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Civil Engineering :: Concrete Technology

  1. Pick up the correct statement from the following:

  2. A.

    Calcium chloride acts as a retarder

    B.

    Gypsum (calcium sulphate) acts as an accelerator

    C.

    Gypsum (calcium sulphate) acts as a retarder

    D.

    Calcium chloride acts as an accelerator

    E.

    Both (c) and (d).


  3. Joints in concrete structures, are provided

  4. A.

    to reduce the tensile stresses likely to be developed due to evaporation of water

    B.
    to minimise the change in the dimensions of the slab
    C.

    to minimise the necessary cracking

    D.
    all the above.

  5. 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

  6. A.

    15, 900 litres

    B.

    16, 900 litres

    C.

    17, 900 litres

    D.

    18, 900 litres


  7. The condition not applicable to water cement ratio law, is

  8. A.

    internal moisture conditions on hydration continue till complete strength is gained

    B.

    concrete specimens may be tested at any temperature

    C.
    concrete specimens need be of same age
    D.
    concrete specimens need be of same size
    E.

    none of these.


  9. High temperature

  10. A.

    increases the strength of concrete

    B.

    decreases the strength of concrete

    C.

    has no effect on the strength of concrete

    D.

    none of these.


  11. The bulk density of aggregates, is generally expressed as

  12. A.

    tonnes/cubic metre

    B.
    kg/cubic metre
    C.
    kg/litre
    D.

    g/cm3

    E.

    none of these.


  13. The grade of concrete M 150 means that compressive strength of a 15 cm cube after 28 days, is

  14. A.

    100 kg/cm2

    B.

    150 kg/cm2

    C.

    200 kg/cm2

    D.

    250 kg/cm2

    E.

    300 kg/cm2


  15. Allowable shear strength of concrete, depends upon

  16. A.

    shear strength

    B.
    tensile strength
    C.

    compressive strength

    D.

    none of these.


  17. The most useless aggregate is one whose surface texture is

  18. A.

    smooth

    B.

    granular

    C.

    glassy

    D.

    honey combed and porous.


  19. To obtain a very high strength concrete, use very fine grained

  20. A.

    Granite

    B.

    Magnetite

    C.

    Barite

    D.

    Volcanic scoria.