Concrete Technology And Design Set 6 MCQs

Q1 | Which of the following losses of pre-stress occurs only in pre-tensioning and not in posttensioning?

elastic shortening of concrete

shrinkage of concrete

creep of concrete

loss due to friction

Q2 | The type of aggregates of same nominal size, which contain less voids when compacted, are

rounded spherical

irregular

flaky

none of these

Q3 | Pre-stress loss due to friction occurs

only in post-tensioned beams

only in pre-tensioned beams

in both post-tensioned and pre-tensioned beams

none of the above

Q4 | Pick up the correct statement from the following:

an increase in water content must be accompanied by an increase in cement content

angular and rough aggregates reduce the workability of the concrete

the slump of the concrete mix decreases due to an increase in temperature

all the above

Q5 | In the method of voids for determination of the quantity of cement paste, it is assumed that

voids in coarse aggregates are filled by fine aggregates

voids in fine aggregates are filled by the cement paste

volume of fine aggregates is equal to total voids in coarse aggregates plus 10% extra

all the above

Q6 | As compared to ordinary Portland cement, use of pozzolana cement

reduces workability

increases bleeding

increases shrinkage

increases strength

Q7 | The following proportion of the ingredients of concrete mix, is not in conformation to arbitrarymethod of proportioning

1 : 1 : 2

1 : 2 : 4

1 : 3 : 6

1 : 4 : 10

Q8 | The strength and quality of concrete, depend upon:

grading of aggregates

surface area of aggregates

shape of aggregates

all the above

Q9 | The factor of safety for

steel and concrete are same

steel is lower than that for concrete

steel is higher than that for concrete

none of the above

Q10 | The preliminary test is repeated if the difference of compressive strength of three test specimens,exceeds

5 kg/cm2

8 kg/cm2

10 kg/cm2

15 kg/cm2

Q11 | Setting time of cement increases by adding

gypsum

hydrogen peroxide

calcium chloride

sodium oxide

Q12 | According to IS: 4561978, the maximum reinforcement in a column is

2 %

4 %

6 %

8 %

Q13 | According to the recommendations of IS : 456-1978, the expansion joints

are provided where plane changes abruptly

are provided to ensure minimum resistance

do not carry reinforcement across them

all the above

Q14 | The impurity of mixing water which affects the setting time and strength of concrete, is

sodium sulphates

sodium chlorides

sodium carbonates and bicarbonates

calcium bicarbonates

Q15 | If the size of panel in a flat slab is 6 m × 6 m, then as per Indian Standard Code, the widths ofcolumn strip and middle strip are

3.0 m and 1.5 m

1.5 m and 3.0 m

3.0 m and 3.0 m

1.5 m and 1.5 m

Q16 | Pick up the incorrect statement from the following:

the bottom and top ends of slump mould are parallel to each other

the axis of the mould is perpendicular to the end faces

the internal surface of the mould is kept clean and free from set cement

the mould is in the form of a frustum of hexagonal pyramid

Q17 | The concrete mix which causes difficulty in obtaining a smooth finish, possess

segregation

internal friction

hardness

bleeding

Q18 | While designing the pile as a column, the end conditions are nearly

both ends hinged

both ends fixed

one end fixed and other end hinged

one end fixed and other end free

Q19 | The internal dimensions of a ware house are 15 m × 5.6 m, and the maximum height of piles is2.70 m, the maximum number of bags to be stored in two piles, are

1500 bags

2000 bags

2500 bags

3000 bags

Q20 | Pick up the incorrect statement from the following. While performing preliminary test on concrete

proportions of the material and water should be the same as to be used at the work site

cement should be mixed by hand in order to maintain uniformity

concrete mix should be stored in air-tight containers

concrete ingredients should be kept at a temperature of 37° ± 2°c

Q21 | In a spherical dome the hoop stress due to a concentrated load at crown is

compressive everywhere

tensile everywhere

partly compressive and partly tensile

zero

Q22 | I.S. Sieve Nos. 10 mm and 4.75 mm are generally used for grading of

coarse aggregates

fine aggregates

neither (a) nor (b)

both (a) and (b)

Q23 | Log Angles machine is used to test the aggregate for

crushing strength

impact value

abrasion resistance

water absorption

Q24 | The property of the ingredients to separate from each other while placing the concrete is called

segregation

compaction

shrinkage

bulking

Q25 | Pick up the correct statement from the following:

higher workability indicates unexpected increase in the moisture content

higher workability indicates deficiency of sand

if the concrete mix is dry, the slump is zero

all the above