FIELD OF THE INVENTION
The present invention relates to Steel slag-Fly ash based brick composition utilizing a
combination of steel slag from steel plant and flyash from power plant. More
particularly, the present invention is directed to Steel slag-Fly ash brick composition
and bricks produced therefrom and a process of manufacture of such bricks.
Importantly, the steel slag based Fly ash bricks of the present invention is suitable
for use in building construction having higher compressive and flexural strength with
increased eart quake resistance as compared to Conventional Red Clay Bricks,
obtained at relatively less cost. The steel slag based brick manufacturing process
would ensure on one hand utiliztion of steel slag and saving energy consumption
with reduction in fuel consumption per ton of brick produced, reduce environmental
pollution avoiding C02 emission, preserve natural resource by utilizing an industrial
co-product to replace natuaral minerals and on the other hand ensure longer life of
the bricks due to higher strength, low permeability as well as resistance to attack by
salinity, moisture, alkali or sulfate, and thus having prospects for wide scale
application in building materials industry/existing fly ash brick industry with immense
potential for financial return.
BACKGROUND ART
The biggest part (about 70% - 80%) of solid waste arisings in an intergrated steel
plant, is metallurgical slag. Disposal/utilisation of slag generated during iron making
in Blast furnace or steel slags during steel making in conveter/furnaces have been a
concern for long to the manufacturers. Over the years external markets have been
developed for blast furnace slags. But since the potential for internal recycling of
steel slag is constrained by productivity and quality considerations, external markets
are also required to be developed for the Steel Slag. By utilizing steel slag,it is
possible to preserve natural resources by utilizing an industrial co-product to replace
a natural mineral and thus reducing the requirement of mining and transport
activities.
In relatively recent years in India, the need for maximum utilization and recycling/
reuse of by-products and waste materials in steel industry is targeted upto 100%, to
comply with "CREP" agreements between the Steel Industry and MoEF, Govt. Of

India. Apart from "CREP", higher utilization of steel slag became priority by steel
plants in India to fulfill the different economic and environmental objectives.
Building industry, a fast growing sector is one of the key areas of infrastructure
development. Out of the total cost of house construction, building materials
contribute to about 70 percent in developing countries like India. There is thus a
need for replacement of costly and scarce conventional building materials by durable,
innovative, cost effective and environment friendly alternate building materials. The
new building material should be environment friendly and preferably utilize
industrial/agro wastes since the generation of wastes generation has increased
several fold during the last few years a result of rapid industrialization, and needs to
be utilized/disposed safely on priority.
It is well known in the construction industry that bricks are the oldest and most basic
Building Material. They are widely used for a variety of Constructional work. Brick
Work and Concrete are widely used for building construction in India. Concrete is
used for columns, beams and roof slab. Concrete application of this kind is called
concrete framed buildings. Concrete framed constructions of four to ten or still
higher stories continue to be common in India.
Red Clay Bricks are among the oldest Building Materials. They are widely used as a
Building Construction Material in India, Building Bricks are subjected to a variety of
loading conditions: compression, shearing, tension or a combination of these.
Conventional Red Clay Building Bricks produced in India, however suffers from
several adverse features, such as :
a. substantially lower strength properties
b. inferior aesthetic looks
c. poor performance features, both with respect to sound and thermal
insulation.
d. hightly irregular dimensions
e. lower productivity of labour
f. higher use of mortar material for building as well as finishing
g. the need for external plastering and surface coating works,
h. seasonal fluctuation in availability
i. in-consistency in size and shape
j. problems of salinity
In India, masonry infilled reinforced concrete frames are a common structural
system for buildings. Masonry infills are used for functional or aesthetic reasons,
rather than as structural elements. Although, these are considered as non-structural
elements, they interact with the frame when the buildings are subjected to lateral
loads. The masonry infills act as diagonal struts between the frame joints. This
diagonal strut results in considerable increase in stiffness and strength of the frame.
During Earth Quake, Infill Walls and Building Bricks are subjected to a variety of
loading conditions: compression, shearing, tension or a combination of these. "Flyash
Bricks" produced from wastes generated in coal based thermal power plants are
already being used as Building Bricks in Infill walls of RCC Framed Tall Buildings and
in Load Bearing Walls of Smaller Buildings due to high strength and less weight.
There has been however need for building bricks of still higher strength and other
required properties at lower cost that can effectively resists Lateral Loads induced by
EarthQuack or Wind Loads, etc.
Fly ash brick making is an established, profitable route for utilization of fly ash
generated from coal based power plants. Flyash Brick and Clay-Flyash Brick making
process and products are well established. Depending upon the fly ash form ( either
wet fly ash from ash pond or dry fly ash from the ESP hoppers), various technologies
exist in India and abroad for manufacture of fly ash brick. There is wFaLG" technology
known in related art which is primarily distinguished as low capital and low running
cost fly ash brick plants, because of which it is quite popular in small scale industry,
conventional fly ash based bricks and the red clay based molded bricks however,
suffer from limitations with respect to compressive/flexural strength and other
required properties like resistance to weather or errosive chemicals for suitability of
application in building/civil construction industry. There has been thus a requirement
to enhance the strength and other desired properties in the conventional fly ash
based bricks.
It is experienced in India that in case of large capacity plants manufacturing fired
flyash-clay or cured flyash bricks, result is far from being satisfactory. Further
developments in respect of high capacity indigenous presses (instead of imported
ones) and thorough tech no-economic evaluation of projects need major attention.

Small plants (of 10,000 bricks /day / shift capacity) employing hand-moulding, egg-
laying / toggle-type machines or mechanical / hydraulic presses have been
performing far better in comparison.
The need for improvement of strength and other desired properties in the
conventional fly ash based bricks for civil structural application thus required
alternative materials and process for developing fly ash based bricks from industrial
wastes to overcome the deficiencies of existing bricks.
It is also known in the art, XRD analysis of steel slags shows that the main
compounds present are:
a. Di-calcium silicate (C2S).
b. Tricalcium Silicate (C3S).
c. Calcium iron oxide.
d. Di-calcium ferrite.
It is aiso noted that steel slag mineral composition is dominated by Di-calcium
silicate which is similar to low heat cement composition in which C2S dominates the
wt %, with presence of Tricalcium silicate and Tricalcium Aluminate in addition. Steel
slag is essentially proto-clinker and XRD analysis shows that steel slag is having a
highly fluxed beta di-calcium silicate phase (C2S).
It is further observed that CaO/SiO2 ratio in the steel slag samples and the cement
samples are the same that is about 3. Thus by observing the composition and
chemical characteristics of Steel Slag, it is inferenced that the same can be used to
make civil engineering products e.g. bricks etc with such slag as low cost input raw
material.
In view of steel slag having similar chemical composition and mineral phases of
cement clinker, attempt has been made at Bokaro Steel Plant of the applicants to
developing "Steel Slag-Flyash" based Bricks, utilizing a combination of steel slag of
steel plant and flyash from power plant, which would ensure enhanced strength and
other desired end properties in the resulating bricks including ensuring earth quake
resistant structures and is also low cost with potential for utilizing steel/power plant
waste material while protecting environment and conserving natural resources.

OBJECTS OF THE INVENTION
The basic object of the present invention is thus directed to developing a Steel slag-
Flyash based brick composition and bricks made thereof and a process for its
manufacture utilizing steel slag from power plants and fly ash from power plants in a
cost effective, environment friendly manner.
Another object of the present invention is directed to developing a Steel slag-Flyash
based brick composition and bricks made thereof whereby natural resource is
preserved by utilizing slag and fly ash, both industrial co-products as the input
ingredient, replacing use of natural mineral and thus reducing requirement of mining
and transport activity.
A further object of the present invention directed to developing a Steel slag-Flyash
based brick composition and bricks made thereof wherein the bricks have higher
compressive and flexural strength as compared to conventional clay/fly ash bricks as
well as capability to providing earthquake resistant structures by way of masonry
infilled reinforced concrete frames used for buildings.
A still further object of the present invention is directed to developing a Steel slag-
Flyash based brick composition and bricks made thereof whereby compliance to
CREP agreement or other environmental requirements in respect of reuse/recycling
of by-product and waste material generated in industry is successfully implemented
saving on production costs.
A still further object of the present invention is directed to developing a Steel slag-
Flyash based brick composition and bricks made thereof wherein the bricks have
good aesthetic look, longer life with increased resistance to alkalies and sulfate
attacks.
A still further object of the present invention is directed to developing a Steel slag-
Flyash based brick composition and bricks made thereof wherein the bricks have
machine finished uniform size requiring comparatively less quantity of cement
mortar during brick work construction.

A still further object of the present invention is directed to developing a Steel slag-
Flyash based brick composition and bricks made thereof wherein the bricks have
improved resistance to salinity and water seepage and thus suitable for humid
atmosphere.
A still further object of the present invention is directed to developing a Steel slag-
Flyash based brick composition and bricks made thereof wherein steel slag contribute
to environmental protection by reducing emission of CO2 gases and enhancing
Carbon credit earning.
A still further object of the present invention is directed to developing a Steel slag-
Flyash based brick composition and bricks made thereof wherein reduction in fuel
consumed per ton of brick produced can be achieved as the steel slag is calcined and
heat of decarbonation is already eliminated.
SUMMARY OF THE INVENTION
The basic aspect of the present invention is thus directed to Steel slag-flyash bricks
comprising of
steel slag content having mineral composition including highly fluxed beta di-calcium
silicate phase (C2S) with favourable CaO/SiO2 ratio in combination with fly ash for
favourable strength and beneficial strength-cost ratio and/or strength weight ratio.
Another aspect of the present invention is directed to a steel slag-flyash brick
comprising
steel slag and fly ash comprising of:
Steel Slag:;
Dry Fly ash:;
Quarry dust:;
Hydrated Lime:;
Gypsum:;
Calcium Chloride:;and
Binder:;
A further aspect of the present invention is directed to said steel slag-flyash bricks
wherein said steel slag comprise content of favourable CaO/SiO2 ratio preferably of
about 3 with Di-calcium silicate dominated mineral composition.
A still further aspect of the present invention is directed to said steel slag-flyash
bricks wherein the steel slag composition involve dominant compounds comprising:
a. Dicalcium silicate (C2S);
b. Tricalcium Silicate (C3S);
c. Calcium iron oxide; and
d. Di-calcium ferrite.
According to yet another aspect of the present invention is directed to said steel
slag-flyash bricks, wherein composition of said steel slag fines comprises
A still further aspect of the present invention is direcdted to said steel slag-flyash
bricks comprises
Fly-ash about 35%;
LD slag about 30%;
Gypsum about 3-5%;
Quarry dust about 20%;
Lime about 10-12%;
Calcium Chloride about 0.25%
Advantageously, said steel slag-flyash bricks are having a strength of 120 to 134
Kg/cm2.

A still further aspect of the present invention is directed to said steel slag-flyash
bricks which are having:
i) increased compressive and flexural strength, relatively at lower/same
price as compared to Conventional Red Clay Bricks,
ii) increased earthquack resitance.
iii) low permeability and enhanced durability
iv) increased long term strength and
v) increased resistance to alkalies and sulfate attacks
vi) plastering over brick surface can be avoided,
vii) nice aesthetic looks, ready acceptance in market,
viii) machine finished uniformity in size requiring comparatively less quantity
of cement mortar,
ix) excellent anti-termite properties
x) consistent quality - above 98% are of first class quality,
xi) characteristics of desired resistant to salinity and water seepage and
therefore best suited for humid atmosphere;
xii) better portability;
xiii) ready availability;
Yet another aspect of the present invention is directed to a process for
manufacturing of Steel slag-flyash bricks as stated above comprising the steps of:
mixing selectively calcium chloride in water followed by addition of fly ash, slag,
Gypsum, Quarry dust, Lime and CaCI2 in desired amounts to provide the bricks of
desired strength and beneficial strength-cost ratio and strength weight ratio.
The objects and advantages of the present invention is described in greater details
with reference to the following non limiting accompanying drawings and example.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 a-e: is the photo images of Steel slag- Flyash bricks produced using sample
mix A,B,C,D & E as per Example I.

Figure 2: is the graph plot of trend of compressive strength of sample type A against
curing time in days.
Figure 3: is the graph plot of comparative trend average compressive strength of
samples A, B & C vs curing time in days.
DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE
ACCOMPANYING DRAWINGS AND EXAMPLES
The present invention relates to Steel slag-Fly ash based brick composition involving
a combination of steel slag from steel plant and flyash from power plant and bricks
produced therefrom and a process of manufacture of such bricks.
The applicants has developed "Steel Slag-Flyash Bricks" using the basic ingeredients
comprising six types of raw materials, such as Steel Slag Fines, Dry Fly ash, Quarry
dust, Hydrated Lime, By-product Gypsum and Calcium Chloride, and tested them as
per the technical requirements of relevant IS code specifications at their Bokaro
Steel Plant.
The Flyash brick composition, process of brick manufacturing and the different
characteristics properties achieved are illustrated with reference to following
illustrative examples:
EXAMPLE I:
According to an embodiment of the present invention, five different samples of
starting mix of raw materials have been prepared and marked A,B,C,D & E as per the
following details:
Sample Type A: The calcium chloride was mixed in water while the appropriate
amount of other raw materials was added in pan mixture. After few minute the water
containing calcium chloride solution was poured in the pan mixture with regular
interval. Hence, 70 kg of Fly ash, 60 kg of LD slag, 10 kg of Gypsum, 40 kg of
Quarry dust, 19.50 kg of Lime and 0.5 kg of CaCI2 were weighted for the preparation

of Sample type A. Similarly, the raw materials for other Sample type were weighted
in appropriate proportion for brick making. The consumption of LD slag was 30 % in
sample type A, in Sample making.
Sample Type B: Sample B was prepared with 80 kg of Fly ash, 100 kg of LD slag,
10 kg of Gypsum andlO kg of Quarry dust.
Sample Type C: Sample C was prepared with 60 kg of Fly ash, 80 kg of LD slag, 10
kg of Gypsum, 30 kg of Quarry dust and 20 kg of Lime.
Sample Type D: Sample D was prepared with 60 kg of Fly ash, 100 kg of LD slag,
10 kg of Gypsum and 20 kg of Quarry dust and 10 kg of Lime.
Sample Type E: Sample E was prepared with 40 kg of Fly ash, 120 kg of LD slag,
10 kg of Gypsum and 20 kg of Quarry dust and 10 kg of Lime.
The above categories of sample mix were used to produce Steel slag-Flyash Bricks
which were tested for compressive strength and other properties. The average
length, breadth and height of the bricks obtained are 23.11cm, 11.06cm and 7.53cm
respectively. Accompanying Figure 1 a-e shows the Steel Slag-Flyash Bricks
produced from different samples according to the invention.
The testing of the different steel slag-flyash bricks produced from the above sample
helped achieving the following important desirable properties.
COMPRESSIVE STRENGTH
The compression tests were conducted for different composition/samples of the
Steel Slag - Flyash Brick", samples on 7th day, 14th day, 21st day and 28th day from
the date of manufacturing. The results of compressive strength of various samples
are given in following Table-1. The trends of compressive strength of different
sample A, B and C are shown in accompanying Figure 2 and in Figure 3. The
sample type D & E could not be tested as cracks developed within 7 days from the
date of manufacturing. The graph of Figure 2 shows the increasing trend of
compressive strength with curing days for Sample Type A.
The comparative trend for compressive strength of three different types of sample A,
B, and C for their average value is shown in Figure 3.
From the graphs, it is evident that the compressive strength is continuously
increasing for sample Type A which has been added with Accelerator CaCI2, whereas
the compressive strength for sample Type B and C are of decreasing trend after 21st
days. The reason may be that the higher percentage of Steel Slag (consists of high
percentage of free lime) in the sample and no CaCI2 Accelerator, leading to lesser
strength and further leads to crack formation in the bricks samples of Type-D and
Type-E during drying/curing time, which is visible in the accompanying Figure 1 d &
e.
Table- 1:
WATER ABSORPTION:
The 'Steel Slag - Flyash Brick", sample Type A had average water absorption of
20.35% which showed similar result for pulverized fuel ash-lime bricks. The water
absorption capacity of the tested brick samples are given in the following Table -2 .
Table-2:
ECONOMICS OF "STEEL SLAG-FLY ASH BRICKS":
The Detailed Cost Calculations for different heads and for different samples are
given in Tables 3a-c in Annexure. The Cost summary for Red Clay Bricks, Flyash
Bricks and Steel Slag-Flyash Bricks are stated in Table-4 shown below;
Table -3a:
Table-3b:
Case-2
'Steel Slag-Flyash Brick", at commercially subsidized cost of LP slag
Table-3c:
'Steel Slag - FIyash
Case-3
Brick at commercially subsidized cost of GBF Slag.
Sample Type A
Table-4:
Note: The current Market Price of Good Quality Red Clay Brick at Bokaro Steel City
is Rs 3.0 / Brick.

STRENGTH-COST RATIOS:
The Cost-Benefit analysis has been carried out based on the prices of ingredients of
"Steel Slag - Flyash Bricks". Hence, the benefit cost ratio in terms of compressive
strength of concrete would be a good parameter in understanding the impact of cost
of Brick Masonry. In this regard, following parameter has been used:
Strength-Cost ratio(SCR) = (Compressive strength of Brick/Cost of Brick) Kg/cm2 /
Rs/Brick.
The SCR values for Different Bricks are shown in the following Table-5 .
Table-5:
Strength Cost Ratio of Different Bricks
A higher value of strength cost ratio (SCR) is preferable since the ratio indicates the
unit of strength achieved in Brick per unit amount of money spent in production of
Brick. A higher value of SCR indicates better utilization of finance to produce the
strength effects in Brick Masonry. Accordingly, Steel slag-Flyash Bricks having
highest SCR is the most preferred option for civil construction.
EARTH QUAKE RESISTANT PROPERTY OF STEEL SLAG-FLYASH BRICKS FOR
USE IN BUILDINGS:
The design of buildings to resist earthquakes involves controlling the damage to
acceptable levels at a reasonable cost. This means that after a severe earthquake,

even a damaged non-functional building should stand so that the safety of the
people within can be justified. Accordingly, the general principles followed during the
construction of earthquake-resistant buildings are as follows:
LIGHTNESS AND STRENGTH WEIGHT RATIO
Since lateral thrust due to earthquake forced on a building is a function of its mass,
the building mass is to be kept as light as practicable, with added concern for upper
portions to avoid top heavy structures. In this regard the unit weight of Bricks for
different Brick types are given below; The strength to weight ratio achieved for
different Brick types are shown in following Table 6.
Table-6:
It is also known in the art that, masonry infilled reinforced concrete frames are a
common structural system for buildings. Masonry infills are used for functional or
aesthetic reasons, rather than as structural elements. Their presence is generally
ignored by the designers and no consideration is given to their own seismic safety or
their effect on the performance of the structure. Although, these are considered as
non-structural elements, they interact with the frame when the buildings are
subjected to laterial loads. The masonry infills act as diagonal structs between the
frame joints. This diagonal strut results in considerable increase in stiffness and
strength of the frame. The increased stiffness, in turn, attracts increased intertia
force during earthquake. Due to this frame-infill interaction, the failure modes of the
global structure may get changed.
These masonry infill walls which are constructed after completion of concrete frames
are considered as non-structural elements. Although they are designed to perform
architectural functions, masonry infill walls do resist lateral forces with substantial
structural action. In addition to this infill walls have a considerable strength and
stiffness and they have significant effect on the seismic response of the structural
system. There is a general agreement among the researchers that infilled frames
have greater strength as compared to frames without infill walls. The presence of the
infill walls increases the lateral stiffness considerably. Due to the change in stiffness
and mass of the structural system, the dynamic characteristics change as well.
In the event of an earthquake, apart from the existing gravity loads, horizontal
racking loads are imposed on walls. However, the unreinforced masonry behaves as
a brittle material. Hence if the stress state within the wall exceeds masonry strength,
brittle failure occurs, followed by possible collapse of the wall and the building. The
strength of "Steel Slag -Flyash" Bricks made using Steel Slag from BSL, have been
found to be 120 to 134 Kg/cm2 as compared to 50 to 75 Kg/cm2 of Conventional
Red Clay Bricks. The Strength weight ratios of Steel Slag -Flyash Bricks are also
very much favourable interms of Steel Slag-Flyash Bricks, followed by Flyash Bricks
as against Conventional Red Clay Bricks.. Thus Steel Slag-Flyash Bricks are more
Earthquack resistant Bricks.
ECO FRIENDLY PROCESS AND PRODUCT:
From environmental impact point of view, commercial production of the "Steel Slag -
Flyash Bricks" according to the invention shall enable substantial utilization of Steel
Slag and flyash from Steel Plants and Power Plants , favoring these industries to
achieve the "CREP" targets in India.
Since the process of producing "Steel Slag-Flyash Bricks" according to the present
invention does not involve any sintering process, it contributes to significant fuel
savings as well as avoidance of pollution associated with burning of fuels. Thus
reduction in Green House Gases emissions like CO2/ etc. is achieved.
Enhanced earnings from sale of carbon credits in the international carbon trading
market. The fact that steel slag has already been calcined, means that the heat of
decarbonation is eliminated. This allows a reduction in fuel consumed per ton of brick
produced. Steel slag can provide a significant contribution on reducing CO2
emissions. Industries when engaged in producing Steel slag-Flyash bricks by
adopting waste utilization and resource conservation in their operations thus
automatically promote environment protection.
"Steel Slag - Flyash Bricks" has been developed, manufactured by innovative use
of Steel slag and tested at Bokaro Steel Plant which has opened up an additional
route for utilization of Steel Slag in steel plants. Utilisation Steel slag 100 % as per
CREP norms has been a problem for Indian Steel Industry.
The cost of production of "Steel Slag - Flyash Bricks" are also found to be lower and
they are found to be stronger than both conventional "Flyash Bricks" and
conventional "Red Clay Bricks". The strength of "Steel Slag -Flyash" Bricks made
using Steel Slag from BSL, have been found to be 120 to 134 Kg/cm2 as compared
to 50 to 75 Kg/cm2 of Conventional Red Clay Bricks. The Strength weight ratios of
Steel Slag -Flyash Bricks are also much superior compared to conventional red clay
or flyash bricks.
Thus Steel Slag-Flyash Bricks are more Earthquack resistant Bricks ensuring
durable structures at relatively lesser cost while also safeguards the environment.
The Steel slag-Flyash bricks according to the invention thus having wide scale
prospects of being produced economically by Integrated Steel Plants by setting up
down stream ancillary units which are economic and eco friendly for advantageous
consumption in making greener Buildings, Compound Walls, Drainage Structures,
Lining of Irrigation Canals, etc .
It is thus possible by way of the present invention to providing a brick composition
involving steel slag and fly ash generated from steel plants and the thermal power
plants respectively and bricks produced using such composition ensuring higher
strength and other desired properties favoring use of such bricks in civil construction
providing earthquake resistant property of the structure, particularly when used in

infill walls with concrete frame. The process of making the steel slag-fly ash based
bricks ensure low cost of production, higher energy saving, environment friendliness
and good aesthetic appearance as well as machine finished surface with uniform size
requiring less quantity of cement morter. Advantageously, these bricks are adapted
to be produced by the existing manufacture of fly ash bricks utilizing same
infrastructure. The process of the invention enable recycling/reuse of the co-
product/waste material from steel plant and power generating plant and thus saving
natural mineral resources. Steel slag-fly ash based bricks according to the present
invention is thus having prospects of wide scale industrial production and application
in civil construction with strong, durable and longer life at less cost.
We Claim:
1. A steel slag-flyash brick comprising of
steel slag content having mineral composition including highly fluxed beta di-calcium
silicate phase (C2S) with favourable CaO/SiO2 ratio in combination with fly ash for
favourable strength and beneficial strength-cost ratio and/or strength weight ratio.
2. A steel slag-flyash brick as claimed in claim 1 comprising
steel slag and fly ash comprising of:
Steel Slag:;
Dry Fly ash:;
Quarry dust:;
Hydrated Lime:;
Gypsum:;
Calcium Chloride:;and
Binder:;
3. A steel slag-flyash brick as claimed in anyone of claims 1 or 2 wherein said steel
slag comprise content of favourable CaO/SiO2 ratio preferably of about 3 with Di-
calcium silicate dominated mineral composition.
4. A steel slag-flyash brick as claimed in anyone of claims 1 to 3 wherein the steel
slag composition involve dominant compounds comprising:
a. Dicalcium silicate (C2S);
b. Tricalcium Silicate (C3S);
c. Calcium iron oxide; and
d. Di-calcium ferrite.
5. A steel slag-flyash brick as claimed in anyone of claims 1 to 4 , wherein
composition of said steel slag fines comprises
SiO2 :lltol5wt%;
CaO :45-47%;
MgO :7-7.5%
Total Fe : 18-25%;

Al2O3 :2-4.5%;
P2O5 :Upto 2 %; and
Basicity : 3-4%
6. A steel slag-flyash brick as claimed in anyone of claims 1 to 5 comprises
Fly-ash about 35%;
LD slag about 30%;
Gypsum about 3-5%;
Quarry dust about 20%;
Lime about 10-12%;
Calcium Chloride about 0.25%
7. A steel slag-flyash brick as claimed in anyone of claims 1 to 6 which is having a
strength of 120 to 134 Kg/cm2.
8. A steel slag-flyash brick as claimed in anyone of claims 1 to 7 which is having:
xiv) increased compressive and flexural strength, relatively at lower/same
price as compared to Conventional Red Clay Bricks,
xv) increased earthquack resitance.
xvi) low permeability and enhanced durability
xvii) ilncreased long term strength and
xviii) increased resistance to alkalies and sulfate attacks
xix) plastering over brick surface can be avoided,
xx) nice aesthetic looks, ready acceptance in market,
xxi) machine finished uniformity in size requiring comparatively less quantity
of cement mortar,
xxii) excellent anti-termite properties
xxiii) consistent quality - above 98% are of first class quality,
xxiv) characteristics of desired resistant to salinity and water seepage and
therefore best suited for humid atmosphere;
xxv) better portability;
xxvi) ready availability;

9. A process for manufacturing Steel slag-flyash bricks as claimed in anyone of
claims 1 to 8 comprising the steps of:
mixing selectively calcium chloride in water followed by addition of fly ash, slag,
Gypsum, Quarry dust, Lime and CaCI2 in desired amounts to provide the bricks of
desired strength and beneficial strength-cost ratio and strength weight ratio.
10. A steel slag-flyash brick and its method of manufacture substantially as
hereindescribed and illustrated with reference to the accompanying examples and
figures.

The present invention relates to a brick composition utilizing a combination of steel
slag from steel plant and flyash from power plant. The invention provides for Steel
slag-Fly ash brick composition and a process of manufacture of such bricks thereof.
Importantly, such bricks are suitable for use in building construction having higher
compressive strength of 120-134 kg/cm2 as compared to 50-75 kg/cm2 for
conventional Red Clay Bricks, as well as earthquake resistant property of structures
obtained at relatively less cost. The steel slag fly ash based brick manufacturing
process ensure on one hand utiliztion of steel slag and saving energy consumption
with reduction in fuel consumption per ton of brick produced. The brick composition
favor reducing environmental pollution avoiding CO2 emission, preserve natural
resource by utilizing an industrial co-product to replace natuaral minerals and on the
other hand ensure longer life of the bricks/structures.