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Speaker 1: Welcome to brain Stuff production of iHeartRadio. Hey brain Stuff,

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Speaker 1: Lauren Vogel bomb here. Why are millennia old ancient Roman

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Speaker 1: piers still standing strong is veritable concrete islands, while modern

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Speaker 1: concrete structures built only decades ago crumble from an onslaught

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Speaker 1: of wind and waves. The answer lies in until now

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Speaker 1: undocumented Roman recipe. Researchers at the University of Utah have

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Speaker 1: discovered that a seawater filters through piers and breakwaters made

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Speaker 1: of age old Roman concrete, the structures actually become increasingly

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Speaker 1: stronger because of the growth of interlocking minerals, including some

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Speaker 1: minerals that are rare or expensive to cultivate in lab settings.

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Speaker 1: The study, published in the journal American Mineralogist, found that

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Speaker 1: as seawater percolates through the concrete in the piers and breakwaters,

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Speaker 1: it dissolves parts of the volcanic ash that was used

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Speaker 1: in construction. This allows new minerals like aluminum, tobomerite, and

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Speaker 1: philip site to form from the leached fluid. It's These minerals,

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Speaker 1: similar in shape to the crystals and volcanic rocks, then

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Speaker 1: form interlocking plates in gaps within the ancient concrete, making

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Speaker 1: the concrete stronger over time. This is pretty much the

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Speaker 1: opposite of what happens to modern concrete structures, which are

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Speaker 1: worn down by the elements and become increasingly cracked and

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Speaker 1: brittle as pores and gaps are compromised by infiltrating sea water.

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Speaker 1: So why aren't we using Roman style concrete? For one,

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Speaker 1: we don't know the recipe. We may think we're at

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Speaker 1: the height of human knowledge, and certainly the Internet gives

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Speaker 1: everyone who has access a leg up, but the ancients

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Speaker 1: had techniques and technologies that have been lost to time.

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Speaker 1: Although University of Utah geologist and lead study author Marie

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Speaker 1: Jackson has poured through ancient Roman texts, she hasn't yet

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Speaker 1: discovered a precise method for mixing the marine mortar, but

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Speaker 1: she's working with geological engineers to recreate the right mix.

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Speaker 1: There's also a load bearing issue. Ancient is the key

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Speaker 1: word in these Roman structures, which took a long long

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Speaker 1: time to develop their strength from seawater. Young cement built

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Speaker 1: using a Roman recipe probably wouldn't have the compressive strength

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Speaker 1: to handle modern use, at least not initially, but that

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Speaker 1: doesn't mean concocting a concrete mix using Roman engineering savvy

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Speaker 1: wouldn't be useful. The concrete could potentially be used to

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Speaker 1: replace other corrodable building materials like steel and modern concrete

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Speaker 1: in newly constructed tidal lagoons, for instance, and other see

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Speaker 1: or see adjacent structures. Maybe in the future we can

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Speaker 1: put this ancient knowledge to use. Today's episode was written

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Speaker 1: by Laurie L. Dove and produced by Tyler Clang. Brain

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Speaker 1: Stuff is production of iHeart Radio's How Stuff Works. For

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Speaker 1: more in this and lots of other load bearing topics,

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Speaker 1: visit our home planet, how stuff Works dot com, and

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