Description:FORM 2
THE PATENT ACT 1970
(39 OF 1970)
&
The Patent Rules, 2003
COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

1 TITLE OF THE INVENTION :
A PROCESS TO PRODUCE CLINKER FREE GEOPOLYMER CEMENT/BINDER(GPC) FORMULATION IN SINGLE COMPONENT SOLID POWDER FORM USING MODIFIED AND ACTIVATED GROUND GRANULATED BLAST FURNACE SLAG.


2 APPLICANT (S)

Name : JSW CEMENT LIMITED.

Nationality : An Indian Company incorporated under the Companies Act, 1956.

Address : JSW CENTRE,
BANDRA KURLA COMPLEX,
BANDRA(EAST),
MUMBAI-400051,
MAHARASHTRA,INDIA.



3 PREAMBLE TO THE DESCRIPTION

COMPLETE

The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF THE INVENTION
The present invention relates to a process to produce clinker free Geopolymer Cement or Binder(GPC) formulation using modified and activated ground granulated blast furnace slag. More particularly, the present invention is directed to providecompletely clinker free, chemically activated ground granulated blast furnace slag (GGBS) based geopolymer cement or binder (GPC), in single component solid powder form.
The most common and essential component of all conventional cements is clinker. As the clinkerization process includes calcination of limestone, it causes enormous emission of CO2. Hence only cement industry contributes ~8 % of global CO2 emission, causes by human.1, 2
The GPC produced by present process being clinker free thus ensure minimum CO2 emission and hence eco-friendly.
BACKGROUND OF THE INVENTION
Cement is the principal binder material for the building construction. As building, being one of the basic requirement of our civilized society, the continuous growing population speeds up the construction world. India is the second largest cement producer across the globe.3 The total cement production capacity of India in financial year 2022 (FY2022) is 545 million tons per annum.2 The total production of cement of India in FY2021 was 294.4 MTPA. It is expected to increase the cement production in India up to 419.92 MTPA in FY2027.3
Cement is the hydraulic binder with basic raw material limestone. Calcium carbonate is the principal component of limestone, which get calcined to form calcium oxide and allowed to react with silica, alumina, hematite at high temperature (>1400 °C) to produce clinker. The conventional ordinary portland cement (OPC) usually produced by grinding the clinker with certain amount of mineral gypsum (3-5 %). One mole of calcium carbonate produces one mole CO2 during calcination. Moreover the high temperature clinkerization takes place in a rotary kiln. Fossil fuels (mainly coal) is the source of energy for this elevated temperature of a rotary kiln. The combustion of fossil fuel also generates a huge amount CO2. Hence ~827 tons of CO2 is released per ton of clinker production (Scope 1 emission).1 Only cement sector contributes at least 8 % of global CO2 emission causing by human.1, 2
Rapid civilization and industrialization cause huge threats (like environment pollution, global warming climate chance and so on) on the mother nature as well as on all the living beings. Hence the cement sector, being one of the principal CO2 emitter, should establish or invent alternate way to produce cement or cement like binder material to reduce the CO2 emission. Research intended to reduce the clinker consumption to produce cement may directly reduce the CO2 emission.
In this concern blended cements has been introduced to the construction world. Blended cement are usually produced by blending some supplementary cementious materials (SCM) with OPC. Although the SCMs are not having any significant binding property by itself, but reacts with OPC through pozzolanic activity or hydraulic bonding during hydration. Hence the SCMs are capable of increase the strength of concrete and reduce the clinker consumption for the cement production. The most common SCMs used in India for blended cement making are fly ash, GGBS, calcined clay etc. Some examples of well-known blended cements are Portland slag cement (PSC), Portland pozzolana cement (PPC), Composite cement, Limestone calcined clay cement (LC3) etc. Blended cements have already reduced the clinker consumption. For example, PSC can be produced with 25-70% replacement of OPC by GGBS (as per BIS standard IS:455 - 2015); PPC can be produced with 15-35% replacement of OPC by fly ash (as per BIS standard IS:1489, Part I-2015); composite cement can be produced by blending 15-35% fly ash and 20-50% GGBS with OPC (as per BIS standard IS-16415-2015). But still all those blended cements has significant usage of OPC as well as clinker.
Granulated blast furnace slag is the by-product of metallic iron extraction process from iron ore. In the blast furnace the impurities (silica, alumina) present in the molten metal react with limestone to form light weight slag. This molten slag floats on the top surface of molten metal and separates physically. This slag is basically composed of calcium silicate, calcium aluminate, alumino silicates etc. After separation from the molten metal, the slags are subjected to rapid quenching (cooling) with high pressure water jet. This rapid quenching is known as granulation, which does not allow the molten slag for crystal growth of different silicates and aluminates present in it. Hence the granulated slag is a highly amorphous glassy material. As per IS 12089, the glass content of granulated blast furnace slag should be more than 85%.GGBS is finely ground glanulated blast furnace slag.
Recent times geopolymer concrete is drawing noteworthy attention as an environment friendly, lower carbon foot print binder material for building construction. The term “Geopolymer” was introduced by Joseph Davidovits.4-5 Geopolymers basically deal with silico-aluminates and poly(sialate). Poly(sialate) is the abbreviated form of silicon-oxo-aluminate. Poly(sialate) is composed of oxo-linked SiO4 and AlO4tetrahedra by sharing the oxygen terminals.4-5 Alkali metal cations are present in the network for as counter charge ions. The network formation, setting and strength gaining mechanism of geopolymer concrete is completely different from the crystal hydration method of conventional clinker based portland cements. In presence of alkali metal hydroxide solution precursors (Al, Si complexes like aluminosilicate oxides, silicates, aluminates) dissolves and reacts together to form three dimensional network with Si-O-Al bonds. In this process Al and Si complexes connect together with oxo linkages (O2-) to form highly networked macro structure and get harden.4-5 Hence this process has been considered as polymerization. Most common precursors for the development for the geopolymers are calcined clay, fly ash, GGBS, etc. Alkali activators, which are mostly in practice are alkali metal hydroxide (NaOH, KOH, Ca(OH)2 etc.), water soluble silicates (sodium silicates), soda ash, alkali metal sulphates, alkali metal phosphates etc.
Geopolymer binders or geopolymer concrete does not necessarily requires lime stones or it’s calcination. So the production of these binder materials for building construction contributes zero CO2 emission to the environment. Again two mostly used precursors (fly ash and GGBS) are industrial by-product. Hence, utilization of these material for infrastructure building for rapid civilization is the great approach for waste utilization.
Cement hydration is an exothermic reaction. Most of the heat liberated during the hydration of conventional Portland cement is caused by the clinker. Excess liberation of heat during hydration of cement causes crack generation in concrete and other cement based structure. Hence higher heat of hydration has adverse effect on durability of concrete. So the cement with lower heat of hydration shows better performance from the durability aspect. Geopolymer binders, being a clinker free material, shows significantly low heat of hydration compared to conventional clinker based Portland cements (i.e OPC, PSC etc).
Although geopolymer binder is an eco-friendly binding material for building construction, there are some shortcomings of existing geopolymers. The main shortcoming of the conventional geopolymer is being a multicomponent system. Most of the reported geopolymer are usually made by mixing precursor (GGBS, fly ash, clay, calcined clay etc), aqueous solution of alkali activator, water and aggregates to make concrete. As the proportion of alkali activator directly regulates the compressivestrength of concrete, it is too much important to optimize and maintain the concrete recipe. This makes the concrete preparation much difficult compared to a conventional one component cement (like OPC, PSC, PPC etc). Another shortcoming of the geopolymer binder is the curing method. Some of the reported geopolymer binders require curing at elevated temperature. This curing process restricts the usage of geopolymer binder for mass building construction.

STATE OF PRIOR ARTS:
Geopolymer has a tremendous potential to be a zero carbon foot print alternate of conventional clinker based cements. Hence from last few decades several geopolymer materials has been disclosed in the form of peer reviewed research articles and in the form of patents. Herein few relevant existing literatures has been discussed briefly as following.
Chinese patent CN110759655B discloses development of a geopolymer from industrial wastes. This invented geopolymer is composed of aluminium ash, blast furnace slag, steel making slags and alkali activators (NaOH, sodium silicate). The geopolymer is required curing at elevated temperature (60 °C) after uniform mixing of all components in aqueous slurry followed by moulding.
South Korean patent KR102140827B1 discloses the development of cementless alkali activated slag based binder, that gains strength on high temperature curing.
Korean patent KR101602620B1 discloses the development of geopolymer from coal gasification slag. This geopolymer has been prepared by mixing coal gasification slag and liquid alkali activator. This geopolymer gains strength bay age curing.
Indian patent INDE007282006 discloses the development of geopolymer cement based of fly ash, ground granulated blast furnace slag (GGBS) and alkali activator. The developed material requires to mix GGBS and fly ash with alkali activators to make the cement. The listed alkali activators in this patent are sodium oxide, sodium hydroxide, sodium silicate, sodium nitrate, potassium oxide, potassium hydroxide, potassium silicate, potassium nitrate. Elevated temperature curing is required for the setting cement paste.
Korean patent KR101388002B1 disclosed the preparation of dry mortar mixture by using GGBD, fly ash, and alkali activator. The alkali activator is composed of anhydrous gypsum from different sources and calcined lime as well as hydrated lime.
Chinese patent CN105541140B discloses the development of geopolymer injection paste. This geopolymer paste is composed of flyash, zeolite powder, clay, and alkali-activator and accelerator (water glass, sodium hydroxide, Calcium hydroxide).
Chinese patent CN108640547B discloses the development geopolymer based on iron tailing and metakaolin. To make the geopolymer iron tailing, metakaolin, caustic sludge has been mixed with alkali activator solution. The alkali activator is the aqueous solution of sodium hydroxide and sodium silicate. The casted geopolymer has been cured at 80 °C.
Czech Republic patent CZ2007115A3 has disclosed the development of a two component geopolymer binding agent. The solid component is composed of metakaolin and ground blast furnace slag. Whereas the liquid component is composed of sodium water glass liquid.
Chinese patent CN108203251A discloses development of alkali activated blast furnace slag gel. The gel is comprising of blast furnace slag powder, cement clinker, gypsum powder, an alkali activator glass fiber and water. Alkali activator is composed of NaOH particles, CaO particles or Na2SiO3.
Hence as a summery,all the above mentioned reports have represented geopolymer in the form of concrete or more than one component system. The chemical activators have been mixed with the precursor materials in aqueous solution form with maintaining certain stoichiometry. Some of those has mentioned the heat treatment is required for curing.
But all these methods make the development as well as the application of geopolymer binder more difficult. As a consequence, the acceptance of geopolymeric binder for mass construction reduces significantly.
Hence a geopolymer binder with one component, solid powder form that is ready to mix with water and aggregate to make mortar or concrete (like conventional cements) followed by ambient temperature water curing can spread the usage of geopolymer widely. Also development of geopolymer in the form of normal cement will definitely increase the acceptability of geopolymer in construction world. This will also definitely offer a huge positive impact to conserve the environment being a minimum carbon foot print material.

OBJECTIVES OF INVENTION
The objectives of the present invention are as followings:-
• Development of eco-friendly, geopolymer cement/binder (GPC) based on chemically activated ground granulated blast furnace slag, in single component solid powder form.
• Development of a conventional cement like binding material without using clinker. Hence the production will leave minor carbon footprint.
• Development of a geopolymer cement/binder, that possess significantly lower heat of hydration compared to conventional Portland clinker based cements like OPC and PSC.
• Development of a process to produce GPCthat can combine all the components of geopolymers (precursor and alkali activator) together in a single component solid powder form, like other conventional cements.
• Like other conventional cements, GPC should be ready to mix with water and aggregate for mortar and concrete application.
• Development of GPC, that exhibits ambient temperature and water curing, like conventional cements.
• The compressive strength, and other performance based parameters (normal consistency, setting times, autoclave expansion, Le-Chatelier expansion) should be in comparable to a conventional cement.
• Beside development of a complete GPC, the other objective of this invention is development of a stable, solid, powdered, chemical activator, which is ready to blend with the conventional geopolymer precursors (fly ash, different metallurgical slag, clay, calcined clay etc.) to make geopolymer.
• Development of a composition as well as a preparation method, that can stabilize highly hygroscopic alkali activators in solid powder form.

SUMMARY OF THE INVENTION
The basic aspect of the present invention is directed to provide clinker free geopolymer cement (GPC) formulation comprising solid powder formulation of (a) alkali chemical activator composition in amounts of 10-20 % by wt comprising of co-ground combination of GGBS (62-67 %), sodium sulphate (20-22 %), solid sodium silicate (0-1 %) andsodium hydroxide (12-17 %) and (b) precursor composition in amounts of 80 to 90 % by wt comprising a blend of GGBS (90-100%), fly ash (0-10%) and kaolin (0-10%) .
A further aspect of the present invention is directed to said clinker free geopolymer cement (GPC) formulation suitable for ambient temperature water curing having selectively (i) 29.00-48.20 MPa compressive strength after 28 days water curing and (ii) concrete trial (M30 grade). 36.50 MPa compressive strength was appeared for concrete cube after 28 days water curing at ambient temperature.
A still further aspect of the present invention is directed to saidclinker free geopolymer cement (GPC) formulation which provides for specific surface area of developed GPC in 340-360 m2/Kg (according to Blaine Air Permeability Apparatus).

A still further aspect of the present invention is directed to said clinker free geopolymer cement (GPC) formulation having Initial setting time and final setting time in the range of 40-90 min and 100-150 min respectively and having autoclave expansion and Le-Chatelier expansion in the range of 0.042-0.087 % and 0-1% respectively.

A still further aspect of the present invention is directed to saidprocess for manufacture of the clinker free geopolymer cement (GPC) formulation as described above comprising:
I) providing said alkali chemical activator comprising the steps of :
a) providing the select composition components comprising of co-ground combination of GGBS (62-67 %), sodium sulphate (20-22 %), solid sodium silicate (0-1 %) andsodium hydroxide (12-17 %);
b) grinding the components in a grinder; and
c) storing the thus ground components comprising said alkali chemical activator ;
II) providing the precursor composition comprising the steps of :
a) providing said select composition of precursor composition in amounts of 80 to 90 % by wt comprising a blend of GGBS (90-100%), fly ash (0-10%) and kaolin (0-10%); and
b) finely grinding and blending the components;
III) finally blending together said alkali chemical activator composition in amounts of 10-20 % by wt with said precursor composition in amounts of 80 to 90 % by wt.

Another aspect of the present invention is directed to said process for manufacture of the clinker free geopolymer cement (GPC) formulation based on chemically activated ground granulated blast furnace slag, in single component solid powder form comprising;
the steps of preparation of GPC precursor and powdered chemical activator; co-grinding of components of chemical activators components followed by storing in a moisture free bag/container; blending of components of precursor components in powder form; both said components are subjected to blend together to make the final GPC in a form ready to mix with water and aggregate for mortar and concrete application.

Yet another aspect of the present invention is directed to said process wherein said precursor of GPC has been developed by mixing GGBS (75-85%), fly ash (0-10%) and kaolin (0-10%).

A further aspect of the present invention is directed to saidprocess as claimed in any one of claims 5 to 7, wherein said chemical activator has been prepared by co-grinding of GGBS (62-67 %), sodium sulphate (20-22 %), solid sodium silicate (0-1 %) and sodium hydroxide (12-17 %) in a high speed blade grinder.

A still further aspect of the present invention is directed to said process that stabilizes highly hygroscopic alkali material (sodium hydroxide and sodium silicate) in solid powder form.

A still further aspect of the present invention is directed to said process wherein said GPC has been prepared by blending precursor (80-90%) and chemcial activator (10-20%).

A still further aspect of the present invention is directed to said process wherein developed GPC offers ambient temperature water curing like other conventional cements.

A still further aspect of the present invention is directed to said process providing said GPC leading to compressive strength of mortar cube after 1, 3, 7 and 28 days water curing at ambient temperature as 7.79-16.45, 15.90-29.40, 21.00-38.1, 29.00-48.20 MPa respectivelyand compressive strength of M30 grade concrete cube after 28 days water curing at ambient temperature is 36.50 MPa.

A still further aspect of the present invention is directed to said process, not requiring any pyro process and free of usage of clinker as well as lime stone, favouring minor amount CO2 emision.

A still further aspect of the present invention is directed to said process wherein the developed GPC has lower heat of hydration compared to conventional Portland clinker based cements like OPC and PSC.

The prime focus of the current invention is thus directed to development of an eco-friendly, geopolymer cement/binder (GPC) based on chemically activated blast furnace slag. This cement/binder is completely free from clinker as well as lime stone. Moreover, the preparation procedure is completely free from any pyro-process. Hence this manufacture possesses causes significantly low CO2 emission. Although most of the conventional geopolymers are composed of multiple components (solid precursor and liquid alkali activator), the developed GPC is a single component and solid powder in form. Hence like other conventional cements, this GPC is ready to mix with water and aggregates for mortar and concrete application. The GPC also offers ambient temperature water curing.
GPC has been developed in solid powder components (precursor and alkali activator), which are subjected to blend together to make the final cement. Precursor is made by blending GGBS (90-100%), fly ash (0-10%) and kaolin (0-10%). Where the chemical activator is made by co-grinding of GGBS (62-67 %), sodium sulphate (20-22 %), solid sodium silicate (0-1 %) and sodium hydroxide (12-17 %) in a high-speed blade grinder. The powdered chemical activator has been stored in a moisture free bag/container. On the final step GPC has been produced by blending powdered precursor (80-90 %) and chemical activator (10-20%).
Different physical parameters (normal consistency, setting times, autoclave expansion and Le-Chatelier expansion) has been tested with the developed GPC. Then the GPC was used for mortar cast and the compressive strength of mortar cubes have been tested after 1, 3, 7 and 28 days curing. Developed GPC shows 29.00-48.20 MPa compressive strength after 28 days water curing.
Developed GPC has been further used for concrete trial (M30 grade). 36.50 MPa compressive strength was appeared for concrete cube after 28 days water curing at ambient temperature.
Hence the current invention represents geopolymer in the form of solid powder, single component cement. Although GPC is completely different form the conventional clinker based cement from the aspect of manufacture process, hydration chemistry, strength gaining and setting mechanism, this invention has kept all the application process, curing process as similar as any conventional clinker based cement.
The above and other aspects and advantages of the present invention are described hereunder in greater details with reference to following accompanying non limiting illustrative drawings and examples.

BRIEF DESCRIPTION OF ACCOMPANIED DRAWINGS
Fig. 1: demonstrates the flowchart of GPC preparation process.
Fig. 2: demonstrates digital images of (a) GPC, (b) Mortar cube made of GPC, and (c) concrete cube made of GPC.
Fig. 3.: demonstrates (a) heat flow curve of OPC, PSC, GPC, and (b) cumulative heat liberation curve of OPC, PSC, GPC.

DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO ACCOMPANYING DRAWINGS AND EXAMPLES
The present invention discloses a chemically activated GGBS based geopolymer cement/binder (GPC) and a process to produce the same. Unlike other conventional clinker based cements, this cement/binder is completely clinker free. Moreover, unlike other existing multicomponent geopolymeric binder, the GPC has been developed in single component solid powder form. This cement offers ambient temperature water curing. Like other conventional cements, developed GPC is ready to mix with water and aggregates to make mortar and concrete. Stepwise, detail description of GPC development is as following.
The flowchart of GPC development has been demonstrated in Figure 1. This preparation procedure of GPC follows two parallel path. A solid powdered chemical activator has been developed through Path 1. Whereas the precursor for GPC has been prepared in Path 2. Finally, these two components (chemical activator and precursor) are subjected to blend together with maintaining together to make GPC.
On Path 1, at first (Step 1.1) GGBS (62-67 %), sodium sulphate (20-22%), solid sodium silicate (0-1%) and sodium hydroxide (12-17 %) was weighed together. In Step 1.2, mixture from previous step(Step 1.1) has been ground finely in a high-speed blade grinder. Utilization of other widely used grinders (ball mill, roller press, vertical roller mill etc.) or pulveriser are not recommended as the highly hygroscopic and soft solid sodium hydroxide pellets or flakes make a sticky coating on the grinder. After grinding the obtained powdered material is the desired chemical activator and to be stored in a moisture resistant bag/container (Step 1.3).
On the parallel path (Path 2) the precursor has been prepared by blending GGBS (90-100%), fly ash (0-10 %), kaolin (0-10 %).
Finally, chemical activator from Path 1 (10-20 %) is blended with the precursor from Path 2 (80-90%) to make GPC. The specific surface area of developed GPC has been maintained in 340-360 m2/Kg (according to Blaine Air Permeability Apparatus). The developed GPC has been stored in a laminated polypropylene bag under closed condition.
The prepared GPC has been used for mortar cast (as per Indian standard IS: 4031) followed by water curing and compressive strength determination. Developed GPC has demonstrated compressive strength in the range of 29.00-48.20 MPa (after 28 days water curing).Fig. 2demonstrates digital images of (a) GPC, (b) Mortar cube made of GPC, and (c) concrete cube made of GPC.

Other physical parameters (initial setting time, final setting time, autoclave expansion Le-Chatelier expansion) has been tested as per Indian standard IS: 4031. Initial setting time and final setting time of GPC have appeared in the range of 40-90 min and 100-150 min respectively. Autoclave expansion and Le-Chatelier expansion have appeared in the range of 0.042-0.087 % and 0-1%.

EXAMPLES:
Several experiments have been carried out with different material compositions to develop different GPC samples. These experiments have demonstrated the effect of all the components of GPC in it’s performance from the aspect of compressive strength gaining as well as other physical parameters.
Examples 1: Preparation chemical activator with variable stoichiometry of the components.
The chemical activator of the GPC is basically composed of GGBS, sodium sulphate, sodium silicate and sodium hydroxide. Sodium hydroxide and sodium silicate are the primary source of alkali in the activator. During hydration alkaline medium helps to make a homogeneous mixture of all silicates, aluminates, aluminosilicates, pozzolanic materials present in the precursor by making a gel. Then silicates, aluminates, aluminosilicates reacts together to make the macromolecular geopolymer network. The role of sodium sulphate in the chemical activator is a geopolymerization accelerator. This salt ensures the prolonged polymerization reaction, that provides the strength gaining process still 28 days. Whereas GGBS in chemical activator (62-67%) acts as a matrix that stabilizes the highly hygroscopic powder alkali materials. Here all the components of the chemical activator have been varied to make different samples of GPC. The prepared GPC samples has been used for mortar cast for the compressive strength check after 1, 3, 7 and 28 days water curing at ambient temperature. The other physical parameters (setting times, autoclave expansion, Le-Chatelier expansion) have also been tested with the developed samples. The compressive strength of the developed GPC samples appears in the range of 41.90-48.20 MPa after 28 days water curing at ambient temperature. All experimental parameters and results are demonstrated in Table 1.

Table 1. Different composition of chemical activator to produce GPC and corresponding physical parameters as well as compressive strength of mortar cube.
GPC Components Example 1.1 Example 1.2 Example 1.3 Example 1.4
Chemical Activator
Composition GGBS 62% 67% 62% 63%
Sodium Sulphate 20% 20% 22% 20%
Sodium Silicate 1% 1% 1% 0%
Sodium Hydroxide 17% 12% 15% 17%
Precursor GGBS 100%
GPC Composition: 15% Chemical Activator + 85% Precursor
Physical Parameters
Normal Consistency 29.25 27.50 27.25 30.75
Initial setting Time (Min) 75 80 75 90
Final Setting time (Min) 120 125 120 130
Autoclave expansion (%) 0.073 0.082 0.046 0.074
Le-Chateliar Expansion (mm) 1.0 1.0 1.0 1.0
Compressive Strength (MPa)
1 Day 16.10 11.00 14.60 14.90
3 Days 29.40 25.05 28.30 27.10
7 Days 38.10 34.20 35.05 35.95
28 Days 48.20 41.90 44.20 42.50

Example 2: Variation of components in precursor
Precursor is the source of basic structural units of a geopolymers (silicates, aluminates, aluminosilicates). In this present invention, GGBS, fly ash and kaolin have been used as precursor. GGBS is the ground granulated blast furnace slag. Basically GGBS is composed of calcium silicate and calcium aluminate in highly amorphous glassy phase. Fly ash possess reactive silica particles that shows pozzolanic reactivity. Kaolin is the naturally occurring clay material and composed of alumino-silicate. In presence of alkali activators these materials react together to form highly networked geopolymer macrostructure and get set.
The following examples demonstrates variation of precursor composition to make different sample of GPC (Table 2). The composition of chemical activator and it’s proportion were kept same (Table 2). The prepared GPC samples has been used for mortar cast for the compressive strength check after 1, 3, 7 and 28 days water curing at ambient temperature. The other physical parameters (setting times, autoclave expansion, Le-Chatelier expansion) have also been tested with the developed samples. The compressive strength of the developed GPC samples appears in the range of 40.35-48.20 MPa after 28 days water curing at ambient temperature. All experimental parameters and results are demonstrated in Table 2.
Table 2-Different composition of precursor to produce GPC and corresponding physical parameters as well as compressive strength of mortar cube.
GPC Components GPC Composition
Example 2.1 Example 2.2 Example 2.3
Chemical Activator
(GGBS: 62%, Sodium Sulphate: 20%, Sodium Silicate: 1%, Sodium Hydroxide: 17%) 15% 15% 15%
Precursor GGBS 85% 75% 75%
Fly ash 0% 10% 0%
Kaolin 0% 0 10%
Physical Parameters
Normal Consistency (%) 29.25 31.75 26.50
Initial setting Time (min) 75 45 45
Final Setting time (min) 120 110 110
Autoclave expansion (%) 0.073 0.087 0.042
Le-Chateliar Expansion (mm) 1.0 1 0.0
Compressive Strength (MPa )
1 Day 16.10 10.95 16.45
3 Days 29.40 24.10 26.45
7 Days 38.10 35.10 32.60
28 Days 48.20 42.60 40.35

Example 3: Preparation of GPC with different dosage of chemical activator.
Herein the proportion of chemical activator in GPC has been varied from 15-20% to make three different samples of GPC (Table 3). These three samples have been used for mortar cast followed by compressive strength check after 1, 3, 7 and 28 days water curing at ambient temperature. The other physical parameters (setting times, autoclave expansion, Le-Chatelier expansion) have also been tested with the developed samples. These experiments have been done to find out the effect of chemical activator proportion on performance parameters. All experimental parameters and results are demonstrated in Table 3.

Table 3. Different ratio of chemical activator and precursor to produce GPC and corresponding physical parameters as well as compressive strength of mortar cube.
GPC Components GPC Composition
Example 3.1 Example 3.2 Example 3.3
Chemical Activator
(GGBS: 62%, Sodium Sulphate: 20%, Sodium Silicate: 1%, Sodium Hydroxide: 17%) 10% 15% 20%
Precursor
(100% GGBS) 90% 85% 80%
Physical Parameters
Normal Consistency (%) 28.75 29.25 29.75
Initial setting Time (Min) 80 75 40
Final Setting time (Min) 150 120 100
Autoclave expansion (%) 0.067 0.073 0.063
Le-Chateliar Expansion (mm) 1.0 1.0 1.0
Compressive Strength (MPa)
1 Day 7.79 16.10 15.55
3 Days 15.90 29.40 28.95
7 Days 21.00 38.10 36.60
28 Days 29.00 48.20 47.15

CONCRETE TRIAL:
One of the GPC samples from Example 1-3 has been used for M30 grade concrete trial. 380 Kg of GPC/M3 concrete has been used in concrete mix design for this experiment. The applicability of developed GPC has been further validated from this concrete trial. Workability of prepared concrete has been checked by monitoring slump retention. Then the concrete has been casted in cube. After 24 h ambient temperature setting and curing, concrete was demoulded and placed for water curing at ambient temperature. The compressive strength has been checked after 3, 7, 28 days curing. Initially the concrete was flowable in nature and slump was195 mm. The workability retains up to 3 h with 100 mm slump. Compressive strength after 3, 7, 28 days curing are 21.00, 28.26 and 36.50 MPa respectively. Hence the developed GPC has shown expected strength as well as compatibility with conventional concrete testing.

DETERMINATION OF HEAT OF HYDRATION:
Heat of hydration of OPC, PSC and one of the GPC samples from Example 1-3 have been determined using an isothermal calorimeter (make: TA Instrument). Fig. 3 has demonstrated results of determination of heat of hydration. The heat flow curve of all samples (Fig. 3a) confirms the exothermic hydration process of all three samples. The cumulative heat liberation with progressive time scale has been demonstrated in Fig. 3b. From this plot it is clear that developed GPC possess lowest heat of hydration (137.8 J/g at 7 days of hydration) compare to PSC (178.0 J/g at 7 days of hydration) and OPC (252.4 J/g at 7 days of hydration).

NON PATENT CITATIONS
1. Concrete needs to lose its colossal carbon footprint, Nature,2021, 597, 593-594, doi: https://doi.org/10.1038/d41586-021-02612-5.
2. Zhenming Li, Xuhui Liang, Chen Liu, Minfei Liang, Klaas van Breugel, Guang Ye. Thermal deformation and stress of alkali-activated slag concrete under semi-adiabatic condition: Experiments and simulations. Cement and Concrete Research 2022, 159, 106887.
3. Indian Cement Industry Analysis, India Brand Equity Foundation, https://www.ibef.org/industry/cement-presentation.
4. J. Davidovits, Geopolymers of the First Generation: SILIFACE-Process, Geopolymer '88, Vol.1, pp. 49-67.
5. J. Davidovit, Geopolymer Chemistry and Applications, 5th edition, ISBN: 9782954453118.
PATENT CITATIONS
1. CN110759655B, Industrial waste based geopolymer.
2. KR102140827B1, Powder-type Alkali activator of Alkali activated Slag binder for high-temperature curing, Alkali-activated slag binder containing the activator for high-temperature curing, concrete composite and product containing the binder.
3. KR101602620B1, Manufacturing method of geopolymer having high strength by using coal gasification slag.
4. INDE007282006, A PROCESS FOR THE PRODUCTION OF GEOPOLYMER CMENT FROM FLY ASH AND GRANULATED BLAST FURNACE SLAG, COPOLYMER CEMENT MADE THEREBY AND PROCESS OF MAKING PRODUCTS THEREOF.
5. KR101388002B1, The composite of non-cement based on blast furnace slag and fly ash, manufacturing method of dry mortar using it.
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, Claims:We Claim:
1.Clinker free geopolymer cement (GPC) formulation comprising solid powder formulation of (a) alkali chemical activator composition in amounts of 10-20 % by wt comprising of co-ground combination of GGBS (62-67 %), sodium sulphate (20-22 %), solid sodium silicate (0-1 %) and sodium hydroxide (12-17 %) and ( b) precursor composition in amounts of 80 to 90 % by wt comprising a blend of GGBS (90-100%), fly ash (0-10%) and kaolin (0-10%).
2. The clinker free geopolymer cement (GPC) formulation as claimed in claim 1 suitable for ambient temperature water curing having selectively (i) 29.00-48.20 MPa compressive strength after 28 days water curing and (ii) concrete trial (M30 grade). 36.50 MPa compressive strength was appeared for concrete cube after 28 days water curing at ambient temperature.
3.The clinker free geopolymer cement (GPC) formulation as claimed in anyone of claims 1 or 2 which provides for specific surface area of developed GPC in 340-360 m2/Kg (according to Blaine Air Permeability Apparatus).

4. The clinker free geopolymer cement (GPC) formulation as claimed in anyone of claims 1 to 3 having Initial setting time and final setting time in the range of 40-90 min and 100-150 min respectively and having autoclave expansion and Le-Chatelier expansion in the range of 0.042-0.087 % and 0-1% respectively.

5. A process for manufacture of the clinker free geopolymer cement (GPC) formulation as claimed in anyone of claims 1 to 4 comprising:
I) providing said alkali chemical activator comprising the steps of :
a) providing the select composition components comprising of co-ground combination of GGBS (62-67 %), sodium sulphate (20-22 %), solid sodium silicate (0-1 %) and sodium hydroxide (12-17 %);
b) grinding the components in a grinder; and
c) storing the thus ground components comprising said alkali chemical activator ;
II) providing the precursor composition comprising the steps of :
a) providing said select composition of precursor composition in amounts of 80 to 90 % by wt comprising a blend of GGBS (90-100%), fly ash (0-10%) and kaolin (0-10%); and
b) finely grinding and blending the components;
III) finally blending together said alkali chemical activator composition in amounts of 10-20 % by wt with said precursor composition in amounts of 80 to 90 % by wt.
6.The process for manufacture of the clinker free geopolymer cement (GPC) formulation as claimed in claim 5 based on chemically activated ground granulated blast furnace slag, in single component solid powder form comprising;
the steps of preparation of GPC precursor and powdered chemical activator; co-grinding of components of chemical activators components followed by storing in a moisture free bag/container; blending of components of precursor components in powder form; both said components are subjected to blend together to make the final GPCin a form ready to mix with water and aggregate for mortar and concrete application.
7. The process as claimed in any one of claims 5 or 6, wherein said precursor of GPC has been developed by mixing GGBS (75-85%), fly ash (0-10%) and kaolin (0-10%).
8. The process as claimed in any one of claims 5 to 7, wherein said chemical activator has been prepared by co-grinding of GGBS (62-67 %), sodium sulphate (20-22 %), solid sodium silicate (0-1 %) and sodium hydroxide (12-17 %) in a high speed blade grinder.
9. The process as claimed in any one of claims 5 to 8, stabilizes highly hygroscopic alkali material (sodium hydroxide and sodium silicate) in solid powder form.
10. The process asclaimed in any one of claims 5 to 9, wherein said GPC has been prepared by blending precursor (80-90%) and chemcial activator (10-20%).
11. The process asclaimed in any one of claims 5 to 10, wherein developed GPC offers ambient temperature water curing like other conventional cements.
12. The process asclaimed in any one of claims 5 to 11, providing saidGPC leading to compressive strength of mortar cube after 1, 3, 7 and 28 days water curing at ambient temperature as 7.79-16.45, 15.90-29.40, 21.00-38.1, 29.00-48.20 MPa respectively
13. The process as claimed in any one of claims 5 to 12, providing said GPC leading tocompressive strength of M30 grade concrete cube after 28 days water curing at ambient temperature is 36.50 MPa.
14. The process asclaimed in any one of claims 5 to 13, not requiring any pyro process and free of usage of clinker as well as lime stone, favouring minor amount of CO2 emision.
15. The process asclaimed in any one of claims 5 to 14, wherein the developed GPC has lower heat of hydration compared to conventional Portland clinker based cements like OPC and PSC.

Dated this the 17th day of January, 2023
Anjan Sen
Of Anjan Sen & Associates
(Applicant’s Agent)
IN/PA-199