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.
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.
Romans created concrete by mixing volcanic ash, quicklime and chunks of volcanic rock. Even though they figured out the ingredients, scientists still didn’t know the recipe. How did the Romans manage to make the concrete so long-lasting? The key turned out to be in the chemical reaction caused by the addition of seawater.
The Roman concrete was made to interact with its environment, as opposed to modern concrete which stays inert and gets damaged over time. Seawater is the reason why the mixture gets stronger. As seawater reacts with volcanic material, new minerals are created that reinforce the concrete.
Researchers, led by University of Utah geologist Marie Jackson, looked at the microscopic structures of Roman concrete samples by subjecting them to numerous spectroscopic tests and imaging techniques. The tests showed a rare reaction took place that spurred the growth of aluminous tobermorite crystals. Further geology detective work proved that the crystals were formed when seawater percolated through the little cracks in the Roman concrete, reacting to the mineral phillipsite, found in volcanic rock.
Jackson expressed her admiration for the genius of the Romans -
Structures like the Pantheon and Trajan’s Markets in Rome were also built with this kind of concrete.
Roman author Pliny the Elder, who wrote the ancient world’s famous science tract “Natural History” once praised Roman concrete, writing “that as soon as it comes into contact with the waves of the sea and is submerged becomes a single stone mass, impregnable to the waves."
Indeed, that’s proven to be true. Jackson is now working on recreating Roman concrete using seawater in San Francisco. This work might prove useful in building longer-lasting and stronger sea walls - a fact of growing importance. A study by European scientists predicts the costs of new coastal reinforcements will reach as high as $71 billion per year during the 21st century. Without them, coastal flooding will lead to trillions of dollars in damages.
Check out this video from the University of Utah on how seawater strengthens Roman concrete:
Read the study in American Mineralogist.
Pay attention to the decisions made by the provinces.
- China leads the world in numerous green energy categories.
- CO2 emissions in the country totaling more than all coal emissions in the U.S. have recently emerged.
- This seems to be an administrative-induced blip on the way towards a green energy tipping point.
NASA astronomer Michelle Thaller is coming back to Big Think to answer YOUR questions! Here's all you need to know to submit your science-related inquiries.
Big Think's amazing audience has responded so well to our videos from NASA astronomer and Assistant Director for Science Communication Michelle Thaller that we couldn't wait to bring her back for more!
And this time, she's ready to tackle any questions you're willing to throw at her, like, "How big is the Universe?", "Am I really made of stars?" or, "How long until Elon Musk starts a colony on Mars?"
All you have to do is submit your questions to the form below, and we'll use them for an upcoming Q+A session with Michelle. You know what to do, Big Thinkers!
If you want to be a better and more passionate communicator, these tips are important.
If you identify as being a socially conscious person in today's age of outrage, you've likely experienced the bewildering sensation when a conversation that was once harmless, suddenly doesn't feel that way anymore. Perhaps you're out for a quick bite with family, friends, or coworkers when the conversation takes a turn. Someone's said something that doesn't sit right with you, and you're unsure of how to respond. Navigating social situations like this is inherently stressful.
Below are five expert-approved tips on how to maintain your cool and effectively communicate.
Calling all big thinkers!
- The next Mega Millions drawing is scheduled for Oct. 23 at 11 pm E.T.
- The odds of any one ticket winning are about 1 in 300 million.
- This might be a record-setting jackpot, but that doesn't mean you have a better chance of winning.
Or how I learned to stop worrying and love my tsundoku.
- Many readers buy books with every intention of reading them only to let them linger on the shelf.
- Statistician Nassim Nicholas Taleb believes surrounding ourselves with unread books enriches our lives as they remind us of all we don't know.
- The Japanese call this practice tsundoku, and it may provide lasting benefits.
Money makes the world go 'round. Unfortunately, it can make both children and adults into materialists.
- Keeping a gratitude journal caused children to donate 60 percent more to charitable causes.
- Other methods suggested by researchers include daily gratitude reflection, gratitude posters, and keeping a "gratitude jar."
- Materialism has been shown to increase anxiety and depression and promote selfish attitudes and behavior.
The Boring Company plans to offer free rides in its prototype tunnel in Hawthorne, California in December.
- The prototype tunnel is about 2 miles long and contains electric skates that travel at top speeds of around 150 mph.
- This is the first tunnel from the company that will be open to the public.
- If successful, the prototype could help the company receive regulatory approval for much bigger projects in L.A. and beyond.
SMARTER FASTER trademarks owned by The Big Think, Inc. All rights reserved.