Editing Portland cement (section)

==History==
Portland cement was developed from natural cements made in Britain beginning in the middle of the 18th century. Its name is derived from its similarity to [[Portland stone]], a type of building stone quarried on the [[Isle of Portland]] in [[Dorset]], England.<ref name="miljö">{{cite book|author1=Gillberg, B. |author2=Fagerlund, G. |author3=Jönsson, Å. |author4=Tillman, A-M.|title=Betong och miljö|trans-title=Concrete and environment|year=1999|publisher=AB Svensk Byggtjenst|location=Stockholm|language=sv|isbn=978-91-7332-906-4}}</ref> The development of modern portland cement (sometimes called ordinary or normal portland cement) began in 1756, when [[John Smeaton]] experimented with combinations of different limestones and additives, including [[trass]] and [[pozzolana]]s, intended for the construction of a lighthouse,<ref name="Blezard">Robert G. Blezard, "The History of Calcareous Cements" in Hewlett, Peter C., ed.. ''Leaʼs chemistry of cement and concrete''. 4. ed. Amsterdam: Elsevier Butterworth-Heinemann, 2004. 1–24. Print.</ref> now known as [[Smeaton's Tower]]. In the late 18th century, [[Roman cement]] was developed and patented in 1796 by [[James Parker (cement maker)|James Parker]].<ref name="Saikia">Saikia, Mimi Das. Bhargab Mohan Das, Madan Mohan Das. ''Elements of Civil Engineering''. New Delhie: PHI Learning Private Limited. 2010. 30. Print.</ref> Roman cement quickly became popular, but was largely replaced by portland cement in the 1850s.<ref name="Blezard"/>  In 1811, [[James Frost (cement maker)|James Frost]] produced a cement he called British cement.<ref name="Saikia"/> James Frost is reported to have erected a manufactory for making of an artificial cement in 1826.<ref name=Reid>{{cite book|last1=Reid|first1=Henry|title=A practical treatise on the manufacture of Portland cement|url=https://archive.org/details/apracticaltreat00lipogoog|year=1868|publisher=E. & F.N. Spon|location=London}}</ref> In 1811 Edgar Dobbs of Southwark patented a cement of the kind invented 7 years later by the French engineer [[Louis Vicat]]. Vicat's cement is an artificial [[hydraulic lime]], and is considered the "principal forerunner"<ref name="Blezard"/> of portland cement.
[[File:Joseph Aspdin plaque 7 Sep 2017.jpg|thumb|left|Plaque in Leeds, England commemorating [[Joseph Aspdin]]|alt=Refer to caption]]
The name ''portland cement'' is recorded in a directory published in 1823 being associated with a William Lockwood and possibly others.<ref name=Francis>{{cite book|last1=Francis|first1=A.J.|title=The Cement Industry 1796–1914: A History|year=1977}}</ref> In his 1824 cement patent, [[Joseph Aspdin]] called his invention "portland cement" because of its resemblance to [[Portland stone]].<ref name="miljö"/> Aspdin's cement was nothing like modern portland cement, but a first step in the development of modern portland cement, and has been called a "proto-portland cement".<ref name="Blezard"/>

[[File:William Aspdin Radford cyclopedia Volume 1.jpg|thumb|upright|[[William Aspdin]] is considered the inventor of "modern" portland cement.<ref name="William Aspdin">{{cite book|last1=Courland|first1=Robert|title=Concrete planet : the strange and fascinating story of the world's most common man-made material|date=2011|publisher=Prometheus Books|location=Amherst, N.Y.|isbn=978-1616144814|url=https://books.google.com/books?id=qRcwAQAAQBAJ&pg=PT190|access-date=28 August 2015}}</ref>|alt=A black and white photograph of William Aspdin]]
[[William Aspdin]] had left his father's company, to form his own cement manufactury. In the 1840s William Aspdin, apparently accidentally, produced [[calcium silicate]]s which are a middle step in the development of portland cement. In 1848, William Aspdin further improved his cement. Then, in 1853, he moved to Germany, where he was involved in cement making.<ref name=Francis/> William Aspdin made what could be called "meso-portland cement" (a mix of portland cement and hydraulic lime).<ref>{{cite journal|last=Rayment|first=D. L.|year=1986|title=The electron microprobe analysis of the C-S-H phases in a 136-year-old cement paste|journal=[[Cement and Concrete Research]]|volume=16|issue=3|pages=341–344|doi=10.1016/0008-8846(86)90109-2}}</ref> [[Isaac Charles Johnson]] further refined the production of "meso-portland cement" (middle stage of development), and claimed to be the real father of portland cement.<ref>Hahn, Thomas F., and Emory Leland Kemp. ''Cement mills along the Potomac River''. Morgantown, WV: West Virginia University Press, 1994. 16. Print.</ref>

In 1859, John Grant of the Metropolitan Board of Works, set out requirements for cement to be used in the [[London sewerage system|London sewer project]]. This became a specification for portland cement. The next development in the manufacture of portland cement was the introduction of the [[rotary kiln]], patented by [[Frederick Ransome]] in 1885 (U.K.) and 1886 (U.S.); which allowed a stronger, more homogeneous mixture and a continuous manufacturing process.<ref name="Blezard"/> The Hoffmann "endless" kiln which was said to give "perfect control over combustion" was tested in 1860 and shown to produce a superior grade of cement. This cement was made at the Portland Cementfabrik Stern at [[Szczecin|Stettin]], which was the first to use a Hoffmann kiln.<ref>{{cite book|last1=Reid|first1=Henry|title=The Science and Art of the Manufacture of Portland Cement with observations on some of its constructive applications|url=https://archive.org/details/scienceandartma00reidgoog|year=1877|publisher=E&F.N. Spon|location=London}}</ref> The Association of German Cement Manufacturers issued a standard on portland cement in 1878.<ref>{{cite web|url=http://www.vdz-online.de/en/vdz/history/|title=125 Years of Research for Quality and Progress|publisher=German Cement Works' Association|access-date=2012-09-30|url-status=dead|archive-url=https://web.archive.org/web/20150116110736/http://www.vdz-online.de/en/vdz/history/|archive-date=16 January 2015|df=dmy-all}}</ref>

Portland cement had been imported into the United States from England and Germany, and in the 1870s and 1880s, it was being produced by Eagle Portland cement near Kalamazoo, Michigan. In 1875, the first portland cement was produced in the [[Coplay Cement Company Kilns]] under the direction of David O. Saylor in [[Coplay, Pennsylvania]], US.<ref>Meade, Richard Kidder. ''Portland cement: its composition, raw materials, manufacture, testing and analysis''. Easton, PA: 1906. The Chemical Publishing Co. 4–14. Print.</ref>  By the early 20th century, American-made portland cement had displaced most of the imported portland cement.