History of Cement

Cement has been in use by humans throughout history; variations of the material were used by the ancient Greeks, Romans and Egyptians, with the earliest archaeological discovery dated to 12-10,000BC in modern-day Turkey. The Romans used a mixture of lime (calcium oxide) and pozzolan – crushed volcanic ash – to create hydraulic cements, which could set under water. Other cements used crushed brick, tiles and ceramic pottery as aggregates. Famous historical buildings made from concrete, still standing today, are the Colosseum and Pantheon in Rome, and the Hagia Sophia in Istanbul.

The Middle Ages were a quiet time in the history of cement; any discoveries made during this era remain unknown, although masons are known to have used hydraulic cements to build structures such as fortresses and canals.

The Industrial Revolution in Europe in the late 18th century saw a flurry of new developments in cement and concrete, with important contributions made by John Smeaton, who discovered that the hydraulicity of lime was directly related to the limestone’s clay content, James Parker, Louis Vicat and Egor Cheliev.

The precursor to modern-day cement was created in 1824 by Joseph Aspdin, a British bricklayer and builder, who experimented with heating limestone and clay until the mixture calcined, grinding it and then mixing it with water. Aspdin named this Portland Cement, after the famously strong building stone from the Isle of Portland in Dorset, UK. His son, William Aspdin, made the first cement containing alite (an impure form of tricalcium silicate).

In 1845, Isaac Johnson fired chalk and clay at much higher temperatures than the Aspdins, at around 1400-1500oC, which led to the mixture clinkering, and produced what is essentially modern-day cement.

Since the 1900s, rotary kilns have replaced the original vertical shaft kilns, as they use radiative heat transfer, more efficient at higher temperatures. achieving a uniform clinkering temperature and produces stronger cement. Gypsum is now also added to the resulting mixture to control setting and ball mills are used to grind clinker.

Other developments in the last century include calcium aluminate cements for better sulphate resistance, the blending of Rosendale (a natural hydraulic cement produced in New York) and Portland cements to make a durable and fast-setting cement in the USA, and the increased usage of cementitious materials to store nuclear waste.

New technologies and innovations are constantly emerging to improve the sustainability, strength and applications of cement and concrete. Some advanced products incorporate fibres and special aggregates to create roof tiles and countertops, for example, whilst offsite manufacture is also gaining prominence with the rise of digitalisation and AI, which could reduce waste and improve efficiency and on-site working conditions. Cements are also being developed which can absorb CO2 over their lifetimes, reducing the carbon footprint of the building material.