Successful pilot project on the use of clinker-efficient cement Dyckerhoff CEDUR

The extensive expansion of renewable energies, such as wind energy, necessary to achieve the legally prescribed CO₂ reduction targets in the energy sector nevertheless requires enormous investments in the corresponding electricity infrastructure. Concrete is needed above all for the foundations that must securely support the pylons of high-voltage power lines and wind turbines. Depending on its size and the soil conditions, the foundation of an electricity pylon consists of around 200 m³ of concrete, which contains a good 70 t of cement.

Cement accounts for the largest share of CO₂ emissions in concrete. However, CO₂ emissions in concrete can be reduced by using cements with several main components. Actually, this is not a new concept. The production and use of cements with several main components, such as Portland limestone, Portland blast furnace, or Portland composite cements with relatively high proportions of limestone powder, blast furnace slag, or fly ash, have long been state of the art in Germany. However, it can be assumed that the availability of blast furnace slag and fly ash in Western Europe will decline in the coming years. Against this backdrop, new composite cements have been developed and introduced. For the Dyckerhoff sites in Amöneburg, Neuwied, and Lengerich—and in the future also Göllheim—this is CEM II/C-M (S-LL) 42.5 N with the brand name CEDUR. Since the end of 2020, this cement has been used predominantly in concrete up to strength class C25/30, and its market share in the ready-mixed concrete segment is growing steadily.

With the aim of avoiding unnecessary emissions, route operators and wind turbine manufacturers have also begun to use concrete with a lower carbon footprint. In order to expand the scope of application of CEDUR, the concrete laboratory at the Wilhelm Dyckerhoff Institut (WDI) investigated possible applications in higher-quality concretes, e.g., with frost-deicing salt exposure, as well as in concretes with higher strength classes from C30/37 to C40/50 and higher, such as those used in the construction of wind turbines. The laboratory tests were positive. However, there was still no corresponding practical application for the time being.

In spring 2024, time had finally come: as part of the construction of the new 380 kV line between Stade and Landesbergen, transmission system operator TenneT Germany intended to test CO2-optimized concrete. The aim was to assess whether and, if so, under what conditions or restrictions a rollout for future overhead line construction projects would be both technically feasible and economically efficient.

In collaboration with our customer Tramira, the concretes developed in the laboratory were adapted to the client's requirements. The project focused on both anchoring using bored piles and shallow foundations for electricity pylons, for which concrete with strength classes C30/37 and C35/45 was planned respectively. The overall aim was to achieve a 30% improvement in the carbon footprint without compromising the construction process, e.g., as a result of slower strength development. Another goal was to use locally available raw materials wherever possible. The concrete based on CEDUR from the Lengerich plant met all these criteria.

The concrete compositions were determined in close consultation with the concrete manufacturer Tramira, with the concretes being designed both for the requirements of this project and for the construction of foundations for wind turbines.

Following static design, the investigations within the scope of the project focused on two applications of concrete foundations: shallow foundations and pile foundations. During construction, a large number of concrete parameters were determined both in the concrete plant and on the construction site. The main focus was on the development of the strength of the concrete depending on the different weather conditions and on proving that the use of clinker-efficient cements is also possible in higher-quality concrete applications. In addition to the mandatory quality tests at the concrete plant and on the construction site, a large number of hardening cubes stored outdoors were also used for continuous monitoring of the building material.

The concreting took place between February and July 2024, allowing for different weather conditions to be taken into account. The pilot project and further investigations showed that the CO₂-optimized concretes based on clinker-efficient CEM II/C-M (S-LL) 42.5 N (na) cement, are also well suited for high-quality applications, such as bored pile concrete and concrete for slab foundations for electricity pylons in this case.

According to its own statements, minimizing CO₂ emissions during the construction and conversion of the energy system is of great importance to the grid operator TenneT Germany. The results obtained in this project show that it is possible to reconcile the client's goals of economic efficiency and climate protection.

Further information can be found in the special edition of the article Sustainable Concrete for the Energy Transition, published (in German language only) in April 2025 in the technical journal “beton” and produced in collaboration with Tramira Transportbetonwerk Minden-Ravensberg and TenneT Germany.

Photos 3, 5, 6: TenneT TSO GmbH

For further information, please contact:
Iris Weise-Rosch, Tel.: +49 611 676-1187
marketing@dyckerhoff.com