Pick up the incorrect statement from the following:
The bottom and top ends of slump mould are parallel to each other
The axis of the mould is perpendicular to the end faces
The internal surface of the mould is kept clean and free from set cement
The mould is in the form of a frustum of hexagonal pyramid
Correct Answer :
D. The mould is in the form of a frustum of hexagonal pyramid
Related Questions
An excess of flaky particles in concrete aggregates
Decreases the workability
Increases the quantity of water and sand
More than 15% are not desirable
All the above
An aggregate is said to be flaky if its least dimension is less than
1/5th of mean dimension
2/5th of mean dimension
3/5th of mean dimension
4/5th of mean dimension
The approximate value of the ratio between direct tensile strength and flexural strength is
0.33
0.5
0.75
1.0
The strength of concrete after one year as compared to 28 days strength is about
10 to 15% more
15 to 20% more
20 to 25% more
25 to 50% more
The effect of adding calcium chloride in concrete is (i) To increase shrinkage (ii) To decrease shrinkage (iii) To increase setting time (iv) To decrease setting time The correct answer is
(i) and (iii)
(i) and (iv)
(ii) and (iii)
(ii) and (iv)
If the engineer-in-charge approves, the 10 cm cubes may be used for the work test of concrete provided maximum nominal size of aggregate, does not exceed
10 cm
15 cm
20 cm
25 cm
The shuttering of a hall measuring 4 m × 5 m, can be removed after
5 days
7 days
10 days
14 days
In a counterfort retaining wall, the main reinforcement in the stem at mid span is provided on
Front face only
Inner face only
Both front face and inner face
None of the above
An ordinary Portland cement when tested for its fineness, should not leave any residue on I.S. sieve No. 9, more than
5 %
10 %
15 %
20 %
M10 grade of concrete approximates
1 : 3 : 6 mix
1 : 1 : 2 mix
1 : 2 : 4 mix
1 : 1.5 : 3 mix
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
The minimum diameter of longitudinal bars in a column is
6 mm
8 mm
12 mm
16 mm
Water required per bag of cement, is
7 kg
14 kg
21 kg
35 kg
The condition not applicable to water cement ratio law, is
Internal moisture conditions on hydration continue till complete strength is gained
Concrete specimens may be tested at any temperature
Concrete specimens need be of same age
Concrete specimens need be of same size
Proper proportioning of concrete, ensures
Desired strength and workability
Desired durability
Water tightness of the structure
All the above
For a reinforced concrete section, the shape of shear stress diagram is
Wholly parabolic
Wholly rectangular
Parabolic above neutral axis and rectangular below neutral axis
Rectangular above neutral axis and parabolic below neutral axis
As compared to ordinary Portland cement, high alumina cement has
Higher initial setting time but lower final setting time
Lower initial setting time but higher final setting time
Higher initial and final setting times
Lower initial and final setting times
The property of the ingredients to separate from each other while placing the concrete is called
Segregation
Compaction
Shrinkage
Bulking
Modulus of rupture of concrete is a measure of
Flexural tensile strength
Direct tensile strength
Compressive strength
Split 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
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
A beam curved in plan is designed for
Bending moment and shear
Bending moment and torsion
Shear and torsion
Bending moment, shear and torsion
The main object of compaction of concrete, is:
To eliminate air holes
To achieve maximum density
To provide intimate contact between the concrete and embedded materials
All the above
Diagonal tension in a beam
Is maximum at neutral axis
Decreases below the neutral axis and increases above the neutral axis
Increases below the neutral axis and decreases above the neutral axis
Remains same
'Ware house pack' of cement means
Full capacity of the ware house
Pressure exertion of the bags of upper layers
Pressure compaction of the bags on lower layers
Packing the ware house
The operation of removing humps and hollows of uniform concrete surface, is known as
Floating
Screeding
Trowelling
Finishing
Maximum percentage reinforcement in case of slabs is limited to
2
4
6
8
For road pavements, the cement generally used, is
Ordinary Portland cement
Rapid hardening cement
Low heat cement
Blast furnace slag cement
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
Workability of concrete is directly proportional to
Aggregate cement ratio
Time of transit
Grading of the aggregate
All of above