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This set of Concrete Technology and Design Multiple Choice Questions & Answers (MCQs) focuses on Concrete Technology And Design Set 2
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