1. The lower water-cement ratio in concrete products
a ) more density
b ) small creep and shrinkage
c ) more bond
d ) all of the above A
2. The entrapped air in concrete
a ) increases workability
b ) decreases workability
c ) increases strength
d ) none of the above
3. The property of fresh concrete , in which the water in the mix tends to rise to the surface while placing and compaction is known as
a ) bleeding
b ) creep
c ) segregation
d ) shrinkage
4. Separation of ingredients from concrete during transportation is known as
a ) bleeding
b ) creep
c ) segregation
d ) shrinkage
5. For making impermeable concrete , the process contains
a ) thorough mixing
b ) proper compaction
c ) proper curing
d ) all of the above
6. After casting , an ordinary cement concrete on drying
a ) shrinks
b ) expands
c ) remains unchanged
d ) can expand or shrink
7. The workability of concrete can be improved by
a ) more sand
b ) more cement
c ) more fine aggregate
d ) fineness of coarse aggregate
8. The workability of concrete can be improved by
a ) increase the size of aggregate
b ) decrease the size of aggregate
c ) increasing the fine aggregate
d ) increasing the flaky aggregate
9. Workability of concrete is directly proportional to
a ) grading of the aggregate
b ) time of transit
c ) aggregate cement ratio
d ) none of the above
10. The workability of concrete is inversely proportional to
a ) water cement ratio
b ) size of aggregate
c ) time of transit
d ) none of the above
11. The following compound that helps in obtaining early strength of cement concrete is
a ) tricalcium silicate
b ) dicalcium silicate
c ) tri calcium aluminate
d ) tetra calcium silicate
12. An air entraining agent when added in concrete improves
a ) strength
b ) workability
c ) density
d ) durability
13. The strength of concrete is directly proportional to
a ) cement water ratio
b ) water cement ratio
c ) sand cement ratio
d ) water aggregate ratio
14. The strength of concrete increases with increase in
a ) water cement ratio
b ) size of aggregate
c ) aggregate cement ratio
d ) moisture content
15. Strength of concrete increases with
a ) increase in water cement ratio .
b ) increase in fineness of cement
c ) decrease in size of aggregate
d ) decrease in curing time
16. Strength of concrete increases with
a ) increase in water cement ratio
b ) decrease in water cement ratio
c ) decrease in size of aggregate
d ) decrease in curing time .
17. Maximum strength of concrete occurs at a water content of
a ) maximum water
b ) minimum water
c ) optimum water
d ) none of the above
18. The approximate ratio of the strength of cement concrete of 7 days to that of 28 days
a ) 0.65
b ) 0.85
c ) 1.0
d ) 1.15
19. The approximate ratio of the direct tensile strength to direct compressive strength test
a ) 0.33
b ) 0.25
c ) 0.10
d ) 0.05
20. The approximate ratio of direct tensile strength to flexural strength is
a ) 0.25
b ) 0.33
d ) 0.90
c ) 0.50
21. The approximate ratio of strength of 30 cm concrete cube to that of 15 cm cube is
a ) 1.10
b ) 1.00
c ) 0.90
d ) 0.75
22. Strength of concrete show an increase with
a ) decrease in rate of loading
b ) increase in rate of loading
c ) unaffected by rate of loading
d ) depends on application of load
23. The durability of concrete is proportional to
a ) sand content
b ) water cement ratio
c ) aggregate ratio
d ) cement aggregate ratio
24. The relation between the modulus of rupture ( fct ) for splitting strength ( fcs ) and direct tensile ( fcr) strength is given by
a ) fcr> fcs >fct
b ) fcr<fcs<fct
c ) fcr = fcs = fct
d ) none of the above
