Self-healing concrete was used to build durable Roman structures: The ancient Romans used a unique type of concrete made by mixing water, pozzolana (volcanic ash) and lime, to give it its durability, according to Science Alert. A team of researchers examining this material found small white lumps of lime amid what seemed to be well-mixed concrete, which they initially ascribed to poor mixing. However, a materials scientist says that the Roman structures’ endurance indicates that this was actually far from being an accident.

Hot-mixing is the secret:After studying samples from Privernum, a 2000-year-old archeological site, they discovered that the concrete was made by mixing quicklime, pozzolana, water, and occasionally slaked lime, at high temperatures. This process — dubbed “hot mixing” — was proven to cause the lime clumps. Aside from producing compounds that would only form at this temperature with the lime, it also facilitates faster construction, as curing and setting times are slashed due to the reactions being sped up. Should it crack, the concrete can heal itself when water fills them. This is done by the liquid reacting with the lime to form a calcium-rich compound that hardens. The crack is filled, preventing its further spreading through the concrete, resulting in a monument that stands the test of time.

Coral reefs at risk as oceans are getting warmer: As our oceans reach record-breaking temperatures, coral reefs are increasingly at risk, says National Geographic. With the El Niño weather pattern, the world's coral reefs are in risk of bleaching — leading schools of fish to search for other corals or die off, affecting the oceanic ecosystem. According to National Geographic, even if the world maintains an average annual increase in temperature of 1.5°C, at least 70% of tropical coral reefs will die.

3D-printing could save the day, for now: Despite the bleak outlook scientists plan to 3D-print fakecoral reefs through the Caribbean Coral Restoration Center. Researchers also aim to cross-breed different corals and to work on their tolerance for warmer temperatures. Their aim is to create composite coral reefs using biorocktechnology to compensate the marine creatures that once took shelter in natural coral reefs and buy time from the devastating outcomes as temperatures soar.

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