Concrete Technology And Design Set 2 MCQs

Q1 | Which of the following has high tensile strength?

plain hot rolled wires

cold drawn wires

heat treated rolled wires

all have same tensile strength

Q2 | Concrete gains strength due to

chemical reaction of cement with sand and coarse aggregates

evaporation of water from concrete

hydration of cement

all the above

Q3 | To determine the modulus of rupture, the size of test specimen used is

150 × 150 × 500 mm

100 × 100 × 700 mm

150 × 150 × 700 mm

100 × 100 × 500 mm

Q4 | Tricalcium aluminate (C3A)

reacts fast with water

generates less heat of hydration

causes initial setting and early strength of cement

does not contribute to develop ultimate strength

Q5 | If the various concrete ingredients i.e. cement, sand and aggregates are in the ratio of 1:3:6, thegrade of concrete, is

m 100

m 150

m 200

m 250

Q6 | Admixtures which cause early setting and hardening of concrete are called

workability admixtures

accelerators

retarders

air entraining agents

Q7 | Pick up the correct statement from the following:

sand stones may be divided into calcareous, siliceous and ferruginous sand stones

concrete using sand stones, cracks due to excessive shrinkage

broken bricks produce a concrete having good fire resisting qualities

all the above

Q8 | Pick up the incorrect statement from the following:

admixtures accelerate hydration

admixtures make concrete water proof

admixtures make concrete acid proof

admixtures give high strength

Q9 | For a reinforced concrete section, the shape of shear stress diagram is

wholly parabolic

wholly rectangular

parabolic above neutral axis and rectangular below neutral axis

rectangular above neutral axis and parabolic below neutral axis

Q10 | Allowable shear strength of concrete, depends upon

shear strength

tensile strength

compressive strength

none of these

Q11 | In slump test, each layer of concrete is compacted by a steel rod 60 cm long and of 16 mmdiameter for

20 times

25 times

30 times

50 times

Q12 | The individual variation between test strength of sample should not be more than

±5 % of average

± 10 % of average

± 15 % of average

±20 % of average

Q13 | Pick up the incorrect statement from the following:

concrete for which preliminary tests are conducted, is called controlled concrete

bulking of sand depends upon the fineness of grains

concrete mix 1 : 6 : 12, is used for mass concrete in piers

all the above

Q14 | The slab is designed as one way if the ratio of long span to short span is

less than 1

between 1 and 1.5

between 1.5 and 2

greater than 2

Q15 | For the construction of cement concrete dams, the maximum permissible size of the aggregates, is

40 mm

50 mm

60 mm

70 mm

Q16 | Pick up the incorrect statement from the following:

with passage of time, the strength of cement increases

with passage of time, the strength of cement decreases

after a period of 24 months, the strength of cement reduces to 50%

the concrete made with storage deteriorated cement, gains strength with time

Q17 | To hydrate 500kg of cement full water needed, is

100 kg

110 kg

120 kg

130 kg

Q18 | Pick up the correct statement from the following:

a highly absorptive aggregate reduces the workability of concrete considerably

the specific gravity of aggregate is important for the determination of the moisture content

the absorption and porosity of an aggregate influence the property of the concrete

all the above

Q19 | In a counterfort retaining wall, the main reinforcement in the stem at mid span is provided on

front face only

inner face only

both front face and inner face

none of the above

Q20 | Under normal conditions using an ordinary cement, the period of removal of the form work, is:

7 days for beam soffits

14 days for bottom slabs of spans 4.6 m and more

21 days for bottom beams over 6 m spans

all the above

Q21 | Water cement ratio is generally expressed in volume of water required per

10 kg

20 kg

30 kg

50 kg

Q22 | To ensure constant moisture content in aggregates

area of each aggregate pile should be large

height of each aggregate pile should not exceed 1.50 m

aggregate pile should be left for 24 hours before aggregates are used

all the above

Q23 | Pick up the correct statement from the following:

cement should be mixed for at least one minute

10% of water is placed in the rotating drum before adding dry material

10% of water is added after placing the other ingredients in the drum

all the above

Q24 | The average permissible stress in bond for plain bars in tension is

increased by 10% for bars in compression

increased by 25% for bars in compression

decreased by 10% for bars in compression

decreased by 25% for bars in compression

Q25 | Concrete mainly consists of

cement

aggregates

water

all the above