Inorganic Polymers (Geopolymers) and Geocements: Environmentally Friendly Ceramic Materials for Low-Technology and High-Technology Applications
Session CM-1 - Preparation and Characterization
CM-1:IL01 Exploring the Limits of Possible Geopolymer Precursors
A. VAN RIESSEN, W. RICKARD, Geopolymer Research Group, Curtin University, Perth, Western Australia
There are many publications in the field of geopolymers that espouse the wide range of precursors that can be utilised to manufacture these materials. This paper will explore some of the more successful precursors that have been utilised as well as describing the spectrum of precursors that have been trialled. A question that is frequently asked is: what makes a precursor suitable for manufacture of geopolymer? In answering this question a set of parameters can be derived that contributes to an efficient and rapid way of characterising potential precursors. Knowing how to characterise materials to draw out the relevant information is challenging but essential for this relatively new field. Producers will also need to know how to cope with variations in composition, particles size and amount of reactive component. It is sometimes difficult enough to make geopolymer but how do you know if you have been successful? What tests can be conducted to ensure the final product is in fact a geopolymer? If a systematic approach is used to answer the questions posed then we are empowered to explore a wider range of materials that could be considered as precursors for the manufacture of geopolymer.
CM-1:IL02 Potential of Secondary Resources as Aluminium-silicate Precursors for Geopolymer Synthesis
S.L.A. VALCKE, P. PIPILIKAKI, H.R. FISCHER, TNO, Delft, The Netherlands
Secondary resources containing (calcium) aluminium-silicate phases, e.g., fly ash, slag or bottom ash, can be used as precursor for binders such as geopolymers. Because secondary resources can be highly variable in terms of their potential to dissolve and form reaction products, analytical methods are needed to evaluate their potential as a precursor and to optimize the geopolymer mix design.
The most commonly used analytical methods (e.g., XRF, XRD) for measuring the characteristics of source materials which influence binder performance, do not capture heterogeneity between the particles and do not necessarily reveal the key parameter that is most dominant for the binder performance.
This paper therefore investigates the potential influence of internal variations of Si:Al ratio between particles and variations in aluminium-silicate types of the source material. For this, feature sizing and chemical typing (FS&CT), semi-quantitative FTIR and solid state 29Si NMR were used. It is found that particular aluminium-silicate types show a remarkably straightforward link with binder strength, despite significant variations in chemistry and particle features of the source materials investigated. These results could also explain particular trends between Si:Al ratio and strength.
CM-1:L03 Interactions between Alkaline Solution and Sand or Metakaolin: Polycondensation Reactions
L. VIDAL, S. ROSSIGNOL, GEMH-ENSCI, Limoges Cedex, France; J-L. GELET, MERSEN, Saint Bonnet-de-Mure, France
The consolidation of sand by alkaline silicate solution is relevant today for the cement setting comprehension. One field application is in electrical protection where the fuse technology is continuously in progress to reduce cost and to the quality environment. In this context, the agglomeration of sand with alkaline silicate solution focuses our interest. Consolidation of agglomerated sand and geopolymer materials involves polycondensation reactions. These in situ mechanisms are difficult to identify and to control because they occur in a complex and evolutional system. This study is based on the behaviour of alkaline silicate solutions in the presence of sand or metakaolin in order to define the type of reaction which occurs. To determine the different solution behaviours, several parameters have been analyzed such as the variation of the pH value, the siliceous species concentration and the ammonium molybdate addition in the solution to complex siliceous species. These experiments have shown that a variation of the pH value and of the siliceous species concentration lead to different interactions between the alkaline solution and the sand or the metakaolin. Moreover, the ammonium molybdate addition in these solutions implies the replacement of Si-O-Al/Si by Si-O-Mo bonds
CM-1:L04 Alkali-activated Fly-ash Foams - Synthesis, Chemo-physical Properties and Microstructure Modeling
V. SMILAUER1, P. HLAVÁÈEK1, F. SKVÁRA2, R. SULC1, L. KOPECKÝ1, 1Czech Technical University in Prague, Faculty of Civil Engineering, Prague, Czech Republic; 2Institute of Chemical Technology Prague, Faculty of Chemical Engineering, Department of Glass and Ceramics, Prague, Czech Republic
Inorganic foams offer several unique properties over their organic counterparts such as fire resistance or UV stability. Inorganic foam specimens were synthesized from fly ash and alumina powder through an alkali-activation process. Depending on mix proportions, bulk densities ranged between 420 and 800 kg/m3. Thermal treatment at 80 C for 12 hours accelerated curing process. Compressive strength was found in the range 3.7-9.0 MPa, flexural strength 0.5-1.7 MPa, Young's modulus 0.6-1.1 GPa, thermal conductivity 0.14-0.16 W/m/K and thermal capacity around 1100 J/kg/K.
Exposing the foams to 800 °C led to small decrease of compressive strength while exposure to 1100 °C sintered the foam to higher compressive strength of 13 MPa. Volumetric shrinkage as large as 20% occurred at 1100 °C without further foam disintegration. Residual compressive strength was determined after leaching in NaCl, HCl, Na2SO4, MgSO4, H2SO4. The highest reduction to 28% occurred in HCl with pH=2.
Digitized microstructures entered finite element analysis to validate a stress-strain diagram. The results testify progressive damage of cell walls during the loading. The foams proved high durability under high temperatures and aggressive environments and demonstrate a high potential for specific applications.
CM-1:L05 Siliceous Species Effect from Various Alkaline Solutions on Géopolymèrisation Mechanism
A. GARZHOUNI, F. GOUNY, E. JOUSSEIN, S. ROSSIGNOL, GEMH-ENSCI, Limoges Cedex, France
The research of new construction materials more economical, with low energy consumption and environmentally friendly remains currently a global challenge. Geopolymer materials have gained interest for their synthesis method, high working performances and wide range of application.
The choice of precursors is a primordial parameter in geopolymerization mechanism and it governs the properties of the final materials. This study focuses on the effect of siliceous species, present in the alkaline solution, on the geopolymer formation. For this purpose, several samples were synthesized from metakaolin and various commercial alkaline solutions. These solutions were characterized by infrared spectroscopy, thermal and thermogravimetric analysis DTA-TGA. The structural evolution of formed geopolymers was investigated using infrared spectroscopy. The measurement of mechanical strength is tested in compression.
The first results showed that siliceous species and water's content, in the alkaline solution, affect the kinetics of geopolymers formation in addition to its mechanical performances.
CM-1:IL06 Fabrication and Characterization of Geopolymers from Japanese Volcanic Ashes
S. HASHIMOTO, H. TAKEDA, H. KANIE, S. HONDA, Y. IWAMOTO, Nagoya Institute of Technology, Nagoya, Japan
Japan is a famous volcano country in the world. So far, 110 volcanoes are registered by Japan Meteorological Agency and 47 volcanoes are under activity now. These volcanic activities lead to many serious problems for Japanese. For example, many volcanic ashes which fall down wherever lead the social activity into a great confusion. Generally, the fell volcanic ashes are collected by special vehicles such as bulldozer and then buried in the landfill disposal place. Much public money is necessary for this processing. Therefore, development of an effective use of the volcanic fly ash is desired in Japan. According to XRD and XRF analysis, the selected Japanese volcanic ash (Mt. Shinmoe) has an amorphous phase of alminosilicate with approximately 30 mass%. Hence, we thought of the fabrication of the hardened body from volcanic ash using an alkali activated reaction, namely geopolymerization. The compressive strength of the hardened bodies from volcanic ash of Mt. Shinmoe after mixing with 6-9 mol/L of sodium hydroxide solution reached to 20-30 MPa. Then the anorthite crystals in the volcanic ash seemed to work as nuclei for the geopolymerization during hardening.
CM-1:IL07 Influence of Industrial Waste Materials and Chemical Mixing Components on the Durability of Alkali Activated Concrete
K. DOMBROWSKI-DAUBE, H. LANGE, J. SACHL, F. DAHLHAUS, Technical University Bergakademie Freiberg, Freiberg, Germany
In times of environmental and economically pressure special focus is to set on the increased utilization or upgrading of waste materials. In numerous publications the suitability of slags and fly ashes as a solid precursor for solid and durable alkali-activated materials has been proven. In this research program the influence of the chemical composition of the alkali-activated binder on the strength and durability of the resulting concrete mixture was investigated. Due to European climate conditions a high resistance of the concrete against freezing and thawing as well as against the action of deicing chemicals is required and has been therefore in the focus. Different solid precursors (fly ashes, slags, a waste material from ore processing) were used in combination with different alkaline activators and chemical additives. In the results can be shown how certain chemical components improve strength and freeze-thaw/frost-deicing salt resistance. Since certain chemical components act contrary on these properties investigations on binder structure are carried out in order to find answers for practical solutions in designing alkali-activated concrete mixtures.
CM-1:L08 Calcium Hydroxide-potassium Carbonate as an Alkali Activator for Kaolinite
H. RAHIER, M. ESAIFAN, J. WASTIELS, Vrije Universiteit Brussel, Brussels, Belgium; H. Khoury, Materials Research Laboratory, University of Jordan, Amman, Jordan
Kaolinite can chemically react with alkaline solutions such as NaOH or KOH solutions. The use of these solutions is however not without safety risks if the material is intended to be used by workers in the field. Ca(OH)2 combined with K2CO3 or (Na2CO3) is found to be an alternative activator. Besides solving the problem of working with an alkaline solution, an advantage of this system is that all the reactive components can be mixed in the dry state and only water needs to be added to start the reactions, as what is done for ordinary Portland cement.
In this study first the reaction between Ca(OH)2 and K2CO3 in aqueous solution is studied since information on this reaction is scares in literature. Next to KOH a double salt is formed, containing Ca and K. This implies that using this alkali activator, a larger amount of K will be need to reach the same reactivity as when pure KOH is used. The reactions are pretty slow (timescale of days at room temperature).
Some preliminary results of the materials made with this activator combined with kaolinite will be shown. A compressive strength of over 30MPa can be obtained for dried specimen, but the strength drops to 40% in wet conditions. This alkali activator is thus promising.
CM-1:IL10 The Secret Life of Inorganic Polymers
K.J.D. MACKENZIE, MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, New Zealand
Inorganic polymers, also called geopolymers, are becoming increasingly used as ecologically-friendly substitutes for Portland cement, in waste remediation applications and as fireproof building materials. However, interesting aspects of their chemistry opens up a range of less-well known possibilities such as: electronic composites with carbon nanotubes, photoactive composites with oxide nanoparticles, bioactive materials, drug delivery agents, dye carrying media, novel chromatography media, precursors for oxide or non-oxide ceramics, fluorescent materials, novel catalysts, sold-state hydrogen storage media, nanoporous materials and fibre-reinforced composites.
This talk will illustrate the range of possibilities for these interesting materials by discussing several of their more novel applications.
CM-1:L12 Granulation of Industrial Waste with Geopolymer Binders
H.W. NUGTEREN1, Y. DE GROOT1, A. KEULEN2, G.M.H. MEESTERS1, 1Delft University of Technology, Faculty of Applied Sciences, Department of Chemical Engineering, Delft, The Netherlands; 2Van Gansewinkel Minerals B.V., The Netherlands
Various mixtures of coal fly ash, blast furnace slag and sand were granulated in a high-shear granulator by using an alkali solution as binding agent. Contrary to common granulation processes, in this research the binding agent has the additional function of an activator to produce geopolymeric bonds during the granulation process. The granules are intended to replace gravel or aggregate in concrete.
The required amount of liquid for proper granulation was 23% in case potassium silicate solution (2.6 mol/kg K2O and 3.25 mol/kg SiO2) was used as the activator solution. When a sodium aluminate waste solution (with 90 g/L Al and 24 g/L of free NaOH) from the aluminium anodising industry was used the liquid demand dropped to 21.5%. The fly ash to slag ratio had no influence on the liquid demand. However, when sand was added, the liquid demand decreased for both activators to around 15%, when 50% of the solid was sand.
Granules were produced in the size range of 4 to 16 mm. Maximum granule strength was obtained with 30% slag. After 28 days ambient curing, breaking forces for 7-8 mm granules were between 300 and 500 N for K silicate activation and 100 - 300 N for aluminate activated granules. The replacement of up to 50% of the fly ash and slag by sand did not change the strength.
CM-1:L13 Ceramic Waste as New Precursor for Geopolymerization
O. FUSCO, A. FREGNI, M.C. BIGNOZZI, Dipartimento di Ingegneria Civile, Chimica, Ambientale e dei Materiali, University of Bologna, Italy; L. GUARDIGLI, R. GULLI, Dipartimento di Architettura, University of Bologna, Italy
Geopolymers, and more in general alkali activated materials (AAM), are a new class of materials obtained by alumino-silicates precursors activated by means of alkaline solutions. Indeed, the term geopolymers is usually strictly referred to pure alumino-silicates such as metakaolin as starting material, whereas when the precursors also contain calcium oxide the resulting products are usually defined AAM. Geopolymerization technology can be more easily considered a sustainable process when industrial waste is used as precursors and the consolidation process occurs at room temperature. If both these hypotheses are satisfied, alkali activation might be a very promising technology for ceramic sector as well as construction industry. In this work, waste coming from ceramic field has been used to obtain at room temperature geopolymers with different porosity tuning the SiO2/Al2O3 molar ratio in the feed. Special focus is addressed to microstructure analysis by means of mercury intrusion prosimeter. In particular, the effects of the grain size distribution of the precursor on pore size distribution and total open porosity are reported and discussed togheter with the thermal stability of the resulting products.
CM-1:L14 Synthesis of Inorganic Polymers using a CaO-Al2O3-SiO2-FeO Based Slag
L. KRISKOVA1, 2, B. BLANPAIN1, P.T. JONES1, Y. PONTIKES1, 2, 1High Temperature Processes and Industrial Ecology Research Group, Department of Metallurgy and Materials Engineering, KU Leuven, Leuven, Belgium; 2Secondary Resources for Building Materials, Consortium in Sustainable Inorganic Materials Management, SIM2, KU Leuven, Leuven, Belgium
In the present paper, the slag consisting of 22 wt.% CaO, 12 wt.% Al2O3, 34 wt.% SiO2 and 20 wt.% Fe2O3was used for the synthesis of inorganic polymers. The main focus of the research was the understanding of the effect of activation solutions' molarity on the properties of synthesized inorganic polymers. The studied slag was, due to the rapid cooling, almost completely amorphous, while traces of hematite were identified as the only present crystalline phase.
The inorganic polymer samples were prepared my mixing the binder, sand and activation solution (50:50 sodium hydroxide and sodium silicate), with the NaOH solution molarities varying from 2M to 10M. Additional water was added to assure samples workability. At 90 days, the compressive strength of samples activated with 6M solution of NaOH or higher was equal and reached 88 MPa. The lower molarities of activating solution resulted in lower compressive strength at both early as well as later reaction times. SEM of produced inorganic polymers revealed the formation of gel between yet unreacted particles, while the EPMA analyses of the formed gel showed the presence of Fe in the gel structure.
CM-1:IL15 Fiber Reinforced Geopolymer Composites
W.M. KRIVEN, S.S. MUSIL, S. CHO, K. SANKAR, T.P. DIETZ, G.P. KUTYLA, Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, IL, USA; A.A. KOLCHIN, S.T. MILEIKO, Solid State Physics Institute, Russian Academy of Sciences, Chernogolovka, Moscow District, Russia
"Geopolymers" or polysialates are a Group I, charge balancing alumino-silicate, ceramic-like gel made by dissolution, polycondensation of precipitation under ambient conditions. Their nominal chemical composition is M2O.Al2O3.4SiO2.11H2O where M is a Group I cation. The ceramic-like, cross-linked product shares the brittle nature of ceramics, but can be reinforced with chopped or unidirectional fibers, or fiber weaves, yielding a strong and tough composite which has additional properties of fire and corrosion resistance. Geopolymers also have refractory adhesive properties up to 1,000°C whereupon they crystallize into a ceramic. This talk summarizes the mechanical properties measured in various fiber-reinforced geopolymers. These include, chopped carbon fibers of 60 or 100 μm in length; chopped basalt fibers of ¼" or ½" in length, chopped Saffil Al2O3 fibers of 3 μm diameter; unidirectional or randomly oriented corn husk fibers; jute weave reinforcements evaluated with and without NaOH pre-treatment; Columbian fique fibers, Nextel 610 and 720 weaves and 550, 610 and 720 unidirectional fibers; as well as single crystal mullite fiber reinforcements. The chopped mullite and alumina fiber composites were examined in 4-point flexure in situ up to 1500°C.
CM-1:IL16 Inorganic Polymers (Geopolymers) as Novel Catalysts for Organic Reactions
M. ALZEER, MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand
Heterogeneous solid acid catalysts such as zeolites, heteropolyacids and supported metals and metal oxides, have attracted much attention as replacements for commonly used but environmentally hazardous and corrosive acid catalysts such as AlCl3, BF3, or liquid HF. Of the solid acids, zeolites have attracted much attention and are being used extensively in the fields of oil refining, petrochemicals, fine and bulk chemicals. The structural features of geopolymers, especially their ion-exchange capabilities, show close similarities with their crystalline analogous (zeolites), suggesting that they might be utilised as advanced catalysts, in view of the possibility of modifying their acidity, porosity and particle shape and size. Here we demonstrate the synthesis and characterisation of a new class of heterogeneous geopolymer-based catalysts and their use in some organic syntheses such as Beckmann rearrangements and Friedel-Crafts alkylations.
CM-1:L17 Carbonation in Metakaolin-based Geopolymer
R. POUHET, M. CYR, Université de Toulouse, UPS, INSA, Laboratoire Matériaux et Durabilité des Constructions, Toulouse Cedex, France
The carbonation of Portland cement-based materials involves the reaction between atmospheric CO2 and calcium ions in the pore solution. The formation of calcium carbonate is responsible of a decrease in the pH of the pore solution from 12.5 to 9, thus leading to the depassivation of steel reinforcement and their possible corrosion.
In geopolymeric matrices, composed of metakaolin and sodium silicate and containing almost no calcium, the alkali ions can also react with CO2 and form alkali carbonates, which cause a drop in pH, but also the formation of efflorescence (white crystals formed in surface). Since the carbonation of geopolymer can have the same consequences on the pore solution than for cement, the risk of corrosion or efflorescence needs to be assessed.
This study investigates the natural and accelerated carbonation of metakaolin-based geopolymer. Analysis methods such as TGA, XRD, IR Spectroscopy, and the analysis of the pore solution are used to determine the nature of the formed carbonates, their effect on the solution pH, and aspect of specimen. The results are discussed and compared with those obtained for the Portland cement to better understand the mechanisms involved in metakaolin-based geopolymer in presence of carbon dioxide.
CM-1:L18 Development of Novel Low Alkali Content Activated Fly Ash Cement (LAFAC)
S. GUPTA, M.F. RIYAD, Advanced Materials Research Group, Dept. of Mechanical Engineering, University of North Dakota, Grand Forks, ND, USA
It is well known that the alkali activation of Fly Ash to produce cementitious materials is an important area of fundamental research. From environmental perspective, the use of alkali activators, for example NaOH, is an environmental concern as it is electrochemically generated with the concomitant production of harmful Cl2 or HCl gas as by products. Recently, we proposed that it is possible to use activate Fly Ash to produce cementitious network by using low concentration of alkaline solutions (<0.05 M). In this presentation, we will present recent results about the successful utilization of this novel technology for fabricating different types of novel composites by using both Class C and Class F fly ash from different sources. The fundamental chemistry responsible for the cementitious behavior of these novel structures will be presented. In addition, detailed mechanical property studies, microstructure analysis, and phase analysis will be presented.
CM-1:L19 A Taguchi Approach for the Synthesis Optimization of Metakaolin Based Geopolymers
A TSITOURAS, S. TSIVILIS, G. KAKALI, National Technical University of Athens, School of Chemical Engineering, Zografou Campus, Athens, Greece
There are several factors that affect geopolymerization, including the type and ratios of the starting materials as well as the curing conditions of the initial mixture. The effect of the synthesis parameters on the formation of inorganic polymers are usually examined by "changing one factor at a time". In this study Taguchi experimental designing model was applied in order to study the synergetic effect of selected synthesis parameters on the compressive strength development of metakaolin based geopolymers. The experimental design involved the variation of three control factors in five levels. The selected factors and the corresponding level range were: i) the alkali to aluminum ratio in the starting mixture (0.5-1.5), ii) the kind of alkali ion (Na and/or K) and iii) the ratio of Si to alkali oxide in the activation solution (0-2.0). The effect of solid to liquid ratio is also examined. The compressive strength of geopolymers was measured and the final products were also examined by means of XRD, FTIR and SEM.
As it is concluded, the optimal synthesis conditions for metakaolin geopolymers are R/Al=0.75, Na/(Na+K)=0.50 and [Si]/R2O=1.50, while the factor having the highest impact on the development of compressive strength is the [Si]/R2O ratio.
CM-1:L21 Corrosion Resistance and Mechanical Performances of Reinforced Fly-ash Geopolymer Mortars
M.E. NATALI, S. MANZI, L. CARABBA, C. CHIAVARI, M.C. BIGNOZZI, Dipartimento di Ingegneria Civile, Chimica, Ambientale e dei Materiali, University of Bologna, Italy; M. ABBOTTONI, A. BALBO, C. MONTICELLI, Centro di Corrosione e Metallurgia "Aldo Dacco'", University of Ferrara, Italy
The growing focus on issues related to the control of CO2 emissions, energy conservation and waste recycling pushes the construction industry to tackle the challenge of sustainable development. The production of ordinary Portland cement (OPC), main product of the sector, is one of the most polluting in terms of CO2 emissions, thus finding alternative binder is becoming an urgent matter. Geopolymers are recently largely investigated for this purpose, but studies concerning the durability of reinforced conglomerates prepared with alkali activated binders are only few. The present work aims at investigating the durability performances of steel reinforced geopolymer mortar samples based on carbon fly-ash in comparison with OPC mortar. The effect of different Na2O/SiO2 molar ratios in the geopolymer mixes is evaluated in terms of mechanical and microstructural properties as well as corrosion resistance in a chloride rich environment. The obtained results show that under the same environmental conditions more limited chloride amounts penetrate in reinforced fly-ash geopolymers where a better corrosion behavior is also detected up to 1 month of exposure. Instead, the corrosion resistance is quite similar to that of reinforced OPC mortar when a period of three months is considered.
CM-1:L23 The Influence of Short Fibres and Foaming Agents on the Physical and Thermal Behaviour of Geopolymer Composites
G. MASI1, 2, W.D.A RICKARD2, A. VAN RIESSEN2, M.C. BIGNOZZI1, 1Department of Civil, Environmental and Materials Engineering, University of Bologna, Bologna, Italy; 2Geopolymer Research Group, Curtin University, Perth, WA, Australia
Short fibres are commonly used as reinforcements to improve the mechanical performance of ceramics, metals and polymers as they are effective in strengthening and toughening these materials. This paper will present the results from two investigations on fly ash based geopolymers. Different concentrations of short fibres were investigated in order to characterise the effect on the flexural behaviour and the toughness of the fibre reinforced geopolymers.
Foaming methods to reduce the density of geopolymers were also investigated as low density geopolymers are increasingly being reported in the literature to be effective in improving the insulating properties. However, there is no consistency in foaming methods and as such this study was performed to compare methods in order to better understand their effect on the properties of geopolymers. The physical, mechanical and microstructural properties of the low density geopolymers are presented and the effects of the source foaming agents characteristics on the hardened composite is discussed, as well as the relative merits of the different procedures to synthesise the foamed geopolymer.
Thermal analysis results from both the fibre reinforced and foamed geopolymer samples will also presented.
Session CM-2 - Applications
CM-2:L01 Photoactive Inorganic Polymer Composites with Oxide Nanoparticles
M. FALAH POORSICHANI, MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand
Here we describe novel photocatalytic geopolymer composites for photodegradation of environmentally harmful organic and some inorganic materials. These metakaolinite-based geopolymers functionalized with metal oxide nanoparticles are synthesised at ambient temperatures which act as photocatalysts in the presence of UV or visible light. The oxide nanoparticles can be synthesized separately to the desired shape and size and can either be added directly to the geopolymer matrix prior to curing, or co-synthesised with the geopolymer during the preparation of the composite. The morphologies and the crystal phase of the products were determined by SEM and XRD. FTIR and MAS NMR confirmed the presence of aluminum, sodium, and metal ions into the Si-O-Si units and structural characteristics of the photocatalytic geopolymer composite respectively. The photocatalytic performance of these new composites, evaluated by degradation of organic dyes in aqueous solution under UV radiation, demonstrated enhanced absorption and photocatalytic ability for the removal of the dye, indicating promising applications for these new materials as cost-effective materials for removing heavy metals from wastewater, purifying polluted drinking water and catalysts for photodegrading hazardous organic pollutants.
CM-2:IL02 Geopolymers for Fire Resistant Applications: Recent Results and Future Directions
W.D.A. RICKARD, A. VAN RIESSEN, Geopolymer Research Group, Curtin University, Perth, WA, Australia
The research community has known about the potential of geopolymers for utilisation in high temperature applications since the mid 1990's, largely due to geopolymers being described as intrinsically thermal resistant. However, it is also known that not all geopolymer formulations have good thermal properties and as such it is not a given that all geopolymers are suitable for high temperature applications. Additionally, thermal resistance does not always translate to fire resistance due to the extremely high temperature gradients during a fire which can introduce damaging effects such as spalling.
This paper will review recent advances in the use of geopolymers as fire resistant materials and discuss potential future directions for research and development including methods for improving their performance.
CM-2:L04 Shape Forming a Meta-kaolin Based Geopolymers Containing PLA Fibers for Membrane Application
H.R. RASOULI1, F. GOLESTANI FARD1, A. MIRHABIBI1, G. MOUSAVI NASAB1, K. MACKENZIE2, 1School of Metallurgy and Materials Engineering, Iran University of Science and Technology, Tehran, Iran; 2MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand
Geopolymers are a new synthetic aluminosilicate groups which show good chemical and mechanical properties same as other ceramic materials while having lower processing temperature and cost.
Synthesize and shape a geopolymeric support membrane based on meta-kaolin is studied in this paper. Two types of kaolinites mixed with sodium silicate and sodium hydroxide solutions used as primary materials. Poly Lactic Acid (PLA) based fibers with 12, 20 and 29µm diameters were employed as pore creating media. Then, membrane bodies were made by extruding optimized geopolymer paste, followed by curing and drying. XRD, FTIR and SEM were used to characterize the chemistry and microstructure of samples. Moreover, compressive strength of samples was measured to evaluate the mechanical properties.
It was found that SiO2/Al2O3 ratio could be optimized at the value of 4 where the geopolymeric characteristics were found to be suitable. The ratio of Na2O/Al2O3 affected the leaching efficiency of PLA fibers and in the present work it varied in the range of 1.5-1.75 depending on the kaolinite source. By optimizing the extrusion parameters, a body with pretty aligned fibers was made. Finally, membrane behavior in terms of permeability was investigated and compared to conventional membranes.
CM-2:IL05 Applications of Fly Ash-based Geopolymer for Structural Member and Repair Materials
W. YODSUDJAI, Department of Civil Engineering, Faculty of Engineering, Kasetsart University, Bangkok, Thailand
The applications of using the fly ash-based geopolymer as a structural member and a repair materials in reinforced concrete structure was conducted. The optimum mix proportion of fly ash-based geopolymer concrete using for structural beam and fly ash-based geopolymer mortar using for repair material were developed. The flexural behavior of fly ash-based geopolymer reinforced concrete and the durability aspect namely the corrosion of steel reinforcement were investigated using the electrical acceleration. For the repair purpose, the fundamental properties; that is, compressive strength, flexural strength, bonding strength between fly ash-based geopolymer mortar and mortar substrate, setting time and chloride penetration were investigated. Also, the behavior of the conventional reinforced concrete beam repaired by the fly ash-based geopolymer mortar was investigated. The behavior of the fly ash-based geopolymer reinforced concrete beam was similar to that of the conventional reinforced concrete beam; however, the corrosion of the steel reinforcement of the fly ash-based geopolymer reinforced concrete beam was higher than that of the conventional reinforced concrete beam. The fundamental properties of the fly ash-based geopolymer mortar were not different from that of the commercial repair materials; however, the reinforced concrete beam repaired by the fly ash-based geopolymer mortars performed a little lower than that of the control reinforced concrete with no repair. As a result, even there will be still a need of improvement there was a good tendency for using the fly ash-based geopolymer as the structural member and the repair materials.
CM-2:IL06 Porous Geopolymers for Counteracting of Urban Heat Island Effect
K. OKADA, Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama, Japan; A. IMASE, T. ISOBE, A. NAKAJIMA, Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology, Tokyo, Japan
Rising temperatures in big cities are an increasing problem. This urban heat-island effect arises from the increasing heat generated by human activity and artificial surface areas. As one possible method for counteracting this effect, we have investigated a passive cooling system using evaporation of water from porous ceramics. Ii is preferable if these porous ceramics could be prepared by a more environmentally friendly process. Geopolymers are green materials solidifying at ambient temperatures by the formation of an alkali aluminosilicate gel only firing kaolinite at 600°C. The geopolymers were prepared from sodium silicate, metakaolinite, NaOH and H2O at SiO2:Al2O3:Na2O:H2O=3.66:1:1:x (8-17), and curing temperatures (CT) of 70-110°C. The porous geopolymers were prepared by kneading PLA fibres of 12, 20 and 29 μm dia. at 13-28 vol% into the geopolymer paste prepared at H2O/Al2O3 = 9. The resulting paste was extruded using a domestic extruder, cured at 90oC for 2 days then dried at the same temperature. The PLA fibres in the composites were removed by alkali treatment and/or heating. The highest capillary rise was achieved in the porous geopolymers containing 28 vol% of 29 μm fibres, estimated by the equation of Fries and Dryer was 1125 mm.
CM-2:L07 Humidity Controlling Wall Tiles by Geopolymerisation
G. CIGDEMIR KORC1, Y. YILDIRIM2, A. KARA1, 3, F. KARA3, 1Ceramic Research Center, Anadolu University, Eskisehir, Turkey; 2Kaleseramik Research and Development Centre, Can, Canakkale; 3Anadolu University, Department of Material Science and Engineering, Eskisehir, Turkey
The humidity range in which a person feels comfortable is from 40 to 65%. The humidity controlling tiles can be utilized as covering materials to regulate the humidity level in rooms when ambient humidity changes. They should be able to absorb the water vapor rapidly from the atmosphere when the humidity is higher than 65%. In addition when the humidity is less than 40% the material should be able to desorb the water vapor to steep the humidity range in the 40 to 65%. The main factors that effect humidity controlling are pore size and distribution. In this study, the sepiolite based mixtures were produced as wall tiles by geopolymerisation method and the humidity controlling abilities were investigated by measuring absorbtion/desorbtion characteristics at lower (40%) and higher (80%) humidity ranges at constant temperature. It was found that the sepiolite based wall tiles have excellent humidity regulating capacity. Production trials were also made up to 10x10cm tiles with success.
CM-2:L08 Solidification/Stabilization of Organic Liquid in Metakaolin-based Sodium Geopolymer
D. LAMBERTIN, A. ROOSES, A. POULESQUEN, F. FRIZON, CEA/DEN/MAR/DTCD/SPDE, Bagnols-sur-Cèze, France
In the field of nuclear waste, organic liquids without wastes disposal are stored in nuclear facilities awaiting treatments. This work reports the results of a geopolymer formulation having significantly enhanced its compatibility with organic compounds and allowing the stabilization of oily wastes in a geopolymer binder. The process consists in obtaining a stabilized emulsion of oil in an alkali silicate solution and then in adding metakaolin to engage the cure of a geopolymer block with an oil emulsion stabilized in the material. The emulsion stability versus time has been characterized by the control of the viscous modulus G'' with dynamic rheology. Under infrared, the characteristic displacement of the Si-O bond stretching signal during the curing process has evidenced the normal geopolymerization occurrence in presence of oil waste and meanwhile no modification of the oil pattern is noticed which underlines the non-attendance of waste/binder interactions. The particle size of the stabilized oil emulsion has been determined by Environmental-SEM and reaches an average of 5 to 10 µm.The material had an easy implementation, and exhibited good mechanical properties. The waste incorporation rate was increased with success up to 30 vol% of the final composite material.
CM:P01 Application of Different Treatment of Illite Clay for Low Temperature Ceramics
G. SEDMALE, A. KOROVKINS, I. SPERBERGA, M. RUNDANS, Riga Technical University, Institute of Silicate Materials, Riga, Latvia; G. STINKULIS, University of Latvia, Department of Geology, Riga, Latvia
This study is focused on modification of the structure and properties of typical 2:1, sheet silicates - illite clay by subjecting them to chemical and mechanical impact to develop ceramic products at lowered sintering temperature.
The present study investigates the impact of chemical and mechanical processing on structure and some properties of 2:1 layer silicate - illite dominate clay (with illite content up to 70%). The starting materials were Quaternary clay samples taken from the clay deposits of Latvia from the 2-3m depth of the soil. For chemical treatment there are used of 1M, 3M, and 6M KOH- and NaOH- water solutions. The solution/clay ratio was fixed to 20% solution at clay powder yielding a good workability of the clay. Treated mixes were investigated by IR-spectroscopy and by thermal analysis at temperature ranged from 20 to 10000C as well as by microscopy. X-ray diffraction was used to determine the crystalline phase changes. Some technological characteristics such as shrinkage, bulk density, porosity and compressive strength was established.
The study shows that alkaline activation of raw illite clay leads to the slight structural changes mainly characterized by water link changes in illite structure together with the remarkably decrease of sintering temperature of ceramic for up to 200-250 °C by comparing with conventional sintering at 950-1000 °C. The sintered at 700 °C ceramic product reaches the compressive strength value 20-25 N/mm2.
CM:P03 Obtaining of Lightweight Geopolymer using Ash from Thermal Power Plants
B.I. BOGDANOV, P. S. PASHEV, Y. H. HRISTOV, University "Prof. d-r Assen Zlatarov", Department of Inorganic Substances and Silicates, Bougas, Bulgaria
A lightweight inorganic polymer is obtained using ash from thermal power plants, metakaolinite and lightweight aggregate. This inorganic material is activated using small amounts of sodium hydroxide and sodium silicate solution. Processing parameters and various curing conditions, such as curing temperature, curing time and moisture, are investigated. Compressive strength, rate of water absorption and density of each sample were measured.
CM:P04 Durability of Fly Ash Geopolymer Mortars in Corrosive Environments, Compared to that of Cement Mortars
A. ASPROGERAKAS, A. KOUTELIA, G. KAKALI, S. TSIVILIS, National Technical University of Athens, School of Chemical Engineering, Athens, Greece
In the present paper the durability of fly ash geopolymer mortars compared to that of cement mortars is investigated. Geopolymers can improve the ecological image of building materials, especially when their production is based on industrial by-products such as fly ash. Three series of fly ash based geopolymer mortars were prepared using calcareous sand to fly ash ratio (S/FA) varying from 0.5 to 2. In addition, cement mortar specimens were prepared (according to EN 196-1) using cement CEM I 42.5 N and CEM II 32.5 N. Durability of geopolymer and cement mortars was evaluated by means of compressive strength development, acid resistance, chloride diffusion and sulfate resistance. It was found that fly ash can be effectively used to produce geopolymer mortars with calcareous sand. Geopolymers exhibit competitive compressive strength compared to that of cement mortars. Geopolymer mortars develop their maximum compressive strength a few days after their casting. Geopolymer and cement mortars exhibit satisfactory resistance to sulphate attack. Cement mortars, generally, show better behavior (compared to geopolymers) in chloride diffusion. Finally, geopolymers indicate improved performance against acid attack, compared to that of cement mortars.