Why Super-Cements May Hold Secrets of the Pyramid Builders

Cement is quite literally the foundation on which modern civilization is built. It’s mankind’s most common building material, and has been a key component in most of the world’s construction projects for over a century.

Its origins are certainly ancient, and stretch back at least far as the Romans, and probably older still. The Romans may have learned cement-making from the Greeks.

The ancient Egyptians before them may have even mastered the technique for making geopolymers – an advanced type of super-cement.

Some scientists have advanced the hypothesis that geopolymers were the technical innovation that allowed the construction of the pyramids, in particular the Great Pyramid of Giza, thus solving one of ancient history’s greatest mysteries.

Like many outsider-pyramid theories, it’s a speculation that gets Egyptologists seriously hot under the collar, and has provoked some fierce debate.

A Short History of Cement

The technology of cement-making comes in and out of history. The Romans, who mixed crushed rock with burnt lime and water to make a flexible and sturdy building material, were certainly cement’s earliest exponents on a large scale; they even coined its name – “caementicium”. It was used in various big public building projects, such as the construction of aqueducts. The Pantheon in Rome is the largest lasting monument to Roman skill in the application of cement – it boasts the world’s largest unreinforced concrete dome, which is still going strong after 2,000 years.

In medieval Europe, the technique faded from memory, although weak pozzolanic concretes did continue to be used to fill-in the cores of stone walls and columns. Modern hydraulic cements came into usage during the 1800s, driven by the needs of the industrial revolution. However, what became clear by the 1950s was that modern concrete was not as durable as the ancient version. Scientists began experimenting to see if they could figure out exactly what the first cement-mixers had been doing differently.

Now For the Science Bit

Ukrainian scientist Victor Glukhovsky was the first boffin to make a breakthrough. He found that adding alkaline activators or aluminosilicate binders to cement created geopolymers – that is, extra-hard ceramics that don’t need firing. Geopolymers are ultra-strong, impermeable to water, and far more resistant to degradation by acids or high temperatures. A mug made of geopolymer is so tough it will bounce off a concrete floor.

In the 1970s, Glukhovsky’s work inspired Joseph Davidovits, a French chemical engineer, to discover the chemistry behind geopolymers and how it can be manipulated in different ways. Davidovits – who became President of the Geopolymer Institute – earned the French Ordre National du Mérite for his study, as well as the ire of Egyptologists. One of his more controversial conclusions was that the pyramids were built using re-agglomerated stone – a sort of geopolymer limestone concrete – rather than blocks of natural stone. Soft limestone with a high kaolinite content was quarried in the wadi on the south of the Giza Plateau, he claimed, then dissolved into a clay-like paste perfect for moulding into blocks.

Recent studies of samples from the pyramids have supported his theory, but it’s still hotly disputed by those who stand by the age old-notion that the pyramids were built purely from quarried stone, elevated on ramps.

Arguments For

In 2006, a Franco-American study – by Professor Gilles Hug, of the French National Aerospace Research Agency (ONERA), and Professor Michel Barsoum, of Drexel University in Philadelphia – concluded that the covering of the pyramids at Giza consist of two types of stone: one type from quarries and another type that was man-made.

They used X-rays, a plasma torch and electron microscopes to compare fragments from pyramids with stone from the Toura and Maadi quarries in Egypt near Giza. They found “traces of a rapid chemical reaction which did not allow natural crystalisation.” Their hypothesis is that the lower parts of the pyramid were built from quarried stone elevated on ramps, while the upper parts were built of cement made from limestone blocks dissolved in Nile-fed water pools, then mixed with fireplace ash and salt and poured into wooden casts. They would have hardened within a few days.

“There’s no way around it,” Professor Hug told Science et Vie magazine (quoted in The Times). “The chemistry is well and truly different.”

Their conclusions were backed-up by Guy Demortier, a materials scientist at Namur University in Belgium. He had been skeptical of the notion at first, but changed his mind after reading Hug and Barsoum’s study. “The three majestic Pyramids of Cheops, Khephren and Mykerinos are well and truly made from concrete stones,” said Demortier, also speaking to Science et Vie.

Arguments Against

Zahi Hawass, head of Egypt’s Supreme Council of Antiquities (SCA), has led the attack on the idea of super-cement being used in the building of the pyramids. He characteristically shot from the hip when speaking to San Diego Union Tribune on the subject recently, through a spokesman. “It’s highly stupid,” he said. “The pyramids are made from solid blocks of quarried limestone. To suggest otherwise is idiotic and insulting.”

Any synthetic material found in pyramids Egyptologists say is just “slop”, left over from modern repairs. They point out that the diversity of shapes among the 2.5 million limestone blocks that comprise the Great Pyramid strongly suggests a mould wasn’t used. Additionally, Egyptologists point out that such a technique would have required massive material resources which weren’t easy to come by, while manpower – exactly what was required for the labour-intensive process of quarrying stones and dragging them up the sides of the pyramid on ramps – was available in abundance.

Davidovits doesn’t buy such arguments, and believes his idea has been shunned because mainstream Egyptologists are pre-disposed towards classic, popular notions of how the pyramids were built. “The big archaeologists – and Egypt’s tourist industry – want to preserve romantic ideas,” he commented, also speaking to the San Diego Union Tribune.

Linn W. Hobbs, professor of materials science at Massachusetts Institute of Technology, spoke out in the Union Tribune too to say that the she feels the defense of Egyptologists is mostly based on stubborn pride. “The degree of hostility aimed at experimentation is disturbing,” he said. “Too many big egos and too many published works may be riding on the idea that every pyramid block was carved, not cast.”

The response from Egyptology’s big guns to Hug and Barsoum’s research was apparently little short of angry. “You would have thought I claimed the pyramids were carved by lasers,” Barsoum said.

It’s not the only example of a pyramid theorist from the outside of the Egyptology establishment being met with enmity. Jean-Pierre Houdin – a French architect who claims that the Great Pyramid was built using an internal ramp as opposed to an external one, as is popularly believed (both theories would technically disproved by Davidovits’ suggestion) – has met stiff resistance in his bid to test his hypothesis with direct access to the Great Pyramid. The super-concrete theorists have been similarly frustrated: until they have access to substantial samples from pyramids – which the SCA are unwilling to give up easily – they won’t be able to conclusively back-up their argument.

The Future of Geopolymers?

For now, the geopolymer theory still exists in the realm of highly educated guess-work, but it’s an interesting and very worthy hypothesis nonetheless. “It could be they used less sweat and more smarts,” said Hobbs. “Maybe the ancient Egyptians didn’t just leave us mysterious monuments and mummies. Maybe they invented concrete 2,000 years before the Romans started using it in their structures.”

Whatever the origins of geopolymers are, they’ve certainly got a big future ahead. The US military in particular is finding new applications for super-cements – in building runways, rocket nozzles and even satellites. The Iranians are on the case too, and have apparently been developing geopolymers for use in building bunkers for their nuclear facilities – the same nuclear facilities that may be threatened one day by the very geopolymer-tipped armaments the Americans are perfecting.

A new global chapter in defence technology may be opening with the implementation of techniques first masterminded by the ancients thousands of years ago.

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