Steel in modern concrete rusts and expands, forming cracks. Now engineers are revisiting the 'self-healing' concrete of Ancient Rome

Steel in modern concrete rusts and expands, forming cracks. Now engineers are revisiting the 'self-healing' concrete of Ancient Rome

Steel in modern concrete rusts and expands, forming cracks. Now engineers are revisiting the 'self-healing' concrete of Ancient Rome After water, concrete is the second most widely used material on the planet. Modern concrete, called Portland cement, has been in use since the late 1890s, but it’s gone through many iterations to get to this point, from the hydraulic lime mixtures of Nabataea traders in 6500 BCE to the gypsum and lime mortars used to bind the Egyptian pyramids.  Now, engineers are finding inspiration by looking back at one of the most prolific eras in concrete’s long history: Ancient Roman architecture.  By mixing volcanic ash, lime, and seawater for their cement mixtures, the Romans created grand structures that have withstood centuries of earthquakes, fires, and floods.  On July 30, a team of international researchers explored the potential use cases of returning to Roman concrete for construction materials.  “The remarkable longevity of Roman concrete has long fas…