Millau Viaduct


Millau Viaduct
Page 42
Country: France
Dates of realisation: Late 2001 - Decembre 2003
Public opening: Decembre 16th, 2004
Millau Viaduct
CHRYSO®Fluid Optima 175
Concrete formulation
• Total volume of concrete
• Geographical situation
Construction of the Millau Viaduct, constituting the last stretch
of the A75 motorway. It enables Clermont-Ferrand to be reached
directly from Béziers, therefore avoiding the Millau traffic
bottleneck. It also is the most direct and cheapest route
between Paris and the Mediterranean sea.
The viaduct of Millau is longer and higher than the bridge of
Normandy, and crosses the Tarn River to the West of Millau.
There were numerous constraints to this construction site :
• geological (protected natural zone),
• climatic (winds, important temperature changes),
• geographical (in between two valleys).
• Details of the project
Admixture used
CHRYSO®Fluid Optima 175
A wide scale of dosage according to the types of concrete
produced: 0.4 % for a B35 up to 1.4 % for a B60G.
Production of consistent quality of concrete while still
achieving the rheological and mechanical characteristics
required, even with major variations of the outside
temperatures: below 0 °C in winter with hot concrete and
above 35 °C in summer (profile taken from the 2003 heat
wave), with protected constituents.
A homogeneous, non viscous concrete which facilitated
pumping and improved pouring into formwork.
With a length of 2,460 metres and piles peaking at 343 metres,
the viaduct of Millau is a world record in height and a technical
Its particularity lays in the choice of a metal deck, supported by
cable stays and based on concrete piles, and on the fact that they
were all set up separately.
There were 9 separate construction sites on this jobsite: the 7
piles were poured simultaneously, while the deck was mounted
• A few figures
• 2,460 m: Total length of the deck
• 7: Number of piles
• 77 m: Height of the shortest
• 250 m: Height of the highest
• 87 m: Height of each pylon
• 154: Number of cable stays
• 4.20 m: Deck thickness
• 32.05 m: Deck width
• 85,000 m3: Total volume of
concrete on the jobsite
• 36,000 tons: Weight of the
metallic structure
80,800 m3
• Only one admixture for 3 specifications
CHRYSO®Fluid Optima 175 allowed the formulation of
different types of concrete, thus meeting geological, climatic and
geographical constraints. Construction was spread over 3 stages:
Casting of the Morrocan wells (foundations): 8,000 m3 of
• B35 with 100% of grinded aggregates and 300 kg of binders
(containing silica fumes)
• Slump: 15 ± 3 cm
• Workability retention: 90 min
• Average compressive strength at 28 days > 50 MPa
• Resistance to tension at 28 days > 4 MPa
Base sections (grounding under each pile and temporary
bedplate): 22,300 m3 of concrete
• B35 for civil engineering, with silica fumes
• Slump: 13 ± 3 cm
• Workability retention: 90 min
• Compressive strength at 28 days > 50 MPa
• Casting of each bedplate: 24 hours non stop
The piles: 50,500 m3 of concrete
• Cement : 420 kg of CEM I 52.5 N PMES CP2 from LE TEIL
• Concrete without silica fumes in order to obtain the clearest
possible surface finish aspect
• B60 resistant to frost, with a flowing consistency (requirements
of the Groupe Rhône-Alpes (GRA))
• W/C: 0.335
• Slump at the DIN table: 50 ± 5 cm
• Workability retention: 90 min
• Average compressive strength at 12 hours at 20 °C: 3 MPa
• Compressive strength at 17 hours: 29 MPa
• Compressive strength at 28 days > 75 MPa
• Tensile strength at 28 days > 6 MPa
Project participants
• Owner: Millau Viaduct Eiffage Company (MVEC)
• Project manager: Setec
• Architect: Lord Norman Foster
Pictures: Eiffage TP
• Company: EIFFAGE TP group
• Concrete supplier: SATM - Bétons Chantiers Prêt (Lafarge)