FTP, what is this material, which when mixed with sand and crushed stone or pebbles makes concr  ete?
Ancient Romans made it from lime and volcanic ash, but knowledge of its making was lost after the fall of the empire. It was rediscovered in 1824 by Joseph Aspdin, who patented his process and named the product after a kind of limestone it resembled  , found on the Isle of Portland. Annual worldwide production now exceeds 800 million tons, some of which is used for grout or mixed with sand to make mortar. FTP, what is this material, which when mixed with sand and crushed stone or pebbles makes concr  ete?
Ancient Romans made it from lime and volcanic ash, but knowledge of its making was lost after the fall of the empire.
Portland cement