250+ TOP MCQs on Workability of Fresh Concrete and Answers

Concrete Technology Questions and Answers for Aptitude test on “Workability of Fresh Concrete”.

1. What do you mean by workability?
a) ASTM C 125 defines workability as the property determining the effort required to manipulate a freshly mixed quantity of concrete with a maximum loss of homogeneity
b) ASTM C 125 defines workability as the property determining the effort required to manipulate a freshly mixed quantity of concrete with minimum loss of heterogeneity
c) The strict definition of workability is the amount of useful external work, against the external friction between the individual particles in the concrete, necessary to produce full compaction
d) The workability is also defined as the ease with which a freshly mixed concrete can be properly compacted and also that it can be transported, placed, and finished
Answer: d
Clarification: The workability is defined as the ease with which a freshly mixed concrete can be properly compacted and also that it can be transported, placed, and finished.

2. Workability of concrete can be improved by the addition of __________
a) Iron
b) Sodium
c) Zinc
d) Sulphur
Answer: c
Clarification: Inorganic retardants include oxides of lead, zinc, phosphate and magnesium salts. Most retarders also act as water reducers.

3. Workability of concrete can be improved by __________
a) More sand
b) More cement
c) More fine aggregates
d) Fineness of coarse aggregate
Answer: b
Clarification: Workability of concrete can be improved by more cement and water with proper water cement ratio.

4. Workability of concrete can be improved by ___________
a) Increasing size of aggregates
b) Decreasing size of aggregates
c) Increasing fine aggregates
d) Increasing flaky aggregates
Answer: a
Clarification: Workability should be obtained by the use of a well-graded aggregate which has the largest maximum particle size possible.

5. Workability of concrete is directly proportional to __________
a) Grading of the aggregates
b) Time of transit
c) Aggregates cement ratio
d) Water cement ratio
Answer: a
Clarification: Grading of aggregate: Poor grading reduces consistency. That’s why it is directly proportional to grading of the aggregates.

6. Workability of concrete is inversely proportional to __________
a) Grading of the aggregates
b) Time of transit
c) Aggregates cement ratio
d) Water cement ratio
Answer: d
Clarification: Workability of concrete is inversely proportional to the Water cement ratio because if the amount of w/c ratio increases, workability decreases.

7. If compaction factor of concrete is .90, then workability is ____________
a) Low
b) Very low
c) Medium
d) High
Answer: c
Clarification: At the less workable end of this group, manually compacted flat slabs using crushed aggregates. Normal reinforced concrete manually compacted and heavily reinforced sections with vibration.

8. A compaction factor of .85 for a cement concrete sample indicates ___________
a) Low workability
b) Medium workability
c) Good workability
d) Very good workability
Answer: a
Clarification: Roads vibrated by hand-operated machines. At the more workable end of this group, concrete may be manually compacted in roads using aggregate of rounded or irregular shape.

9. Adding water increases __________
a) Workability
b) Strength
c) Fame
d) Quality
Answer: a
Clarification: Adding water increases workability because it is inversely proportional to the workability.

10. Why Shape and texture of aggregates is a must?
a) Smooth surfaces give better workability
b) Smooth surfaces give poor workability
c) Rough surfaces give better workability
d) Rough surfaces give poor workability
Answer: a
Clarification: The use of smooth and rounded, rather than irregularly shaped aggregate also increases workability.

Concrete Technology for Aptitude test,