141. Curing a concrete for long period ensures better
A. volume stability
B. strength
C. water resistance
D. all the above
142. Under normal conditions using an ordinary cement, the period of removal of the form work, is :
A. 17 days for beam soffits
B. 14 days for bottom slabs of spans 46 m and more
C. 21 days for bottom beams over 6 m spans
D. all the above
143. While compacting the concrete by a mechanical vibrator, the slump should not exceed
A. 25 cm
B. 50 cm
C. 75 cm
D. 10 cm
144. The maximum thickness of concrete floor of a cement warehouse, is
A. 10/cm
B. 15 cm
C. 20 cm
D. 25 cm
145. The shuttering of a hall measuring 4 m x 5 m, can be removed after
A. 5 days
B. 7 days
C. 10 days
D. 14 days
146. Pick up the correct statement from the following :
A. There should not be any loss of cement from the charged drum of the mixer
B. Cement should be mixed for at least one minute
C. 10% of water is placed in the rotating drum before adding dry material
D. All the above
147. If the effective working time is 7 hours and per batch time of concrete is 3 minutes, the output of a concrete mixer of 150 litre capacity, is
A. 15,900 litres
B. 16,900 litres
C. 17,900 litres
D. 18,900 litres
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