What is it about concrete?
At the core of concrete’s appeal is the freedom and versatility of ‘liquid stone’, writes Felix Mara
What is it about the use of concrete that is so appealing to architects?
To say that it makes them feel as though they’re keeping company with great protean figures, such as Le Corbusier and Louis Kahn, seems to beg the question. More probable is that it takes skill to design and specify good concrete building.
Concrete isn’t a product which, budget permitting, any business-minded architect can order off the shelf, and it therefore presents an alluring challenge.
Perhaps the popular reception, or populist projection, of concrete explains its attraction. It’s still possible, just, to épater le bourgeois with a concrete building, and it might even be accepted as ugly, but nevertheless a work of art, rather than merely ornamental.
But at the core of concrete’s appeal to artist-architects is the opportunity to roll up their sleeves and engage directly with the medium.
‘It’s the most versatile of materials,’ says AKTII director Gerry O’Brien. ‘Being fluid, it is infinitely mouldable.’
‘It’s liquid stone,’ says concrete specialist David Bennett. ‘Structural engineers are retrogenerate people, whereas the innovators and drivers
But concrete also has a scientific dimension. A thoroughly constructive response to the possibilities of modern technology was at the heart of the New Brutalism, which sought to go much further and deeper than many of the comparatively low-tech rendered masonry creations of early Modernism and the International Style.
In recent years, the technical possibilities of concrete have grown exponentially, especially with developments in what Pina Petricone refers to as nanotechnology and biotechnology in her new book, Concrete Technology.
Undoubtedly the most significant advance has been in the area of visual concrete specification (AJ 02.09.10). It is now possible to achieve high-quality, consistent and enduring concrete finishes by following well-documented construction procedures and specifying suitable materials and products. The element of chance can be almost completely eliminated and the view that external concrete is inherently grubby, streaky and weather-prone is no longer tenable.
But Bennett is surprisingly sceptical and argues that little of this technology is actually new or adds much to the expertise of the Romans, although he qualifies this with a number of caveats: spun concrete columns, for example. Using cages which spiral around principal reinforcements, their load-bearing capacity-to-footprint ratios are unrivalled and they can achieve compressive strengths of 120MPa.
Aerated concrete is another exception. It is incredibly light and can be worked with carpentry tools. Computing and fabrication technology has also expanded the possibilities of what can be achieved with formwork, for example with the advent of five-axis CNC routers. There are also some extraordinary finishes available, such as Rieder’s fibreC glass fibre concrete facade panels, which look like shiny metal. High performance Ductal concrete, available with reinforcing microfibres, has exceptional compressive strength and, assuming it achieves its anticipated life of a thousand years, has a low environmental impact.
‘The concrete industry is one sector of construction that has really pushed forward its sustainability agenda,’ says O’Brien. ‘We use it in many ways, from passive thermal mass to active chilled slabs, which minimise floor zones.’ Indeed, concrete can no longer be caricatured as a moustache-twirling enemy of the environment: as an eminently engineerable material, it can be specified with ground granulated blast-furnace slag (GGBS) or the darker, more economical pulverised fuel ash (PFA) instead of deleterious Portland cement.
Bennett criticises certain aspects of concrete construction in Britain. ‘Pigmented ready-mix is taboo here and people expect precast concrete to be bespoke, rather than modular and standardised – and therefore expensive.’
Nevertheless, this week’s building study and case study both demonstrate what can be achieved with rational precast construction in Britain today.
Ultimately these advanced technologies only serve to underpin the artistic possibilities of concrete in architecture. Bennett uses the word ‘rustic’ to describe what he regards as some of the most exciting work in this field, for example Peter Zumthor’s use of rammed concrete construction. And, speaking of new-fangled technology in Concrete Ideas, the American architect Will Bruder says: ‘Just because we can, do we do it? Why would concrete ever want to be translucent?
‘I don’t see any of these nanotechnologies as being a sweeping technology that’s going to transform the way we think about concrete as a culture or as a design profession. Concrete’s great thing will always be the idea of its mass and quality.’
Concrete Ideas ships in an exquisitely-crafted grey box, a play on formwork technology, and its handsome, predominantly greyscale photographs and drawings convey a passion for concrete which you can only read between the lines of its dry, ambivalent text. Petricone’s is nonetheless a revisionist project. Speaking of Venturi and Scott-Brown’s 1972 publication Learning from Las Vegas, she writes: ‘From roughly that point onward, concrete took on increasingly negative cultural connotations and the public at large developed a substantial antipathy towards it.’ That Venturi once worked for concrete past-master Louis Kahn might have offered some insights here.
The book is divided into five sections. These investigate the topics of Abstraction, Operation, Insertion, Section and Speculation and begin with introductory discussions, followed by tantalisingly short entries on ‘current concrete nanotechnologies’, which are, by far, the most interesting pages in the book. They introduce some truly amazing developments, such as super-fluid, bendable, illuminating, conductive, ceramic, ultra-smooth, ultra-thin, smog-eating and self-healing concrete, some more ‘for real’ than others. These are followed by descriptions of projects in Toronto that explore concrete and problems surrounding its reception, which demand exceptionally high levels of reader concentration.
The final section ends with four lively discussions involving the architect Will Bruder, Mark West and George Elvin, which are fitting for a book which is founded on qualitative research and discourse analysis, rather than statistics, and investigates a subject which has a way of encouraging people, especially architects, to wax lyrical, sometimes painfully: ‘How can the now most commonplace building material resurface as a critical presence in the city?’ asks Petricone.
Despite being peppered with some pithy descriptions of jaw-dropping technological advances, this is not a textbook about concrete technology. Its main focus is the reception of concrete and, at least two decades too late, it challenges an orthodox view of the material’s use by architects that could be summarised in the quasi-Hobbesian phrase ‘nasty, brutal and short-sighted’. The red-blooded artist-architects who get most excited about concrete are as likely to take an interest in its reception as they are to read literature about ‘what clients want’ – as far as they’re concerned, clients should be reading books about what architects want.
Concrete Ideas: material to shape a city Petricone, Pina (ed), London, Thames & Hudson, 2012, 246pp, £35.00