We Lost the Recipe for Concrete That Lasts 2,000 Years 😱 Modern concrete often cracks and fails within decades, but Roman structures like the Pantheon stand strong after millennia. Their secret was mixing volcanic ash with quicklime and seawater. This created a chemical reaction that allows the concrete to "heal" its own cracks over time. Roman builders in the 2nd century BCE discovered that mixing volcanic ash (pozzolana) with lime made a mortar that could set underwater. Vitruvius wrote down

Roman engineers discovered something extraordinary nearly 2,000 years ago—a form of concrete that doesn’t weaken with time, but heals itself and grows stronger. Structures built with Roman concrete, especially harbors and seawalls, continue to stand today despite constant exposure to seawater. Modern science has now uncovered why. Important Details: • Roman concrete was made using volcanic ash (pozzolana) instead of modern cement • When seawater enters cracks, it reacts with the ash • This react