344. For making fly-ash building bricks, the following mix of fly-ash, sand and lime, is
A. 80:13:7
B. 70:20 :10
C. 60:35:5
D. none of these.

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345. Dolomite, a rock forming mineral
A. contains brittle crystals
B. is heavier than calcite
C. is a chemical composition of bicarbonate of magnesium and calcium
D. All the above.

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346. Pick up the correct statement from the following :
A. Calcite is a calcium carbonate (CaCO3)
B. Dolomite is chemical composition of magnesium bicarbonate and calcium bicarbonate
C. Gypsum is the hydrated sulphate of calcium (CaSO4.21120)
D. All the above.

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347. The Smith's test of a stone sample is performed to determine :
A. the presence of soluble matter
B. the hardness of the stone
C. the toughness of the stone
D. the compressive strength of the stone.

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348.  Pick up the correct statement regarding Deval's attrition test machine from the following :
A. The diameter and length of cylinder are respectively 20 cm and 34 cm
B. The axes of cylinders make an angle of 30? with the horizontal
C. The cylinders the rotated about horizontal axis for 5 hours at the rate of 30 R.P.M.
D. All the above.

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349.  Pick up the correct statement from the following :
A. The coefficient of hardness of stone used in road work should be greater than 17
B. For a good building stone, percentage wear should be equal to or less than 3 percent
C. The free quartz suddenly expands at a temperature lower than 600?C
D. The argillaceous stones are poor in strength, but resist fire quite well

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350. The stone whose margin of about 20 mm width is sunk on all the edges and whose central portion is made to project about 15 mm, is called
A. reticulated finish
B. tooled finish
C. furrowed finish
D. sunk finish

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