'This has re-written our understanding of Roman concrete manufacture': Abandoned Pompeii worksite reveal how self-healing concrete was made

A detail of the neatly aligned ceramic roof tiles and tuff blocks in a newly excavated site in Pompeii.

Roman concrete is pretty amazing stuff. It's among the main reasons we know so much about Roman architecture today. So many structures built by the Romans still survive, in some form, thanks to their ingenious concrete and construction techniques.

However, there's a lot we still don't understand about exactly how the Romans made such strong concrete or built all those impressive buildings, houses, public baths, bridges and roads.