Bricks

Question 1

Size of Standard Brick (Modular Brick)

Answer 1

19 x 9 x 9 cu. cm

19 x 9 x 4 cu. cm

Question 2

Size of mortar to be applied

Answer 2

1 cm

Question 3

Size of Brick with Mortar

Answer 3

20 x 10 x 10 cu.cm

Question 4

Size of Field Brick

Answer 4

9” x 4.5” x 3”

Question 5

Indent in the brick is called

Answer 5

Frog

Question 6

Size of Frog

Answer 6

10 × 4 × 1 cu. cm

Question 7

Why are frogs provided

Answer 7

To hold mortar

Question 8

Average weight of Bricks

Answer 8

30 - 35 N

Question 9

Classification of Bricks

Answer 9

1st Class
2nd Class
3rd Class
4th Class

Question 10

Characteristics of 1st Class bricks

Answer 10

i. Thoroughly burnt, deep red, cherry or copper color
ii. Smooth surface, parallel, sharp and straight edges
iii. Free from flaws, cracks and stones
iv. Uniform textures
v. No impression should be left on the brick when scratched by nail.
vi. Metallic or ringing sound when two bricks struck against each other
vii. Water Absorption should be 12-15% of its dry weight.
viii. Crushing strength not less than 10 N / sq mm
ix. Built in Kilns

Question 11

Uses of First class brics

Answer 11

Pointing, exposed face work in masonry structures, flooring, reinforced brick work

Question 12

Characteristics of 2nd Class Bricks

Answer 12

i. Thoroughly burnt, deep red, cherry or copper color
ii. Smooth surface, parallel, sharp and straight edges
iii. Small Cracks and distortions present
iv. Uniform textures
v. Moderate hardness
vi. Metallic or ringing sound when two bricks struck against each other
vii. Water Absorption should be 16-20% of its dry weight.
viii. Crushing strength not less than 7 N / sq mm
ix. Built in Kilns

Question 13

Uses of Second Class Bricks

Answer 13

Used for all important or unimportant hidden masonry works, and centering of reinforced brick and reinforced cement concrete (RCC) structures. Plasters

Question 14

Characteristics of 3rd Class Bricks

Answer 14

i. Underburnt
ii. Soft and light colored
iii. Dull sound when struck together
iv. Water Absorption about 25% of dry weight
v. Built in Clamps
vi. Irregular shape and size

Question 15

Use of 3rd Class Bricks

Answer 15

Temporary Structures

Question 16

Characteristics of 4th Class Bricks

Answer 16

i. Overburnt
ii. Badly distorted in shape and size
iii. Brittle
iv. Built in Clamps

Question 17

Use of 4th Class Bricks

Answer 17

Used for foundation and floors in lime concrete and road metal

Question 18

Properties of Good Bricks - Size and Shape

Answer 18

uniform size and plane, rectangular surfaces with

parallel sides and sharp straight edges

Question 19

Properties of Good Bricks - Color

Answer 19

Uniform deep red or cherry colour

Question 20

Properties of Good Bricks - Texture and Compactness

Answer 20

The surfaces should not be too smooth to cause slipping of mortar. It should have a precompact an uniform texture.

Question 21

Properties of Good Bricks - Hardness

Answer 21

Hard - when scratched by a finger nail no impression is made

Question 22

Properties of Good Bricks - Sound

Answer 22

Metallic sound when two bricks struck together

Question 23

Properties of Good Bricks - Water Absorption

Answer 23

Should not exceed 15%

Question 24

Properties of Good Bricks - Crushing Strength

Answer 24

Should be more than 10 N / sq mm

Question 25

Properties of Good Bricks - Efflorescence

Answer 25

Crystalline deposit of salt when water is dried off (Efflorescence) should not be present

Question 26

Properties of Good Bricks - Organic Mater

Answer 26

Should not be present

Question 27

Properties of Good Bricks

Answer 27

i. Size and Shape ii. Color iii. Texture and Compactness iv. Hardness v. Sound vi. Water Absorption vii. Crushing Strength viii. Efflorescence ix. Organic Matter

Question 28

Composition of a Brick

Answer 28

- Silica 50-60% - Alumina 20-30% - Lime 5%-10% < 20% of these: - Magnesia < 1% - Oxides of Fe < 7% - Alkalis < 10% Very Small Percent of these: - CO2 - SO3 - H2O

Question 29

Function of Silica in Brick

Answer 29

- Enables brick to retain its shape and imparts durability | - Prevents shrinkage and warping

Question 30

What happens if there is excess silica in brick

Answer 30

Brick becomes Brittle and weak on burning

Question 31

Function of Alumina in brick

Answer 31

Absorbs water and renders clay plastic

Question 32

What happens if there is excess alumina in brick

Answer 32

The brick will develop cracks on drying

Question 33

Function of Lime in Brick

Answer 33

Reduces Shrinkage on drying

Question 34

What happens if there is excess Lime in brick

Answer 34

It will cause the brick to melt and brick loses its shape

Question 35

Function of Magnesia in Bricks

Answer 35

Affects the color and makes the brick yellow in burning. Causes the clay to soften at slower rate and reduces warping

Question 36

Function of Iron Oxide in Bricks

Answer 36

- Gives red color on burning when excess of oxygen is available - Improves impermeability and durability - Tends to lower fusion point of clay - Gives strength and hardness

Question 37

Harmful Substances in Bricks

Answer 37

- Pebbles, Gravels and Grits - Iron Pyrites - Excess lime, alkalis - Organic Matter - Carbonaceous Materials - Sulphur - Water

Question 38

What happens when pebbles, gravel and grits are present in bricks

Answer 38

They will not allow the clay to be mixed thoroughly and spoil the appearance of the brick. The bricks may crack while working

Question 39

What happens when Iron Pyrites are present in bricks

Answer 39

leads to deceomposition of bricks during burning due to its(pyrite) oxidation. Discolorisation and splitting of bricks

Question 40

What happens when excess Alkalis are present in Bricks

Answer 40

Increases water absorption, causes efflorescence.

Question 41

What happens when Organic Matter are present in Bricks

Answer 41

Upon burning, the organic matter gets charred and leave pores. Increases water absorption and reduces strength

Question 42

What happens when Carbonaceous Materials are present in Bricks

Answer 42

Greatly affects colour of raw clay

Question 43

What happens when Sulphur is present in Bricks

Answer 43

Swells the brick upon burning. If in excess, white patches can be seen in the bricks

Question 44

What happens when Water is present in Bricks

Answer 44

Causes shrinkage during burning