The Manufacture and Testing of Portland Cement.”’ by Major-General HENRYYOUNG DARRACOTT SCOTT, C.B., R.E., F.R.S., Assoc
Proceedings.] SCOTT AND REDGRAVE ON PORTLAXDCEMENT. 67 11 May, 1880. WILLIAM HEKRY BARLOW, F.R.S., President, in the Chair. (Paper No. 1649.) “The Manufacture and Testing of Portland Cement.”’ By Major-General HENRYYOUNG DARRACOTT SCOTT, C.B., R.E., F.R.S., Assoc. Inst. C.E., and G1LBER.r RICHARDBEIIGKAVE, Assoc. Inst. C.E. NOTWITHSTANDINGthat much has been written concerning Portland cement, the history of its early manufacture is involved in con- siderableobscurity. Theinvestigations of Smeaton andPasley in England, of Fuchsand John in Germany, and of Vicat in France, into the nature and causes of the hydraulicity of limes, are well known ; but the discovery of the exact conditions of the manufacture of the cement now recognised as Portland seems to have been only gradually arrive& at. The first mention of acement named, in consequence of its fancied resemblance to Portland stone, “ Portland cement,” occurs inthe specification of a patent, KO. 5,022, grantedto Joseph Aspdin,a bricklayer of Leeds, dated October 21st, 1824. The cement originally made by Aspdin does not, however, appear tu have been a true Portland, nor was his process identical with that which has since been generally adopted in the production of this material. He used, in fact, a double system of calcination, as he employed a hard limestone in lieu of a soft and friable chalk. He specified, first burning t.he limestone to lime, so as to obtain a readily pulverised quicklime ; this lime he mixed with a suitable, or, as he terms it, “a specific quantity, of argillaceous earth or clay,” and then he directed that the mixture should be calcined “in a furnacesimilar to a limekiln, till the carbonic acid is entirely expelled.” This process of double calcination is perhaps, 1 The diacnssion upon this Paper wa8 taken together with that upon the two followiug ones.
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