The mystery of Roman concrete has intrigued scientists, engineers, and architects for centuries. We have been using concrete for about 200 years and yet our concrete is nowhere near as good as the Romans' was.
Engineers and scientists have been trying to figure and explain why Roman concrete was so good for a long, long time. But no one has ever been sure until recently of what the magic ingredient was.
In 2013 a group of scientists did the unthinkable: they analyzed part of an ancient Roman breakwater in a harbor that has stood for 2,000 years. Now they know the chemical composition of the concrete.
The secret appears to be a combination of volcanic ash and lime. But by a weird coincidence it turns out that we produce an industrial byproduct that is chemically very similar to the volcanic ash. So I guess that means we can now start making Roman-quality concrete whenever and wherever we want.
The old Portland cement formula may soon be retired for something more reliable and durable that was used over 2,000 years ago.
But that is not the only change we have made to concrete. For example, we use bombs that destroy even Roman concrete pretty well. We also put heavier stress loads on our concrete structures than the Romans did.
So we also invented reinforced concrete, which has made it possible to build earthquake-proof highways and buildings. We're not about to abandon reinforced concrete for the Roman formula; instead, we'll just make the Roman-quality concrete better and stronger.
Maybe one of the most fascinating types of reinforced concrete is manufactured by a company called Bekaert. They mix steel fibers (they look like little plates) into concrete. This works better than steel rebar to make the concrete stronger. It reminds me of the Bibilcal "bricks without straw" debate between Moses and Pharoah.
Watch this video about how Bekaert's product helped build the underground railway between London and Paris.
