| Cement |
|
|
HISTORY OF CEMENT Evidence has been uncovered in different locations of ancient Egypt, Crete and Mesopotamia demonstrating that lime was used as a building material. Ancient Greeks and Romans have used lime as a hydraulic binder. Roman architect Vitruvius (B.C. 70-B.C. 25) had written about the hydraulic features of puzzolana and lime mixtures in his 10-Volumes book, namely, “On Architecture” and had even recommended a mixture ratio for mortar to be used in buildings to be put up nearby rivers and seashore; two parts puzzolana (pulvis Puteolanus) is to be mixed with one part limestone. Research results have confirmed that in Asia Minor, the plaster used in Çatalhöyük dwellings is approximately 7000 years old. In ancient times, many binders that represent the civilization level of the associated period had been used in Egyptian pyramids, the Great Wall of China and fortresses built at different centuries. Then, about 2000 years before our day, the Romans had started using a hydraulic binder, which resembles the features of today’s cement. They obtained this binder by blending slaked lime with volcanic ashes and later on with baked brick powder. Whereas ancient Greeks were making mortar by blending volcanic tuff they obtained from Island of Santorini with lime, or used hydraulic lime they obtained from limestone that contained clay. Although ancient Greeks and Romans were aware of the hydraulic characteristic of puzzolana and lime mixtures and made use of these materials, they could not arrive at the knowledge to explain how lime is obtained or what was going on chemically during puzzolanic reactions. For instance, Pliny (i.e. Roman scientist Gaius Plinius) had written that it is not comprehensible “why lime, which is obtained through burning of stone by fire, burns once more upon contact with water?” As regards the quality and usage of binders, no significant improvement was attained until 18th Century. John Smeaton, who was assigned to rebuild the Eddystone Lighthouse in 1756, is known to be the first one to realize the chemical properties of lime. The subsequent development was the invention of the binder called the “Roman Cement", by Joseph Parker.
In 1824, a mason named Joseph Aspdin in Leeds obtained a binding agent by baking a mixture of fine particles of clay and limestone and then grinding the baked mixture. Joseph Aspdin, noticing that when water and sand was added into this material, the product resembled the building stones brought in from Portland Island after hardening, received a patent for his binder on 21.10.1824, under the name “Portland Cement”. Although the binder improved extensively in the following years, the “Portland” name was maintained as is. Since the binder invented by Joseph Aspdin was not baked at adequately high temperatures, it never reached the properties of today’s Portland cement. Anyhow it has been confirmed that Joseph Aspdin’s binder was used in the construction of the "Wakefield Arms" building, which is still intact nearby the Kirkgate train station in Britain.
The treatment of raw materials at high temperatures and grinding of these was accomplished later on by an Englishman named Isaac Johnson (1845).
|
|
|
| Cement |
|
|
HISTORY OF CEMENT Evidence has been uncovered in different locations of ancient Egypt, Crete and Mesopotamia demonstrating that lime was used as a building material. Ancient Greeks and Romans have used lime as a hydraulic binder. Roman architect Vitruvius (B.C. 70-B.C. 25) had written about the hydraulic features of puzzolana and lime mixtures in his 10-Volumes book, namely, “On Architecture” and had even recommended a mixture ratio for mortar to be used in buildings to be put up nearby rivers and seashore; two parts puzzolana (pulvis Puteolanus) is to be mixed with one part limestone. Research results have confirmed that in Asia Minor, the plaster used in Çatalhöyük dwellings is approximately 7000 years old. In ancient times, many binders that represent the civilization level of the associated period had been used in Egyptian pyramids, the Great Wall of China and fortresses built at different centuries. Then, about 2000 years before our day, the Romans had started using a hydraulic binder, which resembles the features of today’s cement. They obtained this binder by blending slaked lime with volcanic ashes and later on with baked brick powder. Whereas ancient Greeks were making mortar by blending volcanic tuff they obtained from Island of Santorini with lime, or used hydraulic lime they obtained from limestone that contained clay. Although ancient Greeks and Romans were aware of the hydraulic characteristic of puzzolana and lime mixtures and made use of these materials, they could not arrive at the knowledge to explain how lime is obtained or what was going on chemically during puzzolanic reactions. For instance, Pliny (i.e. Roman scientist Gaius Plinius) had written that it is not comprehensible “why lime, which is obtained through burning of stone by fire, burns once more upon contact with water?” As regards the quality and usage of binders, no significant improvement was attained until 18th Century. John Smeaton, who was assigned to rebuild the Eddystone Lighthouse in 1756, is known to be the first one to realize the chemical properties of lime. The subsequent development was the invention of the binder called the “Roman Cement", by Joseph Parker.
In 1824, a mason named Joseph Aspdin in Leeds obtained a binding agent by baking a mixture of fine particles of clay and limestone and then grinding the baked mixture. Joseph Aspdin, noticing that when water and sand was added into this material, the product resembled the building stones brought in from Portland Island after hardening, received a patent for his binder on 21.10.1824, under the name “Portland Cement”. Although the binder improved extensively in the following years, the “Portland” name was maintained as is. Since the binder invented by Joseph Aspdin was not baked at adequately high temperatures, it never reached the properties of today’s Portland cement. Anyhow it has been confirmed that Joseph Aspdin’s binder was used in the construction of the "Wakefield Arms" building, which is still intact nearby the Kirkgate train station in Britain.
The treatment of raw materials at high temperatures and grinding of these was accomplished later on by an Englishman named Isaac Johnson (1845).
|
|
|

