ABSTRACT
Prior to the development and widescale application of Portland cement, different forms of binders were in use, viz., “Roman cement,” produced by mixing slaked lime with volcanic ash, or “natural cement,” produced by burning a naturally occurring mixture of lime and clay. John Smeaton, a British engineer, who was entrusted to study the repeated structural failures of the Eddystone Lighthouse in Cornwall, is often credited with the discovery sometime in 1756 that cement made from limestone containing considerable proportions of clay was hydraulic in nature. This discovery was made use of in rebuilding the lighthouse in 1759, which stood for 126 years before it had to be replaced. However, little was known about the effect of these constituents on the final product, and consequently the properties of the final product were not consistent. The binders produced varied widely in quality and performance, depending on the initial raw materials used. Over the period 1756 to 1820, further advances in the scientific understanding of cements were made by Vicat and Lesage in France, and Parker and Frost in England, particularly with regard to producing a standard product with known and reproducible properties. It appears that in 1822 James Frost patented and produced “British cement” and in 1824 Joseph Aspdin, a bricklayer and mason from Leeds, took out a patent on a hydraulic cement he called Portland cement, because its colour resembled the limestone quarried at the Isle of Portland. Aspdin’s method involved the careful proportioning of limestone and clay, subsequent crushing and burning to form a clinker, which was then ground to finished cement with known and reproducible properties. Aspdin established a Portland cement factory in Wakefield in England that produced Portland cement used in the construction of 214the Thames River Tunnel in 1828. But the cement produced then was still in the range of hydraulic limes as the raw materials were only calcined and not sintered. It was not until 1847 that I. C. Johnson showed that it was necessary to burn beyond calcination and to use the right proportions of the calcareous material and clay. Subsequently, I. D. White and Sons set up a factory in Kent, leading to the greatest period of expansion in cement manufacture, both in the UK and in Germany and Belgium. Portland cement was used to build the London sewage system in 1859–1867. The manufacture of Portland cement flourished thereafter in England and by 1890 there was a flourishing export business to the USA. The production base in the USA was set up by David Saylor at Coplay, Pennsylvania in 1871 and by 1900 domestic production there rose to 1.7 million tons, galloping to over 15 million tons per annum by 1915. In India, the production of Portland cement started in 1914.
