Cement

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Cement
               The product obtained by burning and crushing to powder either stone containing 1/5 the or 2/5 th clay and remaining carbonate of lime or an intimate mixture of well proportioned calcareous and argillaceous material is called cement. Calcareous material are lime stone , mark, chalk or shells etc. Argillaceous material are silica , clay, oxide of iron etc. Commonly used cement for normal construction work is ordinary Portland cement composition of Portland cement.
a) calcium oxide                        = 60 to 65%
b) silica                                        =  20 to 25% 
c) aluminium oxide                  =  4 to 8%
d) ferrous oxide                         = 2 to 4%       
e) magnesium oxide                 = 1 to 3%
f) Sulphur trioxide                    = .5 to 3%

Cementation value          = 2.8 A +1.1 B + .7C /1.0 D + 1.4 E
A = percentage of silica content by weight
B = percentage of alumina content by weight
C = percentage of ferric oxide by weight
D = percentage of calcium oxide by weight
E = percentage of magnesium oxide by weight

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