An aggregate which passes through 25 mm I.S. sieve and is retained on 20 mm sieve, is said to be flaky if its least dimension is less than
22.5 mm
18.5 mm
16.5 mm
13.5 mm
Correct Answer :
D. 13.5 mm
Related Questions
Pick up the incorrect statement applicable to the field test of good cement.
When one thrusts one's hand into a bag of cement, one should feel warm
The colour of the cement is bluish
By rubbing cement in between fingers, one should feed rough
All the above
Addition of pozzolana to cement causes
Reduction in permeability
Loss of heat of hydration
Reduction in bleeding
All the above
The limits of percentage p of the longitudinal reinforcement in a column is given by
0.15% to 2%
0.8% to 4%
0.8% to 6%
0.8% to 8%
Permissible compressive strength of M 200 concrete grade is
100 kg/cm2
150 kg/cm2
200 kg/cm2
250 kg/cm2
If the storey height is equal to length of RCC wall, the percentage increase in strength is
0
10
20
30
For given water content, workability decreases if the concrete aggregates contain an excess of
Thin particles
Flat particles
Elongated particles
All the above
Vicat's apparatus is used for
Fineness test
Consistency test
Setting time test
Soundness test
On a grading curve, the gap grading is represented by
A horizontal line
A vertical line
N.W. inclined line
N.E. inclined line
Sands of zone I are:
Course
Medium
Medium to fine
Fine
Construction joints are provided
Where B.M. and S.F. are small
Where the member is supported by other member
At 18 m apart in huge structures
All the above
The top diameter, bottom diameter and the height of a slump mould are:
10 cm, 20 cm, 30 cm
10 cm, 30 cm, 20 cm
20 cm, 10 cm, 30 cm
20 cm, 30 cm, 10 cm
Maximum distance between expansion joints in structures as per IS: 456 1978 is
20 m
30 m
45 m
60 m
If fineness modulus of sand is 2.5, it is graded as
Very fine sand
Fine sand
Medium sand
Coarse sand
The cement whose strength is a little lower than the ordinary cement during the first three months but attains afterwards the same strength, is known as
Low-heat Portland cement
Rapid hardening Portland cement
Portland blast slag cement
Portland pozzolana cement
Approximate value of shrinkage strain in concrete, is
0.003
0.0003
0.00003
0.03
The main reinforcement in the heel of a T-shaped R.C. retaining wall is provided on
Top face perpendicular to wall
Bottom face perpendicular to wall
Both top and bottom faces perpendicular to wall
None of the above
Pick up the correct statement from the following:
High percentage of C3S and low percentage of C2S cause rapid hardening
High percentage of C3S and low percentage of C2S make the cement less resistive to chemical attack
Low percentage of C3S and high percentage of C2S contribute to slow hardening
All the above
The minimum cover in a slab should neither be less than the diameter of bar nor less than
10 mm
15 mm
25 mm
13 mm
Pick up the correct statement from the following:
The concrete gains strength due to hydration of cement
The concrete does not set at freezing point
The strength of concrete increases with its age
All the above
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
The most useless aggregate is one whose surface texture is
Smooth
Granular
Glassy
Honey combed and porous
Pick up the incorrect statement from the following:
In properly graded aggregates, bulk density is more
In single size aggregates, bulk density is least
In single size aggregates, bulk density is maximum
None of these
Higher workability of concrete is required if the structure is
Made with cement concrete
Thick and reinforced
Thin and heavily reinforced
Thick and heavily reinforced
Particles of 0.002 mm size are that of
Clay
Sand
Gravel
None of these
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 purpose of reinforcement in pre-stressed concrete is
To provide adequate bond stress
To resist tensile stresses
To impart initial compressive stress in concrete
All of the above
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
Increase in the moisture content in concrete
Reduces the strength
Increases the strength
Does not change the strength
All of the above
Normally pre-stressing wires are arranged in the
Upper part of the beam
Lower part of the beam
Center
Anywhere
According to I.S. : 456, the number of grades of concrete mixes, is
3
4
5
7