Speaker 1: Welcome to brain Stuff production of iHeartRadio. Hey brain Stuff,
Speaker 1: Lauren Vogel bomb here. Why are millennia old ancient Roman
Speaker 1: piers still standing strong is veritable concrete islands, while modern
Speaker 1: concrete structures built only decades ago crumble from an onslaught
Speaker 1: of wind and waves. The answer lies in until now
Speaker 1: undocumented Roman recipe. Researchers at the University of Utah have
Speaker 1: discovered that a seawater filters through piers and breakwaters made
Speaker 1: of age old Roman concrete, the structures actually become increasingly
Speaker 1: stronger because of the growth of interlocking minerals, including some
Speaker 1: minerals that are rare or expensive to cultivate in lab settings.
Speaker 1: The study, published in the journal American Mineralogist, found that
Speaker 1: as seawater percolates through the concrete in the piers and breakwaters,
Speaker 1: it dissolves parts of the volcanic ash that was used
Speaker 1: in construction. This allows new minerals like aluminum, tobomerite, and
Speaker 1: philip site to form from the leached fluid. It's These minerals,
Speaker 1: similar in shape to the crystals and volcanic rocks, then
Speaker 1: form interlocking plates in gaps within the ancient concrete, making
Speaker 1: the concrete stronger over time. This is pretty much the
Speaker 1: opposite of what happens to modern concrete structures, which are
Speaker 1: worn down by the elements and become increasingly cracked and
Speaker 1: brittle as pores and gaps are compromised by infiltrating sea water.
Speaker 1: So why aren't we using Roman style concrete? For one,
Speaker 1: we don't know the recipe. We may think we're at
Speaker 1: the height of human knowledge, and certainly the Internet gives
Speaker 1: everyone who has access a leg up, but the ancients
Speaker 1: had techniques and technologies that have been lost to time.
Speaker 1: Although University of Utah geologist and lead study author Marie
Speaker 1: Jackson has poured through ancient Roman texts, she hasn't yet
Speaker 1: discovered a precise method for mixing the marine mortar, but
Speaker 1: she's working with geological engineers to recreate the right mix.
Speaker 1: There's also a load bearing issue. Ancient is the key
Speaker 1: word in these Roman structures, which took a long long
Speaker 1: time to develop their strength from seawater. Young cement built
Speaker 1: using a Roman recipe probably wouldn't have the compressive strength
Speaker 1: to handle modern use, at least not initially, but that
Speaker 1: doesn't mean concocting a concrete mix using Roman engineering savvy
Speaker 1: wouldn't be useful. The concrete could potentially be used to
Speaker 1: replace other corrodable building materials like steel and modern concrete
Speaker 1: in newly constructed tidal lagoons, for instance, and other see
Speaker 1: or see adjacent structures. Maybe in the future we can
Speaker 1: put this ancient knowledge to use. Today's episode was written
Speaker 1: by Laurie L. Dove and produced by Tyler Clang. Brain
Speaker 1: Stuff is production of iHeart Radio's How Stuff Works. For
Speaker 1: more in this and lots of other load bearing topics,
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