Workability of concrete can be measured using slump, compaction factor and Vebe time.
Consider the following statements for workability of concrete:
(i) As the slump increases, the Vebe time increases.
(ii) As the slump increases, the compaction factor increases.
Which of the following is TRUE?
a. Both (i) and (ii) are True
b. Both (i) and (ii) are False
c. (i) is True and (ii) is False
d. (i) is False and (ii) is True
d
Consider the following statements for air-entrained concrete:
(i) Air-entrainment reduces the water demand for a given level of workability.
(ii) Use of air-entrained concrete is required in environments where cyclic freezing and thawing is expected.
Which of the following is TRUE?
a. Both (i) and (ii) are True
b. Both (i) and (ii) are False
c. (i) is True and (ii) is False
d. (i) is False and (ii) is True
a
Group I contains some properties of concrete/cement and Group II contains list of some tests on concrete/cement. Match the property with the corresponding test.
Group I
P. Workability of concrete
Q. Direct tensile strength of concrete
R. Bond between concrete and steel
S. Fineness of cement
Group II
1. Cylinder splitting test
2. Vee-Bee test
3. Surface area test
4. Fineness modulus test
5. Pull out test
a. P: 2; Q: 1; R: 5; S: 3
b. P: 2; Q: 5; R: 1; S: 3
c. P: 2; Q: 1; R: 5; S: 4
d. P: 2; Q: 5; R: 1; S: 4
a
The cylinder strength of the concrete is less than the cube strength because of
a. the difference in the shape of the cross section of the specimens
b. the difference in the slenderness ratio of the specimens
c. the friction between the concrete specimens and the steel plate of the testing machine
d. the cubes are tested without capping but the cylinders are tested with capping.
b
The modulus of rupture of concrete gives
a. the direct tensile strength of the concrete
b. the direct compressive strength of the concrete
c. the tensile strength of the concrete under bending
d. the characteristic strength of the concrete
c
[CONTAINS GRAPH] Group I contains representative stress-strain curves as shown in the figure, while Group II gives the list of materials. Match the stress-strain curves with the corresponding materials.
Group I
P. Curve J
Q. Curve K
R. Curve L
Group II
1. Cement paste
2. Coarse aggregate
3. Concrete
a. P: 1; Q: 3; R: 2
b. P: 2; Q: 3; R: 1
c. P: 3; Q: 1; R: 2
d. P: 3; Q: 2; R: 1
b
Maximum possible value of compacting factor for fresh (green) concrete is
a. 0.5
b. 1.0
c. 1.5
d. 2.0
b
The creep strains are
a. caused due to dead loads only
b. caused due to live loads only
c. caused due to cyclic loads only
d. independent of loads.
a
Consider a reinforcing bar embedded in concrete.
In a marine environment this bar undergoes uniform corrosion which leads to the deposition of corrosion products on its surface and an increase in the apparent volume of the bar. This subjects the surrounding concrete to expansive pressure.
As a result, corrosion induced cracks appear at the surface of concrete. Which of the following statements is TRUE?
a. Corrosion causes circumferential tensile stresses in concrete and the cracks will be parallel to the corroded reinforcing bar.
b. Corrosion causes radial tensile stresses in concrete and the cracks will be parallel to the corroded reinforcing bar.
c. Corrosion causes circumferential tensile stresses in concrete and the cracks will be perpendicular to the direction of the corroded reinforcing bar.
d. Corrosion causes radial tensile stresses in concrete and the cracks will be perpendicular to the direction of the corroded reinforcing bar
c
The modulus of rupture of concrete in terms of its characteristic cube compressive strength (fck) in MPa according to IS 456:2000 is
a. 5000 fck
b. 0.7 fck
c. 5000 √fck
d. 0.7 √fck
d
[APR 2025]
Column I gives a list of test methods for evaluation properties of concrete and Column II gives the list of properties
Column I
P. Resonant frequency test
Q. Rebound hammer test
R. Split cylinder test
S. Compacting factor test
Column II
1. Tensile strength
2. Dynamic modulus of elasticity
3. Workability
4. Compressive strength
The correct match of the test with the property is:
a. P: 2; Q: 4; R: 1; S: 3
b. P: 2; Q: 1; R: 4; S: 3
c. P: 2; Q: 4; R: 3; S: 1
d. P: 4; Q: 3; R: 1; S: 2
a
Consider the following statements:
I. The compressive strength of concrete decreases with increase in water-cement ratio of the concrete mix.
II. Water is added to the concrete mix for hydration of cement and workability.
III. Creep and shrinkage of concrete are independent of the water-cement ratio in the concrete mix.
The true statements are
a. I and II
b. I, II and III
c. II and III
d. Only II
a
Consider the following statements:
I. Modulus of elasticity of concrete increases with increase in compressive strength of concrete.
II. Brittleness of concrete increases with decrease in compressive strength of concrete.
III. Shear strength of concrete increases with increase in compressive strength of concrete.
The TRUE statements are
a. II and III
b. I, II and III
c. I and II
d. I and III
b
[APR 2024]
If the characteristic strength of concrete fck is defined as the strength below which not more than 50% of the test results are expected to fall, the expression for fck in terms of mean strength fm and standard deviation S would be
a. fm – 0.1645S
b. fm – 1.645S
c. fm – 1.65S
d. fm + 1.645S
c
In a random sampling procedure for cube strength of concrete, one sample consists of X number of specimens. These specimens are tested at 28 days and average strength of these X specimens is considered as test result of the sample, provided the individual variation in the strength of specimens is not more than ±Y percent of the average strength.
The values of X and Y as per IS : 456-2000 are
a. 4 and 10 respectively
b. 3 and 10 respectively
c. 4 and 15 respectively
d. 3 and 15 respectively
d
[CONTAINS GRAPH] The stress-strain diagram for two materials A and B is shown below:
(Graph with Material A more steep and brittle, Material B more ductile)
The following statements are made based on this diagram:
I. Material A is more brittle than material B.
II. The ultimate strength of material B is more than that of A.
With reference to the above statements, which of the following applies?
a. Both the statements are false.
b. Both the statements are true.
c. I is true but II is false.
d. I is false but II is true.
c
The characteristic strength of concrete is defined as that compressive strength below which not more than
a. 10% of result fall
b. 5% of result fall
c. 2% of result fall
d. None of these
b
Which one of the following is categorized as a long-term loss of prestress in a prestressed concrete member?
a. Loss due to elastic shortening
b. Loss due to friction
c. Loss due to relaxation of strands
d. Loss due to anchorage slip
c
Transition curves are provided on the approach to horizontal curves in order to
a. increase jerk to allowable levels
b. minimize the length of the horizontal curve
c. simplify the laying out and construction of the curve
d. reduce jerk to allowable levels
d
On sag (or valley) curves the available sight distance is determined based on
a. design speed
b. height of obstacle
c. height of driver eye
d. night time driving conditions
d
Maximum allowable grades are lower for railways than for highways because
a. construction costs become prohibitive for railways at high grades
b. trains are longer than vehicles which use the highways
c. high grades causes discomfort to passengers
d. steel wheels on steel rails have lower frictional coefficient than rubber tyres on pavements
a
Sliding considerations for stopped vehicles on super elevated horizontal curves provide the following bound on the amount of super elevation, e,
a. e ≥ coefficient of rolling friction
b. e ≥ coefficient of side friction
c. e ≤ coefficient of rolling friction
d. e ≤ coefficient of side friction
b
At highway stretches where the required overtaking sight distance cannot be provided, it is necessary to incorporate
a. at least twice the stopping sight distance
b. half the required overtaking sight distance
c. one third the required overtaking sight distance
d. three times the stopping sight distance
a
The ideal form of curve for the summit curve is
a. spiral
b. parabola
c. circle
d. lemniscates
b
