Sometimes I wonder how we come up with ideas like those outlined in a new study out of Washington State University. It seems researchers discovered that adding waste shrimp shells to cement makes it 40% stronger — and have published the results in the just-released September 2022 issue of the journal Cement and Concrete Composites.
Curious? Take a read of the article Insights into setting time, rheological and mechanical properties of chitin nanocrystals — and chitin nanofibers — cement paste.
It sounds silly at first blush, but it reminds me how technology forms everything around us — and inspiration takes many forms. I’ve always been especially fascinated with materials engineering — the way we figure out how to create the stuff we make our stuff with! For example, we don’t think much about cement yet according to the journal article it is the second most-consumed material on earth. Seriously. Only water tops it.
The technology behind building materials dates back to ancient times, with — once again — cement and concrete leading the way.
Researchers say the proto-concrete arrived around 1300 BC in the Middle East. Builders made pounded-clay buildings, then covered the outsides with a thin, damp coating of burned limestone. The limestone interacted with gases in the air and turned into a hard, protective surface.
By 650 BC a series of oases developments arose, comprised of concrete structures. By 700 BC, kilns churned out mortar for builders who were erecting ruble structures, concrete floors and underground cisterns. The Romans took the material to a whole new level, including developing artificial sand components and new formulations for underwater concrete and for structurally supporting huge buildings — like the Colosseum, which, oh by the way, still stands today.
The downside to human-created material, of course, comes from its environmental impact. The primary binding element of concrete — portland cement — may be responsible for as much as 5% of greenhouse gas emissions globally. Production of that vast amount of concrete we use also sucks up about 15% of industrial energy, as well as huge volumes of sand, water and other elements.
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Meanwhile, in nature, biopolymers appear everywhere, including chitin, the polymer that makes up a shrimp’s exoskeleton. And, it turns out all those shrimp exoskeletons form a terrifying mountain of seafood waste — something to the tune of 6 to 8 million pounds a year that mostly gets dumped into the ocean. Needless to say, this creates an issue for the seafood industry that is almost as large as the environmental issue is for the cement and concrete industry.
Hmm. Can two environmental messes cancel out each other?
The jury may still be out on the long-term answer, but in the short term, materials researchers say that re-use of biopolymers might be worth pursuing.
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The team created nanocrystals and nanofibers using waste shrimp shells. These teeny tiny fibers — 1,000 times smaller than a human hair to put it into perspective — get mixed into the cement paste. The resulting material becomes both 40% stronger and slower to set, a double advantage for construction.
“In the current world, dealing with climate change through the circular economy, we want to use waste materials as much as possible. One person’s waste is another person’s treasure,” Hui Li, research assistant professor in Washington State University’s Composite Materials and Engineering Center told Futurity, a publication that aggregates new university research.
I like that it’s like our favorite swap shop but in industrial form. I’ll take your smelly old shrimp shells and make my cement stronger while using fewer other raw materials and producing less carbon emission while making it.
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I also like that it reminds us how technical creativity takes so many forms, forms we would not necessarily expect. We touch material tech every day, but rarely do we think about how it came to be. The epoxy floor in the garage, the concrete pavers, the wallboard in the house, the Sunbrella fabric on the deck chair, every one of these materials in our build environment was indeed built — built in that place where the human brain and human hand interact to create something new … working the way human brains and hands have been working together since the time before time.
I’m picturing those university researchers sitting around after a dinner of shrimp scampi, poking at the empty shells, talking about how cool biopolymers are and how nature endowed shrimp with an amazing biological ability, and over the second glass of wine laughing at how humans should build so well ... and suddenly we’re exploring chitin nanofibers.
Yeah, it probably didn’t happen that way, but it did take an open mind to make a leap between two seemingly unrelated challenges — and using the power of creative technical thinking to connect the dots and see the possibility around us.
Teresa Martin of Eastham lives, breathes and writes about the intersection of technology, business and humanity.
This article originally appeared on Cape Cod Times: Cape Cod: Shrimp shells make cement 40% stronger, fight climate change