While studying a concrete sample from the wall of the ancient Roman city of Privernum, the team noticed that the lime clasts within the concrete showed signs of having formed in high temperature and low humidity conditions. So, what is the secret of Roman concrete? In contrast, modern concrete begins to degrade after only a few decades. The Pantheon of Rome, for example, remains the world’s largest unreinforced concrete dome, despite being nearly 2,000 years old. Indeed, the Romans have long been thought of as master builders and engineers, whose constructions have stood the test of time as few others have done. The Pantheon of Rome is an unreinforced dome constructed out of Roman concrete. “If the Romans put so much effort into making an outstanding construction material, following all of the detailed recipes that had been optimized over the course of many centuries, why would they put so little effort into ensuring the production of a well-mixed final product? There has to be more to this story.” “The idea that the presence of these lime clasts was simply attributed to low quality control always bothered me,” said Admir Masic, the lead author of the study, in a press release. These chunks of unincorporated lime have often been interpreted as the result of sloppy mixing or low-quality materials. While this formula is not remarkably different from the one we use today, the longevity of the material might have to do with the precise technique used in its preparation and known as “hot mixing.” The team was turned onto this possibility by the ubiquity of lime clasts throughout Roman concrete. Thanks to ancient descriptions of the material by Pliny the Elder and Vitruvius, as well as modern research, we know that Roman concrete was made with volcanic rock and other aggregates bound by a mortar of volcanic ash, lime, and water.
0 Comments
Leave a Reply. |