Jul 5, 2017

Scientists might have found a way to recreate Roman concrete

Mosa'ab Elshamy / AP

Concrete used by the Romans to build their cliff-side cities, bridges and sea walls more than two thousand years ago have withstood time and still stand strong today, while modern concrete exposed to seawater deteriorates within decades.

Now researchers may have figured out what has made Roman concrete so durable, and the University of Utah's Marie Jackson thinks she might be able to recreate it, per the Washington Post. The Roman's secret: the concrete contains tiny crystals that keep it from fracturing.

Why it matters: If successful, the concrete could be used to make sea walls that can protect shoreline environments from flooding and rising seas.

The findings, as detailed by WaPo:

  • Jackson and her colleagues learned that Roman concrete behaves "in many ways, like volcanic deposits in submarine environments." It is filled with tiny growing crystals that act "like tiny armor plates" and keep the concrete from fracturing.
  • A series of tests run by Jackson's team revealed that the aluminous tobermorite crystals were created from a chemical reaction: when seawater flooded through the cracks in the concrete, it reacted with a mineral known as phillipsite found naturally in the volcanic rock.

What's next: "The Romans mined a specific type of volcanic ash from a quarry in Italy" writes WaPo. "Jackson is attempting to recreate this durable concrete using San Francisco seawater and more abundant volcanic rocks. She has several samples sitting in ovens and jars in her lab, which she will test for evidence of similar chemical reactions."

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U.S. coronavirus updates: Death toll surpasses 8,400

Data: The Center for Systems Science and Engineering at Johns Hopkins; Map: Andrew Witherspoon/Axios

Recorded deaths from the coronavirus surpassed 8,400 in the U.S. on Saturday, per Johns Hopkins data. The death toll in the U.S. has risen over 1,000 every day for the past four days, since April 1.

The big picture: President Trump said Saturday America's is facing its "toughest week, between this week and next week." Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said the U.S. should expect to see deaths continue to rise in this period.

Go deeperArrowUpdated 15 mins ago - Health

Coronavirus dashboard

Illustration: Sarah Grillo/Axios

  1. Global: Total confirmed cases as of 8:30 p.m. ET: 1,197,405 — Total deaths: 64,606 — Total recoveries: 246,152Map.
  2. U.S.: Total confirmed cases as of 8:30 p.m. ET: 308,850 — Total deaths: 8,407 — Total recoveries: 14,652Map.
  3. Public health latest: CDC launches national trackers and recommends face coverings in public. Federal government will cover costs of COVID-19 treatment for uninsured. The virus is hitting poor, minority communities harder and upending childbirth.
  4. 2020 latest: "We have no contingency plan," Trump said on the 2020 Republican National Convention. "We're having the convention at the end of August."
  5. Business updates: Restaurants step up for health care workers. Employees are pressuring companies to provide protections during coronavirus.
  6. Oil latest: Monday meeting among oil-producing countries to discuss supply curbs is reportedly being delayed amid tensions between Saudi Arabia and Russia.
  7. Education update: Many college-age students won't get coronavirus relief checks.
  8. 1 🏀 thing: The WNBA postpones start of training camps and season.
  9. What should I do? Pets, moving and personal health. Answers about the virus from Axios expertsWhat to know about social distancingQ&A: Minimizing your coronavirus risk.
  10. Other resources: CDC on how to avoid the virus, what to do if you get it.

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World coronavirus updates: Spain tracks more cases than Italy

Data: The Center for Systems Science and Engineering at Johns Hopkins, the CDC and China's Health Ministry. Note: China numbers are for the mainland only and U.S. numbers include repatriated citizens and confirmed plus presumptive cases from the CDC

Spain overtook Italy in its number of coronavirus cases on Saturday. The global death toll has surpassed 62,000, per Johns Hopkins data.

The latest: About half the planet's population is on lockdown amid the coronavirus crisis. Fatalities are exponentially increasing across Europe, with roughly half of deaths worldwide located in Italy and Spain.

Go deeperArrowUpdated 7 hours ago - Health