# Design of Concrete Structures 2

Objective Questions and Answers of Civil Engineering: Design of Concrete Structures 2

Subject: Design of Concrete Structures 2

Part 2: Objective questions and answers of Design of Concrete Structures

Q1. To determine the modulus of rupture, the size of test specimen used is

a) 150 x150 x500 mm

b) 100 x100 x700 mm

c) 150 x150 x700 mm

d) 100 x100 x500 mm

Q2. Select the incorrect statement

a) Lean mixes bleed more as compared to rich ones.

b) Bleeding can be minimized by adding pozzuolana finer aggregate.

c) Bleeding can be increased by addition ‘of calcium chloride.

d) None of the above

Q3. Workability of concrete is directly proportional to

a) Aggregate cement ratio

b) Time of transit

d) All of above

Q4. Air entrainment in the concrete increases

a) Workability

b) Strength

c) The effects of temperature variations

d) The unit weight

Q5. The relation between modulus of rupture fcr, splitting strength fcs and direct tensile strength fcl is given by

a) Tcr – rcs = tct

b) Fcr>fcs>fc.

c) C) fcr<fcs<fc>

d) Fc5>fcr>fc.

Q6. Strength of concrete increases with

a) Increase in water-cement ratio

b) Increase in fineness of cement

c) Decrease in curing time

d) Decrease in size of aggregate

Q7. The relation between modulus of rupture fcr and characteristic strength of concrete fck is given by

a) Fcr=0.35vf7

b) Fcr=0.57f7

c) Fcr=0.7vf7

d) Fcr=1.2vf7

Q8. According to is: 456 -1978, the modulus of elasticity of concrete ec (in n/mm^2) can be taken as

a) Ec = = 5700

b) Ec = = 570

c) Ec = = 5700fck

d) Ec = where fck n/mm^2 = 700 is the characteristic strength in

Q9. As compared to ordinary portland cement, use of pozzuolanic cement

a) Reduces workability

b) Increases bleeding

c) Increases shrinkage

d) Increases strength

Q10. Admixtures which cause early setting and hardening of concrete are called

b) Accelerators

c) Retarders

d) Air entraining agents

Q11. The strength of concrete after one year as compared to 28 days strength is about

a) 10 to 15% more

b) 15 to 20% more

c) 20 to 25% more

d) 25 to 50% more

Q12. Modulus of rupture of concrete is a measure of

a) Flexural tensile strength

b) Direct tensile strength

c) Compressive strength

d) Split tensile strength

Q13. The effect of adding calcium chloride in concrete is

I) to increase shrinkage

Ii) to decrease shrinkage

Iii) to increase setting time

Iv) to decrease setting time

a) (i) and (iii)

b) (i)and(iv)

c) (ii) and (iii)

d) (ii) and (iv)

Q14. Finer grinding of cement

a) Affects only the early development of strength

b) Affects only the ultimate strength

c) Both (a) and (b)

d) Does not affect the strength

Q15. 1% of voids in a concrete mix would reduce its strength by about

a) 5%

b) 10 %

c) 15%

d) 20%

Q16. The factor of safety for

a) Steel and concrete are same

b) Steel is lower than that for concrete

c) Steel is higher than that for concrete

d) None of the above

Q17. For a reinforced concrete section, the shape of shear stress diagram is

a) Wholly parabolic

b) Wholly rectangular

c) Parabolic above neutral axis and rectangular below neutral axis

d) Rectangular above neutral axis and parabolic below neutral axis

Q18. If a beam fails in bond, then its bond strength can be increased most economically by

a) Increasing the depth of beam

b) Using thinner bars but more in number

c) Using thicker bars but less in number

d) Providing vertical stirrups

Q19. If the depth of actual neutral axis in a beam is more than the depth of critical neutral axis, then the beam is called

a) Balanced beam

b) Under-reinforced beam

c) Over-reinforced beam k

d) None of the above

Q20. If the permissible stress in steel in tension is 140 n/mm^2, then the depth of neutral axis for a singly reinforced rectangular balanced section will be

a) 0.35 d

b) 0.40 d

c) 0.45 d

d) Dependent on grade of concrete also

Part 2: Objective questions and answers of Design of Concrete Structures