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INTRODUCTION
During at least the first half of the nineteenth century mortar meant a mixture of lime and sand, cement meant Roman cement, and concrete at least in terms of buildings was a mixture of fine and coarse aggregate with lime.
Roman cement, which was patented by James Parker in 1796, was an important addition to the constructor's armoury. It was an hydraulic binder, which set in the presence of water, it set quickly, and was waterproof. Previously only some of these characteristics could be obtained by the addition of a puzzolanic additive to lime. It is not now generally appreciated that most Roman cements set in a matter of minutes, so it was not a straight replacement of lime as used in mortar, render or concrete, nor could it be replaced in all respects by Portland cement. New techniques needed to be developed for using it and novel applications were found for it, such as Charles Fowler's tile creasing for floors and roofs. Its use continued after it had been largely superseded by Portland cement because of its quick setting, its waterproofing properties and its superior adhesion to iron and steel compared with nineteenth century Portland cements.
This paper cites contemporary references from the nineteenth and early twentieth century, supplemented by personal observations, to show how Roman cement was applied and used, and for what purposes. The references suggest that it was used more widely than is generally recognised today. The paper concentrates on bond, waterproofing, mortar, concrete and similar uses, because Frank Kelsall1,2 and Ian Bristow3 have written on stucco and render. The paper relates to work in the United Kingdom but it is thought that cements with similar properties were used in the mainland of Europe and in America.
In 1838 the distinguished royal engineer Charles Pasley4 told his readers that a vast quantity of Roman cement was now employed in and near London5 and John Weale's Dictionary of 1849-50 says "a very great consumption of this cement takes place in London".6 It can therefore be expected to be encountered in nineteenth century buildings and deserves to be more widely recognised and understood. Pasley's Observations on Limes and Calcareous Cements was basically about Roman cement, its manufacture and properties, because it...