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05/01/2023 ---- 08/01/2023

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08.01.2023
THEME: TECHNOLOGY

A new study demonstrated that ancient Roman concrete is more advanced than what we use today

The ancient Romans were masters of engineering, constructing vast networks of roads, aqueducts, ports, and massive buildings, whose remains have survived for two millennia. They built many of these structures with concrete. For instance, the Pantheon - AD 128 - is still intact, and some ancient aqueducts still deliver water to Rome today. In contrast, many modern concrete structures have crumbled after a few decades.

The reason for such extraordinary resilience was still unknown until a recent study published in Science, the fruit of collaboration between the University of Udine (IT) and the Massachusetts Institute of Technology (US). In their research, the authors analyzed the chemical composition of 2000-year-old concrete samples obtained from the archaeological site of Privernum, Italy. The observations are based on cutting-edge electron microscopy and x-ray technologies. They discovered that ancient concrete-manufacturing strategies had incorporated several key self-healing functionalities. The unknown self-healing capabilities of ancient concrete are due to the so-called "lime clasts" - white microscopic minerals that are a typical mark of Roman concrete. The lime clasts develop a brittle architecture thanks to a specific hot-mixing manufacturing protocol, creating an easily fractured and reactive calcium source. As tiny cracks start forming within the concrete, they can preferentially travel through the high-surface-area lime clasts. This material can then react with water (like the one that would penetrate a cracked surface on a rainy day), creating a calcium-saturated solution that recrystallizes and fills the crack.

It is worth noting that concrete is the most ubiquitous construction material in the world, but its production has serious environmental consequences. One method to reduce the carbon footprint - which accounts for up to 8% of total global greenhouse gas emissions - is to improve the longevity of concrete. The resulting extended use life, combined with a reduced need for repair, could reduce the environmental impact and improve the economic life cycle of modern constructs. Such a relevant innovation may now be at hand - not thanks to modern science, but to our ancestors' inheritance.

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06.01.2023
THEME: ENVIRONMENT

Exceptional temperatures are occurring in Europe: a trend with potentially serious consequences

While the US is dealing with the consequences of the century winter storm, the situation is diametrically opposite in Europe. National temperature records for January have been established in eight countries. For instance, in Warsaw, the temperature reached 18.9C, while in Spain, it went even further to over 25C on January 1. In Switzerland, temperatures hit 20C in Geneva, and the warm weather has affected ski resorts across the Alps due to the absence of snow. Switzerland's Alps are renowned as the water bank of Europe. According to recent studies, Swiss glaciers are melting at an unprecedented and increasing speed. They have lost more than half their volume in less than a century. With the temperature increase in recent years, the volume loss is accelerating. Comparing topographic images of glaciers from the 1930s to those from the last ten years establishes a link between ice loss and global warming. Furthermore, after the heatwaves involving the whole Northern Hemisphere last summer, regions of ground that were covered by ice for thousands of years became exposed due to melting. Ice measurements last summer were off the chart, showing three times more mass loss over one year than the average over the previous ten years. Glaciers are often referred to as the water towers of Europe. They store the winter snow and release it gently over the summer, providing water for Europe's rivers and crops, and cooling its nuclear power stations. Last summer, severe droughts hit Europe, provoking several issues, such as the need to transport drinking water in dry regions. Considering these recent events, the current high temperatures and accelerated melting glaciers are no good news for the old continent. It is uncertain how some large European areas would survive without a constant mountain water source.

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