The document discusses an experimental investigation into producing cost-effective geopolymer bricks. Geopolymer bricks are made from fly ash or GGBS activated by an alkaline solution. The study will make geopolymer bricks using fly ash and GGBS with sodium hydroxide and sodium silicate activators. Tests will evaluate the compressive strength, water absorption, acid resistance, and efflorescence of the geopolymer bricks. The goal is to manufacture affordable, high-quality geopolymer bricks as an alternative to traditional clay bricks.

1. AN EXPERIMENTAL
INVESTIGATION ON
COST EFFECTIVE
GEOPOLYMER BRICKS

2. CONTENTS
 Abstract
 Introduction
 Objectives
 Methodology
 Materials
Procedure and Output
Summary
 References

3. ABSTRACT
Geopolymer bricks are the new innovation in the
field of brick industry. Geopolymer bricks contain fly ash
as the source material and an alkaline activator for the
activation of polymerization reaction. In this study,
experimental work is supposed to be performed on
geopolymer bricks with fly ash and GGBS as source
materials and sodium hydroxide and sodium silicate as an
activator. The molarity of sodium hydroxide will be low
molarity (1M to 4M) for all the mixtures and the ratio of
sodium hydroxide to sodium silicate was kept as (1 : 2.5).
The brick properties such as compressive strength, water
absorption, acid resistance and efflorescence tests will be
conducted on the test specimens. Our Aim is to
manufacture cost-effective geopolymer bricks without
compromising in quality criteria.

4. INTRODUCTION
Brick is the most commonly used building material in India for more
than 1000 years. Fired clay bricks are most commonly used in India.
But now-a-days fly ash bricks have been tremendously being used
due to the reduction in cost as well as its light weight. Geopolymer
bricks are the latest innovation in the brick industry which consist of
source materials such as fly ash or GGBS activated by an alkaline
activator. The application of geopolymer technology gained
importance due to the reduction of the CO2 emissions by utilizing the
source materials in place of cement. It has been noted that
geopolymer bricks made with fly ash requires higher curing
temperature to achieve higher compressive strength and lower
moisture absorption.

5. WHY FLYASH BRICKS MORE
USEFUL THAN CLAY
BRICKS..??
Flyash bricks are most useful than normal clay bricks
because of the following advantages:
•It reduces dead load on structures due to light weight (2.6 kg, dimension:
230 mm X 110 mm X 70 mm).
•Same number of bricks will cover more area than clay bricks
•High fire Insulation

6. CONTINUED...
Due to high strength, practically no breakage during transport and use.
Due to uniform size of bricks mortar required for joints and plaster
reduces almost by 50%.
Due to lower water penetration seepage of water through bricks is
considerably reduced.
Gypsum plaster can be directly applied on these bricks without a backing
coat of lime plaster.
These bricks do not require soaking in water for 24 hours. Sprinkling of
water before use is enough.
(Source : https://en.wikipedia.org/wiki/Fly_ash_brick)

7. OBJECTIVES
To determine the compressive
strength and water absorption of
Geopolymer based fly ash bricks and
compare with cement based fly ash
bricks and normal clay bricks.
To determine the thermal and fire
resistance of these Geopolymer
based fly ash bricks and make the
comparision with cement based fly
ash bricks.
To determine the Efflorescence and
chemical resistance of these type of
bricks.
To analyse this type of brick in terms
of cost and to obtain suitable
methods to make it cost effective.

8. METHODOLOGY

9. MATERIALS USED
FLY ASH CLASS F
GROUND
GRANULATED
BLAST-FURNACE
SLAG (GGBS)
QUARRY DUST OR
ROBOSAND
SLAG SAND OR
SLAG
SODIUM
HYDROXIDE (NaOH)
SODIUM SILICATE
(Na2SiO3)
WATER

10. FLY ASH CLASS-F
Fly ash, also known as pulverised fuel ash, is a coal combustion product that is composed of the
particulates (fine particles of burned fuel) that are driven out of coal-fired boilers together with the
flue gases. Ash that falls to the bottom of the boiler's combustion chamber is called bottom ash. In
modern coal-fired power plants, fly ash is generally captured by electrostatic precipitators or other
particle filtration equipment before the flue gases reach the chimneys.
The burning of harder, older anthracite and bituminous coal typically produces Class F fly ash. This
fly ash is pozzolanic in nature, and contains less than 7% lime (CaO). Possessing pozzolanic
properties, the glassy silica and alumina of Class F fly ash requires a cementing agent, such as
Portland cement, quicklime, or hydrated lime—mixed with water to react and produce cementitious
compounds. Alternatively, adding a chemical activator such as sodium silicate (water glass) to Class F
fly ash can form a geopolymer.

11. FLY ASH CLASS F PROPERTIES
Chemical Composition of Fly Ash (Class-F)
Chemical composition of Fly ash F Weight in %
Silica 55-65
Aluminium oxide 22-25
Iron oxide 5-7
Calcium oxide 5-7
Magnesium oxide <1
Titanium oxide <1
Phosphorus <1
Sulphates 0.1
Alkali oxide <1
Loss of ignition 1-1.5

12. FURNACE
SLAG (GGBS)
Ground-granulated blast-furnace slag
(GGBS or GGBFS) is obtained by quenching molten
iron slag (a by-product of iron and steel-making)
from a blast furnace in water or steam, to
produce a glassy, granular product that is then
dried and ground into a fine powder. Ground-
granulated blast furnace slag is highly
cementitious and high in CSH (calcium silicate
hydrates) which is a strength enhancing
compound which improves the strength,
durability and appearance of the concrete.
The main components of blast furnace
slag are CaO (30-50%), SiO2 (28-38%), Al2O3 (8-
24%), and MgO (1-18%). In general increasing the
CaO content of the slag results in raised slag
basicity and an increase in compressive
strength.GGBS is used to make durable concrete
structures in combination with ordinary Portland
cement and/or other pozzolanic materials.

13. SLAG SAND OR SLAG
Slag is the glass like by-product left over after a desired
metal has been separated (i.e., smelted) from its raw ore. Slag is
usually a mixture of metal oxides and silicon dioxide. However,
slags can contain metal sulphides and elemental metals. While
slags are generally used to remove waste in metal smelting, they
can also serve other purposes, such as assisting in the
temperature control of the smelting, and minimizing any re-
oxidation of the final liquid metal product before the molten metal
is removed from the furnace and used to make solid metal.
The advantages of this blast furnace slag, such as
increasing strength over long periods of time, low heating speed
when reacting with water, and high chemical durability, are put to
effective use in a broad range of fields including in the
construction of ports and harbors and other large civil engineering
works.

14. M SAND OR ROBOSAND
Manufactured sand (M-Sand) is a substitute of
river sand for concrete construction. Manufactured sand
is produced from hard granite stone by crushing. The
crushed sand is of cubical shape with grounded edges,
washed and graded to as a construction material. The
size of manufactured sand (M-Sand) is less than
4.75mm.
Advantages of Manufactured Sand over River Sand :
Contains no organic, harmful impurities, hence
significant improvement in strength of concrete at
same cement content.
Gradation of particles can be controlled during
production.
As Gradation is controlled there is no wastage due to
oversize materials.

15. Fly ash (C & F) GGBS M sand
Slag sand NaOH flakes Sodium Silicate

16. PROCESS OF MAKING GEOPOLYMER BRICKS
*IOT = Introduction of other things (i.e., Replacement Materials, if any used)

17. DIMENSIONAL OUTPUT
Indian Standard Brick Dimensions
as per BIS
Dimensioned output brick

18. SUMMARY
Ultimately, we are
going to conduct
different tests on
Geopolymer based
Flyash bricks that
are generally
applied on normal
Flyash bricks and
make the
comparision
among Geopolymer
based and normal
Flyash bricks within
the criteria,
Compressive
strength and water
absorption
(Mechanical
Properties)
Efflorescence and
chemical resistance
(Chemical
Properties)
Durability and
thermal resistance
Cost effectiveness
and Economic
value

19. REFERENCES
“Experimental Investigation On Flyash Based Geopolymer Bricks” by
T.Subramani,P.Sakthivel volume 5 issued 5 May 2016, link :
https://www.ijaiem.org/Volume5Issue5/IJAIEM-2016-05-30-44.pdf
S. Ahmari, and L. Zhang, Durability and leaching behavior of mine tailings-based
geopolymer bricks, Construction and Building Materials, 44 (2013), 743–750
G. Silva, D. Castañeda, S.Kim, A. Castañeda, B.Bertolotti, L. Ortega-San-Martin, J.
Nakamatsu and R. Aguilar, Analysis of the production conditions of geopolymer matrices
from natural pozzolana and fired clay brick wastes, Construction and Building Materials
https://en.wikipedia.org/wiki/Ground_granulated_blast-furnace_slag
https://en.wikipedia.org/wiki/Slag
https://en.wikipedia.org/wiki/Fly_ash

20. By
ILA VAMSIKRISHNA
Civil and Structural Engineer