Ultra-high-performance concretes (UHPCs) are reckoned to be the construction material of the future. When they are coloured, however, you have to ensure that the prescribed compressive strength of more than 150 megapascals is still achieved. The iron oxide pigments from LANXESS’s Bayferrox brand are perfect for UHPCs, as has been verified by the association of German cement manufacturers (VDZ) based on an analysis of compressive strength conducted to DIN EN 12390-3.

“Architects and clients can have every confidence in our high-quality pigments for colouring UHPC,” says Oliver Fleschentraeger, Market Segment Manager Construction of the Inorganic Pigments business unit at LANXESS. The iron oxide pigments come in red, yellow, and black, with numerous colour nuances possible within these shades. “As far as we know, Bayferrox pigments are the only iron oxide pigments on the market that are specially certified for use in UHPC,” says Fleschentraeger.

Pressure-resistant, colourful, and environmentally sound The quantity of materials used is a key metric when it comes to assessing a building’s carbon footprint. Not only the choice of materials but also the production chain and construction process are also crucial. So, to save materials and energy and to reduce CO2 emissions during manufacture, planners and architects are increasingly using highly sophisticated high performance components made from UHPC. In addition to the enormous resource savings of up to 80 percent, material-friendly designs reduce carbon dioxide emissions in the manufacturing phase by up to 30 percent. “A significant and pleasing side effect of UHPC is its high resource efficiency, which makes it easier for engineers to meet the demand for sustainable designs,” says Dr. Michael Olipitz, a certified expert in the fields of superstructure, bridge-building, steel structures and structural engineering, and General Manager of the engineering office SDO ZT GmbH based in Graz, Austria. Inorganic iron oxide pigments can provide long-lasting visual enhancement to these structures or even effectively contextualise them with their surroundings – without affecting the rheology or flow behaviour of the concrete.

Delicacy and solidity go hand in hand One spectacular architectural application of coloured UHPC is the Museum of Civilizations of Europe and the Mediterranean (MuCEM) in Marseille, in the south of France. With the exception of two glazed facades, the museum – including most of the roof – is encased in a latticelike concrete structure comprising concrete panels just 10 cm thick. The French architect Rudi Ricciotti made a conscious decision to colour the concrete dark grey to lend the building its own identity within its surroundings and as a stark contrast against the colour of the facade. The precast concrete elements were coloured with Bayferrox 330 and Bayferrox 318 from LANXESS.

Another benefit of the high-quality Bayferrox pigments is that the concrete, once coloured, retains its characteristic texture and exhibits subtle colour nuances, lending the surface a natural appearance. In addition, there are no layers of paint that can flake off of the surface through wear and weathering. Even if the surface is slightly damaged, the colour remains as vivid as ever. This is why iron oxide pigments are the perfect choice for colouring ultrahigh-performance concretes, which, with a projected lifetime of more than 150 years, are around twice as durable as conventional concrete.