Equilibrium — Using Ancient Methods To Develop Cleaner Concrete

Future concrete buildings could be made more durable — and environmentally friendly — using the long-lost building techniques of ancient Rome, a new study has found.

Use of an ancient Roman concrete-mixing technique called “hot mixing” created blocks that could heal themselves when cracked, according to the paper published in Science Advances.

Such self-healing blocks allowed the Romans to build structures like aqueducts, monuments and stadiums that have survived for millennia amid wars, earthquakes and everyday urban pollution and chaos.

Researchers said blocks treated with the method — in which concrete was mixed with reactive quicklime under continuous heat — knit themselves back together within a few weeks after being fractured.

Their ability to self-heal came from chemical flecks left by that hot quicklime — which combined with rainfall from natural limestone and sealed cracks in the concrete. 

Cracks in blocks that had been made without lime, by contrast — as all modern concrete is — never healed, the MIT team found.

Building modern concrete with updated versions of these ancient methods could lead to longer-lived buildings — particularly in the realm of 3D-printed structures, MIT professor Admir Masic said.

Publication: Linda M. Seymour, et al., Hot mixing: Mechanistic insights into the durability of ancient Roman concrete, Science Advances (2022). DOI: 10.1126/sciadv.add1602

Original Story Source: Massachusetts Institute of Technology