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The Romans are generally credited as being the first concrete engineers, but archaeological evidence says otherwise. Archaeologists have found a type of concrete dating to 6500 B.C., when stone-age Syrians used permanent fire pits for heating and cooking. These fire pits, built from area limestone, showed a primitive form of calcining on the exterior faces of the limestone rocks that lined the fire pits and lead to the accidental discovery of lime as a fundamental building material. The newly discovered technology was widely used in Syria, as central lime-burning kilns were constructed to supply mortar for rubble-wall house construction, concrete floors, and waterproofing cisterns.
Lime, quicklime, and burnt lime are the common names for calcium oxide, CaO, a grayish-white powder. Today over 150 important industrial chemicals requires the use of lime in order to be manufactured.. In fact, only five other raw materials (salt, coal, sulfur, air, and water) are used in greater amounts. Lime is used in glass, cement, brick, and other building materials; as well as in the manufacture of steel, aluminum, and magnesium, poultry feed; and in the processing of cane and sugar beet juices. It is strongly caustic and can severely irritate human skin and mucous membrane. Thus, the discovery of lime as a building material opened the door for many other improvements as well.
In Europe, archaeological evidence for early use of concrete is also found from along the banks of the Danube River in Yugoslavia, where in approximately 5600 B.C. it was used to make floors for huts.
In China, as far back as 3000 BC, there is evidence of a type of cement used in the Gansu Province of northwest China.
The Egyptians used cement as far back as 2500 B.C. Some scholars believe that a cementing material produced from either a lime concrete or burnt gypsum was used in forming the Great Pyramid at Giza. The earliest known illustration (dating to about 1950 B.C.) of concrete being used in Egypt is shown in a mural on a wall in Thebes. Archeologists have long thought that the Egyptians were masters of the stone as stone artifacts (hard stone vessels, statues) made of metamorphic schist, diorite and basalt were produced. These smooth and glossy stone artifacts (between 4.000 and 5.000 years old) bear no trace of tool marks. Some archeologists believe that the ancient Egyptian artists knew how to convert ores and minerals into a mineral binder for producing stone artifacts. They believe that many of the Egyptian statues were not carved from rock, but rather were cast in molds, and are synthetic stone statues.
The first evidence for this comes from a new deciphering of the C-14 Irtysen Stele (dating 2.000 BC, Louvre Museum, Paris). The stele is the autobiography of the sculptor Irtysen who lived under one of the Mentuhotep Pharaohs, 11th. Dynasty. The stele C-14 of the Louvre has been often studied. Yet many of its expressions pertain to the domain of stone technology and have been tentatively translated in the past with terms differing so widely that the translators were obviously not able to understand the described technology. According to sculptor Irtysen, cast man-made stone was a secret knowledge. (Egyptian Made-Made Stone Statues in 2000 B.C.: Deciphering the Irtysen Stele,(Louvre C14 6 pages) Was this material a type of cement?
Some scientists are now proposing that the pyramids were made of poured stone, rather than quarried stone. From a geological point of view, the Giza Plateau is an outcrop of the Middle Eocene Mokkatam Formation. Yet, the outcrop that dips into the wadi, where the quarries are located and also the trench around the Sphinx and the Sphinx body, consist of softer thickly bedded marly nummulite limestone layers with a relative high amount of clay. The amount of water-sensitive parts, expressed as weight percent of stone, is strikingly very high, ranging between 5.5% to 29%. It is obvious that the builders took advantage of the thickly bedded softer limestones. The disaggregated muddy material was ready for geopolymeric reagglomeration. Perhaps the biggest surprise encountered in this study deals with the hieroglyphic verbs for to build, namely khusi (Gardiner's list A34). The sign khusi represents a man pounding or packing material in a mold. This is one of the oldest Egyptian hieroglyphs. (Construction of the Egyptian Great Pyramids, 2500 B.C., with Agglomerated Stone. Update of the latest Research,: 42 pages)
The Egyptians also used a more common form of concrete. The durability of their concrete is evidenced by the fact that concrete columns built by the Egyptians more than 3600 years ago are still standing.
The Greeks on the other hand were using cement by 600 B.C., when Greek builders discovered a natural pozzolan that developed hydraulic properties when mixed with lime.
It was the Romans, however, who used cement in large amounts, for huge building projects. Early Roman use of cement dates back to around 300 B.C. Since that period, the Romans steadily improved their concrete technology, they also gave it its name. The word "concrete" comes from the Latin 'concretus', meaning "grown together" or "compounded".
Roman concrete structures still stand today. Both the Colosseum (complete in 82 A.D.) and the Pantheon (completed in 128 A.D.) contain large amounts of concrete. The Basilica of Constantine and the foundations of the Forum buildings also were constructed of concrete. Since Roman cement has been so well studied, it will give us a basis for understanding the issues that are important in investigating Nabataean cement.
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