World Economic Forum's video: Scientists have discovered how the Romans made self-healing concrete

Scientists have discovered how the Romans made self healing concrete. It is the reason why the Colosseum and Pantheon are still standing while modern concrete deteriorates within a decade. So this ancient technique could help make new buildings more sustainable. The key is tiny white lumps called lime clasts, which are not found in modern concrete. Previously, they were dismissed as sloppy mixing, but scientists have found they fulfil a vital role. When cracks appear in the concrete due to weathering, the lime clasts react with water to make a calcium solution which flows into the cracks and crystallizes again. Therefore this self healing concrete fixes any damage before it spreads. Scientists have also created a self healing concrete that lasts four times as long as usual by using an enzyme found in human blood.