Maastricht Economic and social Research and  training centre on Innovation and Technology

 
I&T Weekly holiday break
I&T Weekly is taking a holiday break. We will be back on Friday, January 12, 2018 with a fresh selection of innovation and technology news. On behalf of the entire UNU-MERIT team, we wish our readers an excellent 2018!




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All headlines
  • France announces landmark ban on fossil fuel production
  • Extreme laser bursts may lead to practical nuclear fusion
  • Gene editing staves off deafness in mice
  • Integrated circuits could make quantum computers scalable
  • 'Water cloak' uses electromagnetic waves to eliminate turbulence
  • Cold cigarette lighter will power satellite
  • Why modern mortar crumbles, but Roman concrete lasts millennia
    Modern concrete, used in everything from roads to buildings to bridges, can break down in as few as 50 years. But more than 1000 years after the western Roman Empire crumbled to dust, its concrete structures are still standing. Now, scientists have finally figured out why: a special ingredient that makes the cement grow stronger, not weaker, over time.

    Scientists began their search with an ancient recipe for mortar, laid down by Roman engineer Marcus Vitruvius in 30 BCE. It called for a concoction of volcanic ash, lime, and seawater, mixed together with volcanic rocks and spread into wooden moulds that were then immersed in more sea water. History contains many references to the durability of Roman concrete, including this cryptic note written in 79 BCE, describing concrete exposed to seawater as: 'a single stone mass, impregnable to the waves and everyday stronger.'

    What did it mean? To find out, the researchers studied drilled cores of a Roman harbour from Pozzuoli Bay near Naples, Italy. When they analysed it, they found that the seawater had dissolved components of the volcanic ash, allowing new binding minerals to grow. Within a decade, a very rare hydrothermal mineral called aluminium tobermorite (Al-tobermorite) had formed in the concrete. Al-tobermorite, long known to give Roman concrete its strength, can be made in the lab, but it's very difficult to incorporate it in concrete.

    But the researchers found that when seawater percolates through a cement matrix, it reacts with volcanic ash and crystals to form Al-tobermorite and a porous mineral called phillipsite. So will you be seeing stronger piers and breakwaters anytime soon? Because both minerals take centuries to strengthen concrete, modern scientists are still working on recreating a modern version of Roman cement.

    Science Magazine / American Mineralogist    July 03, 2017