Concrete Technology And Design Set 9 MCQs

Q1 | Shrinkage in concrete can be reduced by using

low water cement ratio

less cement in the concrete

proper concrete mix

all the above

Q2 | The shuttering of a hall measuring 4 m × 5 m, can be removed after

5 days

7 days

10 days

14 days

Q3 | The approximate value of the ratio between direct tensile strength and flexural strength is

0.33

0.5

0.75

1.0

Q4 | 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

Q5 | Workability improved by adding

fly ash

hydrated lime

calcium chloride

all the above

Q6 | Workability of concrete is inversely proportional to

time of transit

water-cement ratio

the air in the mix

size of aggregate

Q7 | Inert material of a cement concrete mix, is

water

cement

aggregate

none of these

Q8 | If a beam fails in bond, then its bond strength can be increased most economically by

increasing the depth of beam

using thinner bars but more in number

using thicker bars but less in number

providing vertical stirrups

Q9 | Pick up the incorrect statement from the following:

a rich mix of concrete possesses higher strength than that a lean mix of desired workability with excessive quantity of water

the strength of concrete decreases as the water cement ratio increases

good compaction by mechanical vibrations, increases the strength of concrete

none of these

Q10 | Ordinary Portland cement is manufactured from

lime stone and clay

gypsum and lime

pozzolana

lime, pozzolana and clay

Q11 | The percentage of reinforcement in case of slabs, when high strength deformed bars are used isnot less than

0.15

0.12

0.30

1.00

Q12 | Addition of pozzolana to cement

decreases workability

increases strength

increases heat of hydration

none of these

Q13 | If 50 kg of fine aggregates and 100 kg of coarse aggregates are mixed in a concrete whose watercement ratio is 0.6, the weight of water required for harsh mix, is

8 kg

10 kg

12 kg

14 kg

Q14 | The minimum cover to the ties or spirals should not be less than

15 mm

20 mm

25 mm

50 mm

Q15 | According to Water-Cement Ratio Law, the strength of workable plastic concrete

depends upon the amount of water used in the mix

does not depend upon the quality of cement mixed with aggregates

does not depend upon the quantity of cement mixed with aggregates

all the above

Q16 | Sands of zone I are:

course

medium

medium to fine

fine

Q17 | According to Whitney's theory, ultimate strain of concrete is assumed to be

0.03 %

0.1 %

0.3 %

3 %

Q18 | 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

Q19 | If the slump of a concrete mix is 60 mm, its workability is

very low

low

medium

high

Q20 | Cube strength of controlled concrete to be used for pre-tensioned and post-tensioned workrespectively should not be less than

35 mpa and 42 mpa

42 mpa and 35 mpa

42 mpa and 53 mpa

53 mpa and 42 mpa

Q21 | The void ratio of

single size coarse aggregate is roughly 0.45

graded coarse aggregate is roughly 0.040

fine aggregate is roughly 0.45

all the above

Q22 | According to IS : 382-1963, a good aggregate should be

chemically inert

sufficiently strong

hard and durable

all the above

Q23 | The compressive strength of 100 mm cube as compared to 150 mm cube is always

less

more

equal

none of the above

Q24 | The diameter of the Vicat plunger is 10 mm and its length varies from

20 mm to 30 mm

30 mm to 40 mm

40 mm to 50 mm

50 mm to 60 mm

Q25 | Gypsum is added for

colour

strength

controlling setting time

none of these