In May 1922 a Canadian-born Scottish chemist, Hugh Alan McKay, filed a revolutionary patent for the Cold Spray process, which was the first genuinely usable bitumen emulsion.
Asphalt Cold Mix Limited was immediately set up in order to use the emulsion on roads, and the exclusive licence for France was awarded to the Société Générale d’Entreprise in July 1924.
Between the wars, France urgently needed to pave its huge road network in order to prevent rapid deterioration and combat the harmful effects of dust. Black products (first made using tar, later using artificial bitumen) satisfied the two requirements of quality and price.
Bitumen emulsion was tremendously successful very soon, under the name of Colas,which was an abbreviation of COLd ASphalt, and a merger with the Royal Dutch Shell Ltd was necessary to finance this development, which led to the creation of a joint subsidiary, which was given the name of Société Routière Colas.