Month: November 2022

Iran: Streiks und neuer Höhepunkt des Aufstands

Keine Ende in Sicht: Die arbeitende Bevölkerung setzt klare Zeichen gegen das Mullah-Regime. Wenn Protestierende erschossen werden, manifestiert sich der Widerstand bei den Trauerfeiern erneut.

Keine Ende in Sicht: Die arbeitende Bevölkerung setzt klare Zeichen gegen das Mullah-Regime. Wenn Protestierende erschossen werden, manifestiert sich der Widerstand bei den Trauerfeiern erneut.

The road to low-carbon concrete

Humanity’s love affair with cement and concrete results in massive CO2 emissions.

Cement works, Ipswich, Suffolk, UK. (Photo by BuildPix/Construction Photography/Avalon/Getty Images)

Enlarge / Cement works, Ipswich, Suffolk, UK. (Photo by BuildPix/Construction Photography/Avalon/Getty Images) (credit: Construction Photography/Avalon via Getty Images)

Nobody knows who did it first, or when. But by the 2nd or 3rd century BCE, Roman engineers were routinely grinding up burnt limestone and volcanic ash to make caementum: a powder that would start to harden as soon as it was mixed with water.

They made extensive use of the still-wet slurry as mortar for their brick- and stoneworks. But they had also learned the value of stirring in pumice, pebbles, or pot shards along with the water: Get the proportions right, and the cement would eventually bind it all into a strong, durable, rock-like conglomerate called opus caementicium or—in a later term derived from a Latin verb meaning “to bring together”—concretum.

The Romans used this marvelous stuff throughout their empire—in viaducts, breakwaters, coliseums, and even temples like the Pantheon, which still stands in central Rome and still boasts the largest unreinforced concrete dome in the world.

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Großbritannien in der Stagflation

Folgen des Brexits und des Regierungschaos unter Truss – die Konservativen beerdigen ihre Rezepte und wollen sogar Steuern für Besserverdiener erhöhen.

Folgen des Brexits und des Regierungschaos unter Truss – die Konservativen beerdigen ihre Rezepte und wollen sogar Steuern für Besserverdiener erhöhen.