From volcanic ash came key ingredients in cement and empire building. The innovations of the Romans never ended, as modern builders show us.
To understand the history of cement the material, it helps to understand the etymology (history) of the word cement. This is because the end result is constant even if, historically, cement has been made and continues to be made of different things.
The history of cement is in line with the history of what we now know as the cement contractor, which predates the asphalt contractor by thousands of years. Cement has been around in the old world for many, many centuries.
The Great Pyramids at Giza, as well as floors and underground cisterns of Syria and Jordan, as well as portions of the Great Wall of China, used types of gypsum and lime mortars. But early cement played a supporting role in these earlier applications, something that bound together quarried boulders.
As a standalone material, the Romans by far made the most use of cement concrete.
Cement as a word goes back to at least the 14th century in English – it can be used as a noun or a verb – but more tellingly it derives from the Latin caementum, for stone chips used in making mortar. Cement was created in some form or another by Greeks, the Macedonians, and quite productively by the Romans (theirs was specifically called opus caementicium), the engineers and builders of aqueducts and roads that knit together an empire. Available to them was volcanic tuff and crushed volcanic ash, which is aluminum silicate (Mount Vesuvius destroyed Pompeii, but from its destructive forces a lot of things were constructed). Combined with lime, water and aggregate, they built the Pantheon in Rome, the extensive system of aqueducts – water systems that made empire building possible – as well as multiple amphitheaters, baths, bridges, dams, circuses and temples.
Remarkably, the Roman Pantheon, a coffered concrete dome, is unreinforced and remains, still intact, the largest such engineering of concrete in the world, 2000 years after its construction. It is considered part of the Roman architectural revolution, and the material also enabled the structural advances of arches, vaults and domes.
What concrete did for the Romans in this architectural revolution was it freed up the designers to go beyond what brick-on-brick and stone materials allowed. A spectacular example is the (now ruined, partially restored) Domus Aurea complex, also known as Nero’s Golden House, built in Rome after the great fire of 64 AD. There, two extravagant dining rooms flanked an octagonal court, topped by a dome that feature a giant central oculus (early version of a skylight), made of Roman concrete construction.
But with the fall of the Roman Empire (5th century), the specific formula for making cement was lost. It wasn’t until about a thousand years later that written descriptions in a manuscript were found. About three hundred years later, Englishman John Smeaton, improvised on the Roman formula to include clay and a new firing method to build a lighthouse in Cornwall. A quarter century later, another Englishman, Joseph Aspdin of Portland, England further improved upon cement manufacturing, creating what is today known as Portland Cement.
Industrial structures made of Portland cement soon became commonplace, followed by houses and, in 1904, the first concrete high-rise building in Cincinnati, Ohio. In 1913, the first ready-mix load (in an early version of a cement mixer truck) made a delivery in Baltimore, Maryland. Hoover Dam and the Grand Coulee Dam, built in the 1930s, showed the immense structural power and economic implications of the material. Fiber reinforced concrete was introduced in 1970 and in 1990 the highest concrete structure in the world was built.
Translucent concrete – which actually transmits light with embedded optical fibers – was developed in 2004 by Hungarian architect Aron Losonczi and scientists at the Technical University of Budapest. While futuristic, its applications may be more artistic than structural. But as the Romans, and the Egyptians before them, understood, the flexibility of cement-based concrete frees up the builder to accommodate both the functions and fancies of human occupants.