Roman Concrete Was Self-Healing

Roman concrete used thousands of years ago is significantly more durable than modern concrete. One of the key differences is self-healing properties—when Roman concrete cracks, it reacts with water which quickly fills in the crack with calcium carbonate.

A recent study looked into how Roman concrete was made and tested these properties. They found that hot mixing must have been used to create quicklime instead of slaked lime. This creates more surface area within the mortar area and is the source of reactive calcium which fills in cracks over time.

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