FIELD OF THE INVENTION
The present invention relates to the field of building materials and more
particularly to a ready-mix plaster material prepared using industrial wastes. The readymix
plaster material of the present invention can be used as mortar for brick jointing and
wall plaster by just adding water to the ready-mix powdered plaster material. The
industrial wastes used for preparing ready-mix plaster material are red mud, fly ash and
bottom ash which allow replacing high amounts of natural sand material used in
conventional building materials.
BACKGROUND OF THE INVENTION
Concrete and plaster are the most commonly used materials in infrastructure
development throughout the world. They are globally accepted construction material in all
types of Civil Engineering structures. Plaster is a building material and generally used for
the jointing of bricks in making wall and protective cover on walls and ceiling. Generally
plaster is manufactured as a dry powder and mixed with water to form a workable paste
just before it is applied to the surface. Plaster is not a strong material and it is not bearing
any load of structure on which it is applied.
There are many type of plaster available in practice such as gypsum plaster, lime
plaster, cements plaster etc. All of these plasters more or less serve the same purpose.
Most common plaster used in construction is a mixture of cement and sand mixed in a
certain ratio.
Conventional cement and sand plaster is nothing but a mixture of natural sand,
portland cement and water in certain ratio used for construction purposes. Natural sand is a
prime material used for the preparation of plaster and also plays an important role in
constructions. However, the availability of natural sand is very limited and procurement of
the same is becoming difficult due to scarcity of the same and environmental issues as
well. Nowadays river erosion and other environmental issues have led to the scarcity of
natural sand. The reduction in the sources of natural sand and the requirement for reduction
in the cost of concrete production has resulted in the increased need to find new alternative
materials to replace natural sand so that excess river erosion is prevented and high strength
2
concrete is obtained at lower cost. Partial or full replacement of natural sand by the other
alternative materials like quarry dust, foundry sand and others are being researched from
past two decades, in view of conserving the ecological balance.
The availability of suitable natural sand for concrete production near the point of
consumption has been exhausted around many populated regions in the world. Moreover,
numerous field observations show that destruction of landscape, reduction of farm and
grazing land, collapsing river banks, deforestation and water pollution are the
environmental effects that result due to sand and gravel mining. This has led to a search for
a new replacement materials for the natural sand. With the rapid development of the
construction industry, building materials which are of good stability and environmental
quality are in great demand.
European Patent Application number EP 2105420A1 discloses a composition for
building material comprising more than 70% of fly ash and bottom ash in combination, a
chemical activator and 2-18% of additive material. EP 2105420A1 is based on chemical
route/activator using hydroxide, sulphate, acetate or chloride salt. The chemical activator
reacts with fly ash and forms binding matrix suitable for the production cold setting fly ash
building construction materials like bricks, block concrete and other high strength
construction materials but not plaster material. Said chemical activator must contain at
least two anions, especially at least three anions such as chloride, hydroxyl and sulfate ions
or hydroxyl, sulfate and acetate ions. The nature and dosages of activator play a crucial
role in setting and hardening process of plaster.
Chinese Patent Application number CN103693924A discloses a mixed Bayer red mud
plastering mortar dry mix using ordinary portland cement (19-13%), Bayer red mud (2-
6%), fly ash (2-6%), cellulose ethers (0.05-0.15%), latex powder (0.19-0.54%), modified
attapulgite (0.57-1.22%) and river sand (approximately 73%) composition. However, CN
103693924A requires 73.65-74.42% of natural sand for preparation of the plaster.
Therefore, CN 103693924A uses a very high amount of river sand which is not desirable to
overcome the environmental effects due to use of natural sand resources.
3
OBJECTIVES OF THE INVENTION
It is an object of the present invention to manufacture a ready-mix plaster material
for various construction purposes.
It is another object of the present invention to manufacture a ready-mix plaster
material utilizing the industrial wastes such as red-mud, fly-ash and bottom ash.
It is other object of the present invention to manufacture a ready-mix plaster that
uses materials which allows reduction in use of natural sand plaster.
SUMMARY OF THE INVENTION
The present invention relates to a ready-mix plaster material prepared by using
industrial wastes such as red mud, fly ash and bottom ash thereby replacing a major
portion of natural sand and cement used in a conventional plaster.
In accordance with an aspect of the disclosure there is provided a ready-mix plaster
material comprising ingredients:
a) red mud in the range of 5-12 w/w%;
b) fly ash in the range of 20-30 w/w% ;
c) bottom ash in the range of 25-45 w/w%;
d) portland cement in the range of 11-17 w/w%; and
e) natural sand in the range of 12-18 w/w%; and
an additive in the range of 0.05-0.2 wt% of total weight of ingredients (a) to (e).
Another aspect of the present invention provides a process for preparing ready-mix
plaster material comprising mixing red mud in the range of 5-12 w/w%; fly ash in the
range of 20-30 w/w% ; bottom ash in the range of 25-45 w/w%; portland cement in the
range of 11-17 w/w%; and natural sand in the range of 12-18 w/w% in a plough shear
mixer to obtain a premix; and adding an additive in the range of 0.05-0.2 wt% of the
premix in the plough shear mixer to obtain the ready-mix plaster material. The mixing may
be carried out for at least 5 minutes to obtain a homogenous dry mixture of ready-mix
plaster material.
These and other features and advantages of the present subject matter will become
4
better understood with reference to the following description. This summary is provided to
introduce a selection of concepts in a simplified form. This summary is not intended to
identify key features or essential features of the claimed subject matter, nor is it intended to
be used to limit the scope of the claimed subject matter.
DESCRIPTION OF THE INVENTION
The present invention relates to a ready-mix plaster material prepared by using
industrial wastes such as red mud, fly ash and bottom ash in place of natural sand.
Accordingly, the present invention provides a ready-mix plaster material comprising:
comprising ingredients:
a) red mud in the range of 5-12 w/w%;
b) fly ash in the range of 20-30 w/w% ;
c) bottom ash in the range of 25-45 w/w%;
d) portland cement in the range of 11-17 w/w%; and
e) natural sand in the range of 12-18 w/w%; and
an additive in the range of 0.05-0.2 wt% of total weight of ingredients (a) to (e).
The ready-mix plaster material of present application is a homogeneous
composition of well graded mix of red mud, fly ash, bottom ash, natural sand, portland
cement and some part of additive. The mixture is prepared in powdered form. It is ready to
use by mixing desired quantity of water in the powdered ready-mix plaster material.
Red mud is a waste-product generated in process of extraction of alumina from
Bauxite ore using Bayer’s process. It is approx 45 to 55% of Bauxite used for alumina
extraction. Tonnes of red mud is generated annually and is difficult to dispose off or
recycle satisfactorily. However, worldwide studies are going on for its fruitful use. The
conventional method of disposal of red mud in ponds has often adverse environmental
impacts. For example, in monsoons, the waste red mud may be carried to the surface water
courses and as a result leaching may cause contamination of ground water if not disposed
in environmentally proven manner. Further, the disposal of large quantities of red mud
poses increasing problems of storage occupying a lot of space. After drying and sieving the
5
red mud (collected from pond) up to desired particle size (95% particles smaller than or
equal to 600 microns and 84% particles smaller than or equal to 300 microns), it is ready to
use in ready-mix plaster material of present application. In an embodiment of the present
invention, red mud is used in the range of 5-12% w/w.
Fly ash is very fine material generated in thermal power plant in process of burning
coal in boilers to produce thermal energy. The total ash generation is normally 35% of total
coal fed in boilers. The fly ash generation is approx 80% of total ash generation. Normally
it is collected through electrostatic precipitators. This fly ash has very fine particle size and
is directly mixed in ready-mix plaster. The preferable size of fly ash has 97% particles
smaller than or equal to 150 microns and 80% particles smaller than or equal to 75
microns. The common environmental pollution problems created by disposal of fly ash,
besides air and water pollution are wastage of large tracts of land which otherwise could be
utilized for useful purposes. In an embodiment of the present invention, fly ash is used in
the range of 20-30 %w/w.
Bottom ash is also a by-product of coal burning in boilers of thermal plant. It is part
of the non-combustible residue of combustion in furnace and is coarser in nature. Bottom
ash generation is 20% of total ash generation in thermal power plant and is usually
disposed along with fly ash. Fly ash being a major proportion of ash generated in coal fired
thermal power plant, has been used recently in portland pozzolona cement manufacturing,
road building and agriculture, land and mine filling etc. However, there are not many
studies using bottom ash component separately especially for providing construction
materials. The inventors of the present invention have used bottom ash in higher amounts
to replace a major portion of natural sand. The bottom ash was used after drying and
sieving with suitable mesh up to desired particle size (93% particles smaller than or equal
to 600 microns and 83% particles smaller than or equal to 300 microns). In an embodiment
of the present invention, bottom ash is used in the range of 25-45 %w/w.
Natural sand is found in river bed. The dried sand is cleaned with sieve size of 1.50
mm for any foreign materials known in the art, again sieved with suitable mesh size up to
required particle size corresponding to grading Zone IV (as per IS: 383-1970), and then it
is ready to use in ready-mix plaster. It is required to improve the workability of material. In
6
an embodiment of the present invention, natural sand is used in the range of 12-18 %w/w.
The natural sand as per grading Zone IV has particle size distribution as shown in Table 1.
Table 1: Particle size distribution of natural sand as per grading Zone IV of IS: 383-1970
IS Sieve
10 mm
4.75 mm
2.36 mm
1.18 mm
600 micron
300 micron
150 micron
% particles passing through IS sieve
100
95-100
95-100
90-100
80-100
15-50
0-15
Very small quantity of additive is mixed directly as it is a ready-made product
available in market. It strengthens the consistency of materials which are based on
hydraulic binders. It also influences the rheology behaviour of the binder matrix in water,
changing the yield point, flow parameters and water retention. The additive can be selected
from the group consisting of starch ether powder, cellulose ether etc. In an embodiment of
the present invention, additive is over and above a total mix of red mud, fly ash, bottom
ash, portland cement and natural sand.
Portland cement is a standard material available in market. It is a binding material
commonly used in building construction industries. It is directly added in ready-mix plaster
of the present invention as a binding material. In an embodiment of the present invention,
Portland cement is used in the range of 11-17 %w/w.
In another embodiment, the present invention provides a process for preparation of
ready-mix plaster material comprising mixing red mud in the range of 5-12 w/w%; fly ash
in the range of 20-30 w/w% ; bottom ash in the range of 25-45 w/w%; portland cement in
the range of 11-17 w/w%; and natural sand in the range of 12-18 w/w% in a plough shear
mixer to obtain a premix; and adding an additive in the range of 0.05-0.2 wt% of the
premix in the plough shear mixer to obtain the ready-mix plaster material. The additive is
added over and above the total amount of red mud, fly ash, bottom ash, portland cement
7
and natural sand. The mixing the plough shear mixer may be carried out for at least 5
minutes to obtain a homogenous dry mixture of ready-mix plaster material.
Yet another embodiment of the present invention provides a process in which red
mud, bottom ash and natural sand have moisture level in the range of 0.01% to 2%.
In still another embodiment, the present invention provides a ready-mix plaster
material in powdered form which can be instantaneously used as a construction material by
mixing with desired quantity of water.
EXAMPLES
The present invention is more particularly described in the following examples, that
are intended as illustrations only, since numerous modifications and variations within the
scope of the present invention will be apparent to those skilled in the art. Unless otherwise
noted, all parts, percentages and ratios reported in the following examples are on a weight
basis and all reagents used in the examples were obtained or are available from the
chemical suppliers. It is to be understood that both the foregoing general description and
the following detailed description are exemplary and explanatory only and are intended to
provide further explanation of the subject matter.
EXAMPLE 1: Preparation of Ready-mix Plaster
Red mud collected from alumina refinery, bottom ash collected from thermal power plant,
and natural sand having close to zero moisture level (about 0.01%) were sieved
individually with a mesh size as per sieve designation in IS: 383-1970 to obtain a desired
particle size: red mud having 95% particles smaller than or equal to 600 microns and 84%
particles smaller than or equal to 300 microns; bottom ash having 93% particles smaller
than or equal to 600 microns and 83% particles smaller than or equal to 300 microns;
natural sand having particle size as per grading Zone IV of IS: 383-1970 code. The redmud,
bottom ash and natural sand, thus obtained, were mixed together in a plough shear
mixer. Fly-ash, collected from thermal power plant having fine particle size (97% particles
smaller than or equal to 150 microns and 80% particles smaller than or equal to 75
microns) and ordinary portland cement were then added to the mixer. The additive starch
8
ether powder was added to the mixture over and above the total mixture of ingredients, as
above and the ingredients were mixed together in the plough shear mixer at least for a
period 3 to 5 minute to obtain the homogenous ready-mix plaster material. The amounts of
all the ingredients used are shown in Table 2.
The ready-mix plaster material obtained in the powder form was then packed using
an air tight bag as a ready-to-use-plaster material. The powdered mixture can be used as
mortar, when required, by mixing desired quantity of water, for brick jointing and wall
plaster. The ready-to-use-plaster material was tested in accordance with the Indian
Standard code IS: 2250:1981 and other ASTM international code.
Table 2: Components used for preparation of ready-mix plaster
Components used
Red mud
Fly ash
Bottom ash
Ordinary portland
cement
Natural sand
(grading Zone IV
of IS: 383-1970)
Additive
(Starch ether)
Composition 1
(%w/w)
10
25
38
14
13
0.08
Composition 2
(%w/w)
5
21
45
11
18
0.2
Composition 3
(%w/w)
12
30
25
17
16
0.05
Indian Standard code IS: 2250:1981 and ASTM international code tests used are as
following.
Drying Shrinkage (Test method ASTM C 596 – 01):
Sample was prepared by adding water in dry mortar. The water was added in the dry
sample as per Manufacturer's Specification as follows: Water-Powder (W/p) ratio – 0.17;
Specimen size: 25 x 25 x 250 mm; Curing condition: Normal water bath curing. Three
specimens of each sample were tested for Drying Shrinkage.
Pull Off Strength Test for Adhesion (Test method ASTM D 4541): Samples were
9
prepared by applying ready-mix Plaster in between 2 AAC blocks & air cured for 28 days;
Specimen size: 50 x 50 mm; Curing condition Air Curing; Equipment used - Pull Off
Tester. Three specimens of each sample were tested for Pull Off Strength Test. Pull off test
is used to measure the adhesion strength between coating and a substrate. In our case
coating is plaster material.
Compressive Strength and Flow Test: Sample was prepared by adding water in received
dry mortar. The water was added in the dry sample for water quantity. W/p ratio – 0.17;
Specimen size: 70.6 x 70.6 x 70.6 mm; Curing condition: Normal water bath curing. Flow
test is used to determine the consistency of mortar i.e. ease of workability.
The test results obtained for the compositions 1, 2, and 3 are as shown below in Table 3.
Table 3: Results of tests for the ready-mix plaster composition of the present application
Sr.
No.
1
2
3
4
5
Type of Test
Water quantity for 25 Kg
sample (Liters)
Consistency Test:
Flow Test (mm)
Compressive Strength
(N/mm2)
a) 7 days
b) 28 days
Pull off test for adhesion
(28 days) N/mm2
Drying Shrinkage (28 day)
Composition 1
6.80
110.00
8.07
15.15
0.67
0.011
Composition 2
6.80
115.00
8.18
16.06
0.67
0.012
Composition 3
6.80
115.00
8.31
15.82
0.68
0.011
As shown in Table 3, the present invention provides a plaster material having good
fluidity, water retention, low shrinkage, good adhesion strength as well as good
compressive strength. As per the test results, the ready-mix plaster of the present invention
falls in Grade MM3 to MM7.5 mortar mix as per IS 2250:1981. The present invention thus
provides a ready-mix plaster material which allows minimum wastage of construction
10
materials used conventionally, using the industrial wastes as well as replacing a large
amount of natural sand. Such a plaster material not only provides a solution for industrial
waste management but also provides overall economic benefit by reducing cost of raw
materials as compared to conventionally used plaster material and also protects ecosystem
by conserving natural resources.
EXAMPLE 2 : Comparative Process for preparation of Ready-mix Plaster Material
Different variations of the compositions 1, 2 and 3 obtained in Example 1 were
prepared to assess the effect of various components used in the compositions. Variant
compositions A to D were prepared by removing red mud, fly ash, bottom ash and natural
sand, respectively, from each of the composition 1, 2 and 3 as obtained in Example 1. The
variant compositions were prepared in accordance with the Table 4-6 as below showing
number of units or parts of each component used to obtain the respective variant
compositions.
Table 4: Components along with number of units or parts of each component used for
preparation of variations of Composition 1 of ready-mix plaster material
Components
used
Red mud
Fly ash
Bottom ash
Ordinary portland
cement
Natural sand
Additive
Composition
1A
Not used
25
38
14
13
0.08
Composition
1B
10
Not used
38
14
13
0.08
Composition
1C
10
25
Not used
14
13
0.08
Composition
1D
10
25
38
14
Not used
0.08
11
Table 5: Components along with number of units or parts of each component used for
preparation of variations of Composition 2 of ready-mix plaster material
Components
used
Red mud
Fly ash
Bottom ash
Ordinary portland
cement
Natural sand
Additive
Composition
2 A
Not used
21
45
11
18
0.2
Composition
2 B
5
Not used
45
11
18
0.2
Composition
2 C
5
21
Not used
11
18
0.2
Composition
2 D
5
21
45
11
Not used
0.2
Table 6: Components along with number of units or parts of each component used for
preparation of variations of Composition 3 of ready-mix plaster material
Components
used
Red mud
Fly ash
Bottom ash
Ordinary portland
cement
Natural sand
Additive
Composition
3 A
Not used
30
25
17
16
0.05
Composition
3 B
12
Not used
25
17
16
0.05
Composition
3 C
12
30
Not used
17
16
0.05
Composition
3 D
12
30
25
17
Not used
0.05
Each of the composition prepared according to Table 4-6 was tested in accordance with the
Indian Standard code IS: 2250:1981 for compressive strength. The results of the same are
shown in Table 7.
12
Table 7: Results of Compressive Strength (28 days) (N/mm2) for the variants of the
compositions 1-3.
Sample
Composition 1
Composition 1 A
Composition 1 B
Composition 1 C
Composition 1 D
28 days
Compressive
Strength
(N/mm2)
15.15
2.38
2.81
2.05
2.23
Sample
Composition 2
Composition 2 A
Composition 2 B
Composition 2 C
Composition 2 D
28 days
Compressive
Strength
(N/mm2)
16.06
0.50
0.88
0.65
0.40
Sample
Composition 3
Composition 3 A
Composition 3 B
Composition 3 C
Composition 3 D
28 days
Compressive
Strength
(N/mm2)
15.82
2.42
2.78
2.26
2.18
As shown in the Table 7, the ready-mix plaster material having desired properties for
building materials is obtained when all the ingredients are present together in the powdered
mixture. Even if one component is removed from the ready-mix plaster of the present
invention, the compressive strength decreases drastically. Thus, it is proved that when all
the components of the composition of the present invention are mixed for obtaining the
desired ready-mix-plaster material they interact to produce a synergistic effect.
EXAMPLE 3 : Comparison of test results for ready-mix plaster and the prior art
The test results obtained for ready-mix plaster of the present application were also
compared with the plaster mortar disclosed in the document CN 103693924A. The
comparative data is provided in table 8 below.
As shown in Table 8, the plaster material of present invention shows comparative
properties with respect to the plaster material of CN 103693924A having higher amounts
of natural sand (73.65 -74.42%). The present invention uses only 10-18 % of natural sand
and still provides the mortar/ plaster which falls in Grade MM3 to MM7.5 mortar mix as
per IS: 2250:1981.
13
Table 8: Comparative properties of the plaster material of CN 103693924A with the
plaster material of the present invention
Sr.
No.
1
2
3
4
5
Type of Test
Water quantity
for 25 Kg sample
(Ltr)
Consistency Test:
Flow Test (mm)
Compressive
Strength (N/mm2)
a) 7 days
b) 28 days
Pull off test for
adhesion (28
days) N/mm2
Drying Shrinkage
(28 day)
Composition
1
6.80
110.00
8.07
15.15
0.67
0.011
Composition
2
6.80
115.00
8.18
16.06
0.67
0.012
Composition
3
6.80
115.00
8.31
15.82
0.68
0.011
Examples of CN 103693924A
Example 1
NA
92
NA
21.3
0.9
0.046
Example 2
NA
94
NA
20.3
0.9
0.042
Example 3
NA
90
NA
19.3
0.8
0.048
Further, CN 103693924A does not use bottom ash as a separate component. It only
uses fly ash, that too in small amounts of 2.86-5.45 %. The present invention on the other
hand uses fly ash in the range of 20-30 w/w% and bottom ash in the range of 25-45 w/w%;
and provides comparable properties of plaster material, thus allowing replacing about 82 to
88 % of natural sand from the plaster material. This allows conservation of the natural
resources and protects the ecosystem for production of plaster material. Thus, the plaster
material of present invention is eco- friendly and also has economic significance as it uses
waste materials.
ADVANTAGES OF THE INVENTION
The present invention provides a plaster material which can be readily and easily
used by just adding desired quantity of water when required for construction purposes.
This allows less wastage of resources compared to traditional cement-sand plaster. The
ready-mix plaster of present application is obtained using a large percentage of industrial
waste materials and very less percentage of natural sand, thereby allowing conservation of
14
the natural resources i.e. natural sand, which is depleting very fast due to unmanaged
utilization, resulting in disturbance of ecosystem. Therefore, the present invention allows
effective utilization and recycling of industrial waste, which otherwise pose a risk to
environment due to disposal of such industrial waste materials in water or as landfills. The
ready-mix plaster of present application is produced in powdered form to be readily used
for construction purposes and can also be used in making bricks, blocks, tiles, sheets, etc.
using compaction and casting known in the art to produce other such construction
materials of interest.
Although the subject matter has been described in considerable detail with
reference to certain preferred embodiments thereof, other embodiments are possible. As
such, scope of the disclosure should not be limited to the description of the preferred
embodiment contained therein.

WE CLAIM:
1. A ready-mix plaster material comprising ingredients:
a) red mud in the range of 5-12 w/w%;
b) fly ash in the range of 20-30 w/w%;
c) bottom ash in the range of 25-45 w/w%;
d) portland cement in the range of 11-17 w/w%; and
e) natural sand in the range of 12-18 w/w%; and
an additive in the range of 0.05-0.2 wt% of total weight of ingredients (a) to (e).
2. The ready-mix plaster material as claimed in claim 1, wherein the additive is starch
ether powder or cellulose ether.
3. The ready-mix plaster material as claimed in claim 1, wherein the red mud has 95%
particles smaller than or equal to 600 microns and 84% particles smaller than or equal
to 300 microns.
4. The ready-mix plaster material as claimed in claim 1, wherein the bottom ash has 93%
particles smaller than or equal to 600 microns and 83% particles smaller than or equal
to 300 microns.
5. The ready-mix plaster material as claimed in claim 1, wherein the natural sand has
following particle size distribution:
IS Sieve
10 mm
4.75 mm
2.36 mm
1.18 mm
600 micron
% particles passing through IS sieve
100
95-100
95-100
90-100
80-100
16
300 micron
150 micron
15-50
0-15
6. The ready-mix plaster material as claimed in claim 1, wherein the fly-ash has 97%
particles smaller than or equal to 150 microns and 80% particles smaller than or equal
to 75 microns.
7. A process for preparation of ready-mix plaster material comprising mixing red mud in
the range of 5-12 w/w%; fly ash in the range of 20-30 w/w% ; bottom ash in the range
of 25-45 w/w%; portland cement in the range of 11-17 w/w%; and natural sand in the
range of 12-18 w/w% in a plough shear mixer to obtain a premix; and adding an
additive in the range of 0.05-0.2 wt% of the premix in the plough shear mixer to obtain
the ready-mix plaster material.
8. The process as claimed in claim 7, wherein the red mud has 95% particles smaller than
or equal to 600 microns and 84% smaller than or equal to 300 microns; the bottom ash
has 93% particles smaller than or equal to 600 microns and 83% particles smaller than
or equal to 300 microns; the fly ash has 97% particles smaller than or equal to 150
microns and 80% particles smaller than or equal to 75 microns; and the natural sand
having following particle size distribution:
IS Sieve
10 mm
4.75 mm
2.36 mm
1.18 mm
600 micron
300 micron
150 micron
% particles passing through IS sieve
100
95-100
95-100
90-100
80-100
15-50
0-15
17
9. The process as claimed in claim 7, wherein the red mud, bottom ash and natural sand
have moisture level in the range of 0.01% to 2.0%.
10. The process as claimed in claim 7, wherein the additive is starch ether powder or
cellulose ether.