Concrete Technology and Design of Concrete Structures MCQ Questions and Answers in Civil Engineering

Question. According to IS: 456-1978, the column or the strut is the member whose effective length is greater than
(a) The least lateral dimension
(b) 2 times the least lateral dimension
(c) 3 times the least lateral dimension
(d) 4 times the least lateral dimension

Answer : C

Question. Which of the following R.(c) retaining walls is suitable for heights beyond 6 m?
(a) L-shaped wall
(b) T-shaped wall
(c) Counterfort type
(d) All of the above

Answer : C

Question. The main reinforcement in the toe of a T-shaped R.(c) retaining wall is provided on
i) top face parallel to the wall
ii) top face perpendicular to the wall
iii) bottom face parallel to the wall
iv) bottom face perpendicular to the wall
The correct answer is
(a) Only (ii) is correct
(b) (i) and (ii) are correct
(c) (iii) and (iv) are correct
(d) Only (iv) is correct

Answer : D

Question. In a ring beam subjected to uniformly distributed load
i) shear force at mid span is zero
ii) shear force at mid span is maximum
iii) torsion at mid span is zero
iv) torsion at mid span is maximum
The correct answer is
(a) (i) and (iii)
(b) (i) and (iv)
(c) (ii) and (iii)
(d) (ii) and (iv)

Answer : B

Question. Shrinkage of concrete depends upon
i) humidity of atmosphere
ii) passage of time
iii) stress
The correct answer is
(a) (i) and (ii)
(b) (ii) and (iii)
(c) Only (iii)
(d) All (i), (ii) and (iii)

Answer : A

Question. High carbon content in the steel causes
(a) Decrease in tensile strength but increase in ductility
(b) Increase in tensile strength but decrease in ductility
(c) Decrease in both tensile strength and ductility
(d) Increase in both tensile strength and ductility

Answer : B

Question. The individual variation between test strength of sample should not be more than
(a) ±5% of average
(b) ±10% of average
(c) ±15% of average
(d) ±20% of average

Answer : C

Question. Ultimate strength of cold drawn high steel wires
(a) Increases with increase in diameter of bar
(b) Decreases with increase in diameter of bar
(c) Does not depend on diameter of bar
(d) None of the above

Answer : B

Question. If the depth of neutral axis for a singly reinforced rectangular section is represented by kd in working stress design, then the value of k for balanced section
(a) depends on as, only
(b) depends on aCbC only
(c) depends on both crst and acbc
(d) is independant of both ast and acbc where d is the effective depth, ast is per-missible stress in steel in tension and ocbc is permissible stress in concrete in bending compression.

Answer : A

Question. In reinforced concrete footing on soil, the minimum thickness at edge should not be less than
(a) 100 mm
(b) 150 mm
(c) 200 mm
(d) 250 mm

Answer : B

Question. For a simply supported beam of span 15m, the minimum effective depth to satisfy the vertical deflection limits should be
(a) 600 mm
(b) 750 mm
(c) 900 mm
(d) More than 1 m

Answer : D

Question. The permissible diagonal tensile stress in reinforced brick work is
(a) About 0.1 N/mm²
(b) Zero
(c) 0.3 N/mm2 to 0.7 N/mm²
(d) About 1.0 N/mm²

Answer : A

Question. The minimum cover in a slab should neither be less than the diameter of bar nor less than
(a) 10 mm
(b) 15 mm
(c) 25 mm
(d) 13 mm

Answer : B

Question. A T-shaped retaining wall mainly conssits of
(a) One cantilever
(b) Two cantilevers
(c) Three cantilevers
(d) Four cantilevers

Answer : C

Question. In a counterfort retaining wall, the main reinforcement is provided on the
i) bottom face in front counterfort
ii) inclined face in front counterfort
iii) bottom face in back counterfort
iv) inclined face in back counterEort
The correct answer is
(a) (i) and (ii),
(b) (ii) and (iii)
(c) (i) and (iv)
(d) (iii) and (iv)

Answer : C

Question. Normally prestressing wires are arranged in the
(a) Upper part of the beam
(b) Lower part of the beam
(c) Center
(d) Anywhere

Answer : B

Question. The load carrying capacity of a helically reinforced column as compared to that of a tied column is about
(a) 5% less
(b) 10% less
(c) 5% more
(d) 10% more

Answer : C

Question. If the depth of actual neutral axis in a beam is more than the depth of critical neutral axis, then the beam is called
(a) Balanced beam
(b) Under reinforced beam
(c) Over reinforced beam
(d) None of the above

Answer : C

Question. Which of the following has high tensile strength?
(a) Plain hot rolled wires
(b) Cold drawn wires
(c) Heat treated rolled wires
(d) All have same tensile strength

Answer : B

Question. Select the incorrect statement
(a) Lean mixes bleed more as compared to rich ones
(b) Bleeding can be minimized by adding pozzuolana finer aggregate
(c) Bleeding can be increased by addition of calcium chloride
(d) None of the above

Answer : D

Question. Sinking of an intermediate support of a continuous beam
i) reduces the negative moment at support
ii) increases the negative moment at support
iii) reduces the positive moment at center of span
iv) increases the positive moment at center of span
The correct answer is
(a) (i) and (iii)
(b) (i) and (iv)
(c) (ii) and (iii)
(d) (ii) and (iv)

Answer : B

Question. A continuous beam is deemed to be a deep beam when the ratio of effective span to overall depth (1/D) is less than
(a) 1.5
(b) 2.0
(c) 2.5
(d) 3.0

Answer : C

Question. Cube strength of controlled concrete to be used for pretensioned and post-tensioned work respectively should not be less than
(a) 35 MPa and 42 MPa
(b) 42 MPa and 35 MPa
(c) 42 MPa and 53 MPa
(d) 53 MPa and 42 MPa

Answer : B

Question. If a beam fails in bond, then its bond strength can be increased most economically by
(a) Increasing the depth of beam
(b) Using thinner bars but more in number
(c) Using thicker bars but less in number
(d) Providing vertical stirrups

Answer : B

Question. In symmetrically reinforced sections, shrinkage stresses in concrete and steel are respectively
(a) Compressive and tensile
(b) Tensile and compressive
(c) Both compressive
(d) Both tensile

Answer : B

Question. If the foundations of all the columns of a structure are designed on the total live and dead load basis, then
(a) There will be no settlement of columns
(b) There will be no differential settlement
(c) The settlement of exterior columns will be more than interior columns
(d) The settlement of interior columns will be more than exterior columns

Answer : C

Question. The recommended value of modular ratio for reinforced brick work is
(a) 18
(b) 30
(c) 40
(d) 58

Answer : C

Question. The average permissible stress in bond for plain bars in tension is
(a) Increased by 10% for bars in compression
(b) Increased by 25% for bars in compression
(c) Decreased by 10% for bars in compression
(d) Decreased by 25% for bars in compression

Answer : B

Question. In order to obtain the best workability of concrete, the preferred shape of aggregate is
(a) Rounded
(b) Elongated
(c) Angular
(d) All of the above

Answer : A

Question. If the permissible stress in steel in tension is 140 N/mm2, then the depth of neutral axis for a singly reinforced rectangular balanced section will be
(a) 0.35 d
(b) 0.40 d
(c) 0.45 d
(d) Dependent on grade of concrete also

Answer : B

Question. The relation between modulus of rupture f_cr, splitting strength f_cs and direct tensile strength f_cl is given by
(a) f_cr - f_cs = f_cl
(b) f_cr > f_cs > f_cl
(c) f_cr < f_cs < f_cl
(d) f_cs > f_cr > f_cl

Answer : B

Question. According to ISI recommendations, the maximum depth of stress block for balanced section of a beam of effective depth d is
(a) 0.43 d
(b) 0.55 d
(c) 0.68 d
(d) 0.85 d

Answer : A

Question. The depth of footing for an isolated column is governed by
i) maximum bending moment
ii) shear force
iii) punching shear
The correct answer is
(a) Only (i)
(b) (i) and (ii)
(c) (i) and (iii)
(d) (i), (ii) and (iii)

Answer : D

Question. The slab is designed as one way if the ratio of long span to short span is
(a) Less than 1
(b) Between 1 and 1.5
(c) Between 1.5 and 2
(d) Greater than 2

Answer : D

Question. In working stress design, permissible bond stress in the case of deformed bars is more than that in plain bars by
(a) 10%
(b) 20%
(c) 30%
(d) 40%

Answer : D

Question. Critical section for shear in case of flat slabs is (adopting standard notations)
(a) At a distance of effective depth of slab from periphery of column/drop panel
(b) At a distance of d/2 from periphery of column/capital/drop panel
(c) At the drop panel of slab
(d) At the periphery of column

Answer : B

Question. In a spherical dome the hoop stress due to a concentrated load at crown is
(a) Compressive everywhere
(b) Tensile everywhere
(c) Partly compressive and partly tensile
(d) Zero

Answer : B

Question. Minimum thickness of load bearing RCC wall should be
(a) 50 mm
(b) 100 mm
(c) 150 mm
(d) 200 mm

Answer : B

Question. The property of fresh concrete, in which the water in the mix tends to rise to the surface while placing and compacting, is called
(a) Segregation
(b) Bleeding
(c) Bulking
(d) Creep

Answer : B

Question. A higher modular ratio shows
(a) Higher compressive strength of concrete
(b) Lower compressive strength of concrete
(c) Higher tensile strength of steel
(d) Lower tensile strength of steel

Answer : B

Question. To minimize the effect of differential settlement, the area of a footing should be designed for
(a) Dead load only
(b) Dead load + live load
(c) Dead load + fraction of live load
(d) Live load + fraction of dead load

Answer : C

Question. For a cantilever of effective depth of 0.5 m, the maximum span to satisfy vertical deflection limit is
(a) 3.5 m
(b) 4 m
(c) 4.5 m
(d) 5 m

Answer : A

Question. In the design of a front counterfort in a counterfort retaining wall, the main reinforcement is provided on
i) bottom face near counterfort
ii) top face near counterfort
iii) bottom face near centre of span
iv) top face near centre of span
The correct answer is
(a) Only (i)
(b) Only (ii)
(c) Both (i) and (iv)
(d) Both (ii) and (iii)

Answer : C

Question. To determine the modulus of rupture, the size of test specimen used is
(a) 150 x 150 x 500 mm
(b) 100 x 100 x 700 mm
(c) 150 x 150 x 700 mm
(d) 100 x 100 x 500 mm

Answer : C

Question. Bulking of sand is maximum if moisture content is about
(a) 2%
(b) 4%
(c) 6% 
(d) 10%

Answer : B

Question. When shear stress exceeds the permissible limit in a slab, then it is reduced by
(a) Increasing the depth
(b) Providing shear reinforcement
(c) Using high strength steel
(d) Using thinner bars but more in number

Answer : A

Question. Poisson’s ratio for concrete
(a) Remains constant
(b) Increases with richer mixes
(c) Decreases with richer mixes
(d) None of the above

Answer : B

Question. Modulus of rupture of concrete is a measure of
(a) Flexural tensile strength
(b) Direct tensile strength
(c) Compressive strength
(d) Split tensile strength

Answer : A

Question. The purpose of reinforcement in pre-stressed concrete is
(a) To provide adequate bond stress
(b) To resist tensile stresses
(c) To impart initial compressive stress in concrete
(d) All of the above

Answer : C

Question. Select the incorrect statement
(a) The loss of prestress is more in pre-tensioning system than in post-tensioning system.
(b) Pretensioning system has greater certainty about its durability.
(c) For heavy loads and large spans in buildings or bridges, post-tensioning system is cheaper than pretensioning system
(d) none of the above

Answer : D

Question. Maximum percentage reinforcement in case of slabs is limited to
(a) 2
(b) 4
(c) 6
(d) 8

Answer : B

Question. Workability of concrete is inversely proportional to
(a) Time of transit
(b) Vater-cement ratio
(c) The air in the mix
(d) Size of aggregate

Answer : A

Question. The diameter of ties in a column should be
(a) More than or equal to one fourth of diameter of main bar
(b) More than or equal to 5 mm
(c) More than 5 mm but less than one-fourth of diameter of main bar
(d) More than 5 mm and also more than one-fourth of diameter of main bar

Answer : D

Question. If the size of panel in a flat slab is 6m x 6m, then as per Indian Standard Code, the widths of column strip and middle strip are
(a) 3.0 m and 1.5 m
(b) 1.5 m and 3.0 m
(c) 3.0 m and 3.0 m
(d) 1.5 m and 1.5 m

Answer : C

Question. For a longitudinal reinforcing bar in a column, the minimum cover shall neither be less than the diameter of bar nor less than
(a) 15 mm
(b) 25 mm
(c) 30 mm
(d) 40 mm

Answer : D

Question. Maximum quantity of water needed per 50 kg of cement for M 15 grade of concrete is
(a) 28 liters
(b) 30 liters
(c) 32 liters
(d) 34 liters

Answer : C

Question. Minimum grade of concrete to be used in reinforced concrete as per IS: 456-1978 is
(a) M15
(b) M20
(c) M10
(d) M25

Answer : A

Question. In counterfort type retaining walls
i) the vertical slab is designed as a continuous slab
ii) the heel slab is designed as a continuous slab
iii) the vertical slab is designed as a cantilever
iv) the heel slab is designed as a cantilever
The correct answer is
(a) (i) and (ii)
(b) (i) and (iv)
(c) (ii) and (iii)
(d) (iii) and (iv)

Answer : A

Question. The percentage of voids in cement is approximately
(a) 25%
(b) 40%
(c) 60%
(d) 80%

Answer : B

Question. The effect of creep on modular ratio is
(a) To decrease it
(b) To increase it
(c) Either to decrease or to increase it
(d) To keep it unchanged

Answer : B

Question. According to Whitney’s theory, ultimate strain of concrete is assumed to be
(a) 0.03%
(b) 0.1%
(c) 0.3%
(d) 3%

Answer : C

Question. 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
(a) (i) and (iii)
(b) (i) and (iv)
(c) (ii) and (iii)
(d) (ii) and (iv)

Answer : B

Question. In T-shaped R.(c) retaining walls, the main reinforcement in the stem is provided on
(a) The front face in one direction
(b) The front face in both directions
(c) The inner face in one direction
(d) The inner face in both directions

Answer : C

Question. 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
(a) Is always less than 1
(b) Is always greater than 1
(c) Can be more than 1
(d) Can be less than 1

Answer : A

Question. The minimum cover to the ties or spirals should not be less than
(a) 15 mm
(b) 20 mm
(c) 25 mm
(d) 50mm

Answer : C

Question. In a counterfort retaining wall, the main reinforcement in the stem at mid span is provided on
(a) Front face only
(b) Inner face only
(c) Both front face and inner face
(d) None of the above

Answer : A

Question. Select the correct statement
(a) Elastic modulus of high tensile steel is nearly the same as that of mild steel
(b) Elastic modulus of high tensile steel is more than that of mild steel
(c) Carbon percentage in high carbon steel is less than that in mild steel
(d) High tensile steel is cheaper than mild steel

Answer : A

Question. For concreting of heavily reinforced sections without vibration, the workability of concrete expressed as compacting factor should be
(a) 0.75 - 0.80
(b) 0.80 - 0.85
(c) 0.85 - 0.92
(d) Above 0.92

Answer : D

Question. The percentage of reinforcement in case of slabs, when high strength deformed bars are used is not less than
(a) 0.15
(b) 0.12
(c) 0.30
(d) 1.00

Answer : B

Question. According to IS : 456-1978, minimum slenderness ratio for a short column is
(a) Less than 12
(b) Less than 18
(c) Between 18 and 24
(d) More than 24

Answer : A