21) Field test for strength of good bricks is to drop it from a height of ______ and they should not
break
(a) 1.2 m
(b) 1.0 m
(c) 0.7 m
(d) 0.75 m
22) The unit weight of reinforced cement concrete is generally taken as
a) 18 kN/m3
b) 22kN/m3
c) 24 kN/m3
d)25 kN/m3
23) Water absorption of vitrified tiles is not more than
(a) 0.5%
(b) 1.0%
(c) 2.0%
(d) 5.0%
24) Efflorescence in cement is caused due to an excess of
a) Alumina
b) Iron oxide
c) Silica
d) Alkalies
25) Continuous kiln is
(a) bull’s trench kiln
(b) Hoffman’s kiln
(c) tunnel kiln
(d) all of the above
26) Percentage of silica in a good brick earth lies between
a) 5 to 10%
b) 20 to 30%
c) 50 to 60%
d) 70 to 80%
27) Alumina in brick earth gives the bricks
(a) strength
(b) colour
(c) plasticity
(d) resistance to shrinkage
28) The type of decay in timber dry rot is due to
a) white ants
b) dampness
c) baceteria
d) fungus
29) Plywood is identified by
(a) volume
(b) weight
(c) area
(d) thickness
30) The frog of brick is normally made on its
a) top face
b) bottom face
c) longer face
d) shorter side