Title of Invention	A NOVEL PRODUCTION PROCESS TO INVIGORATE THE CHARACTERISTIC STRENGTHS OF VARIOUS HYDRAULIC CEMENT COMPOSITIONS
Abstract	A production process to invigorate the characteristic strength of any hydraulic cement such as OPC, PPC, PSG, masonry cement etc., or non-conventional hydraulic cements such as belite cement, FaL-G etc., by blending amorphous and micro-fine RHA right at the pre-bagging stage of cement production wherein OPC and RHA put together constitute 100% in the case of OPC and 95-5% in the case of other hydraulic cements.

Title of Invention

A NOVEL PRODUCTION PROCESS TO INVIGORATE THE CHARACTERISTIC STRENGTHS OF VARIOUS HYDRAULIC CEMENT COMPOSITIONS

Abstract

A production process to invigorate the characteristic strength of any hydraulic cement such as OPC, PPC, PSG, masonry cement etc., or non-conventional hydraulic cements such as belite cement, FaL-G etc., by blending amorphous and micro-fine RHA right at the pre-bagging stage of cement production wherein OPC and RHA put together constitute 100% in the case of OPC and 95-5% in the case of other hydraulic cements.

Full Text	The present invention relates to a production process by which the engineering properties for various hydraulic cement compositions and the derivatives thereon are enhanced by blending with Rice Husk Ash (RHA) for increased durability. INTRODUCTION Hydraulic cement is defined as a product, which sets and hardens in the presence of water, through solid-state solutions, leading to the progressive formation of various hydrated mineralogical phases over ageing to be manifested as crystallographic matrix. For example, while the lime-pozzolanic binders were considered as hydraulic cementitious products with their antecedents of applications in various constructions over millennia, Ordinary Portland Cement (OPC), which is also called as Normal Portland Cement (NPC) in certain countries, has been used as the hydraulic cementitious product since 19th century with improved engineering properties. In recent past, OPC is manoeuvred of its clinker chemistry to yield high strengths, which, in reality, proved only to be high-early strengths associated with increased manifestations of distress, when used in the form of concrete. Prematured release of heat and lime is identified as the root cause for such distress. There upon, attention has gone back to the time-tested lime-pozzolan chemistry and relevant formulations. Consequently, the role of supplementary cementing materials (SCM) is identified to regulate the heat and surplus lime. Blast furnace slag, fly ash, metakaolin and silica fume are some of the popularly used SCMs. SCM is a product, which is amenable to avail the surplus hydrated lime of OPC, contributing hydrated mineralogy akin to that of the latter. If the OPC is blended with one SCM it is identified as binary, two SCMs it is ternary and three SCMs it is quaternary cement. All such blends are currently in vogue as hydraulic cements. These SCMs reduce heat of hydration and avail the surplus hydrated lime released out of OPC for the formation of secondary hydrated mineralogy, contributing for densification of matrix, improved impermeability and enhanced durability. However, the chemistry of some of the blends is slow to compensate which addition of super-pozzolanic materials such as silica fume or metakaolin is one of the solutions, thus giving rise to ternary and quaternary blends. During the production of OPC clinker, approximately one ton of CO2 is belched out for every ton of output, making cement industry as one of the principal contributors of global warming. The blended cements save precious inputs and abate CO2 to the extent of SCM input, attaining the status of eco-friendly cements and draw promotional thrust from Governments, environmentalists, industry and the consumers. FaL-G, a product consisting of fly ash, lime and/or OPC, and gypsum, is another formulation in this direction covered by provisional Patent No. 1425/MAS/96 dt 13.8.1996. OPC attains strength improvement by manoeuvring the clinker chemistry, which is not feasible beyond threshold levels. However, High early Strength Concrete (HSC) and High Performance Concrete (HPC) have been developed, attaining compressive strengths as high as 70-120 MPa by the addition of superplasticisers. Superplasticisers are such class of products, which, upon addition to concrete, facilitate the release of entrapped water from cement flocculations for workability, bringing down the water to cement ratio. Modified ligno suiphonates, sulphonated naphthalene formaldehyde, suiphonated melamine formaldehyde etc., are some of the superplasticisers to cite. These materials, which are generally in liquid form, are amenable to be added only at site-mixing in mortar or concrete, but certainly not at production stage of cement. While superplasticisers contribute to durability enhancement of mortar/concrete by physical means of water reduction, super-pozzolans such as silica fume and metakaolin contribute to the same by chemical means. PRIOR ART : Improving Engineering Performance of Concrete With the manifestation of distress of OPC concretes on one hand and need to conserve high-value inputs such as minerals, energy and power that go into the production of clinker on the other, blended cements gained prominence. While low eariy strength cements such as belite cement and FaL-G are tapped and augmented for strengths at eariy ages, the conventionally used hydraulic cements such as OPC, PPC, PSC etc, are invigorated of their engineering properties for production of high-performance concretes with relatively lower permeability and higher durability by blending superpozzolans such as silica fume and metakaolin. Silica fume and Metakaolin as the superpozzolans Use of superpozzolan is a known art to increase the engineering performance of cement concrete. There are two known superpozzolans, silica fume (SF) and metakaolin (MK). While the former one is the byproduct of ferrosilicon and silicon metal industries the latter one is a sintered product of natural mineral. Both these products have the ability to improve the engineering properties of cement concrete, by availing the surplus hydrated lime released out of cement to fomnulate into hydrated mineralogy, which is additional over the mineralogy formulated by cement hydration. This is how cement concretes do improve in engineering properties. However, whenever superpozzolans are added, the water to binder ratio gets effected because of the super-fine particle size and higher surface area of superpozzolans, which is addressed by adding superplasticisers. The inventors in this patent use RHA as the superpozzolan in order to promote the use of another industrial byproduct as the value added product. Use of rice husk in cement industries In certain cement production plants, use of rice husk as a source of fuel and as a source of silica is in vogue. While keeping the clinker chemistry, end product (cement) specifications and the economy of production in view, the rice husk is fed to the kiln along with coal fines. The raw meal is a blend of ground limestone and, wherever necessary, portions of Bauxite (AI2O3), Iron Ore (Fe2O3), laterite and clay etc. Wherever the limestone falls deficient of silica, replenishing silica to the required modulus by deriving the same from rice husk is one of the approaches. In this context the silica of rice husk is tapped as a mineral substitute but not for its pozzolanic performance. Random use of rice husk ash US Patent No. 5,858,083/12-1-99 discusses a cementitious binder consisting of beta hemihydrate wherein the use of silica fume or RHA was also discussed. In this invention the base input is beta hemihydrate, which is non-hydraulic cement that would not be put to use for structural purpose. Hence the role of RHA for durability enhancement does not arise. This is totally different from the hydraulic cements and derivative concretes envisaged by the present invention, which are meant for structural application, and the purpose of this invention is to increase the engineering performance and durability of structures. SUMMARY OF INVENTION This is an invention to manufacture cements, cement mortars and concretes with improved engineering properties, in contrast to the known prior art, by blending with newly identified superpozzolan, the rice husk ash. The pre.sent invention comprehends the role of RHA as the superpozzolanic materials in the chemistry and mineralogical formation of cement and its derivative products. A production process to invigorate the characteristic strength of any hydraulic cement such as OPC, PPC, PSC, masonry cement etc., or non-conventional hydraulic cements such as belite cement, FaL-G etc., by blending amorphous and micro-fine RHA right at the pre-bagging stage of cement production wherein OPC and RHA put together constitute 100% in the case of OPC and 95-6% in the case of other hydraulic cements. A production process to invigorate the characteristic strength of any hydraulic cement such as OPC. PPC, PSC, masonry cement etc., or non-conventional hydraulic cements such as belite cement, FaL-G etc., by inter-grinding amorphous and micro-fine RHA right at the pre-bagging stage of cement production wherein OPC and RHA put together constitute 100% in the case of OPC blend; and 95-5% in the case of other hydraulic cement blends, the balance being any one or combinations of the SCMs. A production process, where the RHA constitutes generally 5-30% of the ultimate hydraulic cement. A production process for the production of mortar and concrete, based on all types of hydraulic cements, wherein RHA is directly blended generally to the extent of 5-30% of hydraulic cement, contributing to enhance the engineering properties of respective mortar or concrete. DETAILED DESCRIPTION OF THE INVENTION OPC is a hydraulic cement for better engineering performance over age-old lime-mortar or lime-pozzolan binders. However, with the development of higher grades such as 43 grade and 53 grade, OPC proved to be distress-proned, while used as mortar or concrete, because of two salient features viz., high heat of hydration and premature release of hydrated lime. These two features are addressed by blending OPC with SCMs that has given rise to various blends such as binary, ternary, quaternary cements and so on. In order to augment the pace of construction activity and minimize time the concrete structural elements are precast and put to use. There are some other applications where concrete elements are prestressed or post tensioned in order to render higher flexural strengths to the elements without increasing the input of steel and/or concrete. In all these applications early strength of concrete is a necessity without hampering the long term durability. Concretes derived out of OPC do pose late age distresses whereas concretes containing super-pozzolanic materials have significant role to meet this challenge, by reducing heat of hydration and consuming surplus hydrated lime; ail culminating in durability enhancement. In order to minimize the vagaries attached with material mobilization and quality control, Ready Mix Concrete (RMC) is developed. In this approach, concrete is manufactured in a centralized plant under controlled conditions and made available to the construction sites in ready-to-use condition. Thus, addition of SCM and superplasticisers take place under expert supervision for ultimate improvement of concrete quality. The present invention comprehends the role of RHA as the superpozzolanic materials in the chemistry and mineralogical formation of cement and its derivative products towards improved engineering performance. Rice husk contains amorphous silica, which, upon combustion, becomes the predominant constituent in the resultant ash with the ability to perform as superpozzolan in cement mortar and concrete in the lines of silica fume (SF) and metakaolin (MK). The data based on a study by the inventors on the performance of RHA for its superpozzolanic role, in comparison to silica fume and metakaolin on concretes derived out of a typical cement and fly ash blend, are given in the table: This Patent claims its invention in envisaging to add RHA at pre-bagging stage of OPC or any other type of hydraulic cement by certain specified approaches of inter-grinding and/or inter-blending by which the characteristic engineering performance of cement is enhanced right at the production stage, as studied by the inventors on typical mortars of OPC and different blended cements vide the following table: Upon the advent of high-grade OPC, concretes or mortars made out of such OPC have been proved to be of questionable performance at late ages, due to increased surplus lime and heat of hydration. Blended cements have been identified as a solution but the slow pace of strength gain at eariy ages is to be addressed to make blended cements as acceptable as OPC. This Patent claims its invention in adding RHA in the preparation of mortar or concrete with any type of hydraulic cement by which the characteristic engineering performance of such mortar or concrete is enhanced right at the production stage, as shown in the table below. In the above table, chloride permeability is an indicator of engineering performance for durability, as studied through chloride penetration test vide ASTM C-1202. Lesser the Coulomb value lower the permeability and higher the durability. Non-conventional hydraulic cements such as belite cement, FaL-G etc., need to be promoted in the interest of rationalising the use of mineral-intensive, cost-intensive and energy-intensive cement such as OPC. But, keeping in view the market demand for cement products with characteristic high strength, it is desirable to impart high strengths to these cements. This patent also claims its invention of adding RHA at production stage of non-conventional cements such as belite and FaL-G to enhance the characteristic strength. A study by the inventors on typical FaL-G cement is reported in the following table. WE CLAIM 1. A production process to invigorate the characteristic strength of any hydraulic cement such as OPC, PPC, PSC. masonry cement etc., or non-conventional hydraulic cements such as belite cement, FaL-G etc., by blending amorphous and micro-fine RHA right at the pre-bagging stage of cement production wherein OPC and RHA put together constitute 100% in the case of OPC and 95-5% in the case of other hydraulic cements. 2. A production process as claimed in claim 1, where the RHA constitutes generally 5-30% of the ultimate hydraulic cement. 3. A production process as claimed in any one of the preceding claims, for which the RHA is derived out of rice husk combustion at commensurate temperature that gives the ash containing amorphous silica from 20-98%. and having a specific surface area of not less than 1 m2/gm to as high as 20-60 m2/gm. 4. A production process as claimed in any one of the preceding claims, which gives composite cement or derivative concrete that can accept other ultrafine super-pozzolanic materials such as silica fume, metakaolin and/or any type of plasticizers and superplasticisers to render additional engineering performance as mortar or concrete. 5. A production process as claimed in any one of the preceding claims, which gives composite cement or concrete for cast in-situ, precast, prestressed or post-tensioned applications. 6. A production process as claimed in any one of the preceding claims, which gives composite cement for production of mortar or concrete for cast in-situ, precast, prestressed or post-tensioned applications. 7. A production process as claimed in any one of the preceding claims, which gives composite cement for pre-mixed concrete preparation in systems such as Ready-mixed Concrete (RMC) plants. 9 8. A production process to invigorate the characteristic strength of any hydraulic cement such as OPC, PPC, PSC, masonry cement etc., or non-conventional hydraulic cements such as belite cement, FaL-G etc., by inter-grinding amorphous and micro-fine RHA right at the pre-bagging stage of cement production wherein OPC and RHA put together constitute 100% in the case of OPC blend; and 95-5% in the case of other hydraulic cement blends, the balance being any one or combinations of the SCMs. 9. A production process as claimed in claim 8, where the RHA constitutes generally 5-30% of ultimate hydraulic cement. 10. A production process as claimed in any one of the preceding claims, for which the RHA is derived out of rice husk combustion at commensurate temperature that gives the ash containing amorphous silica from 20-98%, and having a specific surface area of not less than 1 m2/gm to as high as 20-60 m2/gm. 11. A production process as claimed in any one of the preceding claims, which gives composite cement or derivative concrete that can accept other ultrafine super-pozzolanic materials such as silica fume, metakaolin and/or any type of plasticizers and superplasticisers to render additional engineering performance as mortar or concrete. 12. A production process as claimed in any one of the preceding claims, which gives composite cement or concrete for production of precast components. 13. A production process as claimed in any one of the preceding claims, which gives composite cement for production of mortar or concrete for cast in-situ, precast, prestressed or post-tensioned applications. 14. A production process as claimed in any one of the preceding claims, which gives composite cement for pre-mixed concrete preparation in systems such as Ready-mixed Concrete (RMC) plants. 15. A production process for the production of mortar and concrete, based on ail types of hydraulic cements, wherein RHA is directly blended generally to the extent of 5-30% of hydraulic cement, contributing to enhance the engineering properties of respective mortar or concrete. 16. A production process for a cement composition and/or its derivatives substantially as herein described with reference to the foregoing description.

Full Text

The present invention relates to a production process by which the engineering properties for various hydraulic cement compositions and the derivatives thereon are enhanced by blending with Rice Husk Ash (RHA) for increased durability.
INTRODUCTION
Hydraulic cement is defined as a product, which sets and hardens in the presence of water, through solid-state solutions, leading to the progressive formation of various hydrated mineralogical phases over ageing to be manifested as crystallographic matrix. For example, while the lime-pozzolanic binders were considered as hydraulic cementitious products with their antecedents of applications in various constructions over millennia, Ordinary Portland Cement (OPC), which is also called as Normal Portland Cement (NPC) in certain countries, has been used as the hydraulic cementitious product since 19th century with improved engineering properties.
In recent past, OPC is manoeuvred of its clinker chemistry to yield high strengths, which, in reality, proved only to be high-early strengths associated with increased manifestations of distress, when used in the form of concrete. Prematured release of heat and lime is identified as the root cause for such distress. There upon, attention has gone back to the time-tested lime-pozzolan chemistry and relevant formulations.
Consequently, the role of supplementary cementing materials (SCM) is identified to regulate the heat and surplus lime. Blast furnace slag, fly ash, metakaolin and silica fume are some of the popularly used SCMs. SCM is a product, which is amenable to avail the surplus hydrated lime of OPC, contributing hydrated mineralogy akin to that of the latter. If the OPC is blended with one SCM it is identified as binary, two SCMs it is ternary and three SCMs it is quaternary cement. All such blends are currently in vogue as hydraulic cements. These SCMs reduce heat of hydration and avail the surplus hydrated lime released out of OPC for the formation of secondary hydrated mineralogy, contributing for densification of matrix, improved impermeability and enhanced durability. However, the chemistry of some of the blends is slow to compensate which addition of super-pozzolanic materials such as silica fume or metakaolin is one of the solutions, thus giving rise to ternary and quaternary blends.

During the production of OPC clinker, approximately one ton of CO2 is belched out for every ton of output, making cement industry as one of the principal contributors of global warming. The blended cements save precious inputs and abate CO2 to the extent of SCM input, attaining the status of eco-friendly cements and draw promotional thrust from Governments, environmentalists, industry and the consumers. FaL-G, a product consisting of fly ash, lime and/or OPC, and gypsum, is another formulation in this direction covered by provisional Patent No. 1425/MAS/96 dt 13.8.1996.
OPC attains strength improvement by manoeuvring the clinker chemistry, which is not feasible beyond threshold levels. However, High early Strength Concrete (HSC) and High Performance Concrete (HPC) have been developed, attaining compressive strengths as high as 70-120 MPa by the addition of superplasticisers. Superplasticisers are such class of products, which, upon addition to concrete, facilitate the release of entrapped water from cement flocculations for workability, bringing down the water to cement ratio. Modified ligno suiphonates, sulphonated naphthalene formaldehyde, suiphonated melamine formaldehyde etc., are some of the superplasticisers to cite. These materials, which are generally in liquid form, are amenable to be added only at site-mixing in mortar or concrete, but certainly not at production stage of cement. While superplasticisers contribute to durability enhancement of mortar/concrete by physical means of water reduction, super-pozzolans such as silica fume and metakaolin contribute to the same by chemical means.
PRIOR ART :
Improving Engineering Performance of Concrete
With the manifestation of distress of OPC concretes on one hand and need to conserve high-value inputs such as minerals, energy and power that go into the production of clinker on the other, blended cements gained prominence.
While low eariy strength cements such as belite cement and FaL-G are tapped and augmented for strengths at eariy ages, the conventionally used hydraulic cements such as OPC, PPC, PSC etc, are invigorated of their engineering properties for production of high-performance concretes with relatively lower permeability and higher durability by blending superpozzolans such as silica fume and metakaolin.

Silica fume and Metakaolin as the superpozzolans
Use of superpozzolan is a known art to increase the engineering performance of cement concrete. There are two known superpozzolans, silica fume (SF) and metakaolin (MK). While the former one is the byproduct of ferrosilicon and silicon metal industries the latter one is a sintered product of natural mineral. Both these products have the ability to improve the engineering properties of cement concrete, by availing the surplus hydrated lime released out of cement to fomnulate into hydrated mineralogy, which is additional over the mineralogy formulated by cement hydration. This is how cement concretes do improve in engineering properties. However, whenever superpozzolans are added, the water to binder ratio gets effected because of the super-fine particle size and higher surface area of superpozzolans, which is addressed by adding superplasticisers.
The inventors in this patent use RHA as the superpozzolan in order to promote the use of another industrial byproduct as the value added product.
Use of rice husk in cement industries
In certain cement production plants, use of rice husk as a source of fuel and as a source of silica is in vogue. While keeping the clinker chemistry, end product (cement) specifications and the economy of production in view, the rice husk is fed to the kiln along with coal fines. The raw meal is a blend of ground limestone and, wherever necessary, portions of Bauxite (AI2O3), Iron Ore (Fe2O3), laterite and clay etc. Wherever the limestone falls deficient of silica, replenishing silica to the required modulus by deriving the same from rice husk is one of the approaches. In this context the silica of rice husk is tapped as a mineral substitute but not for its pozzolanic performance.
Random use of rice husk ash
US Patent No. 5,858,083/12-1-99 discusses a cementitious binder consisting of beta hemihydrate wherein the use of silica fume or RHA was also discussed. In this invention the base input is beta hemihydrate, which is non-hydraulic cement that would not be put to use for structural purpose. Hence the role of RHA for durability enhancement does not arise. This is totally different from the hydraulic cements and derivative concretes envisaged by the present invention, which are meant for structural application, and the

purpose of this invention is to increase the engineering performance and durability of
structures.
SUMMARY OF INVENTION
This is an invention to manufacture cements, cement mortars and concretes with improved engineering properties, in contrast to the known prior art, by blending with newly identified superpozzolan, the rice husk ash.
The pre.sent invention comprehends the role of RHA as the superpozzolanic materials in the chemistry and mineralogical formation of cement and its derivative products.
A production process to invigorate the characteristic strength of any hydraulic cement such as OPC, PPC, PSC, masonry cement etc., or non-conventional hydraulic cements such as belite cement, FaL-G etc., by blending amorphous and micro-fine RHA right at the pre-bagging stage of cement production wherein OPC and RHA put together constitute 100% in the case of OPC and 95-6% in the case of other hydraulic cements.
A production process to invigorate the characteristic strength of any hydraulic cement such as OPC. PPC, PSC, masonry cement etc., or non-conventional hydraulic cements such as belite cement, FaL-G etc., by inter-grinding amorphous and micro-fine RHA right at the pre-bagging stage of cement production wherein OPC and RHA put together constitute 100% in the case of OPC blend; and 95-5% in the case of other hydraulic cement blends, the balance being any one or combinations of the SCMs.
A production process, where the RHA constitutes generally 5-30% of the ultimate hydraulic cement.
A production process for the production of mortar and concrete, based on all types of hydraulic cements, wherein RHA is directly blended generally to the extent of 5-30% of hydraulic cement, contributing to enhance the engineering properties of respective mortar or concrete.

DETAILED DESCRIPTION OF THE INVENTION
OPC is a hydraulic cement for better engineering performance over age-old lime-mortar or lime-pozzolan binders. However, with the development of higher grades such as 43 grade and 53 grade, OPC proved to be distress-proned, while used as mortar or concrete, because of two salient features viz., high heat of hydration and premature release of hydrated lime. These two features are addressed by blending OPC with SCMs that has given rise to various blends such as binary, ternary, quaternary cements and so on.
In order to augment the pace of construction activity and minimize time the concrete structural elements are precast and put to use. There are some other applications where concrete elements are prestressed or post tensioned in order to render higher flexural strengths to the elements without increasing the input of steel and/or concrete. In all these applications early strength of concrete is a necessity without hampering the long term durability. Concretes derived out of OPC do pose late age distresses whereas concretes containing super-pozzolanic materials have significant role to meet this challenge, by reducing heat of hydration and consuming surplus hydrated lime; ail culminating in durability enhancement.
In order to minimize the vagaries attached with material mobilization and quality control, Ready Mix Concrete (RMC) is developed. In this approach, concrete is manufactured in a centralized plant under controlled conditions and made available to the construction sites in ready-to-use condition. Thus, addition of SCM and superplasticisers take place under expert supervision for ultimate improvement of concrete quality.
The present invention comprehends the role of RHA as the superpozzolanic materials in the chemistry and mineralogical formation of cement and its derivative products towards improved engineering performance.
Rice husk contains amorphous silica, which, upon combustion, becomes the predominant constituent in the resultant ash with the ability to perform as superpozzolan in cement mortar and concrete in the lines of silica fume (SF) and metakaolin (MK). The data based on a study by the inventors on the performance of RHA for its

superpozzolanic role, in comparison to silica fume and metakaolin on concretes derived out of a typical cement and fly ash blend, are given in the table:

This Patent claims its invention in envisaging to add RHA at pre-bagging stage of OPC or any other type of hydraulic cement by certain specified approaches of inter-grinding and/or inter-blending by which the characteristic engineering performance of cement is enhanced right at the production stage, as studied by the inventors on typical mortars of OPC and different blended cements vide the following table:

Upon the advent of high-grade OPC, concretes or mortars made out of such OPC have been proved to be of questionable performance at late ages, due to increased surplus lime and heat of hydration. Blended cements have been identified as a solution but the slow pace of strength gain at eariy ages is to be addressed to make blended cements as acceptable as OPC.

This Patent claims its invention in adding RHA in the preparation of mortar or concrete with any type of hydraulic cement by which the characteristic engineering performance of such mortar or concrete is enhanced right at the production stage, as shown in the table below.

In the above table, chloride permeability is an indicator of engineering performance for durability, as studied through chloride penetration test vide ASTM C-1202. Lesser the Coulomb value lower the permeability and higher the durability.
Non-conventional hydraulic cements such as belite cement, FaL-G etc., need to be promoted in the interest of rationalising the use of mineral-intensive, cost-intensive and energy-intensive cement such as OPC. But, keeping in view the market demand for cement products with characteristic high strength, it is desirable to impart high strengths to these cements. This patent also claims its invention of adding RHA at production stage of non-conventional cements such as belite and FaL-G to enhance the characteristic strength. A study by the inventors on typical FaL-G cement is reported in the following table.

WE CLAIM
1. A production process to invigorate the characteristic strength of any hydraulic cement such as OPC, PPC, PSC. masonry cement etc., or non-conventional hydraulic cements such as belite cement, FaL-G etc., by blending amorphous and micro-fine RHA right at the pre-bagging stage of cement production wherein OPC and RHA put together constitute 100% in the case of OPC and 95-5% in the case of other hydraulic cements.
2. A production process as claimed in claim 1, where the RHA constitutes generally 5-30% of the ultimate hydraulic cement.
3. A production process as claimed in any one of the preceding claims, for which the RHA is derived out of rice husk combustion at commensurate temperature that gives the ash containing amorphous silica from 20-98%. and having a specific surface area of not less than 1 m2/gm to as high as 20-60 m2/gm.
4. A production process as claimed in any one of the preceding claims, which gives composite cement or derivative concrete that can accept other ultrafine super-pozzolanic materials such as silica fume, metakaolin and/or any type of plasticizers and superplasticisers to render additional engineering performance as mortar or concrete.
5. A production process as claimed in any one of the preceding claims, which gives composite cement or concrete for cast in-situ, precast, prestressed or post-tensioned applications.
6. A production process as claimed in any one of the preceding claims, which gives composite cement for production of mortar or concrete for cast in-situ, precast, prestressed or post-tensioned applications.
7. A production process as claimed in any one of the preceding claims, which gives composite cement for pre-mixed concrete preparation in systems such as Ready-mixed Concrete (RMC) plants.
9

8. A production process to invigorate the characteristic strength of any hydraulic cement such as OPC, PPC, PSC, masonry cement etc., or non-conventional hydraulic cements such as belite cement, FaL-G etc., by inter-grinding amorphous and micro-fine RHA right at the pre-bagging stage of cement production wherein OPC and RHA put together constitute 100% in the case of OPC blend; and 95-5% in the case of other hydraulic cement blends, the balance being any one or combinations of the SCMs.
9. A production process as claimed in claim 8, where the RHA constitutes generally 5-30% of ultimate hydraulic cement.
10. A production process as claimed in any one of the preceding claims, for which the RHA is derived out of rice husk combustion at commensurate temperature that gives the ash containing amorphous silica from 20-98%, and having a specific surface area of not less than 1 m2/gm to as high as 20-60 m2/gm.
11. A production process as claimed in any one of the preceding claims, which gives composite cement or derivative concrete that can accept other ultrafine super-pozzolanic materials such as silica fume, metakaolin and/or any type of plasticizers and superplasticisers to render additional engineering performance as mortar or concrete.
12. A production process as claimed in any one of the preceding claims, which gives composite cement or concrete for production of precast components.
13. A production process as claimed in any one of the preceding claims, which gives composite cement for production of mortar or concrete for cast in-situ, precast, prestressed or post-tensioned applications.
14. A production process as claimed in any one of the preceding claims, which gives composite cement for pre-mixed concrete preparation in systems such as Ready-mixed Concrete (RMC) plants.

15. A production process for the production of mortar and concrete, based on ail
types of hydraulic cements, wherein RHA is directly blended generally to the
extent of 5-30% of hydraulic cement, contributing to enhance the engineering
properties of respective mortar or concrete.
16. A production process for a cement composition and/or its derivatives
substantially as herein described with reference to the foregoing description.

Documents:

612-mas-1999-abstract.pdf

612-mas-1999-claims filed.pdf

612-mas-1999-claims granted.pdf

612-mas-1999-correspondnece-others.pdf

612-mas-1999-correspondnece-po.pdf

612-mas-1999-description(complete)filed.pdf

612-mas-1999-description(complete)granted.pdf

612-mas-1999-form 1.pdf

612-mas-1999-form 26.pdf

612-mas-1999-other document.pdf

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Patent Number

210256

Indian Patent Application Number

612/MAS/1999

PG Journal Number

50/2007

Publication Date

14-Dec-2007

Grant Date

25-Sep-2007

Date of Filing

02-Jun-1999

Name of Patentee

NATERI KALIDAS

Applicant Address

FAL-G MANSION, 35 SHRI VENKATESWARA COLONY, SHEILANAGAR, VISHAKAPATNAM,

Inventors:

#	Inventor's Name	Inventor's Address
1	NATERI KALIDAS	FAL-G MANSION, 35 SHRI VENKATESWARA COLONY, SHEILANAGAR, VISHAKAPATNAM,
2	N.BHANUMATHIDAS	FAL-G MANSION, 35 SHRI VENKATESWARA COLONY, SHEILANAGAR, VISHAKAPATNAM,
3	PENUMATCHA VENKATA RAMACHANDRA RAJU	6-3-666/B, VII FLOOR, DECCAN CHAMBERS, SOMAJIGUDA, HYDERABAD-500 482,

PCT International Classification Number

C 04 B 7/28

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA