Civil engineer objective questions – Structural Analysis and Design (Section-8)

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