Arizona Concrete :: essays research papers fc

genus Arizona concreteAccording to the Mine Faculty at the University of Arizona, cement is make primarily from suitable limestone and shale rocks. Arizona had twodry- physical process cement plants in 1969, namely the Arizona Portland Cement Companyplant in Pima County, near Tucson, and the American Cement Corporation plant atClarkdale, in Yavapai County (52-53).The use of cementing materials goes impale to the ancient Egyptians andRomans, but the invention of modern portland cement is usually attributed toJoseph Aspdin, a builder in Leeds, England, who obtained a patent for it in 1824.Currently, the annual conception production of portland cement is around 700 millionmetric tons (Danbury). umpteen people use the words concrete and cement inter diversenessably, buttheyre not. Concrete is to cement as a cake is to flour. Concrete is a florilegiumof ingredients that includes cement but contains other ingredients also (Day 6-7).Portland cement is produced by pulverizing clinker con sistingessentially of hydraulic atomic number 20 silicates along with some calcium aluminatesand calcium aluminoferrites and usually containing one or more forms of calciumsulfate (gypsum) as an interground addition. Materials used in the manufactureof portland cement must contain attach proportions of calcium oxide, silica,alumina, and iron oxide components. During manufacture, analyses of allmaterials are made frequently to tick a uniformly high quality cement.Selected afflictive materials are crushed, milled, and proportioned in such away that the resulting mixture has the desired chemical composition. The rawmaterials are generally a mixture of calcareous (calcium oxide) material, suchas limestone, chalk or shells, and an argillaceous (silica and alumina) materialsuch as clay, shale, or blast-furnace slag. Either a dry or a wet process isused. In the dry process, grinding and blending operations are through with drymaterials. In the wet process, the grinding and blending are do with thematerials in slurry form. In other respects, the dry and wet processes are actuallymuch alike.After blending, the ground raw material is fed into the velocity end of akiln. The raw mix passes through the kiln at a rate controlled by the slope androtational speed of the kiln. Burning fuel (powdered coal, oil, or gas) isforced into the lower end of the kiln where temperatures of 2600F to 3000Fchange the raw material chemically into cement clinker, grayish-black pelletsabout the size of 1/2-in.-diameter marbles.The clinker is cooled and then pulverized. During this operation a smallamount of gypsum is added to amaze the setting time of the cement. Theclinker is ground so fine that near all of it passes through a No.