Bricks MCQ – Building Materials

21. As per IS specification, the minimum compressive strength of 1^st class bricks should be

1. 9 N/mm²
2. 12 N/mm²
3. 9 N/mm²
4. 10 N/mm²

22. The different efflorescence deposits are sulphates of

1. Calcium
2. Sodium
3. Iron
4. Both (a) and (b)

23. Which of the following constituent when present in excess quantity changes the colour of the brick from red to yellow

1. alumina
2. silica
3. alkalies
4. lime stone

24. The percentage of alumina in a good brick lies between

1. 20 to 30%
2. 5 to 10%
3. 50 to 70%
4. 40 to 46%

25. A good brick should not absorb water by weight more than

1. 10%
2. 15%
3. 20%
4. 25%

26. Efflorescence is caused if

1. The alkaline salts are present in the bricks
2. The water used for preparing clay contains gypsum
3. The clay used for making bricks contains pyrite
4. All of the above

27. The standard modular size of common building bricks shall be

1. 190 mm × 90 mm × 90 mm
2. 200 mm × 100 mm × 100 mm
3. 200 mm × 90 mm × 90 mm
4. 190 mm × 100 mm × 100 mm

28. The shape of the brick gets deformed due to rain water falling on hot brick. This defect is known as

1. bloating
2. chuff
3. lamination
4. nodule

29. The dolomite bricks are

1. Ordinary bricks
2. Acid refractory bricks
3. Basic refractory bricks
4. Neutral refractory bricks

30. The average compressive strength of 2^nd class bricks should not be less than

1. 75 kg/cm²
2. 12 kg/cm²
3. 10 kg/cm²
4. 15 kg/cm²