Magnesium based cements are some of the oldest building materials in the world, first used around the same time as gypsum. Unlike gypsum plasters though, magnesium oxide based cements can be very strong and durable. There are ancient examples, it was used as mortar by the Romans, in the Great Wall of China, to build Stupas in India, to protect wood structures like the Forbidden City, and in 800 year old timber buildings in Europe.
About sixty years after Joseph Aspdin invented Portland cement in 1824, Stanislaus Sorel rediscovered magnesium based cements and they have continued to be used for specialty applications like high temperature kiln linings, patching cement for airport runways and bridges, oil well mud, and hospital and institutional floors to name a few.
The Japanese used sorel cement for their fortifications in Manchuria. When Mao re-captured Manchuria they gained the Japanese research and made MgO cements part of the Great Leap Forwards. For the Beijing Olympics, MgO boards were used extensively as the premier material to make the games more environmentally sustainable. Taipei 101, the world’s tallest Platinum LEED building, uses it extensively on walls and ceilings, inside and out for decoration and fire proofing. In some places in Europe it is replacing OSB as the sheathing of choice due to its strength, durability, and ease of use.