The present invention relates to construction materials made using Industrial waste. More particularly, the present invention relates to geopolymer binder to be used along with the industrial waste for manufacturing a ready to use powdered building construction materials.
Background of the Invention
Concrete made from Portland Cement is a material that can be used in civil Engineering infrastructure. However, the production of Portland Cement concrete typically results in large scale carbon dioxide emissions and consequently has a large carbon footprint. Cement industries have huge challenges of generating CO2 while cement manufacturing and the industry represents around 5% of global CO2 emissions. To address these shortcoming, other materials such as for example, Geopolymer binder have been used as a substitute for Portland Cement and consume huge volume of industrial solid waste rejects from Limestone and clay mines during the production of Portland cement or industries.
Geopolymer concrete provides an alternative low carbon footprint option to Portland cement concrete. Generally, geopolymer concrete is formed by mixing a binder, sand, and aggregate with water. The binder typically includes the Fly ash, clay, GGBS (Ground granulated blast furnace slag) mixed with an alkali liquid activator such as sodium hydroxide and sodium or potassium silicate. The alkali liquid activator serves to increase the reactivity of the solid components during the concreting. But still, there is a disadvantage of using such alkali liquid activator and that is they pose an Occupational Health and safety (OH&S) hazard and may cause severe injuries such as chemical burns if mishandled during transportation and manufacturing of concrete.
There also exists a challenge pertaining to developing and delivering of a ready to use construction building materials on site due to an inability of construction material to be made fully in powdered form and used directly as and when required on the site.
Thus, there is a need for a solid activator to produce geopolymer concrete that makes it safe and easy to handle. Preferably, this geopolymer materials can produce concrete with comparable properties to concrete made with geopolymer material and using powdered alkali activators. It is known that waste materials from Limestone and clay mines have been tested and found that various chemicals like silica and alumina are already present in them and a huge volume of such solid waste materials can certainly be utilized to convert into geopolymer low carbon alternative building materials, but there still exists a challenge of availing all the essential chemicals for manufacturing a geopolymer composition and because of which one or more additional steps are to be always included for preparing final geopolymer mixture, hence, the implementation for converting the waste materials into geopolymer composition has been challenging and cumbersome in the past.
Below are a few prior arts relevant to the present invention:
US20210101832A1 discloses a geopolymer cement binder and a method of producing the same, wherein the geopolymer cement binder includes a geopolymer precursor including material containing amorphous silicates of one or more of calcium, aluminium, and magnesium, slag cements; fly ash; metakaolin; fumed silica; and rice husks, and magnesium oxide as an alkali activator, which can altogether be mixed with water using high shear mixing to produce geopolymer cement binder.
AU2017306058 discloses a cold fusion concrete formulation that uses no liquid or dry hydroxide additives as a primary activator or a pH elevator, comprising aggregate, activator, cementitious material including Granulated Ground Blast Furnace Slag (GGBFS), retarder and strengthening agent including mainly the hydroxides of alkali and alkali earth metals.
US20180230055 discloses a castable construction material with controlled flow and workability retention comprising binder comprising from 75% to 100% by weight of fly ashes, an activator comprising an alkali hydroxide and an alkali silicate between 3% to 25% by weight, and a workability retention agent selected from the group consisting of polycarboxylate ether polymer (PCE), polyamines, polyethylene imines, polyacrylamides, polyacrylate, etc.
WO2020191444 discloses a geopolymer binder comprising an aluminosilicate material including fly ash and/or slag and an activator including a mixture of sodium silicate and sodium carbonate, a cellulose based organic polymer-based viscosity control agent and retarding additive.
However, still, there is a concern with the building material industry with respect to the use of environmentally friendly chemicals and industrial wastes, minimizing harmful chemical usage, and reducing carbon dioxide emission, and developing ready to use geopolymer formulation for direct use in many application without compromising the characteristics. Also, existing geopolymer formulation poses problems in transportation and handling and their manufacturing method is cumbersome, hence, not cost-effective.
Though one of the above prior arts is avoiding the involvement of liquid for concrete formulation, but still no other above prior arts are providing a formulation or method of manufacturing of concrete with sufficient strength in minimum time and that too in readymade powdered form.
Therefore, there is need to develop a kind of method or approach to develop a geopolymer concrete or binder which is cost-effective, easily transportable, attains high compressive strength in minimum time and enables to avoid the challenges associated with existing geopolymer binders/concrete and provide additional benefits like low CO2 emission and improved consistency and other advantageous features can be achieved and many more.
Summary of the Invention
It is a principal objective of the present invention to provide a readymade geopolymer formulation which is used directly for construction on site without adding any chemical or additional material from outside.
It is an objective of the present invention to provide a geopolymer formulation which is capable of being easily transported from one place to another without causing any spillage or leakage.
It is an objective of the present invention to provide a method for manufacturing geopolymer formulation that avoids generation of hazardous materials in the environment during construction work.
It is an objective of the present invention to provide a method of manufacturing geopolymer formulation and geopolymer formulation in powdered form by avoiding usage of liquid activator constituents required for preparing geopolymer building construction.
It is another objective of the present invention to provide a geopolymer formulation that avoids usage of constituents whose handling is difficult, rather their substitutes are used for developing the geopolymer formulation.
It is another objective of the present invention to provide a geopolymer formulation whose raw materials are mainly derived from the industrial wastes.
According to the present invention, solid binders have been used to prepare geopolymer formulation, which is stable in the atmosphere unlike activators such as hygroscopic sodium hydroxide that readily absorb moisture from the atmosphere. Accordingly, the solid component binders are pre-mixed with silico aluminate material to prepare the geopolymer formulation, which is further used as concrete for precast industries, paver tiles industries, general construction industries, repair mortar and also used as grinding aids for cement industries. The geopolymer formulation is stored stably before being transported or sold in a ready-for-use dry powdered form.
Additionally, said geopolymer formulation does not possess a Dangerous Goods classification. The solid binder component may also yield a product with a similar level of alkalinity as to Ordinary Portland cement. This provides a safer manufacturing process as well as a safer work environment when the geopolymer binder used in the manufacturing of concrete. The solid component binder provides a high pH solution when mixed with water to activate the silico-aluminate material in the geopolymer concrete, thereby increasing the reactivity of the silico-aluminate material (i.e., activating the geopolymer concrete) and enabling it to form concrete with desirable properties.
In the present invention, the geopolymer concrete may be prepared using said geopolymer formulation at a temperature ranging from 10°C to 40°C. The geopolymer concrete may be prepared at ambient temperature without heating. Particularly, the solid binder comprises of waste mines reject, sodium meta silicate, accelerator and retarder, they all may be combined at ambient temperature without heating.
In accordance with one embodiment of the present invention, there is provided a powdered geopolymer formulation for preparing a geopolymer concrete, comprising an industrial waste comprising an activator and waste mines reject forming base material of the geopolymer concrete binder, and a group of chemical binders comprising a geo-polymerization binding material including salts of metasilicates, a superplasticiser including melamine-based admixtures and an accelerator admixture including salts of nitrate or thiocyanate or chloride.
In accordance with the above embodiment of the present invention, there is provided a powdered geopolymer formulation for preparing a geopolymer concrete, comprising an industrial waste comprising an activator and waste mines reject forming base material of the geopolymer concrete binder, and a group of chemical binders comprising a geo-polymerization binding material including salts of metasilicates, a superplasticiser including melamine-based admixtures and an accelerator admixture including salts of nitrate or thiocyanate or chloride, wherein said industrial waste contains oxides of alkali metals, alkali earth metals, metalloids, halogens and transition metals, and said activator is ground granulated blast furnace slag, and wherein said powdered composition is a readymade composition for instant making of building materials including but not limited to concrete cubes upon sufficient geo-polymerization of binding materials.
In accordance with one of the above embodiments of the present invention, wherein said powdered composition comprising 50-80% waste mines reject, 20-30% activator, 3-6% geo-polymerization binding materials, 0-2% superplasticizer and 0-2% accelerator admixture, and said accelerator admixture includes but not limited to calcium nitrate or sodium or potassium thiocyanate or calcium chloride and said superplasticiser including melamine-based admixtures are preferably melamine formaldehyde or any other polycarboxylate ether.
In accordance with one exemplary embodiment of the present invention, wherein ratio for water to chemical binders and water to slag ranges between 0.2 to 0.3 for the preparation of geopolymer concrete.
In accordance with one embodiment of the present invention, there is provided a method of preparing powdered geopolymer concrete formulation comprising pre-mixing a ground granulated blast furnace slag with a group of powdered chemical binders to form an activating mixture followed by blending the same up to a desired grade size, and blending screened industrial waste including waste mines reject with the activating mixture to form the geopolymer concrete formulation, and wherein said method comprising screening of the industrial waste prior to blending it with the activating mixture.
In accordance with just above embodiment of the present invention wherein said waste mines reject forms 50-80 wt%, ground granulated blast furnace slag forms 20-30 wt%, Geo-polymerization binding materials forms 3-6 wt%, superplasticizer forms 0-2 wt% and an accelerator admixture forms 0-2 wt% of the geopolymer concrete formulation.
In accordance with one of the above embodiments of the present invention, wherein said geo-polymerization compressive strength is more than 15 MPa but less than 21 MPa in 1 day.
In accordance with one of the above embodiments of the present invention, wherein said geo-polymerization compressive strength is more than 16 MPa but less than 25 MPa at 3 days.
In accordance with one of the above embodiments of the present invention, wherein said geo-polymerization compressive strength is more than 19 MPa but less than 27 MPa at 7 days.
In accordance with one of the above embodiments of the present invention, wherein said geo-polymerization compressive strength is more than 20 MPa but less than 31 MPa at 28 days.
In accordance with one embodiment of the present invention, there is provided a method of preparing powdered geopolymer concrete formulation comprising pre-mixing a ground granulated blast furnace slag with a group of powdered chemical binders to form an activating mixture followed by blending the same up to a desired grade size, and blending screened industrial waste including waste mines reject of Limestone and clay mines with the activating mixture to form the geopolymer concrete formulation, and wherein said method comprising screening of the industrial waste prior to blending it with the activating mixture, wherein said ground granulated blast furnace slag and waste mines reject comprise of oxides of alkali metals, alkali earth metals, metalloids, halogens and transition metals, and wherein said powdered geopolymer concrete formulation is a readymade composition for instant making of building materials including but not limited to concrete cubes upon sufficient geo-polymerization of binding materials.
In accordance with one embodiment of the present invention, there is provided a method of preparing powdered geopolymer concrete formulation comprising pre-mixing a ground granulated blast furnace slag with a group of powdered chemical binders to form an activating mixture followed by blending the same up to a desired grade size, and blending screened industrial waste including waste mines reject with the activating mixture to form the geopolymer concrete formulation, and wherein said method comprising screening of the industrial waste prior to blending it with the activating mixture, wherein said chemical binder comprising a geo-polymerization binding material including salts of metasilicates, preferably sodium silicate pentahydrate having formula as Na2SiO3·5H2O, a superplasticiser including melamine-based admixtures, preferably melamine formaldehyde or any other polycarboxylate ether; and an accelerator admixture including salts of nitrate or thiocyanate or chloride, preferably calcium nitrate or sodium or potassium or sodium thiocyanate or calcium chloride.
In accordance with one embodiment of the present invention, there is provided a method of preparing powdered geopolymer concrete formulation comprising pre-mixing a ground granulated blast furnace slag with a group of powdered chemical binders to form an activating mixture followed by blending the same up to a desired grade size, and blending screened industrial waste including waste mines reject with the activating mixture to form the geopolymer concrete formulation, and wherein said method comprising screening of the industrial waste prior to blending it with the activating mixture, wherein said geopolymer concrete formulation is moulded at an ambient temperature followed by de-moulding the same after 8-10 hrs and curing for obtaining a desired strengthened geopolymer building materials including but not limited to concrete cubes.
Detailed description of the Invention
The following clearly describes the solutions in the embodiments of the present invention with reference to the accompanying tables and graphical representations in the embodiments of the present invention. Apparently, the described embodiments are merely a part rather than all of the embodiments of the present invention. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.
A detailed description of one or more embodiments of the invention is provided below along with accompanying tables and graphical representations that illustrate the principles of the invention. The invention is described in connection with such embodiments, but the invention is not limited to any embodiment. The invention encompasses numerous alternatives, modifications, and equivalents. Numerous specific details are set forth in the following description in order to provide a thorough understanding of the invention. These details are provided for the purpose of example and the invention may be practiced according to the claims with some or all of these specific details. For the purpose of clarity, technical material that is known in the technical fields related to the invention has not been described in detail so that the invention is not unnecessarily obscured.
The constituents used in the geopolymer composition according to the embodiments are exemplary and can be varied with respect to any addition, deletion and the ratio thereof and the same can vary within the scope of the invention.
The above and other features of the invention will become more apparent in the following analysis and the results indicated in the following examples and associated tables and the graphical representation showing the various characteristics strength of the produced additive, hence the description when read in conjunction with the accompanying tables and graphical representations will be understood in a clear manner. However, the same is not restricted to the associated tables and experimental results and may be further worked upon within the scope.
Example 1 - Chemical analysis of Waste Mines Reject and Slag
Raw Materials Na2O MgO Al2O3 SiO2 SO3 Cl K2O CaO Fe2O3 TiO2
Slag 0.48 7.42 16.57 34.69 1.65 0.038 0.39 37.06 1.54 0.49
Waste Mines reject 0.19 2.29 7.84 20.14 0.41 0.008 0.95 34.22 3.4 0.38

Example 2 - Chemical analysis & Physical Properties of Sodium Meta Silicate
Test Na2O SiO2 Water In soluble Fe (ppm) Whit-eness
% Bulk
Density
g/cc pH Melting
Point PS
(16- 30 Mesh)
Test
Standard 28-30 27-29 <0.2 < 200
ppm > 80 0.80-
0.97 12-13 72.2 C > 90
Test
Result 29.02 28.99 0.06 37 90 0.95 12.65 72.2 C 98 %

Example 3 - Chemical analysis & Physical Properties of Melamine Formaldehyde
Test Physical
Shape Appearance Drying Loss (%) Bulk Density (kg/m3) pH -Value
20% Solution
Test
Standard Powder White
Slightly colored Max.4.0 500 to 800 9.0-11.4

Example 4 - Chemical analysis & Physical Properties of Calcium Nitrate)
Test Molar Mass Melting Point Density Soluble in Formula
Test
Standard 164.088g/mol 561oC 2.5g/cm3 Water/Acetone Ca (NO3)2
Example 5 - Chemical analysis & Physical Properties of Sodium thiocyanate)
Test Molar Mass Melting Point Density Soluble in Formula
Test
Standard 81.072 g/mol 287 degree Celsius 1.735 /cm3 Water/Acetone/alcohol NaSCN
Example 6 - Chemical analysis & Physical Properties of Sodium chloride
Test Molar Mass Melting Point Density Soluble in Formula
Test
Standard 58.443 g/mol 800 degree Celsius 2.17 /cm3 Water NaCl
Example 7 - Designing of Geopolymer Mix
The Mineralogical evaluation of Waste mines reject, and slag indicates it compatibility with the Geopolymer Mortar and Concrete. All raw materials include Geopolymer binder were used for designing of Geopolymer Mixes.
Example 8 - Proportions of raw materials in the designing of Geopolymer Mortar & Concrete
Mix
Design Waste Mines Slag Sodium Metasilicate Sodium Thiocyanate Melamine Formaldehyde Sodium Chloride Calcium Nitrate
1st Mix 66.49% 30% 3.5% 0 1% 0.8 % 0
2nd Mix 75.99% 20% 3.5% 0 1% 0.8% 0
3rd Mix 63.50% 30% 3.5% 1% 1% 0% 1%
4th Mix 65.89 20% 3.5% 0.8% 1% 0% 0
5th Mix 64.50% 30% 3.5% 0 % 0% 0.8% 1%
6th Mix 74.50% 20% 3.5% 0% 1% 0 % 0.8%
7th Mix 73.00% 20% 5.0% 0% 0% 0.8% 0%
Example 9 - Determination of Normal Water Consistency
The Normal water consistencies and Setting Time are determined with the help of Vicat apparatus as follows:
Mix Normal water consistency
(ml)
1st Mix 110ml
2nd Mix 90ml
3rd Mix 125ml
4th Mix 115 ml
5th Mix 90ml
6th Mix 87ml
7th Mix 110ml
Example 10 - Determination of Geo-polymerization Compressive strength
Mortar cubes are prepared in 7.5x7.5x7.5 cubic centimeters mould at ambient temp. The demolded cubes were cured for 1,3,7 and 28 days in water at ambient temp. Three cubes of each specimen are cured, and the geo-polymerization compressive strength has been taken to be an average of three values for each specimen.
Mix
Design 1 day
Mpa 3 days
Mpa 7 days
Mpa 28 days
Mpa
1st Mix 18.8 22.5 24.4 28.5
2nd Mix 20.5 24.8 26.3 30.2
3rd Mix 15.8 16.9 19.3 21.2
4th Mix 16.2 18.5 20.9 22.5
5th Mix 17.4 19.1 20.5 21.0
6th Mix 18.1 19.6 21.1 22.9
7th Mix 19.8 21.8 25.2 26.5
According to the present invention, various mix design has been casted for geopolymer concrete with different ratio of activators, accelerators and retarders, where Mix – 2, 4 and 6 are Comparable better than Mix-1,3,5 and 7. Further, studies were carried out for Mix - 2,4 and 6 further.
Example 11 - Determination of Expansion in corrosive atmosphere
Cylindrical molds of Geopolymer mixer (diameter 3.0 cm and length 3.0 cm) were prepared at a w/c ratio of 0.3. After 24 h the geopolymer cylinders were removed from the molds and kept under water for 28 days for curing. These molds were then kept in N/60 H2SO4 and expansions were measured as a function of time with the help of Le Chatelier's apparatus.
Mix
Design Expansion in mm
2nd Mix 0.5MM
4th Mix 0.85MM
6th Mix 0.68MM
Example 12 - Determination of Water percolation by permeability apparatus
Geopolymer mixes were mixed separately with 42 mL water to form mortars having water/solid (w/s) ratio of 0.3 followed by thoroughly mixing the mortars were in Hobart mixer. Each mortar was placed in a mold. After 24 hrs, the mortars were demolded and immersed in water tanks separately for 20 days. The molds were then fixed in a permeability apparatus where a pressure of 2.0 kg/cm2 was applied (the pressure was slowly increased from 0.5 kg/cm2 to 2.0 kg/cm2). Water percolation was measured at every 1 h in terms of weight of percolated water for 8 h.
Mix
Design Water percolation (%)
2nd Mix 6
4th Mix 11
6th Mix 8.8
Example 13. Determination of Rapid ion Penetration test
According to ASTM C 1202, a rapid chloride ion penetration test was done on concrete at 28 days . The test measures the amount of electrical current carried through 50mm thick slices of 100mm nominal diameter cores over a 6-hour period. A 60-volt direct current potential difference is maintained across the specimen's ends, one of which is immersed in sodium chloride solution and the other in sodium hydroxide solution. The total charge passed, measured in coulombs, was shown to be related to the concrete specimen's resistance to chloride ion penetration. To address the issue of corrosion in reinforced concrete structures, durability tests on concrete were carried out in acidic and basic media, and the results were compared to neutral environment specimens. Concrete's durability refers to its capacity to withstand weathering, chemical, physical, and biological attack while retaining its ideal qualities. The durability of Mix design 2,4 & 6 was tested for 28 days in a hostile acid and alkaline environment. To analyse and conclude concrete qualities, cubes were cured in normal water, NaCl solution, and 1:2 H2SO4 acid solution.
Chloride ion penetrability ASTM C 1202 standards
Charge Passed (Coulombs) Chloride Ion Penetrability
>4000 High (H)
2000-4000 Moderate (M)
1000-2000 Low (L)
100-1000 Very Low (VL)
<100 Negligible (N)
Mix
Design Charge Passed in Coulombs)
2nd Mix 867
4th Mix 984
6th Mix 996

While the invention is amenable to various modifications and alternative forms, some embodiments have been illustrated by way of example in the drawings and are described in detail above. The intention, however, is not to limit the invention by those examples and the invention is intended to cover all modifications, equivalents, and alternatives to the embodiments described in this specification.

The embodiments in the specification are described in a progressive manner and focus of description in each embodiment is the difference from other embodiments. For same or similar parts of each embodiment, reference may be made to each other.

It will be appreciated by those skilled in the art that the foregoing description was in respect of preferred embodiments and that various alterations and modifications are possible within the broad scope of the appended claims without departing from the spirit of the invention with the necessary modifications.

Based on the description of disclosed embodiments, persons skilled in the art can implement or apply the present disclosure. Various modifications of the embodiments are apparent to persons skilled in the art, and general principles defined in the specification can be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure is not limited to the embodiments in the specification but intends to cover the most extensive scope consistent with the principle and the novel features disclosed in the specification.

We claim:

1. A powdered geopolymer formulation for preparing a geopolymer concrete comprising:
an industrial waste comprising an activator and waste mines reject forming base material of the geopolymer concrete binder; and
a group of chemical binders comprising:
a geo-polymerization binding material including salts of metasilicates;
a superplasticiser including melamine-based admixtures; and
an accelerator admixture including salts of nitrate or thiocyanate or chloride.
2. The powdered composition as claimed in claim 1, wherein said industrial waste contains oxides of alkali metals, alkali earth metals, metalloids, halogens and transition metals.
3. The powdered composition as claimed in claim 1, wherein said activator is ground granulated blast furnace slag.
4. The powdered composition as claimed in claim 1, wherein said powdered composition is a readymade composition for instant making of building materials including but not limited to concrete cubes upon sufficient geo-polymerization of binding materials.
5. The powdered composition as claimed in claim 1, wherein said powdered composition comprising 50-80% waste mines reject, 20-30% activator, 3-6% geo-polymerization binding materials, 0-2% superplasticizer and 0-2% accelerator admixture.
6. The powdered composition as claimed in claim 1, wherein said accelerator admixture includes but not limited to calcium nitrate or sodium or potassium thiocyanate or calcium chloride.
7. The powdered composition as claimed in claim 1, wherein said superplasticiser including melamine-based admixtures are preferably melamine formaldehyde or any other polycarboxylate ether.
8. The powdered composition as claimed in claim 1, wherein ratio for water to chemical binders ranges between 0.2 to 0.3 for the preparation of geopolymer concrete.
9. The powdered composition as claimed in claim 1, wherein ratio for water to slag ranges between 0.2 to 0.3 for the preparation of geopolymer concrete.
10. The geopolymer composition as claimed in claim 1, having a geo-polymerization compressive strength more than 15 MPa but less than 21 MPa in 1 day.
11. The geopolymer composition as claimed in claim 1, having a geo-polymerization compressive strength more than 16 MPa but less than 25 MPa at 3 days.
12. The geopolymer composition as claimed in claim 1, having a geo-polymerization compressive strength more than 19 MPa but less than 27 MPa at 7 days.
13. The geopolymer composition as claimed in claim 1, having a geo-polymerization compressive strength more than 20 MPa but less than 31 MPa at 28 days.
14. A method of preparing powdered geopolymer concrete formulation comprising:
pre-mixing a ground granulated blast furnace slag with a group of powdered chemical binders to form an activating mixture followed by blending the same up to a desired grade size; and
blending screened industrial waste including waste mines reject with the activating mixture to form the geopolymer concrete formulation.
wherein said method comprising screening of the industrial waste prior to blending it with the activating mixture.
15. The method as claimed in claim 14, wherein said ground granulated blast furnace slag and waste mines reject comprise of oxides of alkali metals, alkali earth metals, metalloids, halogens and transition metals.
16. The method as claimed in claim 14, wherein said powdered geopolymer concrete formulation is a readymade composition for instant making of building materials including but not limited to concrete cubes upon sufficient geo-polymerization of binding materials.
17. The method as claimed in claim 14, wherein said chemical binder comprising:
a geo-polymerization binding material including salts of metasilicates, preferably sodium silicate pentahydrate having formula as Na2SiO3·5H2O.
a superplasticiser including melamine-based admixtures, preferably melamine formaldehyde or any other polycarboxylate ether; and
an accelerator admixture including salts of nitrate or thiocyanate or chloride, preferably calcium nitrate or sodium or potassium or sodium thiocyanate or calcium chloride.
18. The method as claimed in claim 14, wherein said waste mines reject forms 50-80 wt%, ground granulated blast furnace slag forms 20-30 wt%, Geo-polymerization (binding materials) forms 3-6 wt%, superplasticizer forms 0-2 wt% and an accelerator admixture forms 0-2 wt% of the geopolymer concrete formulation.
19. The method as claimed in claim 14, wherein geo-polymerization compressive strength more than 15 MPa but less than 21 MPa in 1 day.
20. The method as claimed in claim 14, wherein geo-polymerization compressive strength more than 16 MPa but less than 25 MPa at 3 days.
21. The method as claimed in claim 14, wherein geo-polymerization compressive strength more than 19 MPa but less than 27 MPa in at 7 days.
22. The method as claimed in claim 14, wherein geo-polymerization compressive strength more than 20 MPa but less than 31 MPa at 28 days.
23. The method as claimed in claim 14, wherein ratio for water to chemical binders ranges between 0.2 to 0.3 for the preparation of geopolymer concrete.
24. The method as claimed in claim 14, wherein ratio for water to slag ranges between 0.2 to 0.3 for the preparation of geopolymer concrete.
25. The method as claimed in claim 14, wherein said geopolymer concrete formulation is moulded at an ambient temperature followed by de-moulding the same after 8-10 hrs and curing for obtaining a desired strengthened geopolymer building materials including but not limited to concrete cubes.