Why Ancient Roman concrete lasts for millennia but ours crumbles in decades

Scientists solve the mystery of why 2000-year-old Roman concrete still stands strong.

Drilling at a marine structure in Portus Cosanus, Tuscany, 2003. Photo credit: J. P. Oleson.

Scientists resolved the mystery of why coastal structures built by ancient Romans 2,000 years ago are still standing. The concrete used by Roman builders in piers and harbors was made in such a way that it grew even stronger over time. Modern concrete, by comparison, tends to decay in just decades when exposed to saltwater. These findings could have an important role to play as many communities worldwide brace for rising sea levels.

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Technology & Innovation

This Science Team Wants You to Never Have to Buy Another Pair of Glasses

These glycerin "smart glasses" may be the only specs you'll need – although they do need a design intervention at some point.

Sometimes, wearing eyeglasses can be a pain. You need to change them with every new prescription and in addition they don't always serve you well enough. Reading glasses, for example, help you focus up close but become useless if you need to go back to doing other activities. According to the American Academy of Ophthalmology more than 150 million Americans use some type of corrective eyewear, spending $15 billion each year. We may all need glasses at some point, because as a natural side-effect of aging, the lens inside our eyes that adjusts the focal depth depending on what we look at, loses its ability to change focus.

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Surprising Science