Concrete Technology MCQ – Aggregate MCQ

31. The bulking of sand is due to

1. the increase in space between the particles caused the surface tension effect or moisture
2. the swelling of air in voids
3. the viscous effect of moisture
4. none of the above

32. Slump test facilitates

1. controlling of water-cement ratio of concrete during construction
2. the determination of initial and final setting times of cement
3. the determination of workability of concrete
4. none of the above

33. Excess vibration of a green concrete leads to

1. honey combing
2. bleeding
3. segregationot
4. cracking

34. Minimum thickness of lean concrete layer below foundation concrete should be

1. 150 mm
2. 100 mm
3. 200 mm
4. none of the above

35. Vee-bee time for low workability as per IS standard is

1. 5-10 secs
2. 2-5 secs
3. 15-20 secs
4. 10-15 secs

36. Compressive strength of any structural concrete sample should not be less than specified characteristic compressive strength minus

1. 5 MPa
2. 3 MPa
3. 1 MPa
4. 10 MPa

37. Separation of water in the fresh concrete is called

1. Curing
2. Bleeding
3. Segregation
4. Hydration

38. The size of cube for testing of concrete shall be

1. 100 × 100 × 100 mm
2. 75 × 75 × 75 mm
3. 150 × 150 × 150 mm
4. 200 × 200 × 200 mm

39. In what context is the slump test performed?

1. Strength of concrete
2. Workability of concrete
3. Water-cement ratio
4. Durability of concrete

40. A splitting tensile test is performed on a cylinder of diameter ‘D’ and length ‘L’. If the ultimate load is ‘P’, then the splitting tensile strength of concrete is given by

1. 2PD/πL³
2. 4PL/πD³
3. 2P/πDL
4. P/πDL