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Béton brut (french for raw concrete) is a smooth architectural surface made out of concrete. The concrete is left unfinished or roughly-finished after casting and it remains exposed visually. The final surface often shows the forms and structures of the formwork.
The best known proto-Brutalist architecture is the work of the Swiss architect Le Corbusier, in particular his 1952 Unité d’habitation in France and the 1953 Secretariat Building (Palace of Assembly) in Chandigarh, India. Brutalism gained considerable momentum in the United Kingdom during the mid-twentieth century, as economically depressed (and World War II-ravaged) communities sought inexpensive construction and design methods for low-cost housing, shopping centres, and government buildings.
Nonetheless, many architects chose the Brutalist style even when they had large budgets, as they appreciated the ‘honesty’, the sculptural qualities, and perhaps, the uncompromising, anti-bourgeois, nature of the style.
The use of béton brut was pioneered by Auguste Perret and other modern architects. It was used in such buildings as Unité d’Habitation in the early part of the twentieth century. It flourished as a part of the brutalist architecture of the 1960s and 70s.
This largely gave way to structural expressionism as steel structures became more advanced and viable. Wood-imprinted concrete is still very popular in landscaping especially in some of the western European countries.
Exposed concrete surfaces can be varied with different formwork shetting (e.g. board shuttering, smooth formwork, form liner, form moulds, filter fleeces) or with surface processing techniques (e.g. washed concrete surfaces, photo concrete, acidified surfaces). Particularly high quality poured concrete, achieved by leaving enough room between the formwork and the reinforcing bars for the concrete to flow freely, is called Sichtbeton in German, cemento a vista in Italian. This translates roughly into “concrete for viewing.”
Brutalism as an architectural philosophy was often also associated with a socialist utopian ideology, which tended to be supported by its designers, especially Alison and Peter Smithson, near the height of the style. This style had a strong position in the architecture of European communist countries from the mid-1960s to the late 1980s (Bulgaria, Czechoslovakia, GDR, USSR, Yugoslavia). In Czechoslovakia brutalism was presented as an attempt to create a “national” but also “modern socialist” architectural style.