European Geopolymer Network
Limoges – June, 15th 2016
European Geopolymer Network
Limoges – June, 15th 2016
PROGRAM OF THE FIRST EUROPEAN GEOPOLYMER NETWORK 9h00 Opening session
09h30 Joseph Davidovits: Geopolymers based on natural and synthetic metakaolin. A critical review 09h55 Lubica Kriskova et al.: Towards porous inorganic polymers: kinetics of the foaming process 10h20 Cengiz Bagci et al.: TEM Studies of Silicon-Based Ceramic Nano-Particles Synthesized from Sodium Geopolymers
10h40 coffee break and poster session
11h15 Marco Natali et al.: Photocatalytic activity of TiO2 degussa P25 in different geopolymer matrices 11h40 Isabel Sobrados et al.: Electrochemical behaviour of hybrid sol-gel steel embedded in carbonated and chloride contaminated alkali-activated fly ash mortars 12h05 Trudy Kriven et al.: Status Quo of Metakaolin-based Geopolymers Containing Inorganic or Biological Reinforcements
12h30 lunch and poster session 14h00 Visite of the European ceramic Center
14h30 Wallid Hajjaji et al.: Reuse of red mud and lamp glass waste in geopolymers 14h55 Silvania Onisei et al.: Slags in the binary FeOx-SiO2 and ternary FeOx-CaO-SiO2 system 15h20 Najet Saidi et al.: Recycling of geopolymer waste: influence on geopolymer formation and mechanical properties 15h45 Claudio Ferone et al.: Synergistic use of reservoir management wastes to obtain geopolymer bricks
16h10 Round table 17h30 End of the congress
European Geopolymer Network
Limoges – June, 15th 2016
LIST OF THE POSTERS P1 Elettra Papa et al.: Porosity and insulating properties of silica-fume based foams P2 Valentina Medri et al.: Tailoring and study of the porosity in geopolymer based materials P3 Marilyne Soubrand et al.: Importance of geopolymers for the valorization of various type of inorganic waste P4 Julie Peyne et al.: Improving the clay bricks production: experimental clay mixtures and geopolymer binders P5 Alexandre Autef et al.: Study of the geopolymerization rate by thermal experiments P6 Laetitia Vidal et al.: Alkaline silicate solutions properties and their effect on sand agglomeration and geopolymer formation P7 Francisca Puertas et al.: Re-use of waste glass in the preparation of geopolymer: as alternative alkaline solution and solid precursor P8 Nicoletta Toniolo et al.: Geopolymer incorporate silicate waste P8 Giamarco Taveri et al.: Fly-ash/borosilicate glass based geopolymers P9 Jihène Nouairi et al.: Using lakhouat (NW Tunisia) mine tailing in metakaolin based geopolymers P10 Ioanna Papayianni et al.: Alkali activation of high calcium by-products and applications
European Geopolymer Network
Limoges – June, 15th 2016
Geopolymers based on natural and synthetic metakaolin. A critical review Joseph Davidovits
Institut Géopolymère, 02100-Saint-Quentin, France Much of the original research into geopolymers was conducted on calcined kaolinitic clay precursors
known under the generic term of metakaolin. Although metakaolin reacts in alkaline as well as in acidic
medium, the present issue focusses exclusively on the alkaline route.
Forty years ago, in October 1975, in our CORDI laboratory (later Cordi-Géopolymère) in Saint-Quentin,
France, we were testing a new French metakaolin brand named Argical®. It was manufactured with an
advanced technology in a flash calciner instead of being roasted in a rotary kiln or a vertical multiple-
hearths oven. We discovered that this metakaolin was reacting very well with soluble alkali silicates. I
recognized the potential of this discovery and presented an Enveloppe Soleau for registration at the
French Patent Office. It was the first mineral resin ever manufactured. Chapter 1 of the book
Geopolymer Chemistry and Applications describes this major milestone. The title of the patent, Mineral
polymer, was self-evident (Davidovits, 1979). In 1983, at the Central laboratory of Lone Star Industries,
Houston, USA, we started the development of advanced cementicious materials. This research yielded
the discovery of the first metakaolin-based geopolymer cement (the cement PYRAMENT).
However, we had to test at least 10 different metakaolin brands in order to find the right product, which
would react as a geopolymeric precursor, in alkaline medium. Indeed, at that time, the bulk of the various
metakaolins was used essentially as fillers in the paper making and plastic industry. Its specific chemical
reactivity towards alkalis remained confined in the production of very special products, namely synthetic
zeolites, especially the type Zeolite A. In addition, it was striking to discover that the metakaolin sources
for zeolite manufacture were according to Breck (1974) of two types, one calcined at 550°C (low
temperature metakaolin) and the second at 925°C (high temperature metakaolin). Both metakaolins
reacted weakly compared to the metakaolin we had been working with in France. We recognized that
we had had luck when starting the geopolymer research, in Saint-Quentin. We had tested the right source
of metakaolin, from the beginning.
And we became aware of one major parameter in geopolymer science, namely the calcining temperature
of the geological kaolinitic clays. The chemical formula for kaolinite is Si2O5Al2(OH)4. From a
geopolymer standpoint we may write Si-O-Al-(OH)2 with the covalent aluminumhydroxyl - Al-(OH)2
side groups of the poly(siloxo) hexagonal macromolecule [Si2O5]n. This new structural approach has
profound consequences with regard to a better understanding of geopolymerization mechanisms. In
particular, according to the reaction:
Si2O5Al2(OH)4 Si2O5Al2O2 + 2H2O
Metakaolin results from the dehydroxylation of the OH groups in kaolinite. The reactive molecule is an
alumino-silicate oxide Si2O5Al2O2, coined MK-750 in order to pinpoint the calcination temperature.
However, in addition to temperature control, it is the kiln technology, which determines the feasibility
and production of the alumino-silicate oxide MK-750. In calcination carried out in a rigid vertical
multiple-hearths calciner, a sufficiently low water vapour pressure is maintained during the entire
roasting process, providing the desired chemical reactivity (Al in 5-fold coordination). Same for
products manufactured in a flash calciner. This is not the case for metakaolins obtained in a rotary kiln,
commercialized as Portland cement additives. Unfortunately, this later product is more and more used
in geopolymer research because it is easily available. This raises new concerns in terms of reactivity and
reproducibility of the results obtained with this raw material essentially tailored for Portland cement
applications, not for geopolymer technologies. The geopolymer chemistry was invented 40 years ago
because we had the luck to get the right geological raw material and the appropriate calcination process.
Today, there exist new methods based on the synthesis of alumino-silicates. In short, we have: -
Geopolymers based on natural metakaolins MK-750 and - Geopolymers based on synthetic metakaolins
SMK-750;
The review discusses the correlation between reactivity and calcination methods, MAS-NMR
spectroscopy, reaction mechanism and applications. The details were already published online in the
second issue of the Virtual Journal on Geopolymer Science, hosted by the
platform MaterialsToday from Elsevier. (See at http://www.geopolymer.org/news/2nd-virtual-journal-
on-geopolymer-science/).
European Geopolymer Network
Limoges – June, 15th 2016
Towards porous inorganic polymers: kinetics of the foaming process
Kriskova, L.1,*, Denissen, J.1,2, Pontikes, Y.1
1Department of Materials Engineering, KU Leuven, 3001 Heverlee, Belgium 2Faculty of Engineering Technology, Campus Group T Leuven, 3000 Leuven, Belgium
*[email protected] The present paper deals with the synthesis of porous inorganic polymers (IP) from a secondary copper
slag and its main focus lies on the investigation of various parameters (alkali activator molarity and
curing temperature) and their effect on the kinetics of foaming. Since, it had been previously shown that
a porous IP could indeed be synthesised from this type of slag;1 the motivation of the work was to
identify the most crucial parameters influencing the foaming kinetics, as well as to find conditions under
which a stable, well developed foam could be formed, within an industrial operating environment. For
this purpose, a FeO-SiO2 based secondary copper slag was activated with Na-silicate alkali activator
with a SiO2/Na2O molar ratio varying between 1.0 to 1.4, keeping the water content steady at 75 wt.%.
Foaming was achieved by the oxidation of the aluminium in the alkaline environment, liberating H2
gas, and the subsequent gas entrapment. The temperature of the environment during foaming was
controlled by having all the installation inside a water tank with controlled temperature.
In order to determine foaming kinetics, the foaming process was recorded by means of a camera and the
height of the synthesised foam was measured every 5 sec. Results presented in Fig. 1 showed that the
SiO2/Na2O ratio had a major influence on foaming kinetic regardless of the temperature at which the
foaming was performed, e.g. for an increasing the SiO2/Na2O ratio foaming initiated later The increased
SiO2/Na2O ratio had a positive effect on the foaming itself, as could clearly be seen by comparing the
originally introduced amount of material with the final foam volume. The volume increased about 2
times for SiO2/Na2O of 1.0 but about 3.5 times for the ratio of 1.4.
40 60 80 100 120 140 160 180100
150
200
250
300
350
Hei
gh
t (%
)
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FS-1.2
FS-1.4
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150
200
250
300
350
Hei
gh
t (%
)
Time (s)
FS-1.0
FS-1.2
FS-1.4
Figure 1 : Change of the foam height over a time as a function of an activating solution at a) 20 °C
and b) 40 °C
The effect of SiO2/Na2O ratio as well as of the curing temperature on the reaction kinetics was also
evaluated by means of isothermal calorimetry. It was revealed, that the higher SiO2/Na2O ratio resulted
in slower reaction and smaller amount of released heat. This is most probably a consequence of lower
dissolution rate caused by lower Na2O content, combined with an expected higher viscosity. Similarly,
lowering the temperature of environment, resulted in later initiation of the reaction.
References 1 L. Kriskova, et al., Synthesis and characterisation of porous building materials from FeO-SiO2 based slag, 2015,
Proceedings of the 4th International Slag Valorisation Symposium, 229-237.
a) b)
European Geopolymer Network
Limoges – June, 15th 2016
TEM Studies of Silicon-Based Ceramic Nano-Particles Synthesized from Sodium
Geopolymers
Cengiz Bagci1,2 and Waltraud M. Kriven1
1Department of Material Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA 2Department of Metallurgical and Materials Engineering, Hitit University, Corum, 19030, TURKEY Recently, geopolymers (GPs) are being considered as precursors to ceramic formation.1,2 Pure sodium
geopolymers were converted to a high strength ceramic material on heating to develop their mechanical properties
for use in structural applications. Namely, NaGPs crystallized into nepheline (Na2O•Al2O3•2SiO2) plus glass, on
heating at 900-1100 °C.1 By incorporating carbon nano-powders into GPs, we have well achieved to produce
silicon carbide nano-particles.3 In this study, 9 or 18 moles of carbon nano-powder were incorporated into NaGPs
at the stage of GP resins or powdered GPs after curing to make GP carbon precursors for carbothermal reduction,
respectively by the well-known geopolymer route under ambient temperature. Subsequently, GP carbon precursors
were carbothermally reacted in an atmosphere controlled tube furnace at temperatures of 1400°-1600 °C for 2 h
under high purity argon or nitrogen (99.99%) flowing. Depending on GP preparation and carbothermal reduction
conductions, this study revealed that the formation of high yield nano-sized silicon-based ceramic powders by
confirming TEM studies by following standard analysis. Fig.1 shows TEM micrograph corresponding selected
area patterns (SAD) of SiAlON from NaGP9C by confirming ex-situ XRD.
a) b)
Figure 1 : TEM micrographs of NaGP9C heated at 1400 °C /2h under nitrogen (a) SAD pattern of the region (b).
Fig.2 represents TEM SAD patterns of the SiC converted from NaGP18C by confirming ex-situ XRD.
a) b)
Figure 2 : TEM micrographs of NaGP18C heated at 1600 °C /2h under argon (a) SAD pattern of the region (b).
The nanocrystals of these silicon based ceramics (<100 nm) with different morphologies and the crystallite were
determined by TEM corresponding SAD.
REFERENCES 1C. Kuenzel, L. M. Grover, L. Vandeperre, A. R. Boccaccini, C. R. Cheeseman, J. Eur. Ceram. Soc., 2013, 33,
251-8. 2J. L. Bell, P. E. Driemeyer and W. M. Kriven, J. Am. Ceram. Soc., 2009, 92 [3] 607-15. 3C. Bagci, G. P. Kutyla, K. C. Seymour, and W. M. Kriven, J. Am. Ceram. Soc.,2016, 1-10 DOI:
10.1111/jace.14254.
European Geopolymer Network
Limoges – June, 15th 2016
Photocatalytic activity of TiO2 degussa P25 in different geopolymer
matrices
M. Natali 1, A. Galenda 1, , S. Tamburini 1
1 National Research Council - Institute for Energetics and Interphases (CNR-IENI)
Corso Stati Uniti 4 - 35127 - Padova ITALY The use of photocatalytic self-cleaning materials in particular for building facades is of paramount importance because of their continuous exposure to air pollution, degrading their aesthetic appearance. Numerous studies have been conducted on photocatalytic coatings and photocatalytic cements, in particular by adding TiO2 nanopowders to cements [1-3]. Only very few studies exist on the formulation of geopolymers with photocatalytic activity [4,5]. This is quite surprising considering the emerging role of geopolymers as a green building material able to substitute ordinary portland cement in many fields. We here present our preliminary results on a screening of the photocatalytic activity of different geopolymer formulations, both alkaline and phosphate based ones, incorporating TiO2 Degussa P25 nano powder at different levels up to 10% weight. The photocatalytic activity was evaluated by monitoring the bleaching of ethylene blue dye spots deposited on geopolymer samples exposed to UV radiation at 365 nm in air. Comparison was made between samples having different TiO2 contents, samples kept in the dark, as prepared and treated samples. The photocatalytic activity of the examined samples ranged from 4 % to 30 % for UV exposure of 1000 min and was lower than for cement and stucco samples investigated for comparison (54% and 60% degradation respectively). In an effort to understand the observed results samples were characterized by XRD in grazing incidence and SEM-EDS.
REFERENCES: 1 A. Folli, I. Pochard, A. Nonat, U.H. Jakobsen, A.M. Shepherd and D.E. Macphee, 2010, J. Am. Ceram. Soc., 93
, 3360–3369. 2 A.R. Khataee, A.R. Amani-Ghadim M. Rastegar Farajzade & O. Valinazhad Ourang, 2011, Journal of
Experimental Nanoscience, Volume 6, Issue 2, 1745. 3 A. Strini, S. Cassese and L. Schiavi, 2005, Appl. Catal. B-Environ. 61, 90-9. 4 J.R. Gasca-Tirado et al.2012, Microporous and Mesoporous Materials 153, 282–28. 5 Yao Jun Zhang, Li Cai Liu, Yong Xu, Ya Chao Wang, De Long Xu,2012, Journal of Hazardous Materials 209–21,
146–150.
European Geopolymer Network
Limoges – June, 15th 2016
Electrochemical behaviour of hybrid sol-gel steel embedded in carbonated and chloride contaminated alkali-activated fly ash
mortars.
M. Criado 1,2, I. Sobrados1, J. M. Bastidas3, J. Sanz1
1 Materials Science Institute of Madrid (ICMM), CSIC, Sor Juana Inés de la Cruz 3, 28049
Cantoblanco-Madrid, Spain
2 Department of Materials Science and Engineering, The University of Sheffield, Sir Robert
Hadfield Building, Sheffield S1 3JD, UK
3 National Centre for Metallurgical Research (CENIM), CSIC, Avda. Gregorio del Amo 8, 28040
Madrid, Spain
Corrosion of reinforcement steel is one of the main causes of the premature degradation of
reinforced concrete structures. Thus the construction sector is very interested in the development of new
cement binder materials as an alternative to ordinary Portland cement (OPC). In this respect, the most
promising emerging approach is based on raw materials suitable for alkaline activation, essentially
alkali-activated fly ash (AAFA), which originate new binding materials known generically as alkaline
cements.
The protection of metals from their surrounding environment is usually achieved by deposition of
protective coatings on the metal surface to establish a physical barrier against aggressive ions.
The aim of this work was to study the corrosion behaviour of hybrid organic-inorganic coatings
applied on carbon steel embedded in carbonated ordinary Portland cement (OPC) and alkali-activated
fly ash (AAFA) mortars and immersed in a 3 wt% NaCl solution using electrochemical methods. The
sol-gel coatings were prepared by condensation and polymerization of TEOS/MPTS, TEOS/MTES,
TMOS/MPTS and TMOS/MTES mixtures using a molar ratio of 1.0 and deposited by dip-coating on
carbon steel substrates.
Interesting results indicate that corrosion of coated steel rebar embedded in carbonated OPC and
AAFA mortars in the presence of chloride ions was not only dependent on the type of the cementitious
system but also on the nature of reagents forming the coating. Carbon steel reinforcements are
compatible with AAFA mortars, where they show corrosion rates even lower than those recorded in
OPC mortars.
European Geopolymer Network
Limoges – June, 15th 2016
Status Quo of Metakaolin-based Geopolymers Containing Inorganic or
Biological Reinforcements
Waltraud M Kriven,2, 1University of Illinois at Urbana-Champaign, Department of Materials Science and
Engineering, Urbana,, IL USA Metakaoline-based geopolymer composites have been reinforced with a variety of inorganic or organic
reinforcements which can be categorized in terms of their dimensionality i.e. particulates, short fibers,
chopped fibers, randomly oriented longer fibers to form a permiable mat, aligned long fibers and weaves.
Table 1. Summary of Geopolymer Composites containing Inorganic Reinforcements
Reinforcement % addition Flexure strength (MPa)
Chamotte (25 m) 50 wt% 15.33
Dolomite (45 m) 20 wt % 15.92
Mica phlogopite platelets 20 wt% 11.4
Granite powder 55 wt. % 10.3
Dicalcium phosphate (DCP) 15 wt% 9.8
Hydroxyapatite bone ash 15 wt % 9.5
Alumina platelet grinding media 70 wt % 20 (40 at 1000 °C)
Alumina chopped fibers 20 wt % 20
Basalt chopped fibers (1/4 “) 10 wt % 19.5
Basalt chopped fibers (1/2 “) 10 wt % 27
Basalt felt 10 wt % 22.2
Fiberglass felt 10 wt % 5.6
Basalt strand mat 20 vol % 31
Basalt fiber weave 30 vol % 41
E-glass Leno weave 25 wt % 25.6
Carbon fiber weave 20 vol % 269
Nextel 610 alumina (8 satin weave) 50 wt% 45.8
Nextel 720 mullite +15 vol % alumina 50 wt% 46
Table 2 : Summary of Geopolymer Composites containing Biological Reinforcements
Reinforcement % addition Flexure strength (MPa)
Abaca (banana leaf random fibers) 8.0 wt% 52
Corn husk fibers 13 wt % 7.6 (7 % strain to failure)
Jute weave 30 wt % 20.5
Colombian fique / sisal (unidirectional) 50 wt % 11.4
Amazon malva (unidirectional) 5.5 wt % 31.55
Amazon curaua (unidirectional) 8.3 wt % 18.86
Amazon chopped bamboo in Amazonian clay 15 wt % 7
Cork particulates 60 wt % 2.5 (0.75 % strain to failure)
K-based Geopolymer reinforced
with chopped Saffil ® alumina fibers
REFERENCES:
W. M. Kriven, in Comprehensive Composite Materials, to be published by John Wiley, (2016).
European Geopolymer Network
Limoges – June, 15th 2016
REUSE OF RED MUD AND LAMP GLASS WASTE IN
GEOPOLYMERS
W. Hajjaji1,2, C.S. Costa1, S. Andrejkovičová1, J. A. Labrincha3, F. Rocha1 1 Geobiotec, Geosciences Dept, University of Aveiro,3810-193 Aveiro, Aveiro 3910-193, Portugal
2 Natural Water threatment Laboratory CERTE, 273, 8020 Soliman, Tunisia 3 Department of Materials and Ceramic Engineering & CICECO – Aveiro Institute of Materials,
University of Aveiro, Aveiro, Aveiro 3810-193, Portugal
Geopolymers, a class of largely amorphous aluminosilicate binder materials, have been studied
extensively over the past several decades. Incorporation of wastes and by-products, as red mud and
fluorescent lamp glass, was studied to elaborate new metakaolin based geopolymer formulations thought
sodium alkaline activation. The main raw material is metakaolin 1200S (MK) (AGS Mineraux, France),
as alumino-silicate source (geopolymer GMK).The red mud and fluorescent lamp waste glass were used
as additive at different ratio (GR; 10 and 25% for red mud and GG; 25 and 50 % for lamp glass).
The compressive strength (Figure 1) gave initial maximum values (at 1 day curing) around 8 MPa for
the standard metakaolin based products (GMK) and 10% red mud confectioned one (GR10). The amount
of RM had a variable effect on the mechanical properties of geopolymer. The resistance of sample GR25,
for instance, decreased to minimum values below 5 MPa. By extending the curing time, the mechanical
strength increased considerably from day 1 to day 28 for the samples GR10. Longer curing time
improves the geopolymerization state resulting in higher compressive strength1. Once hardened,
specimens based in fluorescent lamp glass (both 25% and 50% added) showed high compressive
strength and toughness at first stage (1 day curing) in respect to metakaolin based one (Figure 1). This
toughness tends to decrease with curing time before stabilizing at 28 days.
Table 1.Compressive strength of tested geopolymers.
Acknowledgement: The work was supported by FCT-Grant SFRH/BPD/72398/2010 co-financed by Programa Operacional Potencial Humano POPH. REFERENCES: 1 W. Hajjaji, S. Andrejkovicová, C. Zanelli, M. Alshaaer, M. Dondi, J.A. Labrincha, F. Rocha. Materials and Design,
2013, 52, 648-654.
European Geopolymer Network
Limoges – June, 15th 2016
Slags in the binary FeOx-SiO2 and ternary FeOx-CaO-SiO2 system
as precursors for inorganic polymers
Onisei, S.*, Crijns, W., Pontikes, Y.
Department of Materials Engineering, KU Leuven, 3001 Heverlee, Belgium *[email protected]
Unlike “geopolymers”1 where the binding phase is almost exclusively an aluminosilicate with Al and Si
in tetrahedral coordination, inorganic polymers (IPs) can exhibit a wider chemistry, thus the former can
be seen as a subset of the latter.2 Of interest for the particular work are Fe-rich IPs, considering that Fe-
silicates are industrially produced by the non-ferrous metallurgy in substantial volumes and remain not
exploited yet as a secondary resource. Apart from the environmental motivation, the role of Fe in these
IPs remains obscure, thus, there is a need to provide insights in their microstructure and resulting
properties.
To address the above, 3 synthetic slags were synthesized, one in the binary FeOx-SiO2 and two in the
ternary FeOx-CaO-SiO2. After water quenching the melt, the semi-vitreous slags were characterised and
their reactivity was assessed. Subsequently, the slags were mixed with a Na-silicate solution and IPs
were formed after curing at room temperature. The properties and microstructure of these IPs were
studied by means of compressive strength measurements, FTIR and SEM, for different curing times.
Results are already presented in Figure 1, where it is demonstrated that the addition of calcium leads to
higher slag reactivity, i.e. dissolution kinetics, and increases the strength of the samples.
Figure 1 : a) Compressive strength of the inorganic polymers from the 3 synthetic slags and b)
Microstructure of the samples
REFERENCES: 1J. Davidovits, Geopolymer Chemistry and Applications, Geopolymer Institute, 2008. 2J.S.J. van Deventer, J.L. Provis, P. Duxson, D.G. Brice, Chemical Research and Climate Change as Drivers in
the Commercial Adoption of Alkali Activated Materials, Waste and Biomass Valorization, 1 (2010) 145-155.
0
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Pa)
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M1
a)
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European Geopolymer Network
Limoges – June, 15th 2016
RECYCLING OF GEOPOLYMER WASTE: INFLUENCE ON GEOPOLYMER FORMATION AND MECHANICAL PROPERTIES
N. Essaidi1, L. Vidal, A. Gharzouni, E. Joussein2 and S. Rossignol1
1 Univ Limoges, CNRS, ENSCI, SPCTS, UMR7315, 87000 Limoges, France.
2 Univ Limoges, GRESE, EA 4330 F-87000 Limoges, France
In recent years, the growth of waste production associated with the awareness of the environmental
problems and the need of sustainable development make waste management a priority [i]. Recycling
has drawn great interest as a way to solve waste problems, reduce environmental pollutions and preserve
natural resources. In this context, geopolymer materials are a new class of binders having the advantage
of using industrial by-products and recycled waste. So far, extensive research on geopolymer has been
conducted since the last decade, the generation of geopolymer waste increases. In this context, an
innovative use of geopolymer waste is their incorporation in different geopolymer formulations which
is in accordance with the “cradle to cradle” concept. Moreover, the possibility to reuse these
geopolymers allows reducing of the amount of raw materials used. Recycling of waste and their use as
aluminosilicate sources seems to be profitable in term of economic and environmental benefits, leading
to greener manufacturing and global sustainable development.
These binders are generated from the activation of an aluminosilicate source with an alkaline solution
[ii iii]. Their formation implies the dissolution of aluminosilicate species in an alkaline environment to
form an amorphous three-dimensional geopolymer network by polycondensation reaction. Based on
such a unique structure, geopolymers may exhibit good mechanical, chemical and thermal properties
making them a promising alternative for a variety of applications [iv].
The present work aims to evaluate the suitability of using crushed geopolymer in addition or substitution
of metakaolin to produce K-based geopolymers materials. For this, the used raw materials were
characterized. Then, the feasibility of consolidated materials was evaluated. Several samples were
prepared by varying the proportion of geopolymer waste. The structural evolution of the reactive
mixtures was monitored by FTIR spectroscopy. Finally, the consolidated materials were characterized
by compression tests. A feasibility study allowed retaining 20% as the waste percentage added or
substituted to the metakaolin to still obtain geopolymer materials. Moreover, it was shown that the
incorporation of the geopolymer waste may disturb the polycondensation rate which was proved to
strongly depend on the solid to liquid ratio and the Si/K ratio of the alkaline solution. Finally,
relationships were demonstrated between the compressive strengths and the chemical compositions of
the different samples. The low reactivity of geopolymer waste can be compensated with the use of highly
reactive alkaline solution or the increase of the amount of metakaolin in the mixture.
References 1 L.A. Guerrero, G. Mass, W. Hogland, Waste Management, 2013, 33, 220-232. ii P. Duxson, A. Fernández-Jiménez, J.L. Provis, G.C. Lukey, A. Palomo, J.S.J. Van Deventer, Journal
Materials Science, 2007, 42, 2917-2933.
iii J. Davidovits, Geopolymer: Chemistry and Applications, 2nd ed., Institut Géopolymère, St-Quentin, 2008. Iv C.A. Rees, J.L. Provis, G.C. Lukey, J.S.J. Van Deventer Colloids and Surfaces A: Physicochemical and Engineering Aspects. 2008, 318, 97–105.
European Geopolymer Network
Limoges – June, 15th 2016
POSTERS
European Geopolymer Network
Limoges – June, 15th 2016
Porosity and insulating properties of silica-fume based foams
E. Papa1, V. Medri1, D. Kpogbemabou2, V. Morinière3, J. Laumonier3, S. Rossignol2
1Institute of Science and Technology for Ceramics – National Research Council of Italy (ISTEC-CNR), Via Granarolo 64, 48018, Faenza (Ra), Italy.
2Univ Limoges, CNRS, ENSCI, SPCTS, UMR7315, F-87000 Limoges, France. 3Institut PPRIME, CNRS, Université de Poitiers, ISAE - ENSMA, F 86962 Futuroscope
Chasseneuil, France The thermal resistance of geopolymers combined with the possibility to obtain lightweight structures,
exploiting the use of reactive fillers, allow the production of composite foams designed for a range of
thermo-acoustic insulating and fire-proofing applications. The use of byproducts and waste materials
combined with the choice of fast, simple and low temperature production processes are the main goals
to obtain low cost and “greener” insulating materials. Geopolymers are good candidate for this purpose,
because they may be synthetized at low temperature and from a variety of starting alluminosilicate
powders, that includes also waste materials as metallurgical slags and fly ashes [1]. Silica fume, a waste
byproduct derived from electric arc furnaces used in the manufacture of ferrosilicon or silicon metal,
was used both as starting silicate powder and pore forming agent for the production of foams. This study
shows the possibility to obtain really porous lightweight foams, with a multi-scale macroporosity, from
a potassium or sodium basic medium and metakaolin and/or silica fume starting powders. The presence
of metal silicon impurities, present in silica fume, was exploited to generate a direct foaming of the
slurry, due to the gaseous production of hydrogen caused by the oxidation, in alkaline medium, of metal
silicon [2]. A slightly elevated temperature (70°C) was enough to promote the development of hydrogen
bubbles, the increase of the viscosity and the consolidation of the foams. The reactivity of the starting
mixture and the related homogeneity greatly affected the development of the final porous structures and
the related insulating properties of the materials.
The foams were characterized in term of macro- and microstructure, porosity distribution, FTIR-ATR
spectroscopy, thermal and acoustic properties achieved. The foams showed really ultra-macroporous
structures, with roughly rounded pores and a total porosity of ≈ 80%. The low bulk densities (0.4-0.6 g
cm-3), the good thermal conductivity values (≈ 0.17 W m-1 K-1) and the acoustic behaviors make the
foams really promising as insulating materials for application, for example, in building and construction
sectors as possible insulating, heat resistance, precast panels.
Figure 1: example of the core section of a potassium silica fume based foam and related SEM microstructure. REFERENCES: 1 J.S.J. van Deventer, J.L. Provis, P. Duxson, D.G. Brice, Waste Biomass Valor. 1, 2010, 145–155. 2 V. Medri, E. Papa, J. Dedecek, H. Jirglova, P. Benito, A.Vaccari, E. Landi, Ceram. Internat. 39, 2013, 7657-7668.
European Geopolymer Network
Limoges – June, 15th 2016
Tailoring and study of the porosity in geopolymer based materials
V. Medri 1, E. Landi 1, E. Papa 1, A. Natali Murri 1, P. Benito 2, A. Vaccari 2
1 CNR-ISTEC, Institute for Science and Technology for Ceramics 2 CHIMIND, Dept. Industrial Chemistry “Toso Montanari”, University of Bologna
Geopolymers are produced by reacting an alumino-silicate powder with an aqueous alkali hydroxide
and/or alkali silicate solution. The production process in aqueous medium allows to tailor the porosity
in the nanometric to millimetric range. Water affects the intrinsic mesoporosity of the geopolymer
matrix, acting as a pore former during the polycondensation stage, while ultra-macroporosity can be
induced in the material by different methods. Hierarchical porous systems, in which mesopores are
directly connected to macro- and to ultra-macropores, can be obtained in this way.
Geopolymers are often compared with ceramics for their similar final properties arising from the
inorganic structure. The main difference, referring to the process formation of these materials, is that
ceramics are usually treated at high temperature for the final consolidation, while geopolymers have the
advantage to be consolidated through a chemical reaction that occurs at low temperature.
Methods used in the formation of porous ceramics can be adapted to obtain geopolymers with different
architectures, pore size distributions, interconnectivity, etc.; direct foaming techniques can be used to
obtain foams with rounded ultra-macroporosity. Freeze-casting, belonging to the sacrificial template
methods, can be used to obtain unidirectional anisotropic macropores, with the formation of unique
geopolymer lamellar porous structures (Fig.1). Lastly, the use of inert or partially reactive fillers results
in a further functionalization of the geopolymer, with effective production of highly macroporous
composites (as showed in Fig. 1 for the geopolymer-vermiculite composite).
The tailoring of the geopolymers porosity is of paramount importance for their potential application in
thermal insulation, filtration, catalysis, etc. Therefore, a deep characterization of the final materials, in
order to understand how the porosity may be developed or modified during the preparation, must be
performed combining different techniques, as N2 adsorption/desorption, Hg intrusion and µ-Computed
Tomography (µ-CT) (Fig.1).
Figure 1: examples of porous geopolymers and techniques to investigate the porosity.
Intrinsic
geopolymer
Sacrificial template – Freeze casting μ-Computed Tomography
Direct foaming – Si0 addition
Induced ultra-macroporosity Study of the porosity
Hg intrusion porosimetry
Addition of filler - vermiculite composite SEM microstructure
European Geopolymer Network
Limoges – June, 15th 2016
Importance of geopolymers for the valorization of various type of
contaminated waste
M. Soubrand 1, E. Joussein 1, S. Rossignol
1 Univ. Limoges, GRESE, EA 3040, 123 Avenue Albert Thomas, 87060 Limoges, France 2 SPCTS, UMR 7315, 12 Rue Atlantis, 87068 Limoges Cedex, France
In a context of contaminated mineral waste management (eg mining sediment, industrial by-
product such as phosphogypsum, slags, sewage-sludge…), the valorization way seems to be
interesting particularly in terms of geopolymers since these materials are increasingly used in
construction at the large scale or simply by inerting. In an economical point, the revaluation of
which are considered as final waste could be optimal if the valorization by geopolymerization
process uses only untreated waste. Moreover these types of waste are classically highly
contaminated in metallic elements which can induce environmental and sanitary risks. In this
way, it is quite important to (i) determine the feasibility of synthesize geopolymer from various
inorganic contaminated waste in substitution to metakaolin, (ii) understand the mechanisms
involved toward two silicate solution (Na and K), and to (iii) evaluate the change in the metallic
element speciation and leaching after geopolymerisation. The raw material as well as
consolidated material were characterized by X-ray diffraction, infrared spectroscopy, and
electron microscopy. The metallic element content was determined using ICP-OES/-MS and
chemical speciation by BCR investigations. The mechanical properties were evaluated and the
leaching behavior realized according to EN12-457 or TCLP. The results evidence the role of
geopolymer to incorporate wastes and stabilize the contaminants. However, the limit of waste
incorporation is by substitution is reactive dependent of waste material, the metakaolin and the
alkaline solution used. Finally, the metallic element bearing phases are mainly dissolved during
alkaline treatment and redistributed in the geopolymer matrix. The leaching experiments clearly
evidenced the possibility to stabilize the metallic element into geopolymer matrix.
European Geopolymer Network
Limoges – June, 15th 2016
Improving the clay bricks production: experimental clay mixtures and geopolymer
binders
Julie PEYNE1,2, Jérôme GAUTRON2, Julie DOUDEAU3, Emmanuel JOUSSEIN4, Sylvie
ROSSIGNOL1 1 SPCTS, CEC, 12 rue Atlantis, 87068 Limoges Cedex, France
2Bouyer Leroux, L’établère, 49280 La Séguinière, France 3Bouyer LerouxStructure, 31 route d’Auch 31170 Colomiers, France
4Université de Limoges, GRESE EA 4330, 123 avenue Albert Thomas, 87060 Limoges, France
As part of optimized energy consumption, clay brick is the ideal solution for the building construction
and eco performance buildings. Indeed, it is characterized by insulation properties, intrinsic to the raw
clay materials used, and by its ability to regulate interior temperature due to its high thermal inertia.
With a view of sustainable development, the goal "waste zero" in the brick clay process is to be achieved.
Thus, the production optimization requires understanding of various phenoma, such as the
manufacturing technique and the impact of raw materials on the production. Nonetheless, characterizatio
methods used currently in the brick production plan don't allow the distinction between clays materials. The aim of this work is to investigate and understand the role of raw materials on the production. This
study consists thus of the use of physic and chemical characterization techniques and of the use of several
raw clays materials used initially in the brick production. First, physical and chemical characterization of the clays were studied. Moreover, the mineralogy was
determined by X ray diffraction and FTIR spectroscopy. The firing behavior was investigated by DTA
measurments. Then, experimental clay mixtures were studied in order to obtain some abacus plots to
help in the brick production understanding. Next, the waste brick products were used in geopolymer
mixtures. Finally, the impact of some clay minerals was determined and it was showed that the waste
brick products are potential aluminosilicate materials for the geopolymer binders synthesis.
European Geopolymer Network
Limoges – June, 15th 2016
Study of the geopolymerization rate by thermal experiments
A. Autef1,2, E. Joussein3, G. Gasgnier2, S. Rossignol1 1 SPCTS, CEC, 12 rue Atlantis, 87068 Limoges Cedex, France
2IMERYS Ceramic Centre, rue soyouz, France 3Université de Limoges, GRESE EA 4330, 123 avenue Albert Thomas, 87060 Limoges, France
Geopolymers are amorphous three-dimensional aluminosilicate binders, which were
named in 1978 by J. Davidovits [i]. Geopolymeric materials may be obtained by a reaction of
an aluminosilicate source (industrial wastes, metakaolin, natural mineral or fly ash) with an
alkaline solution [ii] (generally potassium or sodium silicate) at room temperature. The silicate
solution used to activate aluminosilicate plays an important role in the lifecycle of geopolymers
[iii]. The alkaline silicate created by the dissolution of silica in a basic medium (water + KOH)
was chosen because of its high stability and low cost [iv]. Additionally, the use of quartz as a
substitute for amorphous silica reduces the cost of the final product. Increasing the amount of
amorphous silica in a mixture containing silica and quartz favors a polycondensation reaction
(i.e., geopolymerization) and improves the mechanical properties of the synthesized materials
[v]. The study aimed to investigate the polycondensation reaction during the consolidation step
of geopolymer formation and examine the various equilibriums at different temperatures. In
total, eleven compositions with various amounts of amorphous silica S (high reactivity) and
quartz Q (low reactivity) (from 100%Q to 100%S) were synthesized in basic media with
metakaolin. The synthesized samples were characterized by thermal analyses and mercury
porosimetry tests. Correlations between the loss of water and the molar ratio of each
composition were investigated.
The existence of four reactions during the consolidation process was evidenced (i) the
reorganization of the species, (ii) the dissolution of the metakaolin, (iii) the formation of
oligomers and (iv) the reaction of polycondensation. Moreover, two types of networks were
shown, a silicate solution network for quartz-rich samples and a geopolymeric network for
amorphous silica-rich samples. The nature of the primary network and the reactivity of the
synthesized sample depend on the reactivity of the silica source used.
European Geopolymer Network
Limoges – June, 15th 2016
Alkaline silicate solutions properties and their effect on sand agglomeration
and geopolymer formation
L. Vidal1, E. Joussein2, J-L. Gelet3, J. Absi4, S. Rossignol1
1 ENSCI, SPCTS, UMR 7315, 12 Rue Atlantis, 87068 Limoges Cedex, France 2 Univ. Limoges, GRESE, EA 3040, 123 Avenue Albert Thomas, 87060 Limoges, France
3 MERSEN, 15 Rue Jacques de Vaucanson, 69720 Saint-Bonnet-de-Mure, France 4 Univ. Limoges, SPCTS, UMR 7315, 12 Rue Atlantis, 87068 Limoges Cedex, France
Nowadays, one of the challenges set by companies is the production of materials with low energy
consumption. Governments also encourage this trend as part of environmental respect. This work is
focused on the electrical protection domain and particularly concerns the fuse technology. In this
context, the consolidation of agglomerated sand and geopolymer formation at low temperature with
alkaline silicate solution are proposed. The agglomeration of sand and the formation of geopolymers
imply to better understand the various properties and the interactions with alkaline solutions. For this
purpose, several silicate solutions with various Si/M molar ratios (M = Na or K) and different dilutions
were studied. To determine the behavior of these alkaline solutions, several parameters were studied
such as (i) pH values, (ii) the various silicates species present in the solution which depend on the Si/M
molar ratio, (iii) the effect of adjuvant such as ammonium molybdate, and finally (iv) the microwave
treatment. A correlation between the Si-O-Si peak position, the silicon concentration and the Si/M molar
ratio (M = Na or K) of the solutions was determined by infrared spectroscopy. This relation gives nice
information about the polymerization of the solutions. 29Si MAS NMR experiments of the various
alkaline solutions evidenced the influence of the addition of ammonium molybdate or microwave
treatment on the silicate species. Then, the interactions between alkaline silicate solutions and sand or
metakaolin were determined by measuring the wetting angle. Finally, the effect of different parameters
on the microstructure and mechanical properties of consolidated sand was determined thanks to
mechanical tests and scanning electron microscopy. All these characterizations will help to determine
the parameters permitting to obtain a fuse in one process step by geopolymer coating.
European Geopolymer Network
Limoges – June, 15th 2016
Re-use of waste glass in the preparation of geopolymer: as alternative
alkaline solution and solid precursor
Francisca Puertas1, Manuel Torres-Carrasco2
[email protected] / [email protected] 1,2Eduardo Torroja Institute for Construction Sciences (IETcc-CSIC)-Madrid, Spain
C/ Serrano Galvache 4, 28033
There is growing production of waste glass in the world, and even though this is a fully
recyclable material, the cost and environmental impact associated with its reprocessing makes it easier
and more economically viable, in many places, to landfill it. Therefore, there is an imminent need to
develop alternatives for re-utilisation of waste glass that can bring added value, so that this becomes
more viable than disposal.
Alkaline materials are characterised by how heat of hydration, high mechanical strength
and high resistance to aggressive chemical (acid or sulphate media and so on). In addition, their
manufacture is less energy intensive than Portland cement. These alkaline materials are strongest and
most durable when the activator used is waterglass, a family of synthetic alkaline silicate hydrate
solutions whose processing is costly (because is necessary around 1300 °C to produce it) and highly
polluting (CO2 emissions). One way of improving the economic and ecological balance of alkaline
cements would be to find substitute for these alkaline activators, for instance, with the re-use of urban
and industrial waste glass1-3. The chemical composition of urban and industrial waste glass, based
essentially on SiO2 and Na2O, makes these by-product potential members of the waterglass family of
alkaline activators.
Moreover, in order to maximise the utilisation of the waste glass, this study presents the
results of experiments aiming to produce geopolymers from waste glass, a non traditional material
compared to those usually found in the manufacture of geopolymers (such as blast furnace slag, fly ash
or metakaolin).
Although, waste glass could be used as source of silica and/or alkalis in fly ash, blast
furnace slag or metakalolin-based geopolymers, the study presented here concerns the use of waste glass
alone, activated by an alkaline solution (with alternative solution from the treatment of different waste
glasses). The objectives of this feasibility investigation were multiple:
1. To study the possibility to generate solutions of sodium silicates (as potential waterglass
solutions) by the solubility of different types of waste glass.
2. Formulate geopolymers based on waste glass: as partial replacement of blast furnace slag
binders or through the use of waste glass alone, activated by alkaline solutions.
REFERENCES: 1 M. Torres-Carrasco et al, Materiales de Construcción, 2014, 64, (314), e014 2 F. Puertas and M. Torres-Carrasco, Cement and Concrete Research, 2014, 57, 95-104 3 M. Torres-Carrasco and F. Puertas, Journal of Cleaner Production, 2015, 90, 397-408
European Geopolymer Network
Limoges – June, 15th 2016
Geopolymer incorporate silicate waste
Nicoletta TONIOLO (1), Aldo. R. BOCCACCINI (2)
Institute of Biomaterials, University of Erlangen-Nuremberg, Cauerstr. 6, 91058 Erlangen, Germany
Geopolymers were primarily developed for the construction industry as non-Portland cements due to
the fact that about 5-8% of the global CO2 emissions is generated from Portland production, it is in fact
estimate that for each ton of cement 1 ton of CO2 is generated. 1
A geopolymer is a product of an inorganic polymerization in which an aluminosilicate powder reacts
with an alkaline solution to achieve a chemical composition similar to natural zeolite material but with
an amorphous microstructure instead of a crystalline one. 2
With this new technology it is possible not only to reduce the cement industries CO2 emission, but also
to use waste materials that are currently not used in other industry but are abundant and urgent to dispose
of.
For this purpose in this work fly ash, a residues generated by coal combustion in the thermal power
plants in the east of Germany, was used as aluminosilicate source.
Samples using fly ash as aluminosilicate source material and activated by sodium silicate and sodium
hydroxide solution in different formulations were prepared and characterized. Their mechanical
resistance was assessed by a compressive test after 28 days, Fourier transform infrared spectroscopy
(FTIR) spectra were acquired, crystalline phases were detected by X-ray powder diffraction (XRD) and
finally the structural characterization, pore size and crack distribution were qualitatively evaluated with
scanning electron microscopy (SEM) Fig. 1.
Fig.1. Fly ash geopolymer surface
REFERENCES:
[1] Deschner F. Reaction of siliceous fly ash in blended Portland cement pastes and its effect on the chemistry of hydrate phases and pore solution. 2014:204.
[2] Davidovits J. Geopolymer chemistry and Applications. 3rd Edition.
European Geopolymer Network
Limoges – June, 15th 2016
Fly-ash/borosilicate glass based geopolymers G. Taveri1, I. Dlouhy1
1Institute of Physics of Materials (IPM), Zizkova 22, 61662 Brno, Czech Republic Geopolymers are promising as building and structural materials, nonetheless they still turn out to be too
expensive in comparison with Portland cements. One of ways how to improve the ratio between the
production costs and service properties is to produce geopolymer materials completely from waste
materials. Fly ash from fossil flue power plants has been proved to be a compelling source of alumino-
silicate species, glass powder from wastes, ensuring the right provision of silicate for the required in the
polycondensation process [1]. Moreover, the addition of borosilicates (glassware raw material) as waste
glass source can support the geopolymerization, since boron can act as aluminate inside the process. In
fact, boron oxide can assume a 4-fold coordination, and then participating in dissolution phase in a
tetrahedral configuration, such as [Al(OH)4]– and [SiO(OH)3]– or [SiO2(OH)2]2–
[2].
In this investigation, SEM observation has been carried out on the fly ash and on the final geopolymer
products. Instrumented indentation hardness, bending test and chevron notch flexural tests were carried
out in order to characterize mechanical properties and fracture resistance. Fracture toughness has been
evaluated by using the chevron notch technique, methodology described, e.g. in [4, 5]. The fracture
surfaces of the broken specimen were observed by SEM and confocal microscopy.
Table 1: Micro-indentation hardness values
Table 2:
Three points
bending test results - flexural
strength
Figure 1: Micro-indentation hardness
The results revealed a low flexural strength of the material (Table 2), Vickers hardness showed also
quite low values (fig.1 and Table 1). The fracture toughness values have been found to be about 0.3
MPam1/2 according to the methodology described in [4, 5].
Taking into account the first results, the crack resistance of the prepared material was very low. One of
possible ways how to increase both the crack resistance and bending strength is to produce geopolymer
material of composite type. The idea is based on the use the product of geopolymerization as a binder
for making composites materials, similar to those investigated in [3].
REFERENCES: [1] M. Torres-Carrasco, F. Puertas, Journal of Cleaner Production, 90(2015), 397-408.
[2] L. Weng, K. Sagoe-Crentsil, J Mater Sci, (2007) 42:2997–3006.
[3] T. Alomayri, F.U.A. Shaikh, I.M. Low, Composites: Part B, 50 (2013) 1–6.
[4] J.I. Bluhm, Eng Fract Mech, (1975), 7:593–604.
[5] A.R. Boccaccini, H. Kern, I. Dlouhy, Materials Science and Engineering A, 308, 1-2, 111-117, 2001.
Sample Fmax
N
hmin
µm
hmax
µm
HV 0.2
1 2.01 9.127 11.698 77.96
2 2.03 10.862 13.453 91.76 Sample Fmax
N
FlexStrength
MPa
1 5.56 4.73 2 2.98 5.29 3 3.26 4.13
European Geopolymer Network
Limoges – June, 15th 2016
Using lakhouat (NW Tunisia) mine tailing in metakaolin based geopolymers
J. Nouairi1, W. Hajjaji2,3, C. PATINHA2, E. SILVA2, F. Rocha2, M. Medhioub1 1 Dept of Geology, Faculty of Sciences of Sfax, 3018, Sfax-Tunisia
2 Geobiotec, Geosciences Dept, University of Aveiro, 3810-193 Aveiro. Portugal 3 Natural Water Treatment Laboratory, CERTE, BP 273, 8020 Soliman, Tunisia
Since the late 19th Century, the north of Tunisia, a major lead-zinc province, has seen intense mining
activity1. The open air stored tailings contain huge amounts of potentially toxic elements. Various
natural processes led to their transfer to surrounding soils and water pools2. One imminent case,
Lakhouat (North-western Tunisia) was a lead and zinc ore mine. Its exploitation lasted almost
a century (1892- 1992) and led to huge tailing deposits (600.000 tons)3. The primary aim of this
study is the characterization of Lakhouat tailings and their impacts on the environment by the
assessment of the PTE distribution. The mineralogical analysis showed the existence of pyrite
and galena, confirmed by DRX and SEM analysis.
To neutralize the negative impact of the contaminated mining discharges of Lakhouat, tailing
were used/introduced to produce geopolymers. New metakaolin based geopolymer formulations
were elaborated by addition of mining by-products thought sodium silicate/NaOH activation. The
influence on the microstructure and mechanical properties of compositional variation with partial
replacement of metakaolin by Zn-Pb rich rejects (10-20 %) and Si/Al ratio (2.5 and 3.5) were studied.
At initial stage (7 days curing), the combination of these two amorphous materials (metakaolin and
tailing) exhibited suitable compressive strength values (around 5 MPa).
Figure 1 mining village and tailing of Lakhouat
REFERENCES: 1 SAINFELD P. (1952)- Annales des mines et de la géologie numéro 9 les Gîtes plombozincifères de la Tunisie. Imprimerie S.E.F.A.N. Tunis. 252p. 2 Babbou-Abdelmalek C., SebeiA., and Chaabani A. (2011) - Incurred environmental risks and potential
contamination sources in an abandoned mine site. African Journal of Environmental Science and
Technology Vol. 5(11), pp. 894-915 3 ONM Internal report, 2006
European Geopolymer Network
Limoges – June, 15th 2016
Alkali activation of high calcium by-products and applications I. Papayianni 1, S. Konopisi 2, F. Kesikidou 3
1,2,3 Laboratory of Building Materials, Dept of Civil Engineering, Aristotle University of Thessaloniki (AUTH), Thessaloniki, Greece.
Corresponding author: E-mail: [email protected]
The main industrial by-products in Greece are calcareous fly ash coming from the combustion of lignite
power production in Northern Greece and ladle furnace slag resulting from the domestic metallurgical
industry. These by-products are produced in significant quantities, but eventually most of them are
discarded. The aim of this research is to study the utilization of high calcium by-products in the
production of cement-less building materials.
Figure 1 : Macroscopic images of (a) calcareous fly ash and (b) ladle furnace slag
The research concerns the study of the alkaline-activated pastes (specimen dimensions 25x25x100 mm)
of fly ash and ladle slag, after treating them with a basic alkali-metal silicate solution. Trial mixes of
these by-products were produced at different proportions (10, 20, 30 and 50%) and mechanical and
physicochemical characteristics were tested, in order to detect changes in structure.
Table 1 : Compressive strength of slag, S and fly ash, FA mixtures
Compressive strength, MPa
Mixture 7 days 28 days 90 days 180 days
SFA10 6.7 14.7 20.8 12.8
SFA20 7.3 13.0 22.9 15.1
SFA30 9.9 14.4 21.5 19.4
SFA50 13.7 23.6 32.9 23.3
Based on the test results, the research proceeded to the production of slabs (slab dimensions 200x200x25
mm) designed with recycled glass aggregates, so as to be benefited from the strength and the aesthetic
characteristics of alkali-activated mixtures of industrial by-products. Control tests were performed to
the slabs, such as flexural strength, impact strength, resistance to abrasion and water absorption of the
slabs, in order to check their suitability as wall covering tiles.
REFERENCES: 1 V. M. Malhotra, P. K. Mehta, High-Performance, High-Volume Fly Ash Concrete: Materials, Mixture
Proportioning, Properties, Construction Practice, and Case Histories, 2002, Marquardt Printing Ltd., Ottawa, Canada, Page(s): 14-17. 2 A. Palomo, M. W. Grutzeck, M. T. Blanco, Alkali-activated fly ashes, a cement for the future, Cem Concr Res, Vol. 29, No. 8, 1999, Page(s): 1323-1329. 3 I. Papayianni, S. Konopisi, K. Datsiou, F. Kesikidou, Products of alkali-activated calcareous fly ash and glass cullet, 2014, Int. J. Res. In Eng. And Technology 03 (13), 43-51. 4 J. L. Provis, J. S. J. van Deventer, Alkali-activated materials: State-of-the-Art Report, RILEM TC 224-AAM, 2014, Springer, ISSN 2213- 204X.