Joseph Aspdin (1778–1855)

Cement is one of the most important building materials of the past two centuries, used as mortar to bind brick or stone, to cover structures with render and to make concrete. Portland cement was stronger and more waterproof than traditional lime mortars. It was invented by Joseph Aspdin and patented in 1824.

Aspdin was a bricklayer at Leeds in the north of England. He called his invention ‘Portland cement’ because it looked like the fine white building stone from Portland on the south coast, which was used for high-status buildings in many parts of Britain. Traditional mortar was made by burning limestone. Instead, Portland cement was made by mixing limestone or chalk with clay and then grinding it and firing it in a kiln at a high temperature. The material from the kiln was mixed with gypsum and then milled again.

He developed his invention by experimenting with the older ‘hydraulic cement’, which was made from sources of limestone that naturally contained clay. After patenting his new product he set up a factory to make it at the town of Wakefield. His sons William and James continued to develop the material. James remained in business with his father. William set up his own works in London and Kent in competition with them and later ran another in Germany.

Portland cement was successful but when Aspdin died in 1855 it was not yet famous. The significance of the product became understood in later years. Aspdin expected it to be used mainly for stucco to render the front of buildings or for cast mouldings to imitate carved stone. But it was of greatest importance in making concrete – the principal building material of the twentieth century.

The American Portland Cement Association put up a bronze plaque at Leeds in 1924 acknowledging the importance of Aspdin’s invention for the world.