Concrete Technology MCQ – Aggregate MCQ

111. Admixtures which cause early setting and hardening of concrete are called as

1. workability admixture
2. super plasticizers
3. accelerators
4. retarders

112. When the cement content and workability are kept constant, the greater proportion of fine aggregate will be required if

1. maximum size of aggregate is larger
2. maximum size of aggregate is small
3. all in aggregate is used
4. rounded coarse aggregate is used

113. Most chemically active concrete aggregate a from

1. sedimentary rock
2. igneous rock
3. sand stones
4. metamorphic rock

114. The most commonly used admixture to accelerate the setting time of concrete is which of the following?

1. Gypsum
2. Calcium chloride
3. Calcium Sulphate
4. Silica fumes

115. Which of the following is not a workability enhancing agent ?

1. Air entraining agents
2. Plasticizer
3. Super plasticizer
4. Silica fumes

116. Which of the following aggregate should not be used in the manufacture of concrete as it exhibits alkali-aggregate reaction?

1. Granite
2. Basalt
3. Limestone
4. All of these

117. Fine aggregates are those which pass and retain on these IS sieves respectively. Their sizes are

1. 6 mm and 75 μm
2. 4.75 mm and 75 μm
3. 75 μm and 4.75 mm
4. 10 mm and 4.75 mm

118. The workability of concrete by Vee-Bee test is expressed in

1. cm
2. cm/s
3. percentage
4. seconds

119. The most commonly used admixture which increases the workability of concrete is called as

1. plasticizers
2. retarders
3. accelerators
4. air-entraining agents

120. The water cement ratio is expressed by

1. based on volume of materials
2. based on weight of materials
3. based on density of materials
4. based on percentage of materials used