For more information, write or call:

TECHNOLOGICAL SERVICES DIVISION

Industrial Technology Development Institute (ITDI-DOST)
Telefax: 837-2071 loc. 2265 / 837-6156
e-mail: tsd@itdi.dost.gov.ph
 ISSN 1656 – 6831

Livelihood Technology Series 23

COMMON BRICK
MANUFACTURING

Department of Science and Technology

INDUSTRIAL TECHNOLOGY DEVELOPMENT INSTITUTE
DOST Compound, General Santos Avenue
Bicutan, Taguig City, Metro Manila, PHILIPPINES
http://www.itdi.dost.gov.ph

‘Our Business is Industry…”

2nd edition 2014

Prepared by: ELNILA C. ZALAMEDA

TSD-ITDI

JOSEFINA R. CELORICO
MSD-ITDI

Edited by: VIOLETA B. CONOZA

TSD-ITDI

Cover layout by: LUZMIN R. ESTEBAN

TSD-ITDI

Adviser: NELIA ELISA C. FLORENDO

TSD-ITDI
 Livelihood Technology Series 23
Common Brick Manufacturing

ACKNOWLEDGEMENT

This brochure was made possible through

the research efforts of the Materials Science Division
(MSD), ITDI-DOST.
 COMMON BRICK MANUFACTURE

INTRODUCTION

The use of common bricks as a basic material for

construction has been established and practiced in the
Philippines during the Spanish times. Early Spanish
colonizers, in establishing towns and cities, built churches,
state edifices, and houses of solid blocks like adobe,
limestone, and bricks with lime sand mixture as mortar. This
is proven by the existence, to date, of many ruins of old
Spanish type structures. One typical example of such is the
ruins of Intramuros that once confined the old city of Manila.

Common brick is described as a solid rectangular block

(2”x4”x8” ASTM Standard) made by shaping plastic mass of
clay which is then hardened by drying and firing. Bricks are
usually fired in temperature range of 800oC – 1,000oC
depending on the materials used and the grade desired of the
product.

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RAW MATERIALS

Bricks can be made from a wide range of clays, mud

stones, and shales, all of which can either be secondary or
primary type of materials in terms of occurrence. The
secondary or water-containing minerals are produced by
weathering action of water and air, while primary is of igneous
rock minerals as feldspar and micas. Commonly used as
material for brick-making are high iron bearing (3-10%)
argellacious clays usually found in lowly elevated areas where
they were deposited. These sedimentary clays contain
primarily, compounds of Alumina (Al2O3), Silica (SiO2), and
water with minor amounts of lime (CaO), Magnesia (MgO),
Soda (Na2O), and Potash (K2O). It is the iron present (oxides,
hydroxides, or carbonates) that accounts for the wide range of
colors found in finished bricks (light brown, brown red, to dark
brown).

Most important of the physical properties of clay is its

plasticity. When water is added, the clay can be formed
readily without deformation. In most cases, the blending of
highly plastic clay with non-plastic material, like sand, chamote
or less plastic sandy clay gives a better quality product.

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PRODUCTION OPERATION
1. Mining
Clay is taken from the mine by hand-digging with the aid
of pick-mattock and shovels. Hand-sorting of
unnecessary impurities such as stones and roots is done
at this stage. The clay is then transported by wheel
borrows, to the open pit-stock storage where it is
exposed for weathering.

2. Natural Weathering
Open exposure of clay to natural action of sunshine,
rain, and wind helps in the natural disintegration of clay
lumps and increases the clays workability.
Recommended height of stock pile is 0.5 meter to be
exposed in not less than 2 months.

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3. Proportioning and Proper Mixing
In order to get the desired properties of color, hardness,
and strength, proportionate mixing of clay materials and
sand is necessary. For manual process, sand can be
spread proportionately over clay layers. This is done
alternately like piles of sandwiches. Water is sprinkled
over the layers of sand and clay in appropriate ratio per
batch. Soaking is required for at least overnight, to
guarantee an even distribution of water within the batch
before kneading.

4. Kneading
Clay before forming is prepared by wedging to attain a
homogenous plastic clay. This can be done manually,
with two hands pressing the clay is a rhythmic motion or
mechanically with the aid of a roll kneader or pug mill.

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5. Forming
Clay blocks of the desired dimensions are formed thru
the use of a rectangular wooden frame as mold. The
clay is thrown, with some force, into the mold and
excess clay is scraped by a scraper. The formed clay
brick is released from the mold by slightly tapping the
mould. The brick is left on a pallet for drying.

6. Pre-drying
Before pressing stage partial evaporation of mechanical
water from newly-formed bricks is driven off to attain the
desired hardness. Formed bricks are usually stocked in
pallets, dried for one day, then transferred to pressing
section.

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7. Pressing
Final forming of bricks is done with the aid of a simple
wooden pressing machine. The operation makes the
body a little more compact and assures the uniformity of
shape, smoothness and size of product.

8. Final drying
Before bricks can be fired, the water which was needed
to make the clay plastic during shaping/forming must be
driven off. Without artificial means of drying, it will
require 2 weeks or more to dry a batch of green bricks
under ordinary condition.

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9. Firing
Dried bricks are generally fired in kilns with temperatures
ranging from 800oC to 1,000oC. The operation consists
of loading the bricks inside the kiln, and the actual firing.
The bricks are carefully piled up in accordance with a
prescribed layout, to allow even distribution of heat.
After firing, the bricks are unloaded and inspection is
done.
For small-scale producers, a scove kiln can be used.
This is a semi-permanent kiln that can be built at lower
cost.

PERIODIC KILN

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BRICK USES
Brick is the simplest and most ancient of all building materials,
but no other building material has enjoyed such wide-spread
and continuous popularity. This enduring public acceptance is
based on the unique combination of properties which brick
offers to the owner and builder. This one material can be
used to enclose a structure with a decorative effect, load-
bearing and weatherability, which makes it exceptionally
durable and requires practically no maintenance. Because of
the versatility of the raw material, which can readily be molded
into a great range of shapes and sizes. Modern developments
in brick construction have shown that when attention is given to
efficient masonry work, brick construction can prove cheaper
than many of the newly developed building systems.

BRICK PROPERTIES
From the viewpoint of the user, the most important properties
of bricks are their strength, their absorption properties and
their insulation against sound and fire.

STRENGTH
The compressive strength of building bricks generally varies
from about 50 kg/cm2 – 750 kg/cm2. In many applications
(e.g., in brick veneers, for infill panels in frame structures or for
load-bearing walls in small buildings of one or two stories) this
strength is not required, but it can be useful in engineering
applications.

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ABSORPTION PROPERTIES
The power of the brick to soak up water is one of its most
useful characteristics. When the bricks are being laid, their
suction plays an important part in developing good bond with
the mortar, and in the finished building, the absorption of rain
by the bricks reduces run-off which might otherwise cause
trouble at flashings and around windows or openings. The
water absorbed during wet spell is harmlessly evaporated off
again when the weather clears.

INSULATION
Insulation against air-borne sound depends more on the mass
or weight of the wall than on anything else. A solid brick wall
sets the standard for sound-proofing in both residential and
commercial construction. The fire resistance of brickwork is
also high because the material is inherently resistant to fire,
and its low thermal conductivity ensures that heat is not
quickly transferred through brick walls. Fire rarely damages
brickwork in a building, although thermal expansion of
unprotected steel columns girders or roof trusses may cause
displacement or even collapse of brick walls.

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 ASTM – STANDARD SPECIFICATION FOR
BUILDING BRICK

Physical Requirements

Minimum Compressive Maximum Water

Strength (Brick Flatwise) Absorption by 5-hour
Gross Area, Kg/cm2 boiling, %

Average of 5 Individual, Ave. of 5 Individual,

2 2
Designation brick, kg/cm kg/cm brick, % %
Grade SW 211.37 176 17.0 20.0
Grade MW 176.14 155 22.0 25.0
Grade NW 105.68 88 No limit No limit

NOTE:

SW – Brick should be used in any region when the units

are in contact with the ground, in horizontal
surfaces, or in any position where they are likely to
be permeated with water, i.e., when used in floor.

MW – Brick forms satisfactory in wall areas above grade

in the no weathering region, where the average
compressive strength of the units is at least 176.14
kg/cm2.

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 NW – Brick not exposed to weather maybe Grade NW
when used in walls and shall be Grade SW when
used in floors.

ASTM – American Society for Testing Materials

JIS – Japan Industrial Standards

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 Physical Properties

% Water of Plasticity 13.0 40.7

% Drying Shrinkage 0.00 13.0
% Firing Shrinkage (800°C – 1000°C) 0.00 3.4
% Porosity 20.80 36.00
% Water of Absorption 8.62 42.88
Specific Gravity 1.57 2.32
Modulus of Rupture, kg/cm2 3.35 100.40
Compressive Strength 83.69 167.40

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