Foreign Property News | Posted by Zarni Kyaw
The ancient Romans were master builders and engineers, perhaps most famously represented by the still-functional aqueducts.
And those architectural marvels rely on a unique construction material: pozzolanic concrete, a spectacularly durable material that gave Roman structures their incredible strength.
Even today, one of their structures – the Pantheon, still intact and nearly 2,000 years old – holds the record for the world's largest dome of unreinforced concrete.
The properties of this concrete have generally been attributed to its ingredients: pozzolana, a mix of volcanic ash – named after the Italian city of Pozzuoli, where a significant deposit of it can be found – and lime.
When mixed with water, the two materials can react to produce strong concrete.
An international team of researchers led by the Massachusetts Institute of Technology (MIT) found that not only are the materials slightly different from what we may have thought, but the techniques used to mix them were also different.
The standard understanding of pozzolanic concrete is that it uses slaked lime. First, limestone is heated at high temperatures to produce a highly reactive caustic powder called quicklime, or calcium oxide.
Mixing quicklime with water produces slaked lime, or calcium hydroxide: a slightly less reactive, less caustic paste.
According to theory, it was this slaked lime that ancient Romans mixed with the pozzolana.
Scientist Admir Masic of MIT and the team, led by MIT civil engineer Linda Seymour, carefully studied 2,000-year-old samples of Roman concrete from the archaeological site of Privernum in Italy.
Ref: We Finally Know Why Ancient Roman Concrete Stood The Test of Time (sciencealert)
