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Adjaye's red wave

The architect has explored the possibilities of pink and red-hued concrete on a series of very different US projects, writes Nick Jones

The aesthetic potential of pink and red-hued concrete has been explored in a series of US projects by British Ghanaian architect David Adjaye. The McCarter Switching Station in New Jersey, Ruby City art centre in Texas and The Webster retail store in Los Angeles, all completed in the last couple of years, use pigmented concrete in a variety of ways: both precast and in-situ, with different aggregates and finishes, and with some interesting regional variations.

At the McCarter in Newark, Adjaye wrapped the substation in a 600m-long precast-concrete wall and a canopy of 11m-high columns. Working with a local precaster, they developed a mix containing a mineral-based pigment added during the casting process. “It was a response to the regional vernacular, which is predominantly red brick,” says Adjaye senior director Russell Crader. “We wanted to really try to pigment the concrete, not just add a tone to the finish.”

The practice undertakes rigorous studies into the appearance of concrete, and experiments a lot. “Our process is heavy on learning,” says Crader. “We’ve worked with different aggregates to change the hue of the red – it might be a local stone with a bit of a red tone or a black or brown that changes the pigment ever so slightly.” This is evident on the precast facade at Ruby City, which is a deeper red than the substation, inspired by the San Antonio desert.

“We used a local stone – the clay is heavy in nitrogen which is where the red comes from. And we added recycled red glass to really bring out that colour and make it more haptic and sensory.” In-situ concrete in the same tone is also used, for flooring and an external wall. Crader describes this as an inherently less controlled process, particularly in hot environments, where the amount of water added in the concrete truck can have a significant effect on the finished tone, making it paler.

But having already manufactured the precast concrete proved invaluable: “You can learn a lot from your precast team about the mix design. They can test the PSIs in the factory, and all the qualities of the concrete.” These material explorations have perhaps reached their apotheosis at The Webster, a fashion boutique at the base of an eight-storey mall. The exterior is clad in pink precast panels, punctuated with deep perforations. This effect was created by using a salt additive in the form liner to draw out the moisture as the concrete cures – a process used for sidewalks in the southern US. “That’s part of the joy of concrete, how the craft changes from region to region. You can’t sandblast in some US jurisdictions, for example, you have to use walnut shell grit, so the textures change.” 

Inside the store, a switch to in-situ concrete explores the more fluid nature of the material. The soft pink walls are left exposed, with what Crader describes as a “slight furring” of the joints and boltholes. The idea was to create a sense of movement, with the walls almost falling into the terrazzo-like floor, which has larger chips of limestone, marble, and granite. “The aggregate almost comes to life – it’s a play on what concrete can do.”

For more on how to achieve pigmented concrete, see CQ 256, available at concretecentre.com/archive