This document discusses bricks, including their manufacturing process and key properties. It describes how chemical composition, clay preparation, drying, and burning affect brick quality. Ideal bricks are uniform in color, size and shape, compact, crack-free, and withstand wetting without changing volume. The document also outlines common brick classifications, sizes used in Bangladesh, and special brick types.

1. COURSE NO: ARCH 1201
COURSE TITLE: BUILDING MATERIALS
Lecture 4
BRICK

3. Some factors that affect the quality of bricks…
 Chemical properties of the clay used
 Preparation of the clay
 Process of drying
 Different degrees of burning
“A brick is an artificial kind of stone made of clay,
whose chief characteristics are a plasticity when wet
and stone like hardness after being heated to a high
temperature.”
A Text Book of Engineering Materials- by Dr. M. A. Aziz

4. Silica (55%)
 Exists in all clays
 When in free state, called Flint or Sand
 Prevents cracking, shrinking and wrapping
 Makes brick more shapely and uniform
textured
 Too much Silica can make brick brittle and
weak
ELEMENTS OF BRICK CLAY AND THEIR PURPOSES
…such a mixture of pure clay and sand that can be easily be molded
when wet and dried without cracking or wrapping
A Text Book of Engineering Materials- by Dr. M. A. Aziz

5. Alumina/ Aluminum Oxide (30%)
 Adds plasticity to clays which helps in
molding
 Imparts density
 Too much alumina can make brick crack and
wrap, also too hard
ELEMENTS OF BRICK CLAY AND THEIR PURPOSES
A Text Book of Engineering Materials- by Dr. M. A. Aziz
Iron Oxide (8%)
 Makes brick impermeable and durable
 More Iron Oxide brings more reddish color

6. Magnesia/ Magnesium Oxide (5%)
 Decreases shrinkage
 Small quantity gives yellow color
Lime(1%)
 reduces shrinkage
 Enables silica to melt in burning
 Too much is injurious to brick
Alkalies and organic matter(1%)
 Assist burning bricks
ELEMENTS OF BRICK CLAY AND THEIR PURPOSES
A Text Book of Engineering Materials- by Dr. M. A. Aziz

7. Selection of brick clay
 Should be free from harmful elements
Sedimentary deposits are quite suitable
 Samples are made first, then the clay is
judged
 Different elements are adjusted
MANUFACTURING OF BRICKS
A Text Book of Engineering Materials- by Dr. M. A. Aziz

8. Preparation of brick clay
Weathering: Earth is excavated before
rain and spread out in the ground for a
period time.
Blending: Quality of the brick clay is
improved by adding sand, lime, alumina
and magnesia.
Tempering: Gradually water is mixed
and clay is kneaded under feet of men and
cattle. At present “Pug mill” is used.
MANUFACTURING OF BRICKS
A Text Book of Engineering Materials- by Dr. M. A. Aziz

9. Brick moulding
 Hard boxes
 Made of hard wood, lined with iron or
brass
 Traditionally inner dimension is about
1/10 larger than the burnt brick
MANUFACTURING OF BRICKS
A Text Book of Engineering Materials- by Dr. M. A. Aziz

10. Methods of brick
moulding
1. Hand moulding
• Ground moulding
• Table moulding
2. Machine moulding
• Plastic clay machine
• Dry clay machine
MANUFACTURING OF BRICKS
A Text Book of Engineering Materials- by Dr. M. A. Aziz

11. Brick Drying
MANUFACTURING OF BRICKS
A Text Book of Engineering Materials- by Dr. M. A. Aziz

12. Brick Burning
1. To impart hardness and strength
2. To increase density, making to less
absorbent to water
Clamp Burning
Kilns Burning
MANUFACTURING OF BRICKS
A Text Book of Engineering Materials- by Dr. M. A. Aziz

13. Brick Burning
Hoffman’s kiln
Trench or tunnel kilns
MANUFACTURING OF BRICKS
http://www.fastonline.org/CD3WD_40/GATE_DL/BUILDING/HK/EN/HK.HTM

14.  Uniform in color, size and shape
 Sound and compact
 Free from cracks, air bubbles etc
 Less water absorbent
 Compressive strength 5000 to 8000 psi
 Neither over burnt or under burnt
 Low thermal conductivity
 Non-flammable
 Should not change in volume when wetted
CHARACTERISTICS OF GOOD BRICK
A Text Book of Engineering Materials- by Dr. M. A. Aziz

15. In Bangladesh, according to P.W.D. specification, each brick
should measure
9 ¼” x 4 ½” x 2 ¾”
Why this size?
SIZE OF BRICK
A Text Book of Engineering Materials- by Dr. M. A. Aziz

16.  First class brick
 Second class brick
 Third class brick
 First class bats
 Second class bats
 Picked Jhama bricks
 Jhama bricks
 Jhama Bats
CLASSIFICATION OF BRICK
A Text Book of Engineering Materials- by Dr. M. A. Aziz

17.  Perforated brick
Hollow brick
Checkered brick
Stable brick
Plinth brick
Jamb brick
Paving brick
SPECIAL BRICKS
A Text Book of Engineering Materials- by Dr. M. A. Aziz

18. RECOMENDED REFERENCES
Aziz. M. A: Engineering Materials.
Smith, R. C: Material of construction.
Andres, C. K: Manufactures manuals and brochures,