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171.

For the improvement of workability of concrete, the shape of aggregate recommended is

A.	irregular	B.	angular
C.	round	D.	flaky

172.

Smaller size aggregates require less quantity of water for lubrication.

Yes

173.

Grading of aggregates should be continuous for

lean

rich

174.

The use of air-entraining agents in concrete

A.	increases workability of concrete	B.	decreases bleeding
C.	decreases strength	D.	all of these

175.

The workability of concrete is expressed by

A.	water-cement ratio	B.	slump value
C.	compaction factor	D.	both (a) and (b)

176.

The workability of concrete can be improved by adding

A.	hydrated lime	B.	flyash
C.	calcium chloride	D.	all of these

177.

The steel mould used for slump test is in the form of a

A.	cube	B.	cylinder
C.	frustrum of a cone	D.	none of these

178.

The top diameter, bottom diameter and height of the mould used for slump test are respectively

A.	100 mm, 200 mm, 300 mm	B.	200 mm, 100 mm, 300 mm
C.	200 mm, 300 mm, 100 mm	D.	100 mm, 300 mm, 200 mm

179.

In the slump test, the maximum size of the aggregate should not exceed 38 mm.

Correct

Incorrect

180.

For high degree of workability, the slump value should vary between

A.	0 to 25 mm	B.	25 to 50 mm
C.	50 to 80 mm	D.	80 to 100 mm