22 • January 2018 www.concreteproducts.com
NEWS SCOPE
PRODUCERS
LafargeHolcim Ltd. unit Holcim Deutschland
formulated a series of high performance
concretes for elements lining a 3.4-kilome-
ter tunnel housing the world's most powerful
X-ray laser. Located near Hamburg, Germany,
the European XFEL generates extremely
intense X-ray flashes researchers from
around the world use to map atomic details
of viruses, film chemical reactions, and study
the processes in the interior of planets.
Holcim Deutschland produced special-
ized concrete for the extensive underground
tunnel system, including easy-to-pump,
heavy mixes for radiation shields and
underwater placement. LafargeHolcim engi-
neers 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 inter-
fering 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
HPC mix designs heed laser tunnel aluminum, magnesium, silica sensitivity
TUNNEL PHOTO: European XFEL