Roman concrete grows stronger in seawater

Transcript

As seawater seeps through Roman concrete, it reacts with volcanic ash and lime, creating an alkaline environment that keeps changing the material over time. Inside those cracks, the concrete forms aluminous tobermorite and phillipsite, crystal minerals that help reinforce the structure and even fill gaps. In effect, the sea becomes part of the recipe, and the concrete grows tougher instead of falling apart.