IN 2020
T A B L E O F I N D I C A T O R S
F O C U S 7
Launch of the low-carbon
concrete challenge In 2020, Société du Grand Paris reinforced
its ambition by launching an low-carbon
concrete challenge . The aim is to work with
the construction companies and create the
appropriate conditions for using low-carbon
concretes that are specific to each Grand
Paris Express contract. A dedicated team
has been set up within the Strategy and
Innovation division to manage and monitor
the implementation of this ambition.
This team is working on the eco-design of
concrete structures and is aiming to develop
various solutions that can be implemented at
an equivalent or lower cost by reusing some
of the spoil from the Grand Paris Express in
the production of these low-carbon cements.
Use of processed spoil as
a binder in concrete In September 2020, Société du Grand Paris
co-funded an experiment with ADEME to
evaluate whether clay materials from the
Grand Paris Express could be converted into
an alternative binder that could be used in
concrete formulations to partially replace
traditional cements that emit high levels of
CO2. The results showed that by using this
binder in Grand Paris Express concretes,
carbon emissions could be reduced by a
factor of five.
Environmental innovation
bonus Société du Grand Paris is convinced that
the carbon footprint of concrete can be
reduced even further in public procurement
contracts already awarded, particularly
with regard to the manufacture of stations
internal structures and tunnel linings and
aprons. In December 2020, it therefore
introduced an environmental innovation
bonus to financially incentivise contractors
to develop solutions that use less concrete
and/or replace traditional concretes with
low-carbon concretes, while maintaining
the quality of the structures built.
ACTION 16 Encourage greenhouse gas emissions reduction initiatives
The construction of the Grand Paris Express will generate nearly 4.5 million tonnes of CO2,
half of which is linked to the concrete used on its worksites. Aware that during the construction
phase, the use of concrete is the main source of greenhouse gas emissions, Société du
Grand Paris is doing its utmost to find alternative solutions that emit less CO2.
Optimising infrastructure sizing and environmental performance
As part of an ambitious eco-design approach, the volume of structures has been optimised
to reduce the amount of materials required to build them.
Promoting the use of low-carbon construction materials
Due to the mainly underground nature of the works, Société du Grand Paris requires contractors,
via the specifications, to use slag-based concretes known as low-carbon concretes in the
manufacture of moulded walls, aprons, cover slabs and voussoirs. These concretes produce
significantly less CO2 emissions during their manufacture. Four years after the start of civil
engineering works, more than 70% of the Grand Paris Express is built with low-carbon concrete
containing CEM III cement or an equivalent binder.
Convinced that it is possible to do still more, Société du Grand Paris is encouraging existing
and potential contractors to use innovative materials to reduce the carbon footprint of building
the infrastructure and its real estate projects as much as possible (fibre-reinforced concrete,
wood and bio-based materials, etc.).
Société du Grand Paris has also launched the designed concrete process, which is a
requirement in the latest calls for tender. Contractors are encouraged to propose concrete
formulations based on sustainability and carbon emission criteria to meet the objectives set.
RISKS AND CHALLENGES
2020 ACTIVITY
CSR APPROACH
Actions
IDENTITY