### Building Materials (Concrete)

Q.1.     For a 1:2.5:4.5 concrete mix, sand required per bag of cement would be
(a)        35 litres
(b)        88 litres
(c)        160 litres
(d)        none of these

Q.2.     For a 1:2.5:4.5 concrete mix, coarse aggregate required per bag of cement would be
(a)        35 litres
(b)        88 litres
(c)        160 litres
(d)        none of these

Q.3.     For a 1:2.5:4.5 concrete mix, if bulk densities of fine aggregate(sand) and coarse aggregate are 1.5 kg/litre and 1.6 kg/litre respectively, then sand required per bag of cement would be
(a)        50 kg
(b)        132 kg
(c)        256 kg
(d)        none of these

Q.4.     For a 1:2.5:4.5 concrete mix, if bulk densities of fine aggregate(sand) and coarse aggregate are 1.5 kg/litre and 1.6 kg/litre respectively, then coarse sand required per bag of cement would be
(a)        50 kg
(b)        132 kg
(c)        256 kg*
(d)        none of these

Q.5.     The dry volume of cement concrete is about ____ than is wet volume.
(a)        50% more
(b)        55% more
(c)        50% less
(d)        55% less          (AMIE  June98)

Q.6.     100NT concrete mixer is
(a)        a non tilting concrete mixer
(b)        a tilting type concrete mixer
(c)        capable of yielding 100 litres of finally mixed concrete
(d)        both (a) and (c)

Q.7.     Consider the following statements:
A concrete mixer is specified by the
1.         Volume of the mixing drum
2.         horse power of the prime mover
3.         volume of mixed concrete discharged
4.         mixer drum speed
(a)       1,2 and 5 are correct
(b)        1,3 and 4 are correct
(c)        3 and 5 are correct
(d)        2 and 4 are correct       (IES 1997)

Q.8.     The optimum number of revolutions over which concrete is required to be mixed in a mixer machine is
(a)        10
(b)        20
(c)        50
(d)        100      (IES 1997)

Q.9.     Presence of 5% voids would reduce strength of concrete by
(a)        5%
(b)        10%
(c)        15%
(d)        30%

Q.10.   In mechanical compaction of concrete, stiffer mixes can be used with
(a)        higher w/c ratio
(b)        lower w/c ratio
(c)        any w/c ratio
(d)        none of these

1. b
2. c
3. b
4. c
5. a
6. d
7. b
8. b
9. d
10. b