Laser tunnel’s HPC mixes stingy on aluminum, magnesium and silica

Sources: LafargeHolcim Ltd., Zurich; CP staff

LafargeHolcim and Holcim Deutschland have formulated a series of high-performance concrete mixes for a 3.4-kilometer tunnel housing the world’s most powerful X-ray laser. Located near Hamburg, Germany, the European XFEL generates extremely intense X-ray flashes allowing researchers around the world to map atomic details of viruses, record chemical reactions, and study planets’ interior processes.

The Holcim unit produced specialized concrete for the extensive underground tunnel system, including easy-to-pump, heavy mixes for radiation shields and underwater placement. LafargeHolcim engineers developed additional mixes meeting European XFEL contractor requirements for reduced content of aluminum, natrum, silica and magnesium—common in portland cement and concrete but potentially interfering with highly sensitive measurements in the tunnel. Some concrete mixes required the use of special limestone chippings to attain particularly low silica levels.

LafargeHolcim and its client carried out extensive chemical and physical tests for every concrete mix to ensure tunnel elements reach the highest performance levels. The producer also developed an integrated logistics solution for the European XFEL, ensuring material deliveries complied with strict traffic, dust and noise regulations. With its global research & development center in Lyon, France, and Switzerland staff and operations’ extensive tunneling expertise, LafargeHolcim is uniquely positioned to meet specifications of engineers and architects tackling technologically challenging projects across the globe.