A cement is a powered materials,used in construction that can sets,hardens and bind other materials together.It has such a special properties that when cement is combined with water it develops strong adhesive qualities.It is a fine grayish powder which,when mixed with water forms a thick paste,Cement can be differentiated in two category depending upon the ability of the cement to set in the presence of water.The two different types of cement are:Non-Hydraulic cement and Hydraulic cement.Non-Hydraulic cement will not set in wet conditions but sets as it dries and Hydraulic cement will set in wet condition as well as.

Cement was firat invented by the Egyptians.It was later reinvented by the Greeks and the Babylonians.After some time,the Romans start to produce cement from pozzolana.Pozzolana was an ash found in all of the volcanic areas of Italy.By mixing the ash with lime cement was produced.

The first cement manufactured in the United States was produced in 1871 by David Saylor of Coplay,Pennsylvania.There are two types of raw materials which are used to make cement.They are:Lime containing materials like limestone,marble,oyster shells,marl, chalk and Clay and clay containing materials like shale,slag from blast furnaces,bauxite,iron ore,silica, sand etc.There are few steps on maufacturing of cement.They are listed as below:

• The raw materials i.e containing clay and lime are crushed seperately to a very fine powder by using crusher.
• After crushing these are mixed in the correct proportion.
• After crushing and mixing it should be heated.So lets passed the mixture in the rotating heater. When its temperature reaches to about 1400C to 1500C let it be feed on the rotatory klin which is a tube up to 200metres in diameter,with a long flame at one end.The feeding materials will enters the klin at the cool end and gradually passes down to the hot end,then falls out of the klin and cools down.
• Now after coolong it is pass directly to the cement mill where it will grinds the substance to a fine powder.
• Now finally a small amount of gypsum (a form of calcium sulfate) is normally ground up with the powder.Gypsum is used because it controls the setting properties of the cement when water is added.
• Now finally the cement is ready to use.