CIVIL ENGINEERING MCQ – PART:14
1. The approximate ratio
between the strengths of cement concrete
at 7 days and 28 days is
(a) 3 / 4
(b) 2 / 3
(c) l / 2
(d) l / 3
2. The approximate ratio of strength
of 15 cm × 30 cm concrete cylinder
to that of 15 cm cube of the same concrete is
(a) 1.25
(b) 1.00
(c) 0.85
(d) 0.50
3. Tensile strength
of concrete is measured by
a. direct tension test in the universal testing machine
b. applying compressive load along the diameter of the cylinder
c. applying third point loading on a prism
d. applying tensile load along the diameter of the cylinder
4. A splitting tensile test is performed on a cylinder of diameter ‘D’ and length ‘L’ if the ultimate load is ‘P’, then the splitting tensile strength of concrete is given by
(a) P/ n DL
(b) 2P/ n DL
(c) 4PL/ n D3
(d) 2PD/
n L3
5. The compacting factor test of cement concrete
determines its
(a) strength
(b) porosity
degree of compaction under loads
(d) workability
6. The split tensile
strength of M 15 grade concrete when expressed as a percentage of its compressive strength is
(a) 10 to 15%
(b) 15 to 20%
(c) 20 to 25%
(d) 25 to 30%
7. For a give environment, the most significant factor that influences the total shrinkage
of concrete is
a. cement content of
mix
b. total amount of water added at the time of mixing
c. size of the member concreted
d. maximum size of the coarse aggregate used
8. Consider the following
statements:
The effect of air enterainment in concrete is to
1. increase resistance
to freezing and thawing
2. improve workability
3. decrease strength
Which of these statements are correct?
(a) 1 and 2
(b) 1 and 3
(c) 1 alone
(d) 1, 2 and 3
9. The optimum number of revolutions over which concrete is required to be mixed in a mixer machine is
(a) 10
(b) 20
(c) 50
(d) 100
10. The length of time for which a concrete mixture
will remain plastic
is usually more dependent on
a. the setting time of cement
than on the amount of mixing water and atmospheric temperature
b. the atmospheric temperature than on the amount of mixing water and the setting time of cement
c. the setting
time of cement and the amount of mixing water than on atmospheric temperature
d. the amount of mixing water used and the atmospheric temperature than on the setting
time of cement
11. Which of the following is not an accelerator?
(a) CaCl2
(b) CaSO4
(c) NaCl
(d) Formaldehyde
12. Which of the following admixture
is not a chemically inactive
water proofer?
(a) Soda soaps
(b) Calcium soaps
(c) Wax
(d) Vegetable oils
13. The role of superplasticizer in a cement paste is to
a. disperse the particles
b. disperse the particles
and to remove air bubbles
c. disperse the particles, remove air bubbles and to retard setting
d. retard setting
14. Ultrasonic pulse velocity method in used to determine
(a) compressive strength of concrete
(b) impact resistance of concrete
(c) tensile strength of concrete
(d) quality of concrete
15. The ratio of tensile strength
to compressive strength
of concrete is about
(a) 1 / 5
(b) 1 / 2
(c) 1 / 10
(d) 1 / 20
16. A concrete cylinder of size 15 mm diameter and
300 mm long is tested for split tensile strength of concrete. It failed at a load
of 100 kN. The split tensile strength in N / mm2 is
(a) 0.35
(b) 0.71
(c) 1.42
(d) 2.83
17. The maximum mixing time, of cement concrete,
in minutes is limited to
(a) 2
(b) 4
(c) 6
(d) 10
18. The maturity of concrete is expressed as Maturity
= Σ (time × temperature)
The temperature reckoned as origin is
(a) 0°C
(b) –5°C
(c) –11°C
(d) –16°C
19. A cube of concrete as compared to cylinder of concrete is expected to have compressive strength
(a) less by 5%
(b) less by 15 %
(c) more by 5%
(d) more by 15%
20. Consider the following
statements:
The addition of surfactants in the concrete
mix results in
1. increase in the water cement ratio
2. decrease in the water cement ratio
3. increase in the strength of concrete
4. decrease in the curing duration
5. increase in the density of concrete
of these statements
(a) 1, 3 and 4 are correct just
(b) 2, 3 and 5 are correct
(c) 3, 4 and 5 are correct
(d) 1, 4 and 5 are correct