final_1

1. INTRODUCTION1.1. PreambleIt is widely known that the production of Portland cement consumes considerable energy and at the same time contributes a large volume of CO2 to the atmosphere. However, Portland cement is still the main binder in concrete construction prompting a search for more environmentally friendly materials. One possible alternative is the use of alkali-activated binder using industrial by-products containing silicate materials (Gjorv, 1989; Philleo, 1989). The most common industrial by-products used as binder materials are fly ash (FA) and ground granulated blast furnace slag (GGBS). GGBS has been widely used as a cement replacement material due to its latent hydraulic properties, while fly ash has been used as a pozzolanic material to enhance the physical, chemical and mechanical properties of cements and concretes (Swamy, 1986).Recent research has shown that it is possible to use 100% fly ash or slag as the binder in mortar by activating them with an alkali component, such as; caustic alkalis, silicate salts, and non silicate salts of weak acids (Bakharev, Sanjayan, & Cheng, 1999a; Talling & Brandstetr, 1989). There are two models of alkali activation. Activation by low to mild alkali of a material containing primarily silicate and calcium will produce calcium silicate hydrate gel (C-S-H), similar to that formed in Portland cements, but with a lower Ca/Si ratio (Brough & Atkinson, 2002; Deja, 2002). The second mechanism involves the activation of material containing primarily silicate and aluminates using a highly alkaline solution. This reaction will form an inorganic binder through a polymerization process (Barbosa, MacKenzie, & Thaumaturgo, 2000; Sindhunata, 2006a; Xu, 2002). The term Geopolymeric is used to characterise this type of reaction from the previous one, and accordingly, the name geopolymer has been adopted for this type of binder (Davidovits, 1994). The geopolymeric reaction differentiates geopolymer from other types of alkali activated materials (such as; alkali activated slag) since the product is a polymer rather than C-S-H gel.Blast furnace slag is a by-product generated during manufacturing of pig iron and steel and may be defined according to ACI- 116R as nonmetallic product consisting essentially of calcium silicates and other bases that is developed in a molten condition simultaneously with iron in a blast furnace. It consists primarily of silicates, alumina-silicate and calcium- alumina- silicates. The cooling process of slag is responsible mainly for generating different types of slags required for various end users. The physical and pozzolanic properties of slag vary widely with the process of cooling. Granulated blast furnace slag is a non-toxic material and can be a good raw material for making high-value and user friendly cementitious material for different civil engineering applications. Red mud, also known as bauxite residue, is a waste produced from the alumina industry. Depending on the quality and purity of bauxite ores, the quantity of red mud generated varies from 55-65% of the processed ores (Paramguru et al. 2005). In addition, according to a recent US Geological Survey report (2009), bauxite ores mined globally amount to 202 million tons (MT) in 2007 and 205 MT in 2008, which indicates the huge quantity of red mud generated worldwide annually. Red mud is characterized by strong alkalinity (e.g., pH = 12 -13) and high water content. Nowadays, all over the world, the most common disposal way of red mud is to store it within specially constructed landfill sites near the alumina refinery plants, which is very costly and tends to be harmful to the surrounding environment due to its high alkalinity. Although extensive research has been conducted to reuse red mud (Glanville and Winnipeg 1991; Singh and Prasad 1996; Singh et al. 1997; Marabini et al. 1998; Yalcin and Plescia 2000; Ayres et al. 2001; Cundi et al. 2005), to date there is still no viable and environmentally acceptable solution for utilization of red mud. In fact, there is a common agreement that geopolymerization could convert a wide range of aluminosilicate waste materials into building materials with excellent physical and chemical properties as well as long-term durability (Davidovits 1991; Davidovits et al. 1994; krivenko 1998; Usherov-Marshak 1998; and Krivenko and Skurchinskaya 1991).The various aluminosilicate materials such as flyash, Metakaolin, GGBS, Silica fume etc can be used as source materials for alkali-activation. Of late, most of the research on alkali-activation has been used fly ash as the starting materials. However, studies on Alkali-activated blast furnace slag are still very limited. Thus more study has to be carried out before arriving at any definite conclusion. In order to have complete understanding of the possibilities of applications of AAS in different fields, a thorough study of its manufacturing processes, synthesizing parameters, mix design are very much essential.

This research describes the geopolymer technology as an innovative means of reuse of red mud which features high alkalinity and provides alumina, and blast furnace slag which provides reactive silica (amorphous phase) absent in red mud. Furthermore, sodium silicate, the only constituent that is a non-waste used for geopolymer synthesis, will also provide additional Si and Na for alkaline activation of red mud and GGBS. In effect, this process turns industrial waste outputs (i.e. red mud and blast furnace slag) into an input for another industry. The objective of this research is to investigate the potential utilization of red mud and blast furnace slag as raw materials for the production of blended alkali activated composites that can be used as a valuable resource for civil infrastructure constructions.

1.2. Geopolymer terminology and chemistryIn 1978, Davidovits proposed that an alkaline liquid could be used to react with the silicon (Si) and the aluminium (Al) in a source material of geological origin or in by-product materials such as fly ash and rice husk ash to produce binders. Because the chemical reaction that takes place in this case is a polymerization process, Davidovits coined the term Geopolymer to represent these binders.Geopolymers are members of the family of inorganic polymers. The chemical composition of the geopolymer material is similar to natural zeolitic materials, but the microstructure is amorphous instead of crystalline.

The schematic formation of geopolymer can be shown as described by Equations (1-1) and (1-2).

(1.2)(1.1)The chemical reaction may comprise the following steps : Dissolution of Si and Al atoms from the source material through the action of hydroxide ions. Transportation or orientation or condensation of precursor ions into monomers. Setting or polycondensation / polymerisation of monomers into polymeric structures.However, these three steps can overlap with each other and occur almost simultaneously, thus making it difficult to isolate and examine each of them separately.Water is released during the chemical reaction that occurs in the formation of geopolymers. This water, expelled from the geopolymer matrix during the curing and further drying periods, leaves behind discontinuous nano-pores in the matrix, which provide benefits to the performance of geopolymers. The water in a geopolymer mixture, therefore, plays no role in the chemical reaction that takes place; it merely provides the workability to the mixture during handling. This is in contrast to the chemical reaction of water in a Portland cement mixture during the hydration process.A geopolymer can take one of the three basic forms: Sialate is an abbreviation for silicon-oxo-aluminate. Polysialates are chain and ring polymers with Si4+ and Al3+ in IV-fold coordination with oxygen and range from amorphous to semi-crystalline.

(i) Poly (sialate), which has [-Si-O-Al-O-] as the repeating unit.(ii) Poly (sialate-siloxo), which has [-Si-O-Al-O-Si-O-] as the repeating unit.(iii) Poly (sialate-disiloxo), which has [-Si-O-Al-O-Si-O-Si-O-]

Figure 1 : Possible chemical structure of geopolymeras the repeating unit.

Figure 2 : Basic forms of Geopolymer according to Davidovits.

1.3. Historical development of GeopolymersIn the 1930s, alkalis, such as sodium and potassium hydroxide, were originally used to test iron blast furnace ground slag to determine if the slag would set when added to Portland cement.

In the course of studying the testing systems for slag, Belgian scientist Purdon (1940) discovered that the alkali addition formed a new, rapid-hardening binder. He examined the sodium hydroxide on a variety of minerals and glasses containing silicon and / or aluminum and concluded it in two steps;(1) Liberation of silica, alumina and lime and(2) Formation of hydrated calcium silicates, aluminates as well as regeneration of alkaline solution. It was proposed that the hardening mechanism of alkali activated alumino silicate binder involves dissolution of Si or Al in the presence of sodium hydroxide, and precipitation of calcium silicate or aluminum hydrate with the generation of sodium hydroxide. Alkali-activated slag cements (called Trief cements) were used in large-scale construction as early as the 1950s. The usual activation is done by adding 1.5 % NaCl and 1.5 % NaOH to 97 % ground slag mix.

In 1957, Victor Glukhovsky, a scientist working in the Ukraine at the KICE (Kiev Institute of Civil Engineering in the USSR) investigated the problem of alkali-activated slag binders and in the 1960s and 1970s ultimately identified both calcium silicate hydrates, and calcium and sodium alumino-silicate hydrates (zeolites) as solidification products. He also mentioned that rocks and clay minerals react during alkali treatment to form sodium alumino-silicate hydrates (zeolites), confirming earlier work carried out on clay reactivity. Glukhovsky called the concretes produced with this technology "soil silicate concretes" and the binders "soil cements".

Earlier, Flint & al (1946), at the National Bureau of Standards were developing various synthesizing processes for the extraction of alumina starting from clays and high-silica bauxites.

Howell (1963) developed a Zeolite A type, using calcined kaolin (metakaolin) instead of kaolinite, preventing the formation of hydrosodalite. In 1972, the ceramicist team Jean Paul Latapie and Michel Davidovics confirmed that water-resistant ceramic tiles could be fabricated at temperatures lower than 450C, i.e. without firing. One component of clay, kaolinite, reacted with caustic soda at 150C. The industrial application of this kaolinite reaction with alkali began in the ceramic industry. In 1969, Besson, Caillere and Henin at the French Museum of Natural History, Paris, produced hydrosodalite from various phyllosilicates (kaolinite, montmorillonite, halloysite) at 100C in concentrated NaOH solution, (Besson et al., 1969).Finally, Davitovits synthetisized a kind of mineral polymer material with cross-linked polysialate chain. Hydroxylation and polycondensation reaction of natural minerals such as clay, slag, fly ash and pozzolan on alkaline activation below 1600C developed this polymeric chain. This inorganic polymer was first named polysialate in 1976 and later coined as Geopolymer.

Milestones in alumino-silicate chemistry

1.4. Alkali-activation of cementitious materialsIt is widely known that the production of Portland cement consumes considerable energy and at the same time contributes a large volume of CO2 to the atmosphere. However, Portland cement is still the main binder in concrete construction prompting a search for more environmentally friendly materials.One possible alternative is the use of alkali-activated binder using industrial by-products containing silicate materials (Gjorv, 1989; Philleo, 1989). The most common industrial by-products used as binder materials are fly ash (FA) and ground granulated blast furnace slag (GGBS). GGBS has been widely used as a cement replacement material due to its latent hydraulic properties, while fly ash has been used as a pozzolanic material to enhance the physical, chemical and mechanical properties of cements and concretes (Swamy, 1986).GGBS is a latent hydraulic material which can react directly with water, but requires an alkali activator. In concrete, this is the Ca(OH)2 released from the hydration of Portland cement. While fly ash is a pozzolanic material which reacts with Ca(OH)2 from Portland cement hydration forming calcium silicate hydrate (C-S-H) gel as the hydration product. Thus, when used with Portland cement, GGBS or fly ash will not start to react until some Portland cement hydration has taken place. This delay causes the blended cements to develop strength more slowly at early ages compared to the normal Portland cement. Recent research has shown that it is possible to use 100% fly ash or slag as the binder in mortar by activating them with an alkali component, such as, caustic alkalis, silicate salts, and non silicate salts of weak acids (Bakharev, Sanjayan, & Cheng, 1999a; Talling & Brandstetr, 1989). There are two models of alkali activation. Activation by low to mild alkali of a material containing primarily silicate and calcium will produce calcium silicate hydrate gel (C-S-H), similar to that formed in Portland cements, but with a lower Ca/Si ratio (Brough & Atkinson, 2002; Deja, 2002). The second mechanism involves the activation of material containing primarily silicate and aluminates using a highly alkaline solution. This reaction will form an inorganic binder through a polymerization process (Barbosa, MacKenzie, & Thaumaturgo, 2000; Sindhunata, 2006a; Xu, 2002). The term Geopolymeric is used to characterise this type of reaction from the previous one, and accordingly, the name geopolymer has been adopted for this type of binder (Davidovits, 1994). The geopolymeric reaction differentiates geopolymer from other types of alkali activated materials (such as, alkali activated slag) since the product is a polymer rather than C-S-H gel.

Figure 3 : Schematic representation of the alkali activation reaction process

1.5. ApplicationsAccording to Davidovits (1988b), geopolymeric materials have a wide range of applications in the field of industries such as in the automobile and aerospace, nonferrous foundries and metallurgy, civil engineering and plastic industries. Davidovits (1999) classified the type of application according to the Si:Al ratio as presented in figure 3.

Figure 4: Application of Geopolymer.

One of the potential fields of application of geopolymeric materials is in toxic waste management because geopolymers behave similar to zeolitic materials that have been known for their ability to absorb the toxic chemical wastes.

Balaguru et. al. (1997) reported the results of the investigation on using geopolymers, instead of organic polymers, for fastening carbon fabrics to surfaces of reinforced concrete beams. It was found that geopolymer provided excellent adhesion to both concrete surface and in the interlaminar of fabrics. In addition, the researchers observed that geopolymer was fire resistant, did not degrade under UV light, and was chemically compatible with concrete.

In Australia, the geopolymer technology has been used to develop sewer pipeline products, railway sleepers, building products including fire and chemically resistant wall panels, masonry units, protective coatings and repairs materials, shotcrete and high performance fibre reinforced laminates (Gourley, 2003; Gourley & Johnson, 2005).Use of GGBS in building material industry is not new, but practical application of geopolymerization technology allows making it much better since the discovery of alkali-activated cements and concretes, they have commercially produced and used for different purposes in a variety of construction projects in the former Soviet Union, China and some other countries. These commercial products and application include: structural concrete, masonry blocks, concrete pavements, concrete pipes , Utility poles, Concrete sinks and trenches, Autoclaved aerated Concrete, Refractory concrete, Oil-well cement and stabilization and solidification of hazardous and radioactive wastes.During the past two decades, alkali-activated cements and concretes have attracted much interest all over the world due to their advantages of low energy cost, high strength and good durability compared to Portland cement.

1.6. Objective of the Present ResearchThe objective of the present research is to investigate the effect of synthesizing parameters on engineering properties of blended alkali-activated blast furnace slag composites. The blast furnace slag in granular form was obtained from Tata Metalliks Lltd. Kharagpur, India. Each year India produces around eleven million tons of GGBS, which can be significantly utilized in the manufacturing of construction materials which is environment-friendly and will greatly reduce primary energy, saves bulk of quarrying as well as potential landfill. Red Mud was acquired from Ujjal Chemical works, Nadia, West Bengal,India.A comprehensive experimental program has been conducted to appreciate the engineering properties of blast furnace slag based blended alkali activated composites at ambient as well as elevated temperatures.The proposed research has been followed in the path as shown below:1. (Blast furnace slag + Red Mud) with percentage composition of 80, 20 respectively was found to be the best paste mix from compressive strength consideration.2. Temperature study of the paste mix - 300C, 500C, 700C for 4 hours.3. Mortar cubes were casted with varying alkali content (6%,8%,10%) using GGBFS:RM = 80% : 20% and sand: source material will be varied as given below Sand: Source material 1 : 1 2 : 1 1 : 24. Mortar cubes were then studied under elevated temperature of 300C, 500C and 700C.5. Study on the effect of synthesizing parameters such as Alkali content, silicate content on the physico-mechanical properties of blended AAS composites, that is, compressive strength, bulk density, water absorption, apparent porosity, UPV and sorptivity.

1.7. Organization of the thesisThe thesis is organized into five chapters. Chapter one describes the motivation for developing blended alkali activated slag and as an alternative binder for concrete. Chapter two reviews the literatures on the environmental impact of ordinary Portland cement, the history of alkali activation of cementitious material, the reaction mechanisms and properties of Alkali Activated Slag (AAS), the type of raw materials suitable for alkali activated binder, and chemical degradation and the transport properties affecting the durability properties of concrete. Chapter three reports on the experimental studies on the strength development of blended alkali activated slag mortar. Chapter four reports on the experimental studies on the strength and other properties of AAS, including water sorptivity, water absorption, bulk density, apparent porosity. Chapter five includes the conclusions and recommendations for further research.

Chapter 2: Review of Existing Literature

Preamble Literature on blended Geopolymer is very scarce and limited. Very few studies have been carried out where supplementary materials were used with starting material. Most of the available literature on geopolymer materials deals with synthesizing parameters pore morphology, microstructure survey, durability study and other structural properties. Lot of research has been carried out to study different types of geopolymer and alkali activated slag. Some available papers are presented here.

SL. no.LITERATURE

1

TITLE: Property of geopolymer cements

AUTHOR: Joseph Davidovits

SUMMARY: Geopolymer cement hardens rapidly at room temperature and provides compressive strength in the range of 20 Mpa. Final 28 day compressive strength is in the range of 70-100 Mpa. X-ray diffraction result had shown that the polycondensation of various alkali- alumino -silicate present in geopolymer binder, are actually amorphous material.

2

TITLE: Effect of mix composition on compressive strength and microstructure of fly ash based geopolymer compositesAUTHOR: Prof. Dr. Somnath Ghosh & Ravindra N ThakurSUMMARY: Alkali content, Silica content, water content and curing condition greatly affect the Compressive Strength of geopolymer mix. Water plays an important role during dissolution, polycondensation & hardening stages of geopolymerisation. Reduction of water content improved compressive strength. The choice of curing temperature & curing time affected final compressive strength of geopolymer. The increase in compressive strength was observed with increasing duration of heat curing and curing temperature.

3

TITLE: Effect of silica fume additions on porosity of fly ash geopolymersAUTHOR: Debabrata Dutta, Suresh Thokchom, Partha Ghosh and Prof. Dr. Somnath GhoshSUMMARY: They studied the effect addition of silica fume on the pore characteristics of fly ash based geopolymer composites. Porosity, compressive strength, water absorption and micro structural studies have been performed for the resulting geopolymers. It has been found that addition of silica fume to fly ash based geopolymer mortar specimens improves the total porosity. However, it increases porosity in case of geopolymer pastes. Incorporation of silica fume enhances the compressive strength of mortar specimens whereas it causes a significant drop for the paste specimens. Water absorption values were found directly related to total porosity of specimens. For paste specimens, water absorption gradually increases with introduction of silica fume into mix.

4

TITLE: Experimental study on Geo-Polymer concrete incorporating GGBSAUTHOR: V. Supraja, M. Kanta RaoSUMMARY: It was found that compressive strength is increased with the increase in the molarity of sodium hydroxide. Compared to hot air oven curing and curing by direct sun light, oven cured specimens gives the higher compressive strength but sun light curing is convenient for practical conditions.

5TITLE: Strength and Water Penetrability of Fly Ash Geopolymer ConcreteAUTHOR: Monita Olivia and Hamid R. NikrazSUMMARY: Geopolymer mixtures with variations of water/binder ratio, aggregate/binder ratio, aggregate grading, and alkaline/fly ash ratio were investigated. They concluded that the water/solids ratio is the most influential parameter to increase strength, and to decrease the water absorption/AVPV and water permeability. An optimum aggregate/binder ratio of 3.50 contributed to the high strength of the concrete, whereas, to obtain a low porosity of fly ash geopolymer, the ratio needs to be increased to 4.70.

6

TITLE: Parametric Study on the Properties of Geopolymer Mortar Incorporating Bottom AshAUTHOR: Djwantoro HardjitoC ,Shaw Shen FuSUMMARY: They concluded that increase of bottom ash content decreases the compressive strength of geopolymer mortar. Increase of curing temperature increases the compressive strength of the geopolymer mortar. . Increase in concentration of KOH solution also increases the compressive strength of geopolymer mortar.Increase of bottom ash content increases workability of fresh geopolymer mortar but it decreases with bottom ash content more than 75%.

7

TITLE: Compressive Strength and Interfacial Transition Zone Characteristic of Geopolymer Concrete with Different Cast In-Situ Curing ConditionsAUTHOR: Muhd Fadhil Nuruddin, Andri Kusbiantoro, Sobia Qazi, Nasir ShafiqSUMMARY: The paper explained the compressive strength development through polymerization process of alkaline solution and fly ash blended with Microwave Incinerated Rice Husk Ash (MIRHA). Three curing conditions, which are hot gunny curing, ambient curing, and external humidity curing were applied. The compressive strength development of geopolymer concrete was much affected by the curing condition during maturing period. Therefore proper curing method was important to obtain acceptable geopolymer concrete structures. The external exposure curing condition used in this research was an acceptable technique to produce good concrete structures.

8

TITLE: Alkali-activated fly ash-based geopolymers with zeolite or bentonite as additives.AUTHOR: Hu Mingyu, Zhu Xiaomin, Long FumeiSUMMARY: They studied the synthesis of geopolymers at ambient temperature by using fly ash as the main starting material, zeolite or bentonite as the supplementary material, and NaOH and CaO together as activators. Though fly ash is pozzolanic material, its reactivity is much lower than that of metakaolin. Therefore, its reaction rate is quite low at ambient temperature. To explore this property, the following supplementary materials were used in this study to accelerate the geopolymerization and to improve the properties of the fly ash-based geopolymers. As an exploration, in this work NaOH and CaO were used together as alkali-activator.

9

TITLE: Inflence of Slag as additive on the compressive strength of Fly Ash based GeopolymersAUTHOR: Zongjin Li and Sifeng LiuSUMMARY: To improve the compressive strength of FA-based geopolymer at lower temperature had been made. Moreover, slag was used as additive. Up to 4% by weight of dry powders slag was incorporated into fly ash-based geopolymer 10% metakaolin and 90% fly ash, to improve its compressive strength. Compressive strength of 53.1 and 70.4 MPa cured at 30C and 70C for 14 days, respectively, have been achieved. The mechanism of slag as an additive on compressive strength improvement was investigated using XRD and MIP.

10

TITLE: Fire-resistant geopolymer produced by granulated blast furnace slagAUTHOR: Cheng and ChiuSUMMARY: He found that the setting time of geopolymer paste made with GGBS as the source material along with metakaolinite, was affected by the curing temperature, type of alkaline activator, and the actual composition of the source material. The setting time of geopolymer paste was observed to range from 15 to 45 minutes at 60C.

11

TITLE: Effect of Incorporating Silica Fume in Fly Ash GeopolymersAUTHOR: Suresh Thokchom, Debabrata Dutta, Somnath GhoshSUMMARY: They investigated the effect of incorporating silica fume on physic mechanical properties and durability of resulting fly ash geopolymers. Silica fume in the range of 2.5% to 5% was incorporated with the alkali activated fly ash. Durability of geopolymer materials was assessed by regular monitoring of its physical appearance, weight changes and compressive strength changes on exposure to magnesium sulphate solution. It was noted that apparent porosity of geopolymer paste specimen increases with increase in silica fume content. Geopolymer paste incorporated with silica fume resulted in higher sorptivity while it for geopolymer mortars.

12

TITLE: Evaluation of Geopolymer properties with temperature imposed on activator prior mixing with fly ashAUTHOR: Debabrata Dutta, Suman Chakrabarty, Chandan Bose, Somnath GhoshSUMMARY: It provides with the effect of temperature on activators before mixing. It was found that temperature in which activator was subjected prior mixing effects compressive strength significantly.

13TITLE: Effect of Curing Conditions on the Compressive Strength and Microstructure of Alkali-activated GGBS pasteAUTHOR: Mohd. Nadeem Qureshi and Somnath GhoshSUMMARY: They presented the effect of curing method on the strength development of alkali- activated blast furnace slag paste. Alkali activation was done using a combination of potassium hydroxide and sodium silicate. The test parameters include the curing methods (water curing at 270C, heat curing at 500C and controlled curing with relative humidity 50%, 70% and 90 % at 270 C), alkali content with 6.41 %, 8.41 %, 10.41% and 12.41 % of the mass of GGBS. The compressive strength results showed that there is an increase in compressive strength with the increase in age of water curing and controlled curing specimens. A comparison of hot cured specimens, the increase in compressive strength with age was less. Further heat curing has shown to adversely affect compressive strength and to create internal micro cracking as well as surface cracks. The higher compressive strengths were obtained from water cured specimens.

14TITLE: Hydration of alkali-activated slag: comparisonwith ordinary Portland cementAUTHOR: A. Gruskovnjak, B. Lothenbach, L. Holzer, R. Figi and F. WinnefeldSUMMARY: They investigated and compared alkali-activated slag binders (AAS),pure slag and ordinary Portland cement (OPC). The precipitation mechanisms during binder hydration in the AAS and OPC systems exhibit significant differences: in AAS the formation of the outer product CSH is much faster than in OPC. The high Si concentrations in the pore solution during the early hydration of AAS are related to the fast dissolution of Na-metasilicate. The fast reaction of Na is an important factor for the voluminous precipitation of CSH within the interstitial space already during the first 24 h. In addition to the Na-metasilicate component, the high fineness of the slag represents a further important factor for the fast hydration of AAS. The small slag particles (less than 2 micron) are completely dissolved or hydrated within the first 24 h, whereas hydration of the larger particles is much slower. The fast formation of a gel-like matrix in AAS is the product of a fast through solution precipitation, which contrasts with the slower dissolutionprecipitation mechanism of a topotactic growth of CSH in OPC.

15TITLE: Mineral Phase and Physical Properties of RedMud Calcined atDifferent TemperaturesAUTHOR: Chuan-shengWu and Dong-yan LiuSUMMARY: Different characterizations were carried out on red mud uncalcined and samples calcined in the range of 100C1400C. In the present paper, the phase composition and structural transition of red mud heated from room temperature were indicated by XRD, TG-DTA, and SEM techniques. The mean particle diameter, density, and bond strength of these samples also have been investigated. The results indicate the decomposition of gibbsite into Al2O3 and H2O between 300C and 550C and calcite intoCaO and CO2 in the interval of 600800C. Tricalcium aluminate and gehlenite are formed in the range of 800900C. Combined with the SEM images, the results of physical property testing show that the particle size and the strength each has a continuous rise during the heat treatment from 150C to 1350C. But the value of density will undergo a little drop before 450C and then increases to a higher value at the temperature of 1200C. These obtained results provide an important base for the further studies of comprehensive utilization of red mud.

16

TITLE: Effect of the addition of red mud on the corrosion parameters of reinforced concreteAUTHOR: D.V. Ribeiro, J.A. Labrincha, M.R. Morelli SUMMARY: Red mud, the main waste generated in aluminum and alumina production by the Bayer process, is considered hazardous due to its high pH. The characteristic of high alkalinity associated with the presence of aluminosilicates facilitates the assimilation and formation of compounds by reaction with chloride ions. The high pH also provides greater protection of rebars, which is reflected in the low corrosion potential and high electrical resistivity (filler effect) of concrete. In this study, the chloride concentration was monitored by measuring the conductivity of the anolyte. Red mud proved to be a promising additive for concrete to inhibit the corrosion process. The corrosion potential was monitored by electrochemical measurements and the electrical resistivity was evaluated using sensors embedded in concrete test specimens. The results showed that the addition of red mud is beneficial to concrete, reducing its chloride migration rate (diffusion coefficients) and corrosion potential and increasing its electrical resistivity.

17TITLE: The strength and microstructure of two geopolymers derived from metakaolinand red mud-fly ash admixture: A comparative studyAUTHOR: Jian He , Jianhong Zhang, Yuzhen Yu, Guoping ZhangSUMMARY: The effects of source materials on the microstructure and mechanical properties were studied by comparing two types of geopolymers synthesized from metakaolin, a non-waste material, and the admixture of two wastes, red mud and fly ash. Unconfined compression testing was conducted to assess their curing time and mechanical properties, while X-ray diffraction and scanning electron microscopy employed to examine geopolymerization reactions and the composition and microstructure of the end products. For a given Si/Al ratio, the metakaolin-derived geopolymer exhibits higher compressive strength than the waste-based one. Both geopolymers contain a significant amount of voids and unreacted phases as inactive fillers within the geopolymer binder, resulting in complexity and variability in their mechanical behavior. The difference in strength and microstructure between the two geopolymers is attributed to the different reactivity of source materials, percentage of nonreactive fillers, and alkalinity for geopolymerization reactions.

18TITLE: Geopolymerization of Red Mud and Fly Ash for Civil InfrastructureApplicationsAUTHOR: Jian He and Guoping Zhang, A.M. ASCE, P.E.SUMMARY: This paper presents a study that investigates the geopolymerization of red mud, a major industrial waste from alumina refining, and fly ash, also an industrial waste from coal combustion, using very limited non-waste materials. Different synthesis parameters (e.g., red mud to fly ash ratio, sodium silicate solution to solid mixture (red mud and fly ash) ratio, and different types of sodium silicate solution) were varied to assess their influences on the mechanical properties of final geopolymer products. The results of unconfined compression testing show that thesefactors have significant influence on the mechanical properties of the synthesizedgeopolymers. Depending on the synthesis conditions, the unconfined compressive strength ranges from 3 to 13MPa, and the high values are comparable with certain types of Portland cement. The process of geopolymerization was confirmed by the composition of the final products analyzed by X-ray diffraction. The findings suggest that the two major industrial wastes, red mud and fly ash, can be reused to produce geopolymers that may replace Portland cement and hence be applied in civil infrastructure construction.

19TITLE: Synthesis and characterization of red mud and rice husk ash-basedgeopolymer compositesAUTHOR: Jian He , Yuxin Jie , Jianhong Zhang , Yuzhen Yu , Guoping ZhangSUMMARY: A new type of geopolymer composite was synthesized from two industrial wastes, red mud (RM) and rice husk ash (RHA), at varying mixing ratios of raw materials and the resulting products characterized by mechanical compression testing, X-ray diffraction, and scanning electron microscopy to assess their mechanical properties, microstructure, and geopolymerization reactions. Prolonged curing significantly increases the compressive strength and Youngs modulus, but reduces the ductility. Higher RHA/RM ratios generally lead to higher strength, stiffness, and ductility, but excessive RHA may cause the opposite effect. The compressive strength ranges from 3.2 to 20.5 MPa for the synthesized geopolymers with nominal Si/Al ratios of 1.683.35. Microstructural and compositional analyses showed that the final products are mainly composed of amorphous geopolymer binder with both inherited and neoformed crystalline phases as fillers, rendering the composites very complex composition and highly variable mechanical properties. Uncertainties in the composition, microstructure, the extent of RHA dissolution, and side reactions may be potential barriers for the practical application of the RMRHA based geopolymers as a construction material.

Chapter 3: Experimental Investigation

3.1 Manufacturing process of Alkali Activated Composite mixAlkali activated composites prepared by mixing blast furnace slag and red mud with alkali activator solution. The mixture is usually homogenous slurry which is dark gray to brown in colour. The composite was cohesive in nature in fresh state. In present research, for manufacturing of the composite, following range of different constituents were selected. Blast furnace slag : 80% by weight of mixRed Mud (Bauxite Mud) : 20% by weight of mixAlkali content (%K2O) : 6% to 10% by weight of binding materialFine Aggregate : 50% to 200% by weight of binding material

Figure 3.1: wooden cubical mould

Following manufacturing process was adopted for preparing alkali activated composite specimens.i. Mix sodium silicate solution, sodium hydroxide pellets and water according to mix proportion, to make alkaline activator, at least one day prior to its use in manufacturing alkali activated slag.ii. Hand mixing was used for preparing alkali activated slag mix.iii. Mix slag, red mud and alkaline activator to make a homogeneous paste. iv. Transfer the mix to wooden/steel moulds.v. Vibrate fresh alkali activated binder mix in the moulds on vibration table for 2-3minutes to remove entrapped air in the mix.vi. Rest period of 24 hours is given to fresh specimens. Remove specimens from moulds at room temperature prior to placing them in water for water curing for 3days, 7days. vii. The specimens were left to air drying at room temperature until tested.

3.1.1 Characterization of ingredients for blended Alkali activated composite mortarBlended alkali activated mortar was made from Blast furnace slag and red mud activated with a combination of potassium hydroxide (KOH) and sodium silicate solution (Na2SiO3) and mixed with local sand. Blast furnace slag from Tata Metalliks, Jamshedpur, India was used for investigation. Red Mud was obtained from Ranaghat, West Bengal. Consistency of the slag and red mud was ensured it was procured in bulk from same batch, mixed and packed in the plastic sealed container.The river sand obtained from local source was used as fine aggregate for preparing mortar specimen. Sand is having Fineness modulus of 3.2. The sand was made saturated surface dry (SSD) before using in the mix to avoid water absorption from activator solution. The sand was stored in plastic sealed container to maintain its properties.Potassium hydroxide in pellets form (K2O=77.5%, H2O=22.5%) were supplied by Merck Chemical with 97% purity. Sodium Silicate solution (Na2O=8%, SiO2=26.5%, H2O=65.5%) were supplied by Merck Chemicals. The SiO2-to-K2O ratio (Silicate modulus) in the alkaline activating agent was adjusted by adding KOH to soluble glass in order to obtain required silicate modulus. Laboratory tap water was used in the synthesis of blended alkali activated slag mortar.

3.2 Tests at fresh and hardened stateThe main purpose of testing of alkali activated composites is to investigate the engineering properties of the composites and to characterize microstructure of specimens, synthesized at different test conditions. The laboratory tests will be conducted as per relevant Indian standard codes and in some special tests, ASTM standard were followed. The details of various test procedure use in the present research are described in the following sections.

Figure 3.2: Measurement of Workability using mini slump cone3.2.1 Workability and Setting time measurements

The workability of fresh alkali activated composites mix may be determined using mini slump cone as shown in the Figure above. The dimensions of the mini slump cone mould are: top diameter 70mm, bottom diameter 100mm and height 60mm. The mould is fixed firmly on a flow table and filled with fresh mortar. The mortar is tamped down with spatula to ensure proper compaction. When the mould is full the top surface is leveled and it is immediately lifted vertically allowing mortar to flow on flow table. The flow diameter is measured in two perpendicular directions and average of the two is considered as flow diameter as a measure of workability. Depending on flow diameter, workability of alkali activated composite mix may be classified as stiff, moderate and high.

Figure 3.3: Measurement of setting time using Vicat apparatusA Vicat needle, as shown in Fig., is used to measure the setting time of alkali activated binders. The modified Vicat needle essentially consisted of a needle of 1 mm diameter cross-section and 100 g, conforming to ASTM C191-04. A cylindrical container of 75 mm diameter was filled with 50 mm of the freshly prepared pastes. Values of penetration distances were obtained every ten minutes. The initial setting time is obtained when the penetration of needle is 25mm.

On the other hand, the final setting time is the time required to reach a penetration distance of zero mm. At the final setting, alkali activated binders are almost in hardened state. Moulding without causing material damage is not possible thereafter.3.2.2 Bulk density and apparent porosityThe bulk density and apparent porosity for geopolymer specimen is determined according to Archimedes principle with water as immersion medium. The procedure to be adopted is as follows: i> Dry all specimens in a ventilated oven at 65C for 48 hours. ii> Record the weight of dried specimens as Wd. iii> Immerse the specimens in water at room temperature (28C) for minimum 48 hours.iv> Weight the specimens while suspended by a thin wire and completely submerged in water and record Wi.v> Remove specimens from water and allow water to drain off by placing them on a wire mesh, removing visible surface water with a damp cloth; weigh and record saturated weight as Ws. The bulk density and apparent porosity was then calculated as follow:

Dry density (Kg/m3 ) = [Wd / (Ws-Wi)] x 1000Apparent Porosity (%) = [(Ws-Wd) / (Ws-Wi)] x 1003.2.3 Compressive strength The direct compressive strength of hardened specimens will be obtained at the age of 7 days, using 2000kN capacity digital compressive testing machine. At 7 days age, three identical samples were tested in accordance with ASTM C-109 -02 and the mean values of compressive strength are reported in relevant tables and graphs. Also for the specimens heated at elevated temperature, compressive strength will be measured after the specimens attain room temperature. A typical testing of mortar specimen is shown in Figure.

Figure 3.4 : Compressive Strength Testing Machine3.2.4 Water Absorption

Figure 3.5: setup for water absorptionThe volume of pore space in specimen matrix, as distinct from the ease with which a fluid can penetrate it, is measured as absorption. Water absorption is usually measured by drying a specimen to a constant mass, immersing it in water, and measuring the increase in mass as a percentage of dry mass. In the present research, water absorption of specimens will be determined as per ASTM C-642. The 28 days aged specimens is dried for 48 hours at 65C & then immersed in water for 24 hours. The test specimens soaked in water is removed from the immersion container, wiped clean and weighted immediately in saturated-surface-dry (SSD) condition to find increase in mass. 3.2.5 Water Sorptivity Permeability test measure the response of concrete to pressure, which is rarely the driving force of fluid entering concrete, there is a need of another type of test. Such a test measures the rate of absorption of water by capillary suction of unsaturated concrete placed in contact with water; no head of water exists. The sorptivity test according to Neville A.M. determines the rate of capillary rise absorption by mortar/ concrete cube. The specimens rest on small supports in a manner such that only the lowest 2 to 5mm of the cube is submerged. The increase in the mass of the prism with time is recorded. The specimens should be dried prior to the experiment.

It has been shown that there exists a relation of form. I= St where,I = increase in mass per unit area (gm/mm2) since beginning of the test per unit of cross- sectional area in contact with water; as increase in mass is due to ingress of water. It is expressed in mm.t = time, measured in minutes, at which the mass is determined.S = Sorptivity in mm/min0.5

The detail of experimental set up is shown in figure below.

Figure 3.6: setup for sorptivity

3.2.6 Ultrasonic Pulse Velocity (UPV)Ultrasonic Pulse Velocity method consists of measuring the time of travel of an ultrasonic pulse, passing through the mortar/ concrete. The mortar cube specimens having dimension 50mm 50mm 50mm will be used in this study. Typical test setup for ultrasonic testing is shown in Figure. Direct transmission of pulse is employed for the study. Although the pulse velocity is affected by a number of factors, the most important parameter is the porosity of mix. The ultrasonic pulse velocity measurement was conducted as per IS 13311 (Part-1): 1992 standard using a commercially available PUNDIT system. The testing system consisted of a pulsar/receiver unit with a built-in data acquisition system and a pair of narrow band, 150-kHz transducers. UPV measurements could be performed to monitor the internal structure of mortar nondestructively. The test procedure is as follows: Ultrasonic pulse is produced by the transducer which is held in contact with the surface of the specimen. The transit time (T) of the pulse is measured for path length (L). The Pulse Velocity (V) is given by: V = L /T

Figure 3.7: Setup for Ultrasonic Pulse Velocity

3.3. Detail of MixesFollowing table summarized the different mixes that were tried during the experiment with Alkali activated blended slag mortar. Main features are:-i) % of K2O is varied between 6%, 8%, 10%.ii) SiO2/K2O is kept constant.iii) Binding material/Sand is varied between 1:2 to 2:1.iv) Elevated temperature range was varied between 300,500,700C.

TABLE 3.1 : DETAILS OF MIXESType%K2OSiO2/K2OBinding Material/ Sand

Mortar611:2

Mortar611:1

Mortar6

12:1

Mortar811:2

Mortar811:1

Mortar812:1

Mortar1011:2

Mortar1011:1

Mortar1012:1

3.4. Detail of Experimental Programme:

TABLE 3.2 : OBJECTIVE OF THE EXPERIMENTAL PROGRAMMESl. No.Test methodPropertySpecimen typeNumber of specimenObjective

1Workabilityand setting timeFlow characteristic of paste/mortarFresh alkali activated composite paste/mortar3To determine the flow ability

2Compressive strength testCompressive strength of alkali activated composite.Cube(50mm*50mm*50mm)3To determine the compressive strength of the hardened paste/mortar

3Sorptivity testTo appreciate the tendency of unidirectional flow through the test specimen

Cube(50mm*50mm*50mm)3To appreciate the tendency of unidirectional flow through the test specimen.

4Water absorption testPorosity of alkali activated compositeCube(50mm*50mm*50mm)3To measure the porosity of the material

5Apparent porosityPorosity of alkali activated compositesCube(50mm*50mm*50mm)3To appreciate the porosity level.

6Ultrasonic Pulse Velocity (UPV)Compactness of the material.Cube(50mm*50mm*50mm)3To appreciate the density, void, insipient flaws, and strength.

4. Results and discussion

4.1 PreambleMortar can function in two ways. Firstly, it should provide a uniform bedding surface for the units. This is ensured when plastic mortar has reasonable workability so that it can be spread easily under the influence of the trowel and it flows into all the crevices of the units, thus correcting any dimensional irregularities. Secondly the mortar binds the units into monolithic mass. The hardened mortar must possess sufficient strength to hold the units together and ensure adequate durability to resist the destructive forces of the weather. The strength to sustain loads in a masonry wall is provided by the units; the mortar is merely the "glue" that holds them together. Thus any approach to mortar technology requires an understanding of the workability of plastic mortar and strength of hardened mortar.

Initially (Blast furnace slag + Red Mud) with percentage composition of 80, 20 respectively was found to be the best paste mix from compressive strength consideration.The following table shows the detail mixes of alkali activated paste samples.

Table 4.1: Detail Mixes Of Alkali Activated Paste Samples Sample IDComposition (in %)Activator Soln.Silicate ModulusWater: Binding MaterialCuring ConditionCompressive Strength (in Mpa)

Red MudBFS

GP 101006% KOH10.27Water51.48

GP A20806% KOH10.26Water46.8

GP B40606% KOH10.27Water26.4

GP C50506% KOH10.28Water17.6

GP D60406% KOH10.3Water7.2

GP E70306% KOH10.3Water6.4

The compressive strength results are plotted and shown in Figure 4.

Figure 4: Compressive Strength vs percentage composition of binding material

Mortar cubes were casted with varying alkali content (6%,8%,10%) using GGBFS:RM = 80% : 20% and source material : sand was varied as given below Source material : Sand 1 : 1 2 : 1 1 : 2Mortar cubes were then exposed to elevated temperature of 300C, 500C and 700C. The samples were then studied on the effect of synthesizing parameters such as Alkali content, binding material to sand ratio, temperature level on the physico-mechanical properties of blended AAS composites, that is, compressive strength, bulk density, water absorption, apparent porosity, UPV and water sorptivity. The following figures show the results obtained.

4.2 Effect of alkali concentration on compressive strength

Figure 4.1: Compressive Strength vs Alkali Concentration( (BFS+RED MUD) : Sand = 1:1, Normal Water Curing)



Figure 4.4: Compressive Strength vs Alkali Concentration( BM:Sand = 1:1 , Temperature = 300C)









4.2.1 Effect of binding material to sand ratio on compressive strength

Figure 4.13: Compressive Strength vs BM:Sand( Alkali concentration= 6% , Normal Water Curing)



4.2.2 Effect of elevated temperature on compressive strength

Figure 4.16: Compressive Strength vs Elevated Temperature( Alkali concentration= 6% , BM:Sand = 1:1 )

Figure 4.17: Compressive Strength vs Elevated Temperature( Alkali concentration= 8% , BM:Sand = 1:1)

Figure 4.18: Compressive Strength vs Elevated Temperature( Alkali concentration= 10 % , BM:Sand = 1:1 )



Figure 4.21: Compressive Strength vs Elevated Temperature( Alkali concentration= 10 % , BM:Sand = 2:1)




4.3 Effect of alkali concentration on water absorption

Figure 4.25: Water Absorption vs Alkali Concentration( BM:Sand = 1:1 , Normal water curing)



Figure 4.28: Water Absorption vs Alkali Concentration( BM:Sand = 1:1 , ElevatedTemperature = 300C)

Figure 4.29: Water Absorption vs Alkali Concentration( BM:Sand = 1:1 , Elevated Temperature = 500C)





Figure 4.34: Water Absorption vs Alkali Concentration( BM:Sand = 1:2 , Elevated Temperature = 300C



4.3.1 Effect of elevated temperature on water absorption

Figure 4.37: Water Absorption vs Temperature Level( Alkali Concentration = 8% , BM : Sand = 1:1)

Figure 4.38: Water Absorption vs Temperature Level( Alkali Concentration = 10 % , BM : Sand = 1:1)







4.4 Effect of alkali concentration on apparent porosity

Figure 4.45: Alkali concentration vs Apparent Porosity( BM : Sand = 1:1, Normal water curing)



Figure 4.48: Alkali concentration vs Apparent Porosity( BM : Sand = 1:1, Elevated Temperature = 300C)









4.4.1 Effect of elevated temperature on apparent porosity

Figure 4.57: Apparent Porosity vs Temperature Level(Alkali Concentration = 6%, BM : Sand = 1:1)

Figure 4.58: Apparent Porosity vs Temperature Level(Alkali Concentration = 8%, BM : Sand = 1:1)

Figure 4.59: Apparent Porosity vs Temperature Level(Alkali Concentration = 10%, BM: Sand = 1:1)

Figure 4.60: Apparent Porosity vs Temperature Level(Alkali Concentration = 6% ,BM : Sand = 2:1)






4.5 Effect of alkali concentration on UPV

The ultrasonic pulse velocity method has been used to study the homogeneity and quality grading of internal structure of Geopolymer composites. UPV is mainly related to its density and modulus of elasticity. The following figures show the effect of alkali content, binding material to sand ratio and elevated temperature on UPV of blended alkali activated slag mortar specimen.

Figure 4.66: UPV vs Alkali content (BM: Sand = 1:1, Normal water curing)

Figure 4.67: UPV vs Alkali content (BM: Sand = 2:1, Normal water curing)

Figure 4.68: UPV vs Alkali content (BM : Sand = 1:2, Normal water curing)

Figure 4.69: UPV vs Alkali content (BM : Sand = 1:1, Temperature level=300C)

Figure 4.70: UPV vs Alkali content (BM : Sand =2:1, Temperature level=300C)





Figure 4.75 : UPV vs Alkali content (BM : Sand =1:1, Temperature level=700C)



4.5.1 Effect of elevated temperature on UPV

Figure 4.78: UPV vs Temperature Level(Alkali content=6%, BM:Sand=1:1)


Figure 4.80: UPV vs Temperature Level(Alkali content=10%, BM:Sand=1:1



Figure 4.83: UPV vs Temperature Level(Alkali content=10%, BM:Sand=2:1




4.6 Effect of alkali concentration on Sorptivity

Figure 4.87: Sorptivity vs Alkali content(BM:Sand =1:1)



4.6.1 Effect of elevated temperature on Sorptivity

Figure 4.90: Sorptivity vs Temperature level(Alkali content=6%, BM:Sand=1:1)





Figure 4.95: Sorptivity vs Temperature level(Alkali content=10%, BM:Sand=1:2

5. Concluding remarks

Currently, hydrated Ordinary Portland Cement (OPC) is the most common binder used in concrete. The production of OPC requires large amounts of energy, emitting approximately 5% of global CO2 emissions annually. Alkali activated slag (AAS) composites is a relatively new material, with the potential to be an alternative to OPC. Blended AAS composites have a lower environmental impact. This research will facilitate the implementation and wider use of blended AAS mortar as a potential new building material and provide a foundation for future explorations into Geopolymer composites. Based on the results of the experimental study on engineering properties of Blended Alkali Activated Composited mortar, the following conclusions are made.

The preparation of AAS mortar has been accomplished by mixing of alluminosilicate source material such as blast furnace slag, red mud with an activating solution that contains alkalinity and soluble silicates. Potassium Hydroxide was used as alkaline solution successfully with supplemented by Sodium Silicate as soluble silicates.

Chemistry of the source material (here Blast Furnace Slag) and supplementary material used is red mud and activating solution affect the success of alkali activated composite. The parameters such SiO2/K2O in the activator solution, percentage of K2O in the composite matrix affect the property of composite product developed.

The process of curing and hardening is different for AAS mortar compare to cement composites. Slag based alkali activated composite gains strength with duration of water curing. Curing duration has been found to affect the development of strength and the pore structure. Hence, Water Sorptivity, Water absorption, Apparent porosity and density depends greatly on curing condition. Duration of water curing is an important parameter.

Addition of water for proper mixing of mortar and addition of filler material like sand, affect the workability and strength development of AAS mortar. Proportion of sand in excess of binding material is responsible for reduction in the compressive strength and also increase in porosity, water absorption. Thus ultimately affect the durability of blended AAS mortar. Use of more sand in comparison to binding material (slag, red mud) is also uneconomical as sand is natural resource which is depleting day by day and slag,red mud are byproduct/ waste material creating environmental problems. Addition of water should be optimised to get a workable mixture of reasonably good strength. Hence, the parameters water/binding material ratio, BM/sand ratio can be suitably adjusted to get blended alkali activated composite mortar of desired specification.

AAS blended with Red mud has significantly lower resistance to elevated temperature due to its volume expansion and cracking. This is due to the presence of Titanium dioxide in the chemical composition of red mud.

Blended AAS material is not a wonder material. It needs to be specifically tailored to be able to handle itself in certain situations, just like ordinary cement based composites. There are some areas where future research is needed to appreciate alkali activated material in a better way which will establish itself as a cost effective as well as more reliable material in extreme environments compare to a cement based composites. The following areas may be considered for future research.1. Detail study on durability of blended slag based alkali activated composite ie. may be exposed to acid, sulphate , chloride environment etc.2. Effect of synthesizing parameters on shrinkage.3. More study on the properties of blended AAS mortar produced by changing silicate modulus, curing methods.4. Detail study is needed to improve porosity of AAS mortar.

Reference[1] Joseph Davidovits, Property of geopolymer cements. Geopolymer Institute 02100Saint-quintin ,France.Iinternational Conference on Geopolymer cement and concrete Kiev Ukraine in 1994

[2] Somnath Ghosh, Ravindra N.Thakur Effect of Mix Composition on Compressive Strength & Microstructure of Fly Ash Based Geopolymer Composites. ARPN Journal of Engineering & Applied Sciences. Vol 4, No. 4 June 2009.

[3] Debabrata Dutta, Suresh Thokchom, Partha Ghosh and Somnath Ghosh, Effect Of Silica Fume Additions On Porosity Of Fly Ash Geopolymers, ARPN Journal of Engineering and Applied Sciences OCTOBER 2010 ISSN 1819-6608

[4] V. Supraja, M. Kanta Rao Experimental study on Geo-Polymer concrete incorporating GGBS International Journal of Electronics, Communication & Soft Computing Science and Engineering, ISSN: 2277-9477, Volume 2, Issue 2

[5] Monita Olivia and Hamid R. Nikraz, Strength and water penetrability of fly ash Geopolymer concrete, ARPN Journal of Engineering and Applied Sciences, VOL. 6, NO. 7, JULY 2011.[6] Hardjito & Fung- Parametric Study on the Properties of Geopolymer Mortar Incorporating Bottom Ash ,Concrete Research Letters Vol. 1(3) 2010[7] Muhd Fadhil Nuruddin, Andri Kusbiantoro, Sobia Qazi, Nasir Shafiq; Compressive Strength and Interfacial Transition Zone Characteristic of Geopolymer Concrete with Different Cast In-Situ Curing Conditions , World Academy of Science, Engineering and Technology 49 2011.[8] Hu Mingyu, Zhu Xiaomin, Long Fumei Alkali-activated fly ash-based geopolymers with zeolite or bentonite as additives,Cement and Concrete Composites, Volume 31, Issue 10 (November,2009),p.762-768. ISSN: 0958-9465 Elsevier Science

[9] Zongjin Li and Sifeng Li, Influence of Slag as additive on the compressive strength of Fly Ash based Geopolymers, February 2012, ISSN 0899-1561, American Society Of Civil Engineers.[10] Cheng and Chiu. Fire-resistant Geopolymer produced by granulated blast furnace slag, by (Minerals Engineering 16 (2003) 205210)[11] Suresh Thokchom,Debabrata Dutta, Somnath Ghosh, Effect of Incorporating Silica Fume in Fly Ash Geopolymers, by World Academy of Science, Engineering and Technology 60 2011

[12] Debabrata Dutta, Suman Chakrabarty, Chandan Bose, Somnath Ghosh Evaluation Geopolymer properties with temperature imposed on activator prior mixing with fly ash.,International Journal Of Civil And Structural Engineering Volume 3, No 1, 2012

[13] Mohd. Nadeem Qureshi , Somnath Ghosh, Effect of Curing Conditions on the Compressive Strength and Microstructure of Alkali-activated GGBS paste; International Journal of Engineering Science Invention ISSN (Online): 2319 6734, ISSN (Print): 2319 6726.[14] A. Gruskovnjak, B. Lothenbach, L. Holzer, R. Figi and F. Winnefeld, Hydration of alkali-activated slag: comparison with ordinary Portland cement; Advances in Cement Research, 2006, 18, No. 3, July, 119128[15] Chuan-shengWu and Dong-yan Liu, Mineral Phase and Physical Properties of Red Mud Calcined at Different Temperatures; Hindawi Publishing Corporation, Journal of Nanomaterials, Volume 2012, Article ID 628592, 6 pages, doi:10.1155/2012/628592

[16] .V. Ribeiro, J.A. Labrincha, M.R. Morelli, Effect of the addition of red mud on the corrosion parameters of reinforced concrete; Cement and Concrete Research 42 (2012) 124133,Elsevier.

[17] Jian He , Jianhong Zhang, Yuzhen Yu, Guoping Zhang, The strength and microstructure of two geopolymers derived from metakaolin and red mud-fly ash admixture: A comparative study; Construction and Building Materials 30 (2012) 8091,Elsevier.[18] He and Guoping Zhang, A.M. ASCE, P.E., Geopolymerization of Red Mud and Fly Ash for Civil Infrastructure Applications, Geo-Frontiers 2011 ASCE 2011

[19] Jian He , Yuxin Jie , Jianhong Zhang , Yuzhen Yu , Guoping Zhang, Synthesis and characterization of red mud and rice husk ash-based geopolymer composites; Cement & Concrete Composites 37 (2013) 108118,Elsevier[20] J. Davidovits , Geopolymer , Man-made Rock Geosynthesis and the Resulting Devolopment of Very Early High Strength Cement, Journal of Materials Education, 16 [2-3] 91-137(1994).[21] D. Hardjito and B. V. Rangan . (2005) Development and properties of low-calcium flyash based geopolymer concrete , Research Report GC , Faculty of Engineering , CurtinUniversity of Technology, Perth, Australia , 1-130 .[22] Thokchom Suresh , Ghosh Partha , Ghosh Somnath 2009 Effect of Water Absorption ,Porosity and Sorptivity on Durability of Geopolymer Mortars ARPN Journal of Engineeringand Applied Sciences , vol 4 , no. 7 , Sep 2009 .

[23] Neville, A. M. and Brooks, J, 1990, Concrete Technology, Essex, Longman Group,UK [24] Prof. Dr. Joseph Davidovits Geopolymer Institute, 30 years of successes and failures in Geopolymer Applications. Market trends and potential breakthroughs. Geopolymer 2002 Conference, October 28-29,2002, Melbourne, Australia.

Appendix-I - Calculation regarding alkali activated GGBFS-RM mixCalculation for different ingredients needed for producing blended alkali activated slag mortar of specified parameters:Parameters% of K2O=8SiO2/K2O in activator solution=1Water/Binding Material (BFS+Red Mud) =0.37BM: Sand=1:1Assume Quantity of binding material=1000gmTherefore quantity of K2O @ 8% of BM=80gmTherefore quantity of SiO2 using above mentioned ratio=80gm1000gm Sodium Silicate contains 265gm of SiO2, 80gm of Na2O and 655gm of water.Therefore to get 80gm of SiO2 in activator solutionQuantity of Sodium Silicate needed=301.89gmThis amount of Sodium Silicate contains quantity of Na2O=24.15gm and water=197.74gmTherefore rest of K2O= 80gm which was obtained from Potassium Hydroxide (KOH) solution.1000gm Potassium Hydroxide in pellets form contains 839.29gm of K2O and 160.71gm of water.Therefore to get 80gm K2O in activator solutionQuantity of Potassium Hydroxide needed=95.32 gmQuantity of water present in 95.32 gm of Potassium Hydroxide in pellets form=15.32gmTherefore Water from these chemicals = (197.74gm+15.32gm) =213.06gmTo produce a alkali activated slag based mortar specimen of Water/Fly ash=0.35, total water needed= 350 gmExtra water that was added= (350gm-213.06gm) =136.94gmAs in the level of the product KOH pellets is 84% pure. Considering theseQuantity of KOH required=110.57 gm.Keeping the above mentioned parameter Sand required=1000gm.

1

final_1

Documents

binder materials

activation of material

pozzolanic material

activated binder

silicate materials gjorv

nontoxic material

types of alkali

pozzolanic properties