A customizable and eco-friendly geopolymer concrete composition comprising of binder material selected from fly ash and red mud and ggbs

Abstract

The present invention relates to a novel mix design methodology and development of strength versus alkali activator solution (AAS) to binder ratio relationship for geopolymer concrete by employing class F fly ash, red mud and GGBS all together as binder materials. The invented mix comprises said class F fly ash, GGBS and red mud in the select ratio of 50:30:20 and is ambient curable without needing additional heating for curing and provides concrete with compressive strength up to 72 MPa. This is the first report having substantial amount (~20%) of red mud in the geopolymer composition. The design mix is customizable and provides an opportunity to the user to choose between the strength or AAS to binder ratio from the developed strength versus alkali activator solution (AAS) to binder ratio relationship.

Description

FIELD OF THE INVENTIONThe present invention is pertinent to the method of designing medium to highstrength geopolymer concrete mixes with the combination of fly ash, GGBS, andiron-rich red mud, in the proportions of 50:30:20. Proposing a new relationshipbetween 28th day compressive strength and AAS to binder material ratios is alsopart of the invention.BACKGROUND OF THE INVENTIONWith the ever-increasing growth of infrastructure globally, the usage of concretepenetrated deep into a level of routine usage. Specifically, ordinary Portlandcement (OPC) based concrete usage became customary. As a result of thecolossal quantity of cement production, the cement industries alone contributionsto World's CO2 emissions rose to as high as 7%, top amongst any other industry.Consequently, efforts are on to devise alternative binders to cement in order toreduce the greenhouse gas burden on the environment.Typical ingredients of regular concrete include Portland cement, water,aggregates, and certain admixtures that modify the behavior of the mix. Cementin the presence of water undergoes a chemical reaction to form a bonding agentand coat the surface of the aggregate, and it finally hardens to give a solidproduct called OPC concrete.Geopolymer concrete is a green concrete, which does not require any cementaddition; rather, it consumes materials that are rich in aluminosilicates. Upon theaddition of an alkaline activator solution to the material rich in aluminosilicatesundergo geopolymerization to give a hardened product called geopolymerconcrete. Generally, geopolymer concrete requires heat curing to accelerate thegeopolymerization reaction for ensuing better early compressive strength. It doesnot require wet curing, as it is a crucial step in OPC.The source of silica and alumina in abundance had been spotted by researchersin various industrial wastes generated in large quantities creating environmentaland ecological problems apart from occupying large tracts of valuable cultivableland. Many industrial sectors, like aluminium, steel, power plants and biomass,have conserved these mineral values in the form of wastes. In aluminium,industrial waste such as red mud (RM), formally termed bauxite residue, isan industrial waste generated during the processing of bauxite ore intoalumina using the Bayer process. It is composed of various oxide compounds,including the iron oxides which give its red colour. Red mud is a probablemodifier in geopolymer because of its high pH value, alumina content, andleaching characteristicsSteel industrial waste, Ground-granulated blast-furnace slag (GGBS or GGBFS),is obtained by quenching molten iron slag (a by-product of iron and steel10making) from a blast furnace in water or steam, to produce a glassy, granularproduct that is then dried and ground into a fine powder. Ground-granulatedblast furnace slag is highly cementitious and high in CSH (calciumsilicate hydrates) which is a strength enhancing compound and improves thestrength, durability and appearance of the concrete.Another waste material- a by-product of burning pulverized coal in electricgeneration power plants is fine powder of Fly ash which is a pozzolan, asubstance containing aluminous and siliceous material that forms cement in thepresence of water. When mixed with lime and water, fly ash forms a compoundsimilar to Portland cement. Depending on the source of coal there may be twotypes of fly ashes, Class F fly ash- originates from anthracite and bituminouscoals, and class C fly ash- originates from subbituminous and lignite coals. ClassF fly ash is having lower calcium than class C fly ash wherein both containalumina and silica and Class F fly ash displays higher loss on ignition (LOI) thanClass C fly ash.Evaluation of alkali-activated fly ash geopolymers is a major field of activeresearch since, as mentioned earlier, it possesses considerable cementitiousproperties. However, the limitations such as longer setting time, unpredictableworkability, efflorescence, and low strength (when cured at ambient conditions)of geopolymer have restrained its field use. Several additives have beenemployed for fly ash-based geopolymer to improve the strength and durability,however, variation in particle size, strength activity index, chemical andmineralogical compositions of these additives have very diverse effects on thegeopolymer. Hence, investigation of each of the modifiers to justify the effectiveutilization is not absolute since identical material from two different sources maynot behave similarly (Bajpai, R., Shrivastava, A. & Singh, M. Properties of fly ashgeopolymer modified with red mud and silica fume: a comparative study. SNAppl. Sci. 2, 1846 (2020). https: / / doi.org / 10.1007 / s42452-020-03665-3)There are numerous reports / patents involving different industrial wastes morespecifically Fly ash, GBSS and red mud, alone, as the raw materials forpreparation / manufacture of geopolymers for different applications. Reportsrelevant to the present invention along with 7 days and 28 days compressivestrength are as follows:Table 1: Reported formulations of Geopolymers along with 7 days and 28 dayscompressive strengthThe relevant prior arts are summarized as below:US20070125272A1 relates to geopolymer based concrete and methods of castingconcrete based on geopolymers to form products such as pipes, poles, railwaysleepers and the like wherein the aluminosilicate material is selected from thegroup consisting of fly ash, ground blast furnace slag, metakaolin, silica fume,synthetic aluminosilicate, scoria and pumice.US7846250 provides geopolymeric compositions intended for use in carbondioxide injection or production wells or storage reservoirs and preferably in asupercritical carbon dioxide condition. The geopolymeric composition is formedfrom a suspension comprising an aluminosilicate source, a metal silicate, an alkaliactivator, a retarder and / or an accelerator and a carrier fluid wherein the oxidemolar ratio M2O / SiO2 is greater than 0.20 with M an alkali metal.US8512468 relates to geopolymer mortar (another form of geopolymer) formed bymixing about 35% to about 45% by weight pozzolanic material, about 35% toabout 45% by weight silicon oxide source, about 15% to about 20% by weightalkaline activator solution, and about 0.3% to about 2.5% by weight copper ionsource. The pozzolanic material may be fly ash and the silicon oxide source maybe sand. The alkaline activator solution may be a sodium hydroxide solutioncontaining sodium silicate. The geopolymer mortar may have a viscosity in therange of about 25,000 to about 50,000 centipoise, optionally additives, such assurfactants, thermal spheres, anti-sagging agents, adhesion primers, or fibersmay be added to the composition.US8864901 reveals that inorganic polymer compositions comprising the reactionproduct of a reactive powder, an activator, and optionally a retardant. Thereactive powder includes fly ash, calcium sulfoaluminate cement, and less than10% by weight Portland cement. In some examples, the composition issubstantially free from alkanolamines.US9090508B2 discloses the geopolymeric composite ultra-high performanceconcrete (GUHPC) mix, comprising:(a) a binder comprising one or more selected from the group consisting ofreactive aluminosilicate and reactive alkali-earth aluminosilicate;(b) an alkali activator comprising an aqueous solution of metal hydroxide andmetal silicate;(c) one or more aggregate that has a particle size between about 0.075 and 10mm; and(d) one or more filler that has a particle size of between about 0.05 and 75 μm,wherein a packing density of all solid components in the GUHPC mix is at least0.5 (v / v), and the binder, aggregate and filler have the same or differentchemical compositionsUS9242900 discloses preparing of porous materials at an ambient temperatureincludes forming a mixture including a geopolymer resin and a liquid betweenwhich a nanoscale (1-1000 nm), microscale (1-1000 m), and / or milli-scale (1-10mm) phase separation occurs. The liquid can include organic liquids fromagricultural, geological, industrial, or household sources. The geopolymer resin isformed by combining one or more inorganic materials selected from the groupconsisting of fumed silica, rice husk ash, silica fume, silicates, aluminates,aluminosilicates, organosilanes, clays, minerals, metakaolin, calcined clays, flyash, slag, pozzolan, incinerated utility waste, glass powder, and red mud with analkaline or basic solution.US9296654 relates to a product formed from a first material including ageopolymer resin material, a geopolymer resin (a geopolymer resin is anaqueous mixture formed by dissolving selected metal precursors in an alkalisolution), or a combination thereof by contacting the first material with a fluidand removing at least some of the fluid to yield a product. The first material maybe formed by heating and / or aging an initial geopolymer resin material to yieldthe first material before contacting the first material with the fluid. In somecases, contacting the first material with the fluid breaks up or disintegrates thefirst material (e.g., in response to contact with the fluid and in the absence ofexternal mechanical stress), thereby forming particles having an externaldimension in a range between 1 nm and 2 cm.US9308511 discloses methods, apparatuses, and systems for fabricating porousmaterials using thixotropic gels. A shear force is applied to a thixotropic materialcausing the material to flow. Multiple components are added to the thixotropicmaterial while applying the shear force causing the multiple components to bedistributed in the material. The shear force is removed such that the staticproperties of the thixotropic material in the absence of the shear force retain adistribution of the multiple components in the thixotropic material to form acomposite gel material that includes liquid within a network of inter-connectedsolid particles that include the distributed plurality of components. The liquid inthe composite gel material is removed to form a porous composite material.US9290416B1 provides a geopolymer concrete prepared by predicting amechanical property of a geopolymer concrete formed using a predeterminedequation with each of a plurality of fly ash materials, selecting as a sourcematerial for the geopolymer concrete one of the fly ash materials that yields apredicted value of the mechanical property that is equal to or greater than atarget value for the mechanical property, and mixing the fly ash source materialwith an alkaline activator solution, a fine aggregate, and a coarse aggregate.US20070084382 concerns a method for preparing materials containing bindersystems derived from amorphous silica and bases as well as the materialsprepared by the method. Relative to known methods, the present advancementallows for continuous production of material. The product achieved by theinvention has a broad range of applications, such as for construction materials,insulating materials, fire proof materials, reinforcement materials etc.US20110271876 pertains to geopolymer compositions, methods of producing thecompositions, and uses thereof. The geopolymer compositions broadly arecomprised of a geopolymer binder and an aggregate and, once cured, can exhibitcompressive strengths in excess of that of Portland cement-based concreteformulations, adheres to most surfaces and can be used in the formation of amortarless building block, floor screed, bench, building block brick, supportcolumn or pre-molded column, beam, paving stone, a reinforced geopolymercomposition, a steel reinforced geopolymer composition, or as a substitute forstructural concrete in foundations, beams, columns, or slab with the addition asnecessary of steel reinforcement.US20120024196 is about tailored geopolymer composite binders for cement andconcrete applications. A geopolymer composite binder including (i) at least onefly ash material having less than or equal to 15 wt % of calcium oxide; (ii) atleast one gelation enhancer; and (iii) at least one hardening enhancer having adifferent composition from a composition of the at least one fly ash material.US20130319294 (Use Of Compounds Containing Aluminium Oxide And SiliconOxide For Producing A Hydrophilic Building Product) The use of a binder systemcomprising compounds containing aluminium oxide and silicon oxide forproducing a hydrophilic building product, characterized in that the sum of theoxides calculated as Al2O3 and SiO2 in the binder system is ≧40% by weight,based on the water-free binder system, and the contact angle of an oil dropplaced on the surface of the cured building product is ≧90°, where the contactangle determination is carried out under water, is proposed. The saidhydrophilicity makes the building product easy to clean, with simple rinsing withwater often being sufficient.US20140047999 offers process for production of acid and high temperatureresistant cement composites, where the matrix is alkali activated F fly ash alone,F Fly ash combined with ground slag or ground slag alone. F-fly ash produceslower quality alkali activated cement systems. On the other hand the lack ofcalcium oxide results in very high resistance to medium and highly concentratedinorganic or organic acids. The high strength and low permeability of pure F-flyash cement systems is achieved by using in the composition un-densified silicafume, the amorphous silicone dioxide obtained as by products in production offerro-silicones. Precipitated nano-particle silica made from soluble silicates andnano-particle silica fume produced by burning silicon tetra chloride in thehydrogen stream.US20140238273 reveals a method of producing a geopolymer product, whichcomprises: preparing an activated geopolymer premix by addition to ageopolymer premix of an activator compound that initiates a condensationreaction in the geopolymer premix; forming the activated geopolymer premixinto a desired configuration to form a geopolymer structure; and curing thegeopolymer structure to produce the geopolymer product, wherein thecharacteristics of the activated premix are controlled and the condensationreaction allowed to proceed for a period of time prior to forming such that whenformed the activated premix forms a self-supporting geopolymer structure.CN102464475A discloses a method for producing a superhigh strengthprestressed concrete pipe pile in a low carbon mode wherein the raw materials iscomposed of gelling material, broken stone, sand, magnetic-treated water, amagnetic-treated polycarboxylic acid water reducer and mekralon. The ratio ofwater to gel is 0.16-0.22, the gelling material is composed of 52.5 Portlandcement and a mineral admixture, the admixture is composed of ultrafine glassbeads, silicon powder, zeolite powder and fly ash. Compressive strength mayreach up to C120 super high strength concrete requirement, the breaking energyis increased, the method for producing the superhigh strength prestressedconcrete pipe pile in the low carbon mode can be realized.WO2009049085A2 discloses a process (100) for treating flue gas (110)containing fly ash and carbon dioxide. In the process, carbon dioxide and fly ashare contacted (115) with an aqueous metal hydroxide solution (120) to convertcarbon dioxide into a metal carbonate, and wherein the metal carbonate and themetal hydroxide cause the fly ash to undergo a geopolymerization reaction andform a geopolymerized fly ash. The geopolymerized fly ash is recovered (135) fordisposal or for further use, such as a concrete additive.WO2011135584A3 reveals a geopolymer-based concrete composition comprisingfly ash, an alkaline activator having Na2O:SiO2 molar ratio in the range of 0.68-1.13, calcium hydroxide, and water, along with inert aggregates and ordinaryPortland cement. The composition provides concrete having high thermalstability, high acid resistance, quick setting, cost effective, and can be cured atroom temperature. The composition is easy-to-make and reduces CO2 emissionsby up to 70%.WO2014141051A1 relates to a composite binder comprising: one or more Class Ffly ash materials, one or more gelation enhancers, and one or more hardeningenhancers, wherein each of the one or more Class F fly ash materials comprises15 wt.% or less calcium oxide, and wherein the composite binder is a Portlandcement-free binder for concrete. Also provided are Geopolymer CompositeCellular Concretes (GCCCs) including the composite binder and methods ofmaking these GCCCs.WO2016030904A1 discloses a method of forming geopolymer precast productcomprising: forming a geopolymer concrete composition comprising an alkalimetal silicate component, Aluminum oxide containing source materials,granulated blast furnace slag, fly ash (grade F), fine and coarse aggregates,water; and casting the geopolymer concrete into a mold and subjecting themolded concrete to consolidation using a suitable vibration table with curing atroom temperature.CN101570426A relates to geo-polymer recycled concrete and a preparationmethod thereof. The geo-polymer recycled concrete is prepared from rawmaterials of recycled coarse aggregate, recycled fine aggregate, fly ash, blastfurnace slag powder, water, sodium silicate, sodium hydrate, naphthalenesulfonate formaldehyde condensation compound and calcium saccharateaccording to certain mixing proportion by adopting a special stirring process. Theproduct of the geo-polymer recycled concrete can be widely applicable to roadengineering, structural engineering and other various civil engineeringconstructions.Traversal of the prior arts reveals that geopolymer concrete mix design availableor proposed till now are mostly based on the trial and error approach, whereaggregates content is fixed purely based on the weight percentage basis and donot account for their specific gravity values. The mass of aggregate required percubic meter of concrete is obtained from the product of the total mass ofconcrete per cubic meter and percentage of aggregate assumed (fixed). Anapproximate value as that of the mass of OPC concrete is taken as the total massof concrete, for materials mass calculations. This means that the aboveprocedure does not follow any specific standards, and more importantly, itignores the effect of the specific gravity of materials used. Because of this, thetrial and error approach reported so far yields inconsistent results. Obviously,when these methods are employed, users cannot attain uniform results all thetime. When the type or quality of aggregate changes, so does the strength.Currently, there is no method to give the AAS required for a particularcompressive strength or vice-versa.In the case of ordinary concrete, water to cement ratio governs the ultimatecompressive strength of the final product, even though there will be variation dueto other components such as fine and coarse aggregate type, size and content,admixture type and content. But if all the components are kept the same, thenwater to cement ratio governs the ultimate strength.It is evident from the above that there have been numerous efforts by theinventors across the world to develop geopolymer concrete design mixes usingvarious materials rich in aluminosilicates such as fly ash, metakaolin, rice huskash, mine tailings, etc., but none has attempted to develop mix designprocedure, which utilizes large amounts of red mud (rich in iron), fly ash andGGBS apart from avoiding heat curing but concurrently using more acceptedwater to cement ratio concept (here in this study, AAS to binder material ratio).Objective of the InventionBasic objective of the present invention is to provide medium to high strengthgeopolymer concrete mixes with the combination of fly ash, GGBS, and iron-richred mud- all industrial wastes responsible for serious problem to the environmentand method of designing the same.Another objective of the present invention is to provide said geopolymer concretemix which would employ a substantial amount of red mud, may be 20% or moreof the total weight of the composition geopolymer concrete mix.Another objective of the present invention is to provide said geopolymer concretemix which would not require the commonly practiced elevated temperaturecuring facility instead geopolymer concretes could be produced at ambienttemperature.Another objective of the present invention is to develop said geopolymer concretemix relying on, AAS to binder materials ratio which is similar to more acceptedwater to cement ratio concept.Another objective of the present invention is to provide said geopolymer concretemix which would account for specific gravity of all the raw materials to be used inthe mix design while calculating the quantity of raw materials to maintain theselected ratio of the mix to avoid trial and error method and provide forconsistent results for all the batches.Another objective of the present invention is to provide said geopolymer concretemix which will require settling time comparable to normal Portland cement.Another preferred objective of the present invention is to provide saidgeopolymer concrete mix which would enable to provide for customizablecompressive strength of the final concrete based on the selection of AAS tobinder ratio.Another objective of the present invention is to provide a process which is simple,easy to carry out and suitable for easy scale up.Summary of the InventionIn the primary embodiment the present invention is directed to provide acustomizable and eco-friendly geopolymer concrete composition includingindustrial wastes comprising of binder material selected from fly ash and iron richred mud in amounts of upto 20 % by wt. and heat generating amounts of GGBSin combination co-acting with alkaline activator solution (AAS) selected fromNaOH and sodium silicate maintaining AAS / binder ratios at 0.4- 0.8.Another embodiment of the present invention is directed to provide saidcustomizable and eco-friendly geopolymer concrete composition wherein saidindustrial waste include fly ash 50 % by wt, GGBS 30 % by wt, and iron-rich redmud 20 % by wt and specific gravity of binder materials involved selectivelyranged from 2 to 2.2 preferably 2.1, 2.8 to 3.0 preferably 2.93 and 2.95 to 3.05preferably 3.05 for fly ash, GGBS and red mud respectively and preferablyinvolved in the ratio of 50:30:20 respectively selectively based on saidrespective specific gravity of the said constituents from industrial waste fordesired room temperature curable medium to high strength concrete.Another embodiment of the present invention is directed to provide saidcustomizable and eco-friendly geopolymer concrete composition wherein saidalkaline activator solution (AAS) comprising NaOH and sodium silicate whereinAAS / binder ratios is maintained at 0.4- 0.8 and total concentration of AAS is 14M generating green geopolymer concrete with strength in the range of 65 to 75MPa preferably as high as 72 M MPa on 28th day.Yet another embodiment of the present invention is directed to provide saidcustomizable and ecofriendly geopolymer concrete composition wherein ratio ofsaid NaOH and sodium silicate is 2:3 andwherein said NaOH is 97% pure pellets and said sodium silicate is a compositionof 10% Na2O, 27% SiO2, and 63% water.Further embodiment of the present invention is directed to provide saidcustomizable and eco-friendly geopolymer concrete composition whereincompressive strength is customizable based on the compressive strength versusAAS to binder ratio relationship for the various spectrum of geopolymer concretesand preferablyincluding naphthalene based superplasticizer along with combined grading for asetting time in the range of 225 to 245 minutes preferably about 235 minutesand similar DIN standard curve matching with normal concrete (DIN B) attaininggood packing of binder and resultant aggregates with dense and less porousconcrete, advantageous in terms of strength as well as a durability.Still further embodiment of the present invention is directed to provide saidcustomizable and eco-friendly geopolymer concrete composition whereinselectively (a) concrete mix of only flyash and activator having Na2SiO3 to NaOHratio 1.5 and keeping molarity of the NaOH solution constant at 14M providegeopolymer concrete with ~ 45 MPa compressive strength and (b)concrete mix of only flyash (80-60%), GGBS (20-40%) and activator havingNaOH molarity of 14 and Na2SiO3 to NaOH ratio of 1.5, and alkaline activatorsolution to binder solids ratio of 0.5 provides geopolymer with 53-79 MPAcompressive strength.Another preferred aspect of the present invention is directed to provide a processfor the manufacture of the customizable and eco-friendly geopolymer concreteinvolving the composition comprising:providing industrial wastes comprising of binder material selected from fly ashand iron rich red mud in amounts of up to 20 % by wt. and heat generatingamounts of GGBS in combination with co-acting alkaline activator solution (AAS)selected from NaOH and sodium silicate maintaining AAS / binder ratios at 0.4- 0.8enabling desired for room temperature curable high strength concrete.Further aspect of the present invention is directed to provide said process whichis carried out involving said industrial waste include fly ash 50 % by wt, GGBS 30% by wt, and iron-rich red mud 20 % by wt preferably in the ratio of 50:30:20respectively selectively based on the specific gravity of the said constituents fromindustrial waste.Further aspect of the present invention is directed to provide said processcomprising the steps ofa. providing required amounts of coarse aggregates, fine aggregates, flyash, red mud, and GGBS as per the mix proportioning in the abovementionedorder in a concrete mixer;b. dry mixing for about 4-5 minutes followed by addition of sodiumsilicate solutionc. adding NaOH solution (prepared at least 6 hours prior to mixing) withcontinued mixing;d. optionally, adding naphthalene based superplasticizer to the mix andcontinuing the mixing till the uniformity in the mix is achieved.;e. casting thorough and complete mixed concrete cube specimens byplacing preferably in equal layers and ensuring proper compactionwith the aid of vibrating table;f. keeping aside the prepared specimens for sufficient hardening;g. removing the specimens from molds for curing at ambienttemperature;h. providing concretes strength in the range of 65 to 75 MPa includingpreferably up to 72 MPa on 28th day of curing.Still further aspect of the present invention is directed to provide said processwherein fly ash used comprised of SiO2 (61.92), Al2O3 (28.1), Fe2O3 (4.15),CaO (0.89), Na2O (0.37), K2O (0.8), Other Oxides (3.3), LOI (0.48)said GGBS comprised of SiO2 (33.1), Al2O3 (16.6), Fe2O3 (0.6), CaO (34.8),Na2O (0.2), K2O- (0.5), Other Oxides- (8.4), LOI (0.3) andSaid Red mud comprised of SiO2 (14.6), Al2O3 (24.26), Fe2O3 (50.11), CaO(1.03), Na2O (3.3), Other Oxides- (0.7), LOI (6.05) andwherein specific gravity of the binder materials involved selectively ranged from2.0 to 2.2 preferably 2.1, 2.8 to 3.0 preferably 2.93 and 2.95 to 3.15 preferably3.05 for fly ash, GGBS and red mud respectively;and remaining portion in the mix comprises fine aggregate passing 4.75 mm sizesieve, coarse aggregates of various fractions such as 20 mm passed, 12.5 mmpassed, and 6.3 mm passed, respectively, having specific gravity values of: 2.63,2.70, 2.71, and 2.68 respectively.DETAILED DESCRIPTION OF THE INVENTIONAs mentioned hereinbefore the present invention provides a new mix design forthe development of geopolymer concrete using fly ash, GGBS along withconsiderable percentage of red mud, as binder materials in place of cementwherein % composition of the same is based on specific gravity. The inventionalso provides AAS (alkaline activator solution) to binder ratio chart to preparemix with customizable compressive strength.The majority of the mix designs developed or under usage involving fly ash,metakaolin, GGBS and other waste materials, either in isolation or in combinationso far are mostly based on trial and error approach. However, developing a mixdesign is very difficult because of the large number of variables involved in it.There is no such methodology for geopolymer concrete production by using flyash, GGBS and red mud, combination as binder materials. Indian red mud whichis employed for the present invention as one of the major ingredients comesunder the high iron content (> 50%) category. Significantly high iron contentcauses hindrances to the bond formations which may be a reason why red mudusage in concrete production is negligible.Another important feature with regard to mix designs available so far forgeopolymer concrete is that most of the designs adopt combined grading ofaggregates, which is not a default consideration. Using the combined grading ofaggregate, well compact and densely packed geopolymer concrete can beachieved. Combined grading suitable for normal concrete might also be suitablefor geopolymer concrete, as its fresh properties resemble that of OPC somewhat.In addition, considering specific gravity of all the materials used in makinggeopolymer concretes nullifies the disadvantages in the prior mix designsdeveloped for geopolymer concrete, which are based on the percentage weight.The step of giving leverage to specific gravity makes the proposed methodologyuniversally acceptable irrespective of the aggregate properties.Another main drawback in many of the currently available mix design proceduresis dearth of an option, to the user, to select the AAS to binder solids ratio toproduce the concrete of their desired compressive strength and vice-versa.Therefore, a versatile mix design that considers the aforementioned parametersis need of the hour to promote the suitability of the green concrete such as GPCover the currently used OPC. In the current mix design, a fundamental graphbetween 28th day compressive strength and AAS content is developed and basedon this graph, the user can determine either the AAS required for a particularcompressive strength or vice-versa.Geopolymer concretes usually require elevated temperatures for fasterdissolution of alumina and silica species, basic constituents of binder materials,and for expeditious geopolymerization to occur. If fly ash and red mud have to beused as binder materials for making geopolymer concrete, heat curing isimperative. The heat curing requirement may restrict the production ofgeopolymers on a larger scale, and hence avoiding heat curing can help inincreasing the number of geopolymer concrete users. This limitation can beovercome by adding GGBS. GGBS being exothermic in nature, generatessubstantial heat internally within the matrix upon reacting with activatorsolutions. The elevated heat supplied by the GGBS reaction helps in rapidgeopolymerization and, thereby, circumvents the necessity of external heatcuring. Further, GGBS addition in the binder mix improves the compressivestrength characteristics and profoundly affects setting times of the concrete mix.Thus, the amount of GGBS into the mixture of fly ash and red mud plays a verycrucial role for the final characteristics of the GPC.It is to be understood that both the foregoing general description and thefollowing detailed description for the mix design methodology and strengthversus AAS to binder ratio relation for geopolymer concrete made with class F flyash, red mud, and GGBS, all together, as binder materials are exemplary, andare intended to provide further explanation of the invention as claimed. Theadvancement according to the present invention is discussed in further detail inrelation to the following non-limiting exemplary illustrations wherein:Figure 1: Variation of compressive strength with Na2SiO3 / NaOH ratioFigure 2: Variation of compressive strength with NaOH molarityFig. 3: Compressive strength of fly ash-GGBS geopolymer mortarFig.4: Compressive strength of fly ash-GGBS-red mud geopolymer mortarFig. 5. Combined Aggregate Grading Curve, DIN-grading curve adopted for thestudy Size of the aggregate (mm) on X-axis and % of Passing of the aggregateon Y-axisFig. 6. Mixing and Ambient Temperature CuringFig. 7. Strength versus AAS / Binder ratio curveExamplesUnlike the mix proportioning of normal concrete (OPC) where the water contentis chosen based on the maximum size of the aggregate used in the mix, the AAShas been kept constant as 200 kg / m3 for all the mixes of geopolymer concretesfor the present invention. In the case of normal concrete, water, the cost ofwhich is negligible, is used to prepare the mixes. On the other hand, alkalineactivator solution, the costliest ingredient in geopolymer concrete as compared toOPC, is used in making geopolymer concrete.Steps followed to determine the specific combination of the present inventiona. Fly ash and AAS quantity kept constant for mixb. Select ratio of Na2SiO3 / NaOH and NaOH determinedc. By slow replacement of fly ash, GGBS is introduced and based on compressivestrength and settling time the ratio is fixed.d. Keeping GGBS constant Flyash is replaced with red mud providing select ratioof fly ash-GGBS-red mud combination of 50%:30%:20%Keeping the AAS content constant, the design mixes for geopolymer concrete forvarious AAS / binder ratios (in place of water / cement ratio) have been developed.As the standard water / cement ratio versus compressive strength curve is thewidely followed one for designing normal concrete mixes, following a similarprocedure with minor deviations simplifies the design mix procedure forgeopolymer concrete. In this present invention, a standard AAS / binder ratioversus compressive strength curve valid exclusively for geopolymer concretemade with the abovesaid industrial by-products have been developed.Example-1After fixing the AAS content in all the mixes, the next step is to determine theindividual quantities of the alkaline activators such as sodium hydroxide, sodiumsilicate, and optimum molarity of sodium hydroxide solutions. In order todetermine the select NaOH molarity and Na2SiO3 to NaOH ratio, preliminaryinvestigations are made at laboratory scale samples. For this purpose, a set ofsamples are cast to study the influence of varying (a) Na2SiO3 to NaOH solutionratios (1, 1.5, 2, and 2.5) and (b) molarity of NaOH (10M, 12M, 14M, 16M, and18M) on the compressive strength properties of fly ash based geopolymermortar.Determining the select AAS concentrationMix proportioning: Class F fly ash is used as binder material, Sodium hydroxideand sodium silicate are used as an alkaline activator solution. Initially, the ratiobetween alkaline solution and fly ash was kept constant at 0.5 for all the mixdesigns. Then, mix design has been done by varying the Na2SiO3 to NaOH ratiosranging from 1.0 to 2.5, but by keeping molarity of the NaOH solution constantat 12M. After finding out the select silicates to hydroxides ratio, design mix wasre-worked by altering the NaOH molarity (10, 12, 14, 16, and 18M), maintainingsaid select silicates to hydroxides ratio. The mortar mix proportions for varioussilicates to hydroxide ratios and for different sodium hydroxide molarities arepresented in Table 2 below.Table 2 : Mix proportions for various ratios of Na2SiO3 / NaOH and NaOHmolarityFor each mix, a set of 9 cubes of size 10×10×10 cm3 each is cast correspondingto various Na2SiO3 to NaOH ratios and NaOH molarity, as listed in Table 2.Initially, fly ash and sand are dry mixed for 5 minutes followed by gradualaddition of NaOH and Na2SiO3 solution i.e. over a period of 30 Sec. The mixture isthen blended for another 5 minutes. Identical mixing process and castings arefollowed for individual mix. Contents in the cube are compacted adequately byplacing the mould on vibrating table. Later, the moulds are kept for oven curingat 70°C for a period of 24 hours. After 24 hours of oven curing, the moulds areremoved from oven and then demoulded after attaining room temperature.Demoulded samples are kept under the ambient conditions until the day oftesting. The mix design is prepared by following Absolute Volume method andEuropean Standards (DIN 1045-2).Testing of samplesAll the specimens are cast and cured as per the procedure explained above andthe compressive strength tests are performed (a) at the age of 1, 7 and 28 daysfor the specimens made with different silicates to hydroxide ratios for a constantNaOH molarity of 12M, and (b) at the age of 7 and 28 days for specimens madewith different molarity of NaOH, but with constant Na2SiO3 to NaOH ratio of 1.5.Tests have been carried out in accordance with ASTM C109 standard.Influence of Na2SiO3 / NaOH and NaOH Molarity on Compressive StrengthFigure 1 shows the influence of Na2SiO3 to NaOH ratio on the compressivestrength of fly ash based geopolymer mortar. It is evident from the figure thatthe compressive strength increased initially with an increase in Na2SiO3 to NaOHsolution ratio of up to 1.5 and beyond that it decreased continuously. Studiesalso demonstrate that increase in concentration of NaOH solution increases thecompressive strength of geopolymers. Therefore, tests have been conducted onthe specimens that are prepared by keeping the Na2SiO3 to NaOH ratio constantat 1.5 and altering the NaOH molarity, to observe the effect of increase in themolarity on the compressive strength. From the plot of NaOH molarity drawnagainst 7 & 28-day compressive strengths (Figure 2), it is seen that with anincrease in the molarity from 10 to 16M the compressive strength is increasedand beyond this molarity, it decreased. From the experimental work, it isobserved that better workability and compressive strength can be attained whenthe alkaline solution contains Na2SiO3 to NaOH in the ratio of 1.5 and NaOHmolarity of 14M (at higher molarities the workability and setting times getsaffected).The AAS employed in this study comprises of sodium hydroxide and sodiumsilicate solution. The sodium silicate solution is brought from the local chemicalsuppliers and its chemical composition consists of 10% Na2O, 27% SiO2, and63% water. Sodium hydroxide of 14M is used in this study and is prepared bymixing 560 grams of sodium hydroxide pellets, having 97% purity, and water ofrequired quantity to make one liter total solution.Example-2Geopolymer concrete developed using fly ash, alone, as binder material displaymoderate compressive strength and is not economical. It also requires heatcuring for faster setting and better geopolymerization. For rapid dissolution ofaluminosilicates of the binder materials and better geopolymerization to takeplace, heat curing is generally adopted in geopolymer concrete production. Asstated above one option to avoid heat curing has been found by adding GGBS inthe mix. Therefore, further study has been conducted by adding GGBS to fly ashand AAS mix. In the mix, fly ash is replaced with GGBS in percentages of 10, 20,and 30. The substitution of GGBS is found to improve the strength properties anddecrease the setting times of the geopolymer concrete, simultaneously avoidingheat curing. Studies on the geopolymer concrete mixes extended by adding redmud as one of the binder materials. Preliminary investigations are carried out todetermine the select binder material composition i.e. fly ash, GGBS and red mud.In order to determine the select composition, preliminary investigations arecarried out for a) fly ash and GGBS, and (b) fly ash, GGBS, and red mudcombination. For this, experimental investigations are conducted to study thecompressive strength properties of geopolymer mortars developed using theabove combinations.Mix proportioningFrom the above study, sodium hydroxide molarity and sodium silicate to sodiumhydroxide ratio are determined as 14 and 1.5, respectively. To determine theselect binder material (solids) combination, NaOH molarity of 14 and Na2SiO3 toNaOH ratio of 1.5, and alkaline activator solution to binder solids ratio of 0.5, arekept constant for all the mix designs. Then, mix design has been done by varyingthe fly ash and GGBS proportions, as shown in Table 3. After determining theoptimum fly ash and GGBS proportions, the selective fly ash, GGBS, and red mudproportions are then determined by keeping the GGBS proportion constant (i.e.select GGBS proportion determined from fly ash-GGBS study), as shown in Table4.Table 3: Mix proportions for various fly ash-GGBS combinationTable 4: Mix proportions for various fly ash-GGBS-red mud combinationNote: FGR: Fly ash-GGBS-Red mud; AAS / BS = 0.5For each mix, a set of 9 cubes of each size 10×10×10 cm3 are cast. Initially,binder solids and sand are dry mixed for 5 minutes followed by gradual additionof NaOH and Na2SiO3 solution. The mixture is then blended for another 5minutes. Identical mixing process and castings are followed for individual mix.Contents in the cube are compacted adequately by placing the mould on vibratingtable. After 24 hours of ambient curing, the cubes are demoulded and kept underambient conditions until the day of testing. The mix design is prepared byfollowing Absolute Volume method and European Standards (DIN 1045-2).Testing of samples: All the specimens are cast and cured as per the procedureexplained above and the compressive strength tests are performed at the age of7, 14, and 28 days for the specimens made with different fly ash - GGBSproportions, and fly ash, GGBS, and red mud proportions. Tests have beencarried out in accordance with ASTM C109 standard.Compressive Strength BehaviourFig. 3 shows the compressive strength variation with the addition of GGBS to flyash in the mix. It can be observed from the figure that the compressive strengthincreased with an increase in GGBS content in the mix. There is no significantincrease of compressions strength for 14 days and 28 days sample and increaseof compressive strength is almost linear. However, for 7 days compressivestrength increases synergistically for 20 to 40 % of GGBS. It is also observed thatwith increasing addition of GGBS in fly ash drastically decreased the settingtimes. Keeping the compressive strength and setting times of the geopolymers inmind, the fly ash and GGBS proportions are fixed at 70% and 30% (assuming240 min setting time is acceptable).Further, by keeping the GGBS proportion in the mix at 30%, the mixproportioning of fly ash-GGBS-red mud combination has been done as shown inTable 4. The compressive strength obtained for the same at 7, 14, and 28 dayshas been plotted as shown in Fig. 4 which depicts that, the compressive strengthat all ages is increased with an increase in the red mud content up to 20% only,and thereafter, there is a drastic decrease in the strength. The same has beenobserved at all ages. Therefore, based on the study, fly ash-GGBS combination of70%:30% and fly ash-GGBS-red mud combination of 50%:30%:20% areselected.Example-3Method for preparation of geopolymer and 28 days compressive strengthand AAS / binder ratioTo address the issue of workability, employment of naphthalene basedsuperplasticizer resulted in, a setting time of 235 minutes, which is assumed tobe an acceptable setting time.The materials used in the geopolymer concrete have different specific gravityvalues, and the designing of mix on the weight basis (which is followed bymajority of reported processes) does not give uniform results, and hence, theabsolute volume method which considers the specific gravity of each material isexploited to get uniform results. Furthermore, good packing of binder andaggregates gives dense and less porous concrete, which can be advantageous interms of strength as well as a durability point of view. Therefore, combinedgrading, as shown in Fig. 5 has been used, and a similar DIN standard curvematching with normal concrete (DIN B) is employed. DIN grading curves arefollowed in this study as it considers the combined aggregate grading that is veryeffective to attain uniform grading and the end concrete mix.The specific gravity values of binder materials such as fly ash, red mud, andGGBS employed for the mix are 2.1, 3.05, and 2.93, respectively. The remainingportion in the mix contains fine aggregate passing 4.75 mm size sieve, coarseaggregates of various fractions such as 20 mm passed, 12.5 mm passed, and 6.3mm passed, respectively, has specific gravity value of 2.63, 2.70, 2.71, and 2.68respectively. Percentage Fraction of aggregates along with quantities includingthe quantities of alkaline activator and binder materials used for the mix designare shown in Table 5.Table 5: Mix Design ProportionAs mentioned earlier, AAS is the costliest ingredient among the materials used ingeopolymer concrete, and in order to achieve the workable mix, the AAS contentis fixed to 200 kg / m3 (based on the fresh properties measurements). Keeping theAAS content constant, the geopolymer concrete mixes at various AAS / binderratios such as 0.4, 0.5, 0.6, 0.7, and 0.8, have been designed, as shown in Table5.Raw materials such as coarse aggregates, fine aggregates, fly ash, red mud, andGGBS, are calculated as per the mix proportioning and are placed in the abovementionedorder. These ingredients are at first dry mixed in a concrete mixer forabout 4-5 minutes, and then sodium silicate solution is added. While the mixingis continued, NaOH solution (prepared at least 6 hours prior to mixing) is addedto the contents. Followed by required quantity of naphthalene basedsuperplasticizer is added to the mix and the mixing is continued till the uniformityin the mix is achieved. Ensuing thorough and complete mixing, concrete cubespecimens are cast by placing in 3 equal layers and by giving proper compactionwith the aid of vibrating table. The prepared specimens are then kept aside toensure that they are sufficiently hardened. Specimens then removed from moldsare cured at ambient temperature till the time of testing (i.e. 28 days). Fig. 6shows the concrete specimens kept for curing under ambient temperature.The cured specimens are then subjected to compressive strength tests at 28thday. Based on the obtained results, a relationship between 28 days compressivestrength and AAS / binder ratio is developed, as shown in Fig. 7. It is worthhighlighting that this proposed relationship in the form of a mathematical curveserves as a guide for a user either to choose the target 28th day compressivestrength and thereby, determine the corresponding AAS / binder ratio orAAS / binder ratio and thereby determine the corresponding 28th day compressivestrength. The AAS / binder ratio range is considered from 0.4 to 0.8 in this study.AAS / binder ratio, even lower than 0.4, can also be used to produce the proposedconcrete. However, to simplify the things, strength versus AAS to binder ratiocurve is developed for the ratios from 0.4 to 0.8 only and the same results areextended accordingly in the proportionate manner. The extended curve, which isfit mathematically, can be used for the AAS to Binder ratios less than 0.4 as wellas greater than 0.8.Based on the elaborate laboratory experimental investigations as discussedabove, selective binder materials fly ash, GGBS, and red mud contents are fixedat 50%, 30%, and 20%, respectively. At this ratio, with variable content of AASgeopolymers obtained have shown better workability and strength propertieseven cured at ambient temperature, which eliminate the necessity of heat curingcompletely. As a representative example preparation of geopolymer having 28day compressive strength 60-64 MPa comprises the steps ofi. charging 1103.32 Kg of coarse aggregates, 670 Kg of fineaggregates, 220 Kg of fly ash, 88 Kg of red mud and 132 Kg ofGGBS into a concrete mixer;ii. Dry mixing for about 4-5 minutes followed by addition of 120 Kg ofsodium silicate solutioniii. Adding 80 Kg of NaOH solution (prepared at least 6 hours prior tomixing) with continued mixing;iv. Adding naphthalene based superplasticizer (5.2 Kg) to the mix andcontinuing the mixing for 3-4 mins for achieving uniformity in themix;v. casting thorough and complete mixed concrete in the cube byplacing in 3 equal layers and ensuring proper compaction with theaid of vibrating table for about 45 Sec;vi. Keeping aside the prepared concrete for sufficient hardening;vii. Removing the concrete specimens from molds for curing atambient temperature;viii. Providing concretes strength upto 60-64 MPa on 28th day ofcuring.The oxides composition of the binder materials and binder materialcharacterization are shown in Table 6 and 7 respectively.Table 6: Oxides Composition of Binder MaterialsTable 7: Binder Material CharacterizationThus in the primary embodiment the present invention provides medium to highstrength geopolymer concrete mixes involving fly ash, GGBS, and iron-rich redmud-all are industrial wastes causing serious problem to the environment in theratio of 50:30:20. Because of negative impacts of the red mud, being highlyalkaline and iron-rich, there are only few reports involving the same. Presentinvention accentuates the said minimum usage of red mud to 20%, the largestpercentage usage of red mud in a single application so far. Keeping the red mudconcentration 20%, present invention attains green geopolymer concrete withstrength as high as 72 MPa on 28th day by purely using the industrial waste of flyash, red mud, and GGBS.In another embodiment of the invention, curing of the said medium to highstrength geopolymer concrete mix takes place at room temperature. For bindermaterials comprising of fly ash and red mud heat curing is imperative to makegeopolymer concrete. This limitation is overcome by adding GGBS into thebinding mixture of fly ash and red mud. Being GGBS exothermic in nature, itgenerates substantial heat internally within the matrix upon reacting withactivator solutions which helps in rapid geopolymerization and, thereby,circumvents the necessity of external heat curing. Importantly, addition of 30%GGBS addition in GPC helps to avoid heat curing with acceptable setting timeswith simultaneous improvement of compressive strength.The highlight feature of this invention is that it considers the specific gravitiesalong with the combined grading to produce medium to high strength concreteusing industrial wastes such as fly ash, red mud, and GGBS, in tandem. Theconstituents for geopolymer concrete have different specific gravity values, anddesigning of the mix on weight basis does not give uniform results, and hence,the absolute volume method which considers the specific gravity of each materialis employed to get uniform results and the selective ratio of fly ash: GGBS: redmud of 50:30:20 is based on the specific gravity measurements. Furthermore,good packing of binder and aggregates gives dense and less porous concrete,which is advantageous in terms of strength as well as a durability point of view.Therefore, combined grading, has been successfully used for the presentinvention.In another embodiment of the present invention developed relationship between28 days compressive strength and AAS / binder ratio wherein this proposedrelationship in the form of a mathematical curve serves as a guide for a usereither to choose the target 28th day compressive strength and thereby,determine the corresponding AAS / binder ratio, or AAS / binder ratio and therebydetermine the corresponding 28th day compressive strength. The invention isthus special due to the user friendly nature (user can choose either strength orAAS / binder ratio) and easy to follow steps of mix design for producinggeopolymer concretes using Indian red mud (having very high iron content),class F fly ash, and GGBS to avoid heat curing as well as to improve the strengthproperty. Its inventiveness lies in producing green, cement free, eco-friendlygeopolymer concrete with strength as high as 72MPa at 28th day by purely usingindustrial waste of fly ash, red mud and GGBS. The proposed mix design is morerationale, scientific and holistic in approach rather than mere resorting to trialand error approach, which most of the existing methods follow.Thus the advantages attained by the present invention are as follows;(i) Utilization of iron-rich red mud up to 20% along with the fly ash and GGBS,(ii) Avoiding the need of elevated temperature curing facility as the geopolymerconcretes are produced at ambient temperature,(iii) Accounts for the specific gravity of all raw materials used in the mix design,(iv) Proposes compressive strength versus AAS to binder ratio relationship for thevarious spectrum of geopolymer concretes to the end-users, and(v) Simple and easily understandable mix design procedure.The present mix design method, which is disclosed and claimed, is a newmethodology not confined to the specified weight % only. One has to follow thepresent procedure or little variation of it, to arrive at the selective binder materialcomposition. The selective material composition varies with material to material,also with the variation of chemical oxides composition of the binder material(s).So, everyone has to follow the procedure, which is elaborated in this invention, toattain the selective binder material compositions.

Claims

1. A customizable and eco-friendly geopolymer concrete composition including industrial wastes comprising of binder material selected from fly ash and iron rich red mud in amounts of upto 20 % by wt. and heat generating amounts of GGBS in combination co-acting with alkaline activator solution (AAS) selected from NaOH and sodium silicate maintaining AAS / binder ratios at 0.4- 0.8.

2. The customizable and eco-friendly geopolymer concrete composition as claimed in claim 1 wherein the said industrial waste include fly ash 50 % by wt, GGBS 30 % by wt, and iron-rich red mud 20 % by wt and specific gravity of binder materials involved selectively ranged from 2 to 2.2 preferably 2.1, 2.8 to 3.0 preferably 2.93 and 2.95 to 3.05 preferably 3.05 for fly ash, GGBS and red mud respectively and preferably involved in the ratio of 50:30:20 respectively selectively based on said respective specific gravity of the said constituents from industrial waste for desired room temperature curable medium to high strength concrete.

3. The customizable and eco-friendly geopolymer concrete composition as claimed in anyone of claims 1 or 2 wherein said alkaline activator solution (AAS) comprising NaOH and sodium silicate wherein AAS / binder ratios is maintained at 0.4- 0.8 and total concentration of AAS is 14 M generating green geopolymer concrete with strength in the range of 65 to 75 MPa preferably as high as 72 M MPa on 28th day.

4. The customizable and ecofriendly geopolymer concrete composition as claimed in anyone of claims 1 to 3 wherein ratio of said NaOH and sodium silicate is 2:3 and wherein said NaOH is 97% pure pellets and said sodium silicate is a composition of 10% Na2O, 27% SiO2, and 63% water.

5. The customizable and eco-friendly geopolymer concrete composition as claimed in anyone of claims 1 to 4 wherein compressive strength is customizable based on the compressive strength versus AAS to binder ratio relationship for the various spectrum of geopolymer concretes and preferably including naphthalene based superplasticizer along with combined grading for a setting time in the range of 225 to 245 minutes preferably about 235 minutes and similar DIN standard curve matching with normal concrete (DIN B) attaining good packing of binder and resultant aggregates with dense and less porous concrete, advantageous in terms of strength as well as a durability.

6. The customizable and eco-friendly geopolymer concrete composition as claimed in anyone of claims 1 to 5 wherein selectively (a) concrete mix of only flyash and activator having Na2SiO3 to NaOH ratio 1.5 and keeping molarity of the NaOH solution constant at 14M provide geopolymer concrete with ~ 45 MPa compressive strength and (b) concrete mix of only flyash (80-60%), GGBS (20-40%) and activator having NaOH molarity of 14 and Na2SiO3 to NaOH ratio of 1.5, and alkaline activator solution to binder solids ratio of 0.5 provides geopolymer with 53-79 MPA compressive strength.

7. A process for the manufacture of the customizable and eco-friendly geopolymer concrete involving the composition as claimed in anyone of claims 1 to 6 comprising: providing industrial wastes comprising of binder material selected from fly ash and iron rich red mud in amounts of up to 20 % by wt. and heat generating amounts of GGBS in combination with co-acting alkaline activator solution (AAS) selected from NaOH and sodium silicate maintaining AAS / binder ratios at 0.4- 0.8 enabling desired for room temperature curable high strength concrete.

8. The process as claimed in claim 7 which is carried out involving said industrial waste include fly ash 50 % by wt, GGBS 30 % by wt, and ironrich red mud 20 % by wt preferably in the ratio of 50:30:20 respectively selectively based on the specific gravity of the said constituents from industrial waste.

9. The process as claimed in anyone of claims 7-8 comprises the steps of a. providing required amounts of coarse aggregates, fine aggregates, fly ash, red mud, and GGBS as per the mix proportioning in the abovementioned order in a concrete mixer; b. dry mixing for about 4-5 minutes followed by addition of sodium silicate solution; c. adding NaOH solution (prepared at least 6 hours prior to mixing) with continued mixing; d. optionally, adding naphthalene based superplasticizer to the mix and continuing the mixing till the uniformity in the mix is achieved.; e. casting thorough and complete mixed concrete cube specimens by placing preferably in equal layers and ensuring proper compaction with the aid of vibrating table; f. keeping aside the prepared specimens for sufficient hardening; g. removing the specimens from molds for curing at ambient temperature; h. providing concretes strength in the range of 65 to 75 MPa including preferably up to 72 MPa on 28th day of curing.

10. The process as claimed in anyone of claims 7 to 9 wherein fly ash used comprised of SiO2 (61.92), Al2O3 (28.1), Fe2O3 (4.15), CaO (0.89), Na2O (0.37), K2O (0.8), Other Oxides (3.3), LOI (0.48) said GGBS comprised of SiO2 (33.1), Al2O3 (16.6), Fe2O3 (0.6), CaO (34.8), Na2O (0.2), K2O- (0.5), Other Oxides- (8.4), LOI (0.3) and Said Red mud comprised of SiO2 (14.6), Al2O3 (24.26), Fe2O3 (50.11), CaO (1.03), Na2O (3.3), Other Oxides- (0.7), LOI (6.05) and wherein specific gravity of the binder materials involved selectively ranged from 2.0 to 2.2 preferably 2.1, 2.8 to 3.0 preferably 2.93 and 2.95 to 3.15 preferably 3.05 for fly ash, GGBS and red mud respectively; and remaining portion in the mix comprises fine aggregate passing 4.75 mm size sieve, coarse aggregates of various fractions such as 20 mm passed, 12.5 mm passed, and 6.3 mm passed, respectively, having specific gravity values of: 2.63, 2.70, 2.71, and 2.68 respectively.