In praise of concrete

Look around you. See any concrete? If you’re in Europe, chances are good you live and work in concrete-based structures. Concrete is to infrastructure what carbon is to life: intrinsic. Your water supply is channeled in concrete aqueducts. The bridges and sidewalks you cross every day on your way to work are concrete. Concrete dams prevent flooding and guarantee constant electricity for thousands of people. And, of course, you can sleep well at night knowing that the concrete in your basement fallout shelter will shield you from radioactive fallout in the event of nuclear war. Nothing could be more commonplace. More, well, boring. Let’s face it, concrete is about as sexy as nostril hair. It’s there, it certainly serves an important purpose, but it’s not always unequivocally appreciated.

Spend a few minutes talking with Architecture Professor Roberto Gargiani, however, and you’ll never take this amazing material for granted again. It has a long and rich history, peopled with vibrant characters. According to Gargiani, it provided the impetus for the scientific study of geology and helped spawn the vast academic and industrial empire that is known as engineering. And it’s continuing to evolve today, the subject of intense scientific, engineering and architectural attention.

Concrete dates to prehistoric times. The Romans used natural cementitious materials found in the soil, called pozzolans, to bind their concretes. Natural pozzolans are forged in volcanoes, which explains why volcano-studded Italy was an important reference point in the history of concrete. Mixing concrete was an artisanal skill; recipes were passed down from generation to generation. Naples was full of terraced concrete houses. These structures were impermeable to water, wind- and fire-proof, and earthquake resistant. When compared with wood, which regularly burnt, rotted, leaked, collapsed and/or succumbed to insects, it was the Holy Grail of building materials. But transporting pozzolans from Italy was prohibitively expensive, as was burning enough wood to attain the extremely high temperatures required to turn chalk into pozzolans artificially. “Geologic research was motivated by the interest in obtaining local sources of natural pozzolans,” explains Gargiani. From there, geologists branched out to invent and rediscover the recipes for mixing concrete – transforming it from a traditional craft into a documented science.

As Europe industrialized in the 18th and 19th centuries, the French, English, and Dutch, among others, were interested in using concrete, particularly for military and naval infrastructures – ports, bunkers, underground storage facilities and the like. The development of coal-fired kilns meant that pozzolans could be cheaply produced from abundant sources of limestone and chalk. Concrete was here to stay.

In France, the Ecole des Ponts et Chaussées was established to train people to erect bridges, dams, and other infrastructures in concrete. With this institutionalized approach, research into concrete became very structured and organized. Every year, a report had to be published and sent to the director, outlining the knowledge gained and problems encountered. Thus the grand French engineering tradition was born – along with the pressure to publish! – with concrete at its core.

It wasn’t until the 20th century that concrete came out of the basement. Until then, whenever it showed its face aboveground it was disguised to look like natural stone, all traces of molding painstakingly removed. The famous architect Le Corbusier changed all that. He gave concrete its own identity, and since then, architects have explored concrete as a medium of expression; colors, textures, embedded objects enrich the palette of possibilities. Technological innovations are producing “smart” (sensorstudded) and “green” (incorporating waste materials) concretes. What’s not to like?