Design of Concrete Structures 1

Objective Questions and Answers of Civil Engineering: Design of Concrete Structures 1

Subject: Design of Concrete Structures 1

Part 1: Objective questions and answers of Design of Concrete Structures

 

Q1. The property of fresh concrete, in which the water in the mix tends to rise to the surface while placing and compacting, is called

a) Segregation

b) Bleeding

c) Bulking

d) Creep

 

Q2. The most commonly used admixture which prolongs the setting and hardening time is

a) Gypsum

b) Calcium chloride

c) Sodium silicate

d) All of the above

 

Q3. The approximate value of the ratio between direct tensile strength and flexural strength is

a) 0.33

b) 0.5

c) 0.75

d) 1.0

 

Q4. The compressive strength of 100 mm cube as compared to 150 mm cube is always

a) Less

b) More

c) Equal

d) None of the above

 

Q5. The property of the ingredients to separate from each other while placing the concrete is called

a) Segregation

b) Compaction

c) Shrinkage

d) Bulking

 

Q6. Workability of concrete is inversely proportional to

a) Time of transit

b) Water-cement ratio

c) The air in the mix

d) Size of aggregate

 

Q7. Approximate value of shrinkage strain in concrete, is

a) 0.003

b) 0.0003

c) 0.00003

d) 0.03

 

Q8. Increase in the moisture content in concrete

a) Reduces the strength

b) Increases the strength

c) Does not change the strength

d) All of the above

 

Q9. The percentage of voids in cement is approximately

a) 25%

b) 40%

c) 60%

d) 80%

 

Q10. As compared to ordinary portland cement, high alumina cement has

a) Higher initial setting time but lower final setting time

b) Lower initial setting time but higher final setting time

c) Higher initial and final setting times

d) Lower initial and final setting times

 

Q11. In order to obtain the best workability of concrete, the preferred shape of aggregate is

a) Rounded

b) Elongated

c) Angular

d) All of the above

 

Q12. Bulking of sand is maximum if moisture content is about

a) 2 %

b) 4%

c) 6%

d) 10%

 

Q13. Poisson’s ratio for concrete

a) Remains constant

b) Increases with richer mixes

c) Decreases with richer mixes

d) None of the above

 

Q14. The fineness modulus of fine aggregate is in the range of

a) 2.0 to 3.5

b) 3.5 to 5.0

c) 5.0 to 7.0

d) 6.0 to 8.5

 

Q15. Examine the following statements:

I) factor of safety for steel should be based on its yield stress,

Ii) factor of safety for steel should be based on its ultimate stress,

Iii) factor of safety for concrete should be based on its yield stress,

Iv) factor of safety for concrete should be based on its ultimate stress.

The correct statements are

a) (i) and (iii)

b) (i)and(iv)

c) (ii) and (iii)

d) (ii) and (iv)

 

Q16. Diagonal tension in a beam

a) Is maximum at neutral axis

b) Decreases below the neutral axis and increases above the neutral axis

c) Increases below the neutral axis and decreases above the neutral axis

d) Remains same

 

Q17. If nominal shear stress tv exceeds the design shear strength of concrete xc, the nominal shear reinforcement as per is : 456-1978 shall be provided for carrying a shear stress equal to

a) Xv

b) Xc

c) Xv – tc

d) Tv + tc

 

Q18. If the depth of neutral axis for a singly reinforced rectangular section is represented by kd in working stress design, then the value of k for balanced section

a) Depends on as, only

b) Depends on acbc only

c) Depends on both crst and acbc

d) Is independant of both ast and acbc 

where d is the effective depth, ast is permissile stress in steel in tension and acbc is permissible stress in concrete in bending compression.

 

Q19. Modulus of elasticity of steel as per is : 456-1978 shall be taken as

a) 20 kn/cm^2

b) 200 kn/cm^2

c) 200kn/mm^2

d) 2xl06n/cm^2

 

Q20. Maximum quantity of water needed per 50 kg of cement for m 15 grade of concrete is

a) 28 liters

b) 30 liters

c) 32 liters

d) 34 liters

 

Part 1: Objective questions and answers of Design of Concrete Structures

 

Q1. Answer b

 

Q2. Answer a

 

Q3. Answer b

 

Q4. Answer b

 

Q5. Answer a

 

Q6. Answer a

 

Q7. Answer b

 

Q8. Answer a

 

Q9. Answer b

 

Q10. Answer a

 

Q11. Answer a

 

Q12. Answer b

 

Q13. Answer b

 

Q14. Answer a

 

Q15. Answer b

 

Q16. Answer c

 

Q17. Answer c

 

Q18. Answer a

 

Q19. Answer c

 

Q20. Answer c