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| Historical Background |
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Early Cement Throughout history, cement has played a key role as a construction material. Throughout the world, the use of cement in large civic works can be traced from antiquity through modern times. The earliest construction cements, which would today be classified as non-hydraulic cements, were developed as civilization and agricultural communities first began to develop thousands of years ago. Wherever primitive mud bricks were used by early cultures, they were bedded together with a thin layer of clay slurry, primitive forms of binding substances that can be classified as cements. Mud-based cement materials were also used to secure the walls of timber or wattle and daub structures. Lime, a key ingredient in cement to this day, was used for the first time as an additive during ancient times, and was critical for stabilizing mud floors and early homes. With the advent of fired bricks, and their use in larger structures, various cultures started to experiment with higher-strength mortars based on bitumen in Mesopotamia, gypsum in Egypt and lime in many other parts of the world. Many of those materials are still important ingredients in modern cement production. Early civilizations thus created the first cement which would develop though time into the cement used today. The name "cement" goes back to the Romans who used the term "opus caementitium" to describe masonry which resembled concrete and was made from crushed rock with burnt lime used as a binder. Volcanic ash and pulverized brick additives which were added to the burnt lime to obtain a hydraulic binder were later referred to as “cementum” by the Romans, translated to “cement” in English. Roman engineers are credited with creating the first hydraulic cement, the type of cement commonly used today, by being the first to hydrate traditional cement and mix it with a pozzolan, or material which exhibits cementitious properties, such as pumice, and therefore create a sturdier and stronger cement substance. Many examples of structures made with this early cement are still standing throughout Europe, notably the huge dome of the Pantheon in Rome. Modern Cement The prominence of cement disappeared during mediaeval times throughout the world. Modern cements began to be developed at the start of the Industrial Revolution around 1700. Rapid growth and technological development lead to the need for strong cement to be used in construction projects that would be durable and perhaps come into contact with sea water. The need for a faster settling time also encouraged the development of new cements. In Britain, early industrialization led many in the country to attempt to develop quality cement. In 1780s, engineer James Parker developed what was named “Roman cement,” which set in 5-15 minutes. The success of his product led other manufacturers to develop rival products by burning artificial mixtures of clay and chalk. In the early 1800s, French scientist Louis Vicat devised a method of combining chalk and clay into an intimate mixture, which, after being burnt, produced a high quality artificial cement. In 1824, using a similar procedure in Britain, engineer Joseph Aspdin patented what he called Portland cement, because the materials in the cement made it a color similar to Portland stone, a type of building stone quarried on the Isle of Portland in England. In 1842, William Aspdin further improved on his father Joseph’s cement, creating the first Portland cement that is directly related to the cement used in modern construction. Although manufacturing costs were considerably higher than before, William’s Portland cement set at a reasonable pace and developed strength quickly, making it a very suitable cement to use as an ingredient for concrete. The use of concrete in construction grew rapidly from 1850 onwards, while Portland cement was the primary cement used for concrete construction. By the end of the 1800s, concrete, based on Portland cement, had become a highly appreciated construction material throughout Europe. To this day, Portland cement is the predominant cement used in the cement industry worldwide. |
