ABSTRACT
The Englishman, John Payne, was granted a patent in 1728 for a process involving the casting of molten blastfurnace slag to basalt-like bricks that was used in a variety of ways, for example, to line cellars and build chimneys. In 1737, Belidor recommended the use of broken blastfurnace slag in mortar and concrete. In 1862, Emil Langen discovered the latent hydraulic properties of ground granulated blastfurnace slag. 'Latent hydraulic' means, that, once activated, the slag reacts with water to give a cementitious material.
