Ultra-high-performance concretes reliably colored with Bayferrox
Ultra-high-performance concretes are regarded as the construction material of the future. In coloring them, however, it must be ensured that the specified compressive strengths of over 150 MPA continue to be reached. The iron-oxide pigments of the Bayferrox brand from Lanxess have been proven to be suitable for use in UHPC. This was confirmed by the Association of German Cement Works (VDZ), based on investigations of compressive strength in accordance with DIN EN 12390-3.
“Architects and builders are on the safe side when coloring UHPC with our high-quality pigments,” emphasizes Oliver Fleschentraeger, Market Segment Manager Construction in the business area Inorganic Pigments at Lanxess. The choice of color comprises red, yellow and black iron oxides. Within this color group, a wide range of color shades is possible. “Bayferrox pigments, to our knowledge, are the only iron-oxide pigments on the market that are especially certified for reliable use in UHPC,” points out Fleschentraeger.
Resistant to pressure, colorful and environmentally safe
The quantities of the materials used are important for the eco-balance. The materials chosen, as well as the production chain and construction, are also crucial. Planners and architects focus on slender and very high-performance construction components of UHPC to save material, energy and CO2 emission during production. Apart from the enormous savings in resources of up to 80 %, vast amounts of carbon dioxide as high as 30 % can be saved in the production phase by using constructions with appropriate materials.
“A not insignificant side effect of UHPC is the high resource efficiency. With it, engineers are better able to satisfy the demand for sustainable constructions,” says Dr. Michael Olipitz, certified expert in the sectors of building construction, bridge construction, steel construction and structural design, as well as managing director of the engineering consultants SDO ZT GmbH from Graz, Austria. Inorganic iron-oxide pigments can durably enhance the visual perceptions of buildings or even effectively put them into a context with their surroundings – without affecting the flow behavior of the concrete.
Filigree lightness and solid durability
A spectacular example for the application of colored UHPC in architecture is the Musée des Civilisations de l’Europe et de la Méditerranée (MuCEM) Marseille in southern France. Except for two glazed façades, the museum, including the major part of the roof surface, is wrapped in a lattice-like concrete construction, consisting of concrete panels of only 10 cm thickness. In implementing the building, the French architect Rudi Ricciotti consciously decided on coloring the concrete in a dark-gray shade in order to give the building its own identity by the color contrast of the façade to the surroundings. The precast concrete elements were colored with Bayferrox 330 and Bayferrox 318 from Lanxess.
An additional advantage of the high-quality Bayferrox pigments: the colored concrete retains its characteristic concrete texture and shows slight color nuances, giving the surface a natural look. Moreover, no color layer can get detached from the surface due to wear or weather effects, and the color remains visible permanently and unchanged even after slight damages to the surface. Iron-oxide pigments are therefore the perfect choice for coloring ultra-high-strength concretes that, with their projected lifetime of more than 150 years, achieve about double the durability of conventional concrete.
