaine in the Bordeaux agglomeration for the production of materials that will respect the label “Bâtiment frugal bordelais” of the city and its architectural code. – ocher color. of limestone buildings.
Traditional concrete is gray and homogeneous, very often we try to hide it with plaster or formwork. Our cement-based concrete restores local and traditional colors, respecting the identity of the regions. Grainy or smooth, they are beautiful. Architects have to capture it!
Materrup focuses on 3 production segments. Ready-mixed concrete that is poured into the mixer. Prefabricated production of concrete blocks, slabs or even stairs made in the factory, and finally finishing materials such as plaster, mortar and glue, details in turn, engineer and partner Manuel Mercier.
With Materrup, we are moving from ordinary Portland cement to custom cement, as we use special clays for certain purposes. The point is not to remove ordinary concrete, but to replace it where it is not needed.
With its family structure and desire to become a company with a mission, Materrup is today a little finger in this sector of large cement groups and construction giants. Its dynamism and technology attract the attention of major market players, and sometimes envy. More restrictive norms and rising energy and carbon prices, lines will have to move. An easily and quickly industrialized company can sign several partnerships, ensuring that it continues to control its technology, which is protected by approximately 35 international patents. You should have this when you are the only company in the world that owns a clay composition.