How Cement Evolved Through the Ages

Invention of Pozzolana:
Humans have used cement throughout history. Various forms of the substance date back to some 12,000 years ago, with the earliest archaeological find being a whitewashed floor formed of burnt limestone and clay that was discovered in modern-day Turkey. In the Fertile Crescent, where it was found that lime could be manufactured from burnt limestone to build mortar, the first fired clay bricks were created. Around 800 BC, the Phoenicians discovered how to make hydraulic lime, which was not only stronger than anything before used, but also hardened under water. This hydraulic lime was made by burning lime and volcanic ash, which is now known as “pozzolana.”
The Romans created new construction techniques that allowed them to construct massive structures with sturdy foundations. “Opus caementitium,” a sort of concrete constructed of lime with aggregates of sand and crushed rock, was one such breakthrough. This was mostly utilised as formwork in between masonry stones or bricks. As aggregates, other cements used broken tiles, bricks, and ceramic pottery. The expertise and building procedures of the time were thoroughly detailed by the Roman architect and engineer Marcus Vitruvius Polllio, which later served as the foundation for construction techniques for hundreds of years. The Colosseum and Pantheon in Rome, as well as the Hagia Sophia in Istanbul, are famous ancient structures made of concrete that are still standing today.

Utilization of Hydraulic Cement:
The Middle Ages were a calm period in cement history. No discoveries were produced during this time, however it is known that
masons utilised hydraulic cements to construct forts and canals.
While alchemists studied the characteristics and reactivity of substances, frequently using coded language, knowledge in the guilds of the Middle Ages was a secret that was passed on orally to students rather than being written down. There was no such thing as concrete at the time, thus most mortars were made of sand and lime. John Smeaton, who established that the hydraulicity of lime was directly proportional to the limestone’s clay content, James Parker, Louis Vicat, and Egor Cheliev made significant contributions to the creation of cement and concrete during the European Industrial Revolution in the late 18th century.

The Birth of Portland Cement:
In 1824, Ingenious British stonemason Joseph Aspdin created cement as we know it in the 19th century by heating a mixture of
powdered limestone and clay on his kitchen stove and grinding the mixture into a fine powder. After the renownedly sturdy building stone from the Isle of Portland in Dorset, UK, Aspdin gave this cement the name Portland Cement. The first alite-containing cement was created by his son, William Aspdin (an impure form of tricalcium silicate).
Isaac Johnson burnt chalk and clay in 1845 at temperatures between 1400 and 1500°C, far higher than the Aspdins, which caused the mixture to clinker and yield what is essentially today’s cement. The use of reinforced columns, girders, and other structural elements during this period of innovation allowed for the construction of taller, larger structures, etc., and significantly reduced the dominance of steel construction. The use of reinforced concretes first appeared in France in the 1840s. Many other nations adopted the first cement standard for Portland cement that was established in Germany in 1878, outlining the initial test procedures and minimum qualities.

Global cement output and use both increased at the turn of the century. Due to their use of radiative heat transfer, which is more
effective at higher temperatures, rotary kilns have taken the place of the traditional vertical shaft kilns since the early 1900s. generates stronger cement by achieving a constant clinkering temperature. Ball mills are currently used to grind clinker, and gypsum is added to the final mixture to control setting. Other advancements over the past century include the use of calcium aluminate cements for improved sulphate resistance, the blending of Portland and Rosendale cements in the USA to create a strong and quick-setting cement, and an increase in the use of cementitious materials for the storage of nuclear waste.

The Future of Concrete and Cement
In order to increase the durability, strength, and applicability of cement and concrete, new technologies and innovations are continually being developed. Some cutting-edge products, like roof tiles and countertops, combine fibres and unique materials, while offshore manufacturing is also becoming more popular with the rise of digitalization and AI, which might minimise waste and enhance productivity and working conditions on-site. Additionally, cements and concrete that can absorb CO2 over the course of their lifetimes are being developed, lowering the carbon footprint of the construction material.