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The Secrets of Roman Concrete Imagine Building Structures That Last 2,000 Years

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The Secrets of Roman Concrete Imagine Building Structures That Last 2,000 Years THE SECRETS OF ROMAN CONCRETE IMAGINE BUILDING STRUCTURES THAT LAST 2,000 YEARS. HOW DID THEY DO IT? Photo by Lakisha Campbell BC Nightly News, August 7, 2002, Matt Lauer anchoring: It was one of ROMAN CONTRACTORS & CONTRACTS The Colosseum, or Flavian Amphitheater, sits Nthose catchy, uplifting, end-of-the “Aside from the employment of soldiers near the southeast end of the Forum, between broadcast stories. It seems a man has been from the Legion, and government slaves, the Palatine and Esquiline hills of Rome. stealing coins for 30 years out of a public which were common in the ancient states, Begun by the Emperor Vespasian in circa 75 fountain. Not just any fountain, mind you, but the main construction force behind the A.D., and completed by his son Titus in 80 the Trevi fountain, in Rome—an icon of building of large projects, excluding the A.D., it is the most imposing of Roman antiq- romanticism immortalized in the Fellini film many military roads, bridges and fortifica- uities. The vast, four-storied oval is 617 feet “La Dolce Vita”and the American classic, tions, were contractors….in fact they pos- by 512 feet, much of which is still standing. “Roman Holiday,” with Audrey Hepbu r n . sessed the same basic function of our Lost to the ages are tier on tier of marble seats Lovers and tourists are seen frolicking about modern contractors,” writes David Moore. that originally accommodated some 45,000 an old-world fountain complex of spectacular They even had the same gripes. He spectators, but were looted by succeeding beauty, the water looking as clean and pure quotes the Roman engineer Vitruvius, as generations. The Colosseum encloses an and effervescent as if poured from a million follows: “things of this sort should be arena measuring 250 feet by 151 feet, the bottles of Perrier. known to architects, so that, before they site of gladiatorial combats until 404 A.D. It is said, the reporter intones, that if you begin upon buildings, they may be careful The structure has been damaged several turn your back to the fountain, make a wish not to leave disputed points for the house- times by earthquakes and fire, but those por- and flip a coin over your shoulder into the holders to settle after the works are fin- tions built with Roman concrete endure. water, your wish will come true—and indeed ished, and so that in drawing up contracts — Stephani Miller the video captures people doing so. The the interests of both employer and con- money, the reporter continues, is supposed to tractor may be wisely safe-guarded.” morning some 32 years prior, on which I first go to a Catholic charity, but now this man— As to construction contracts, says encountered Roman construction. It was in the video shows a suitably crazed-looking Moore, the Romans employed highly Mrs. Olaette Cerny’s Latin I class, and the Roman first taunting police, then being carted sophisticated oral and written contracts subject was Via Appia—the Appian Way— away—has been arrested for stealing it! that “were explicit in assigning detailed that most famous and important of Roman It is never said how he got away with it for responsibilities” for all parts of the job, roads, portions of which are still in use today. 30 years. But no matter: n ow comes the including labor and materials—and there Begun in 312 B.C. by the Roman censor denouement, the silver lining:“He can take were even arbitration clauses. Appius Claudius Caecus, it was the main away my money,” a pretty young woman says route from Rome to Greece, stretching some to the television camera, “but he can never to the Aqueducts of Ancient Rome. “Just like 350 miles. Roughly 20 feet wide, it was large take away my wish.” they conquered other people, they would con- enough to permit two chariots, one per lane, quer nature with their engineering. In the end, to travel simultaneously. It even had “rest THE REALLY ROMANTIC STORY for this city of a million people, they had 11 areas” every 10 miles or so—horse changing Hmmm. Not bad—unless you know the aqueducts, 11 channels of over 300 miles, stations with taverns and, of course, latrinae. really romantic story NBC missed. From delivering perhaps 150 to 200 gallons per But back to Roman Bath: “This bridge car- whence, might you suppose, does the water person per day, an amazing amount for the ried two aqueducts,” the narrator continues, for the Trevi fountain come? The municipal ancient world.” “the Aqua Claudia on the bottom and the water supply? Nope. It comes directly from The most stunning footage of all wa s mostly missing channel of the Anio Novis the Salone springs, some 11 miles outside of devoted to the Romans’ Aqua Claudia aque- aqueduct on the top.” My head spun. An Rome, and it is delivered there by the Aqua duct. Prized for its sweet-tasting mountain underground water main, 40 miles long? An Virgo, a Roman concrete aqueduct built in the spring water, it stretches 50 miles beyond above-ground, 60-foot high, double-decker year 19 B.C. during the reign of Caesar Rome, reaching into the foothills of the aqueduct? Equally impressive: the aqueducts Augustus. Put another way, Jesus Christ was Apennines. The water travels its first 40 miles ran solely on gravity—so the entire 50-mile not yet born when this aqueduct was built— u n d e rground. “But eve n t u a l l y, mountains length of the Aqua Claudia was built on a and it is still delivering water to the city. come to an end,” said the Roman Bath narra- progressively downward slope. How was this I knew this because I’d seen the NOVA doc- tor. “That’s when aqueducts emerge, in a possible, given the limitations of ancient umentary on public television, Roman Bath, spectacular display of Roman engineering. tools and technology? which devoted considerable attention and Graceful arcades of arches, 60 feet high, car- The engineering and construction wa s video footage to the aqueduct—that graceful rying water in channels along the top.” impressive, no question. But like a lightbulb and beguiling monument to Roman ingenu- Spectacular indeed. Watching the show, I going off in my brain, I recalled at that very ity. “The Romans would not take ‘no’ for an became engulfed in a wave of splendid nos- instant precisely what it was that had so cap- answer,” says Peter Aicher, author of Guide talgia, recalling a certain sun-splashed fall tivated me as a schoolboy so many years (continued) CONSTRUCTOR/September 2002 13 S E C R E T S S E C R E T S S E C R E T S unearth one shiny nugget, how eve r : a n ROMAN LABORERS & GUILDPERSONS intriguing website, w w w. r o m a n c o n c r e t e . c o m, ROMAN CONCRETE PLACEMENT: The Roman construction labor force which in turn touted a book, The Roman Pan - A CLASSICAL CONFRONTATION! consisted of slaves, freedmen, poor citi- theon—The Triumph of Concret e , written by Romans used the same essential con- zens, soldiers from the Legions, and Da vid Moore, P.E. crete ingredients we use today, but they skilled labor—guild persons—Moore used them in a vastly different manner. writes. “It was the guilds that provided the THE DEFINITIVE STUDY “First a semi-fluid mixture of lime, poz- skilled labor needed to fasten timber Soon I was on the horn talking with Moore, zolan, and small stones or brickbats was pieces into the scaffolding trusswork that a most courtly and agreeable gentleman, who poured in....” writes J.H. Middelton in spanned large openings in the construc- volunteered to send a copy. When it arrived, I The Remains of Ancient Rome, “Then a tion of arches and domes. They also pro- found to my great satisfaction that the title layer of larger stones, from 3 to 6 inches vided the metal work and other was misleading. Although it begins with an across, was laid by hand. Then a second refinements of the structures.” exploration of the Pantheon in voluptuous layer of fluid cement was poured in, and The guilds were not collective bargai n - detail, the overwhelming bulk of this 239- so on.” Moore agrees, with one modifica- ing devices but almost akin to distinct page masterpiece, richly detailed and exquis- tion: he believes that “the pozzolan-lime social classes much like the caste system itely footnoted, comprises the defi n i t ive mortar was compacted around the pieces of India. Once born into a guild, you study of Roman concrete—who, where, of aggregate by tamping, which is the p i c ked up the trade and practiced it when, what, why, and how. Moore draws only method of removing the voids and throughout your lifetime. Guilds had their heavily on ancient Roman sources, quoting closing the molecular structure of the own meeting halls and even their own god- extensively the five authors whose writings mortar to make lasting concrete.” There dess, Minerva—the deity of handiwor k . on concrete remain—Cato the Censor, Mar- is a “confrontation” among archeologists Numa, the early second Roman king, orga- cus Vitruvius Pollio, Pliny the Elder, Statius concerning the Roman placement of nized the following guilds: flute-players, the Poet, and the Emperor Julian. mortar, he explains. “Some say it was goldsmiths, dryers, cobblers, tanners, copper He also presents a rigorous boil-down of poured.
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