51. The main disadvantage of concrete blocks used for masonry as Compared to bricks is
- lower strength
- higher moisture content
- more requirement of mortar
- shrinkage due to moisture movement
52. The bricks which are extensively used for basic refractories in furnaces are
- Chrome bricks
- Sillimanite bricks
- Magnesite bricks
- Fosterite bricks
53. Load applied during the compressive strength test of brick till its failure is at the rate of _______ kg/cm2 per minute.
- 100
- 10
- 140
- 160
54. Unit weight of common burnt clay bricks used as building material as per IS : 875 (Part 1) – 1987 is
- 1600 to 1920 kg/m3
- 700 kg/m3
- 2500 kg/m3
- 1400 kg/m3
55. The Bureau of Indian Standards (BIS) has classified the common burnt clay bricks on the basis of
- compressive strength
- size of the brick
- water absorption capacity
- efflorescence on brick
56. When the deposit of efflorescence is more than 10% but less than 50% of the exposed area of the brick, the presence of efflorescence is
- moderate
- slight
- heavy
- serious
57. Consider the following statements:
- IS 3583 refers to Burnt Clay Paving Bricks.
- IS 5779 refers to Burnt Clay Soling Bricks.
- IS 3952 refers to Burnt Clay Hollow Bricks.
- IS 2222 refers to Burnt Clay Bricks.
Which of the above statements are correct?
- i, ii and iii only
- i, ii and iv only
- iii and iv only
- i, ii, iii and iv
58. Consider the following statements regarding refractory bricks in furnaces:
- The furnace is fired at temperatures more than 1700°C.
- Silica content in the soil should be less than 40%
- Water absorption of bricks should not exceed 10%
- Chrome bricks are known as basic bricks.
Which of the above statements are correct?
- i and ii only
- ii and iv only
- i and iii only
- iii and iv only
59. Which of the following statements are wholly correct regarding broken-brick aggregate usable in concretes?
- Broken-brick aggregate is obtained by crushing waste bricks and it has a density varying between 1000 kg/m3 – 1200 kg/m3
- Such aggregate is usable in concrete for foundation in light buildings, floorings and walkways.
- Such aggregate may also be used in light-weight reinforced concrete floors.
- i and ii only
- ii and iii only
- i and iii only
- i, ii and iii
60. Efflorescence test is conducted for burnt clay bricks to find out the
- presence of alkaline substance
- hardness
- soundness
- presence of cracks or holes