Concrete is one of the most ubiquitous substances used in modern construction. From making massive skyscrapers to building giant boats to cinder blocks used by students for makeshift furniture, concrete underpins our modern life.
But this was not always so. The use of concrete as a building material disappeared from use after the fall of the Roman Empire in approximately 400 A.D. For around 1200 years the art and science of creating concrete was completely lost and architecture suffered as a result.
Perhaps one of the shining examples of Roman concrete being used as a building medium is in the construction of the Panthenon.
But first a little etymology: Pantheon is a derivative from the ancient Latin and comprises two parts. The first Pan means all or everything, found in such modern used words as panacea or cure all or even pandemic which is a global outbreak of disease. The second part of the word Theon, relates to theos or of the Gods, found in modern terms such as theology or the study of God. The word in its entirety means All Gods. And so was this temple. Originally filled with statues of every Roman God at the time.
There is some controversy over who actually built this temple and with good reason as the concrete dome construction has never seen its equal even in modern times, but I will get to that in a moment.
The earliest records on the building itself have inscribed one Marcus Agrippa as being responsible for the construction of this edifice. However archaeological evidence suggests that whilst Agrippa’s name still decorates the force of the building the body of the building was destroyed at least twice in fire, in 80 and 110 A.D. respectively. There are some records of Emperor Hadrian had a reconstruction commissioned for the building, but again evidence is scant and there are no official claims he made to the building as he had with many of the other constructions he commissioned such as Hadrian’s wall. The most likely, but least well-known candidate for being responsible for the construction of the Pantheon, as we know it today, is the architect Apollodorus of Damascus.
Here’s a fact for you. The largest unreinforced concrete dome ever built is the Pantheon. That’s right, the largest ever built. At a whopping 43 metres and with walls over 6 metres thick this is an incredible construction. The dome forms a perfect sphere with the height of the dome and the diameter being 43 Metres. Instead of a cap stone which was necessary for all stone arch and vaulted construction there is an oculus of nearly nine metres in diameter. The walls are made from concrete and have survived being sacked, burned and raided for precious metals. The structure was rededicated as a catholic church in the 7th century and has remained for that purpose ever since.
The greatest mystery is the longevity of the Pozzolanic Roman concrete which had a high content of Alumina and silicates. But today we still don’t know how it has survived.
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