This set of Concrete Technology Questions and Answers for Entrance exams focuses on “Tests on Workability of Fresh Concrete”.
1. The water–cement ratio is the ratio of ___
a) Weight of water to the weight of cement
b) Volume of water to the volume of cement
c) Density of water to the Density of cement
d) Weight of water to the weight of aggregates
Explanation: The water–cement ratio is the ratio of the weight of water to the weight of cement used in a concrete mix.
2. A lower ratio leads to ___
a) Higher strength and durability
b) Higher strength but low durability
c) Lower strength but high durability
d) Lower strength and durability
Explanation: A lower ratio leads to higher strength and durability, but may make the mix difficult to work with and form.
3. Workability can be resolved __________
a) With not using of plasticizers
b) With use of plasticizers
c) With the use of both plasticizers and super plasticizers
d) With not using of both plasticizers and super plasticizers
Explanation: Plasticizers and super plasticizers helps to improve the workability to construct the building.
Explanation: It is clear vision from the image that the amount of water is more as compared to cement.
Explanation: Option A figure has low porosity because the content of water is less as compared to cement.
6. How to improve the workability of concrete.
a) Increase the w/c ratio
b) Decrease the w/c ratio
c) Decrease the size of aggregates
d) Don’t mix it for longer time
Explanation: Increasing the water cement ratio, helps in improving the workability of the concrete.
7. What is workability?
a) When it is easily placed and compacted heterogeneous
b) When it is easily placed and compacted homogenous
c) When it is not easily placed
d) When it is easily placed but not compacted homogenous
Explanation: Concrete is said to be workable when it is easily placed and compacted homogeneously i.e without bleeding or Segregation.
8. What is the compaction factor for low degree of workability?
Explanation: The compaction factor for low degree of workability is .85 and .95 is the compaction for the high degree.
9. What is the compaction factor for medium degree of workability?
Explanation: The compaction factor for medium degree of workability is .92 and .78 is the compaction for very low degree.
10. What is the Vee-Bee time for medium degree of workability?
a) 10-20 sec
b) 5-10 sec
c) 2-5 sec
d) 35 sec
Explanation: 2-5 sec is the Vee-Bee time for the medium degree of workability and 10-20 sec is for very low.
Sanfoundry Global Education & Learning Series – Concrete Technology.
To practice all areas of Concrete Technology for Entrance exams, here is complete set of 1000+ Multiple Choice Questions and Answers.