SSC-JUNIOR ENGINEER (Civil & Structural) Online Exam 2017 (Part-IV)

Total Questions: 50

21. If a grading curve is horizontal between the portions of 20 mm I.S. sieve and 4.75 mm I.S. sieve, the graded aggregates do not contain

Correct Answer: D. All options are correct
Solution:If gradial curve is horizontal between the portions of 20 mm I.S. sieve and 4.75 mm I.S. sieve than it means the graded aggregate contains the size of 4.7 mm to 20 mm particles in it.

22. Saw dust can be rendered chemically inert by boiling it in water containing

Correct Answer: A. ferrous sulphate
Solution:No explanation given in the book

23. Pick up the correct statement from the following

Correct Answer: D. All options are correct
Solution:No explanation given in the book

24. For construction of structures in sea water, the cement generally preferred to is

Correct Answer: A. Portland-pozzolana cement
Solution:For construction of structures in sea water Portland-pozzolana cement are used. This is also known as PPC. Its a integrated cement which is formed by synthesising OPC cement with pozzolanic materials in a certain proportion.

Generally it has 15-25% fly ash mixed with the 65-75% portland clinker and 3-6% of gypsum. Pozzolana cement has very good resistance against sulphate attack hence is used in hydraulic structures, marine structures, construction near the sea shore, dam construction etc.

25. The strength of concrete made with angular aggregate and rounded aggregate is practically same at the water/cement ratio is

Correct Answer: D. 0.65
Solution:Generally angular aggregate are rough and rounded aggregate are smooth. So the surface area of angular aggregate are large as compare to rounded aggregate. But in case of the value of 0.65 of water cement ratio both aggregate have same strength.

26. Pick up the correct statement from the following:

Drying shrinkage is affected by

Correct Answer: D. All options are correct
Solution:Drying shrinkage is affected by the following:
  • The relative humidity of the atmosphere when the concrete is placed.
  • The length of time.
  • The water cement ratio of the concrete.

27. The compound constituent of cement abbreviated by C₃A represents:

Correct Answer: B. tricalcium aluminate
Solution:No explanation given in the book

28. Deleterious substances in aggregate are undesirable because they may:

Correct Answer: D. All options are correct
Solution:Deleterious substances in aggregate are undesirable because they may affect the strength, workability and long term performance of concrete. They may have intrinsic weakness, softness and fineness and they may have interfere with the chemical reaction of hydration.

29. If the modular ratio is m, steel ratio is rand overall depth of a beam is d, the depth of the critical neutral axis of the beam is

Correct Answer: B. {m/ (m + r)} * d
Solution:If the modular ratio is m, steel ratio is rand overall depth of a beam is a. The depth of neutral axis of beam is

30. According to the steel beam theory of doubly reinforced beams

Correct Answer: D. All options are correct
Solution:Simply we can say that there is no concrete in compression zone because concrete is weak in tension. In this theory the concrete is completely neglected and the moment of resistance is taken equal to the moment of steel. In this the permissible stress is compressive steel is taken as equal to the permissible stress in tensile steel.