85.  Pick up the correct statement from the following :
A. An increase in water content must be accompanied by an increase in cement content
B. Angular and rough aggregates reduce the workability of the concrete
C. Large size aggregates increase the workability due to lesser surface area
D. All the above

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86. The top diameter, bottom diameter and the height of a slump mould are :
A. 10 cm, 20 cm, 30 cm
B. 10 cm, 30 cm, 20 cm
C. 20 cm, 10 cm, 30 cm
D. 20 cm, 30 cm, 10 cm

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87.  Pick up the incorrect statement from the following :
A. The bottom and top ends of slump mould are parallel to each other
B. The axis of the mould is perpendicular to the end faces
C. The internal surface of the mould is kept clean and free from set cement
D. The mould is in the form of a frustum of hexagonal pyramid

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88. If the slump of a concrete mix is 60 mm, its workability is
A. very low
B. low
C. medium -
D. high

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89.  Workability of concrete ratio is determined by
A. tensile strength test
B. slump test
C. compaction factor test
D. flexural strength test

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90.  In slump test, each layer of concrete is compacted by a steel rod 60 cm long and of 16 mm diameter for
A. 20 times
B. 25 times
C. 30 times
D. 40 times

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91.  Pick up the correct statement from the following :
A. Segregation is necessary for a workable concrete
B. Consistency does not affect the workability of concrete
C. If the slump increases, workability decreases
D. None of these

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