Minimum grade of concrete to be used in reinforced concrete as per IS: 4561978 is
M 15
M 20
M 10
M 25
Correct Answer :
A. M 15
Related Questions
Modulus of elasticity of steel as per IS: 4561978 shall be taken as
20 kN/cm²
200 kN/cm²
200 kN/mm²
2 × 106 N/cm²
The recommended value of modular ratio for reinforced brick work is
18
30
40
58
In T-shaped R C. retaining walls, the main reinforcement in the stem is provided on
The front face in one direction
The front face in both directions
The inner face in one direction
The inner face in both directions
According to ISI recommendations, the maximum depth of stress block for balanced section of a beam of effective depth d is
0.43 d
0.55 d
0.68 d
0.85 d
According to Whitney's theory, depth of stress block for a balanced section of a concrete beam is limited to
0.43 d
0.537 d
0.68 d
0.85 d Where d is effective depth of beam
In order to obtain the best workability of concrete, the preferred shape of aggregate is
Rounded
Elongated
Angular
All of the above
The temperature reinforcement in the vertical slab of a T-shaped R.C. retaining wall is
Not needed
Provided equally on inner and front faces
Provided more on inner face than on front face
Provided more on front face than on inner face
Admixtures which cause early setting and hardening of concrete are called
Workability admixtures
Accelerators
Retarders
Air entraining agents
Pick up the correct statement from the following:
The free water is the amount of water added while mixing and the amount of water held on the surface of the aggregates prior to mixing
The total water is the free water and the amount actually absorbed by the aggregates
Neither (a) nor (b)
Both (a) and (b)
The type of aggregates of same nominal size, which contain less voids when compacted, are
Rounded spherical
Irregular
Flaky
None of these
Critical section for shear in case of flat slabs is at a distance of
Effective depth of slab from periphery of column/drop panel
d/2 from periphery of column/capital/ drop panel
At the drop panel of slab
At the periphery of column
Pick up the correct statement from the following:
Continuous grading is not necessary for obtaining a minimum of air voids
The omission of a certain size of aggregate is shown by a straight horizontal line on the grading curve
The omission of a certain size of aggregate in concrete increases the workability but also increases the liability to segregation
All the above
Select the correct statement
Elastic modulus of high tensile steel is nearly the same as that of mild steel
Elastic modulus of high tensile steel is more than that of mild steel
Carbon percentage in high carbon steel is less than that in mild steel
High tensile steel is cheaper than mild steel
Concrete is unsuitable for compaction by a vibrator if it is
Dry
Earth moist
Semi-plastic
Plastic
Pick up the correct statement from the following:
Construction joints are necessarily planned for their locations
Expansion joints are provided to accommodate thermal expansion
Construction joints are provided to control shrinkage cracks
All the above
Maximum distance between expansion joints in structures as per IS: 456 1978 is
20 m
30 m
45 m
60 m
Which of the following R.C. retaining walls is suitable for heights beyond 6 m?
L-shaped wall
T-shaped wall
Counterfort type
All of the above
In pre-stressed concrete
Forces of tension and compression change but lever arm remains unchanged
Forces of tension and compressions remain unchanged but lever arm changes with the moment
Both forces of tension and compression as well as lever arm change
Both forces of tension and compression as well as lever arm remain unchanged
Pick up the incorrect statement from the following:
A rich mix of concrete possesses higher strength than that a lean mix of desired workability with excessive quantity of water
The strength of concrete decreases as the water cement ratio increases
Good compaction by mechanical vibrations, increases the strength of concrete
None of these
A higher modular ratio shows
Higher compressive strength of concrete
Lower compressive strength of concrete
Higher tensile strength of steel
Lower tensile strength of steel
Water required per bag of cement, is
7 kg
14 kg
21 kg
35 kg
Joints in concrete structures, are provided
To reduce the tensile stresses likely to be developed due to evaporation of water
To minimise the change in the dimensions of the slab
To minimise the necessary cracking
All the above
You are asked to construct a massive dam, the type of cement you will use, is
Ordinary Portland cement
Rapid hardening cement
Low heat cement
Blast furnace slag cement
The void ratio of
Single size coarse aggregate is roughly 0.45
Graded coarse aggregate is roughly 0.040
Fine aggregate is roughly 0.45
All the above
Pick up the correct statement from the following:
Construction joints in columns are provided a few cm below the junction of beam
Construction joints in columns are provided at the bottom hunching
Construction joints in beams and slabs are provided within middle third
All the above
In a spherical dome the hoop stress due to a concentrated load at crown is
Compressive everywhere
Tensile everywhere
Partly compressive and partly tensile
Zero
Workability of concrete for a given water content is good if the aggregates, are
Rounded aggregate
Irregular aggregate
Angular aggregate
Flaky aggregates
Concrete gains strength due to
Chemical reaction of cement with sand and coarse aggregates
Evaporation of water from concrete
Hydration of cement
All the above
Construction joints are generally provided in concrete
Roads
Retaining walls
Lining of canals
All the above
The rock which is not calcareous, is:
Lime stone
Chalk
Laterite
None of these