RRB JE exam Civil Engineering Building Materials Important MCQs – 8

81. Which of the following cements is suitable for use in massive concrete structures such as large dams ?
a) ordinary Portland cement
b) low heat cement
c) rapid hardening cement
d) sulphate resisting cement
Correct Option: b

82. Proper amount of entrained air in concrete results in
i)    better workability
ii)   better resistance to freezing and thawing
iii) lesser workability
iv)  less resistance to freezing and thawing The correct Correct Optionwer is
a) (i) and (ii)
b) (i)and(iv)
c) (ii) and (iii)
d) (iii) and (iv)
Correct Option: a

83. The most common admixture which is used to accelerate the initial set of concrete is
a) gypsum
b) calcium chloride
c) calcium carbonate
d) none​​ of the above
Correct Option: b

84. The maximum quantity of calcium chloride used as an accelerator in cement in percentage by weight of cement is
a) 1
b) 2
c) 3
d) 4
 Correct Option: b

85. The basic purpose of a retarder in concrete is
a) to increase the initial setting time of cement paste in concrete
b) to decrease the initial setting time of cement paste in concrete
c) to render the concrete more water tight
d) to improve the workability of concrete mix
Correct Option: a

86. Which of the following cements contains maximum percentage of dicalcium silicate?
a) ordinary Portland cement
b) low heat cement
c) rapid hardening cement
d) sulphate resisting cement
Correct Option: b

87. The most commonly used retarder in cement is
a) gypsum
b) calcium chloride
c) calcium carbonate
d) none of the above
Correct Option: a

88. Three basic raw materials which are needed in large quantities for production of steel are
a) iron ore, coal and sulphur
b) iron ore, carbon and sulphur
c) iron ore, coal and lime stone
d) iron ore, carbon and lime stone
Correct Option: c

89. Compared to mild steel, cast iron has
i)    high compressive strength
ii) high tensile strength
iii) low compressive strength
iv) low tensile strength
The correct Correct Optionwer is
a) (i) and (ii)
b) (ii) and (iii)
c) (iii) and (iv)
d) (i)and(iv)
Correct Option: d

90. Which of the following gradients exerts maximum influence on properties of steel?
a) iron
b) carbon
c) manganese
d) sulphur
 Correct Option: b