Chemical Composition of Cement

Q. The setting time of cement can be increased by the addition of

1. Sodium
2. Gypsum
3. Calcium Chloride
4. Hydrogen Peroxide

Q. In cement, ratio of silica : Lime : alumina is approximately

1. 10 : 4 : 1
2. 4 : 10 : 1
3. 1 : 10 : 4
4. 1 : 4 : 10

Q. Four main oxides present in ordinary Portland cement are $CaO,A{l}_2{O}_{3}Si{O}_{2}andF{e}_2{O}_3.$ Identify the correct ascending order of their proportions in a typical composition of OPC

1. $A{l}_2{O}_3,F{e}_2{O}_3,CaO,Si{O}_2$
2. $A{l}_2{O}_3,CaO,F{e}_2{O}_3,Si{O}_2$
3. $F{e}_2{O}_3,A{l}_2{O}_3,Si{O}_2,CaO,$
4. $A{l}_2{O}_3,F{e}_2{O}_3,CaO,Si{O}_2$

Q. To increase the initial setting time of cement, the compound responsible is _______.

1. Tricalcium Silicate
2. Gypsum
3. Dicalcium Silicate
4. Tricalcium aluminate

Q. Which of the following oxide is in the highest percentage in Ordinary Portland Cement ?

1. Iron Oxide
2. Magnesium Oxide
3. Calcium Oxide
4. Aluminium Oxide

Q. Which one of the following slows down or retards the setting action of cement

1. Sulphur trioxide
2. Alkaline
3. Calcium sulphate
4. Magnesia

Q. Quantity of Gypsum in ordinary Portland cement is:

1. 3%
2. 4%
3. 5%
4. 6%

Q. For low alkali cement, alkali content is usually restricted to X% by weight, where X is:

1. 0.04
2. 0.4
3. 0.50
4. 0.60

Q. If the $N{a}_{2}Oand{K}_{2}O$ content in a given cement is 1.0% and 0.5%, the total alkali content in the cement in terms of Equivalent $N{a}_{2}O$ can be taken as ______.

1. 1.5 %
2. 1.1 %
3. 1.3 %
4. 1.0 %

Q. The chemical ingredient of cement which provides quick setting property to the cement is

1. Lime
2. Silica
3. Alumina
4. Iron Oxide

Q. Deficiency of which of the following oxide causes reduction in setting time of cement :

1. $CaO$
2. $A{l}_2{O}_3$
3. $F{e}_2{O}_3$
4. $MgO$