Question

Which of the following is not present in portland cement?
\[
  A.\;C{a_3}A{l_2}{O_6} \\
  B.\;C{a_3}Si{O_5} \\
  C.C{a_2}Si{O_4} \\
  D.C{a_3}{\left( {P{O_4}} \right)_2} \\
 \]

Answer 1

Hint: We must know that the portland cement is a common material and is the basic ingredient of concrete. Portland cement forms a paste with water that hardens on binding with sand and rock.

Complete step by step answer:
We can use portland cement popularly as a binding material in the form of a finely ground powder that is prepared by burning and grinding a mixture of limestone and clay or limestone and shell.
When it is mixed with water, the Constituents of Portland cement reacts chemically with the water that leads to the process of hydration and decomposition or hydrolysis. These processes make the mixture harden and thus it develops strength.
Portland cement is composed of following chemicals, namely, \[C{a_3}A{l_2}{O_6}\]​ ( tricalcium aluminate), \[C{a_3}Si{O_5}\]​ ( tricalcium silicate), \[C{a_2}Si{O_4}\] ( Dicalcium silicate), \[N{a_2}O\] (Sodium oxide), \[{K_2}O\] (Potassium oxide), \[CaS{O_4}.2{H_2}O\] (Calcium sulfate dihydrate ) and \[C{a_4}A{l_2}F{e_2}{O_{10}}\]​ (Tetracalcium- aluminatferrite)
The Portland cement is composed of 60% calcium oxide, 25% silica, 7% of alumina, 2 to 2.5% magnesia and 2 to 2.5% ferric oxide.
We know calcium silicates and calcium aluminates are forms of Calcium oxide.
So, Portland cement does not contain calcium phosphate.
$\therefore $The correct option is the option D.

Additional information:
We must know that Joseph Aspdin from England is the inventor of the basic process of Portland cement manufacturing. Portland cement has been named so for the resemblance of the cement when set to portland stone from the Isle of Portland.
There are five types of Portland cement available in the world market depending upon their content, properties and usage. Percentage of above mentioned contents of Portland cement varies from type to type.

Note:
Calcium phosphate has nutritive value; we can use it as an antacid and also as a dietary supplement in veterinary medicines. It is used in medicine as a calcium supplement dose.