11) The sand in mortar
(a) prevents shrinkage
(b) spreads mortar
(c) allows carbon dioxide from the atmosphere to penetrate deeply
(d) all the above
12) The approximate proportion of dry cement mortar required for brickwork is
a) 60%
b) 45%
c) 30%
d) 10%
13) The compound responsible for initial setting of cement is
(a) Tricalcium aluminate
(b) Tricalcium silicate
(c) Dicalcium silicate
(d) Tetra alumino ferrite
14) Plaster of paris is obtained by calcining
a) gypsum
b) bauxite
c) lime stone
d) kanker
15) The fuel generally used for burning lime stone is
(a) firewood
(b) charcoal
(c) coal
(d) any one of these
16) Initial setting time of concrete ceases at
a) -100C
b) -40C
c) 00C
d) 40C
17) Which one of the following statement is correct?
(a) Fat lime contains hardly 5% clay
(b) Hydraulic lime contains 5.30% clay
(c) Poor lime contains more than 30% clay
(d) All the above
18) Which one of the following does not react with concrete ?
a) Sewage water
b) Sulphuric acid
c) Vegetable oil
d) Alcohol
19) The heaviest metal is
(a) steel
(b) lead
(c) tin
(d) cast iron
20) For a RCC slab the slump of concrete should be
a) 0-25 mm
b) 25-50 mm
c) 75-100 mm
d) 50-125 mm