With environmental concerns on the rise in the entire western world, one would easily think that concrete, with its industrial and modern image, is on the way out. In fact, concrete is continuing to grow throughout the world, with the unabated love of urban planners and architects.
Concrete is the perfect mix of vintage and modern. It has been in use for many millennia, under various forms, though its use was limited until new technological breakthroughs in the 18th centuries, when its market share started growing, a growth which is still ongoing today. It contemplates many a competitor in the building business, but holds an edge on each one of them. Nowadays, its most up-and-coming contender is timber. But even facing the building material which wrongfully holds the most ecological image, concrete holds its ground. Surprisingly, one of the aspects for which concrete is being favored again is its health benefits. The reason behind this advantage is simple: wood being an organic matter, it is also one of the preferred living environments for micro-organisms, which find food and shelter in its fibers.
These organisms can be rather visible, such as the ever-problematic termites which can bring an entire construction to the ground, but most are microscopic, such as those contained in grease. In the case of micro-organisms they can prove all the more dangerous because their microscopic size make them invisible to the naked eye, and sometimes contaminate the inhabitants whereas micro-organisms simply have no place to nest in concrete.
In an era where, into the bargain, originality is key in the architects' world, concrete also offers simply more possibilities than other do. Simply put, there is virtually no limit to the constructions accessible to concrete. The Rome Colosseum, the CN tower, and the Corco Vado are all concrete structures which could not have been built with any other material. Likewise, skyscrapers are a concrete production, even if some of them are made of concrete mixed with steel. The highest wooden construction to date is the University of British Columbia, which culminates at 175 feet.
Concrete sports the double advantage of having its strength beefed up (known as reinforced concrete, with bars or fiber, made of glass, plastic or steel), and being applicable to 3D printing – though this technology is still nascent: 3D printing Industry reported on a new-generation robot “capable of creating complex mesh structures to be used as framework for concrete. Concrete 3D printing is currently undertaken by several enterprises, including Apis Cor and CyBe.” In a recent Canadian debate about whether buildings should go for concrete or timber, Jim Munro sided that according to architects and builders, “structural soundness, low noise transmission, weather resistance and long-term sustainability will remain focused on concrete”.
Considering safety hazards, wood is less of a loser than one might think. Fire retardant treatment is applied to wood panels and segments. However, they are composed of heavy chemicals, which somewhat defeats the purpose of wood, if one is appealed to its for its natural origin. Also, treated wood will retard fire only for so long, with a maximum of 30 minutes, as International Timber assures. “Fire-resistant linings, such as plasterboard, can be used to protect the timber. And the spread of flame on exposed timber can be reduced by surface coating or impregnating chemical treatments.” In fact, concrete is the best of all materials in terms of fire resistance. Wood will eventually, and quite rapidly burn and, while steel will not burn, it will lose its compressive strength. While steel will melt around 1200° C, it will lose most of its building-frame qualities at half this temperature – which will be rapidly reached in a large fire. In contrast, concrete will not burn and will prevent fires from expanding from one room to the other.
Naturally, wood is praised for its beauty, and its various essences which can give a building character. Concrete engineers therefore have designed ways to stretch the appearance of concrete, in some cases to quite good-looking surfaces. For some more information, the American society of Concrete Decorators organizes yearly contests, with highly startling contenders. Unknown to many is also the fact that concrete is one of the environmental high-rankers since it is totally recyclable. New technologies enable concrete to be hashed into aggregate for new concrete, or to be used as an underlayer for road construction. In a time when the environmental impact of constructions is high on the list of concerns for architects, concrete pulled a trump card. Wood – for its part – often requires long transport, leaving a hefty carbon footprint behind it, hence being denounced by many environmentalists.