The ancient Romans’ durable concrete, known as pozzolanic concrete, owes its resilience to unique ingredients and innovative techniques.
Traditionally thought to mix volcanic ash with slaked lime, new research from MIT reveals the Romans likely used a “hot mixing” process, adding quicklime to pozzolana at high temperatures. This method created lime clasts, giving Roman concrete the ability to self-heal. When cracks form, these lime clasts react with water to fill the gaps, a feature seen in ancient Roman seawalls.
Tests on modern versions of this concrete demonstrated similar self-repair abilities, and researchers are now exploring its commercial potential as a sustainable alternative to conventional concrete.