1824.
In 1824, British construction worker Joseph Aspdin invented cement and patented Portland cement. He used limestone and clay as raw materials, mixed them in a certain proportion, calcined the clinker in a shaft kiln similar to burnt lime, and then ground it into cement. Because the color of the cement after hardening is similar to the stone used for construction in Portland, England, it was named Portland cement. It has excellent construction performance and is of epoch-making significance in the history of cement.
Extended information:
The earliest discovery process of cement:
In 1756, British engineer J. Smeaton was studying the properties of certain lime hardening in water It was discovered at the time that in order to obtain hydraulic lime, limestone containing clay must be used for firing; the ideal composition of masonry mortar for underwater construction is composed of hydraulic lime and volcanic ash. This important discovery laid a theoretical foundation for the research and development of modern cement.
The early mixture of lime and volcanic ash is very similar to modern lime pozzolana cement. Concrete made of cemented gravel with it is not only stronger after hardening, but also resistant to the erosion of fresh water or salt water. For a long time, it has been widely used as an important cementing material in civil construction, water conservancy, national defense and other projects.
Reference: Baidu Encyclopedia-Cement