Pick up the correct statement from the following:
An increase in water content must be accompanied by an increase in cement content
Angular and rough aggregates reduce the workability of the concrete
The slump of the concrete mix decreases due to an increase in temperature
All the above
Correct Answer :
D. All the above
Related Questions
Pick up the correct statement from the following:
Sand obtained from pits, is washed to remove clay and silt
Sand obtained from flooded pits, need not be washed before use
The chloride in sea shore sand and shingle may cause corrosion of reinforcement if the concrete is porous
All the above
The rock which is not calcareous, is:
Lime stone
Chalk
Laterite
None of these
Addition of pozzolana to cement
Decreases workability
Increases strength
Increases heat of hydration
None of these
Permissible compressive strength of M 200 concrete grade is
100 kg/cm2
150 kg/cm2
200 kg/cm2
250 kg/cm2
According to IS: 4561978, the maximum reinforcement in a column is
2 %
4 %
6 %
8 %
For a slab supported on its four edges with corners held down and loaded uniformly, the Marcus correction factor to the moments obtained by Grashoff Rankine's theory
Is always less than 1
Is always greater than 1
Can be more than 1
Can be less than 1
For the construction of cement concrete floor, the maximum permissible size of aggregate, is
4 mm
6 mm
8 mm
10 mm
A concrete having a slump of 6.5 cm, is said to be
Dry
Earth moist
Semi-plastic
Plastic
The commercial name of white and coloured cement in India, is
Colorcrete
Silvicrete
Snowcem
All the above
According to Whitney's theory, ultimate strain of concrete is assumed to be
0.03 %
0.1 %
0.3 %
3 %
Log Angles machine is used to test the aggregate for
Crushing strength
Impact value
Abrasion resistance
Water absorption
Due to shrinkage stresses, a simply supported beam having reinforcement only at bottom tends to
Deflect downward
Deflect upward
Deflect downward or upward
None of the above
In case of hand mixing of concrete, the extra cement to be added is
5 %
10 %
15 %
20 %
Approximate value of shrinkage strain in concrete, is
0.003
0.0003
0.00003
0.03
The grade of concrete not recommended by I.S. : 456, is
M 100
M 200
M 300
M 500
If fineness modulus of sand is 2.5, it is graded as
Very fine sand
Fine sand
Medium sand
Coarse sand
Efflorescence in cement is caused due to an excess of
Alumina
Iron oxide
Silica
Alkalis
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
For compacting plain concrete road surface of thickness less than 20 cm, we use
Internal vibrator
Screed vibrator
Form vibrator
None of these
Permissible compressive strength of M 150 concrete grade is
100 kg/cm2
150 kg/cm2
200 kg/cm2
250 kg/cm2
The maximum thickness of concrete floor of a cement warehouse, is
10 cm
15 cm
20 cm
25 cm
Shrinkage in concrete can be reduced by using
Low water cement ratio
Less cement in the concrete
Proper concrete mix
All 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
The size of fine aggregates does not exceed
2.75 mm
3.00 mm
3.75 mm
4.75 mm
The ratio of the diameter of reinforcing bars and the slab thickness is
1/4
1/5
1/6
1/8
Vicat apparatus is used for
Fineness test
Consistency test
Test for setting time
Test for tensile strength
For concreting of heavily reinforced sections without vibration, the workability of concrete expressed as compacting factor should be
0.75 - 0.80
0.80 - 0.85
0.85 - 0.92
Above 0.92
A continuous beam is deemed to be a deep beam when the ratio of effective span to overall depth (1/D) is less than
1.5
2.0
2.5
3.0
In reinforced concrete footing on soil, the minimum thickness at edge should not be less than
100 mm
150 mm
200 mm
250 mm
The compressive strength of 100 mm cube as compared to 150 mm cube is always
Less
More
Equal
None of the above