B O O K O F A B S T R A C T S

O R G A N I Z I N G & S C I E N T I F I C

C O M M I T T E E

IOANNA PAPAYIANNI, PROFESSOR AUTH

HANS-JOACHIM FEUERBORN, ECOBA

FERNANDO CALDAS VIEIRA, ECOBA PRESIDENT

STAMATIS TSIMAS, PROFESSOR NTUA

AGGELIKI MOUTSATOU, PROFESSOR NTUA

TOMASZ SZCZYGIELSKI, POLISH CCP UNION

NIKOLAI BECH, ECOBA

ROD JONES, UNIVERSITY OF DUNDEE

LINDON SEAR, QUALITY ASH ASSOCIATION

ENRIC VZQUEZ, EM. PROFESSOR ETSENG.C.C.P

IRINA PUTILOVA, MOSCOW POWER ENGINEERING INSTITUTE

ARGYRO KASTANAKI, PPC

PANAGIOTIS TSIAMPAS, PPC

NIKOS KOUKOUZAS, ITESK

3CCP Management in Europe

F. Caldas-Vieira1,2, H.-J. Feuerborn1

1 European Coal Combustion Products Association e.V (ECOBA), EU, e-mail: info@ecoba.org2 EDP Gesta~o da Produa~o de Energia, S.A., Portugal, email: caldas.viera@edp.pt

AbstractIn Europe (EU 27) more than 100 million tonnes of Coal Combustion Products (CCPs) were produced with the production of heat and steam in coal-fired power stations. The CCPs include combustion residues such as boiler slag, bottom ash and fly ash from different types of boilers as well as desulphurization products like spray dry absorption product and FGD gypsum. Over the last decades, the production of these CCPs has been increased in the member states due to legal requirements for flue gas cleaning.

CCP management include safe disposal, storage and utilisation. Based on trials in some countries several environmental and technical benefits with their use were observed. Meanwhile, the utilisation of CCPs is well established in some European countries and practised for a long time. Due to large volumes and constant properties they are mainly utilised in the building material industry, in civil engineering, in road construc-tion, for construction work in underground coal mining as well as for recultivation and restoration purposes in open cast mines. The use has developed by the years and is mostly based on requirements of standards or other specifications which are subject to regular revision by CEN or national authorities.

The utilisation of CCPs in Europe is being influenced by political decisions and environmental regulations. At present, the most important political decisions force increased clean coal technologies regarding most effective combustion and CO

2 reduction. The environmental regulations have to be considered in the prod-

uct/waste discussion following the revision of the Waste Directive. A consistent evaluation scheme is the most important legal base for the utilisation of CCPs which have been registered as products according the REACH regulation. But also CEN product standards will include requirements for environmental param-eters in future.

This paper gives on overview on the management of CCPs in Europe including updates on production and utilisation of CCPs and on the impact of political decisions and environmental regulations on quantity and quality as well as on the management of CCPs.

Keywordscoal combustion products, fly ash, FGD gypsum, production, use, product, waste, standardization, legislation.

4The variability of Greek fly ashesEstimations for their future evolution

A. Kastanaki1, D. Sotiropoulos2, E. Papadopoulou3

1 PPC S.A., Thermal Power Plants Operations Department, Solomou 41, Athens 106 82, email: a.kastanaki@dei.com.gr.2 PPC S.A., Thermal Power Plants Operations Department, Solomou 41, Athens 106 82, email: d.sotiropoulos@dei.com.gr.3 PPC S.A., Thermal Power Plants Operations Department, Solomou 41, 106 82 Athens

AbstractAlthough the initial Power Plants design was based on their feeding by the near-by lignite mines, during the last years, environmental and energy reasons forced the changing of this strategy with mixing of different qualities from different mines, which led in differentiated fuel mixes in each Power Plant, in order to meet special energy and environmental targets.

The new strategy is strongly bind to the variability of the produced quality of fly ash, but did not changed finally the ranking of these fly ashes to the main two categories (1 and 2) described in the Greek Specifications of calcareous ashes.

According to the mines exploitation design plan up to 2054, it is estimated that the fly ash ranking in these two categories will remain at the same levels as today, although the available quantities will be diminished by time.

Keywordsfly ash, quality ash variability, ash classification.

5Use of Calcareous Fly Ash in Germany

H.-J. Feuerborn1, B. Mller2, E. Walter3

1 VGB PowerTech e.V., Essen, Germany, e-mail: hansjoachim.feuerborn@vgb.org2 MUEG Mitteldeutsche Umwelt und Entsorgung GmbH, Braunsbedra, Germany, email: mueller_bernd@mail.mueg.de3 CVattenfall Europe Generation AG, Cottbus, Germany, email: enrico.walter@vattenfall.de

AbstractIn German lignite fired power stations about 10 million tonnes of ashes and 5 million tonnes of flue gas des-ulphurisation gypsum are produced every year. Most of the ashes are used for the refilling and reclamation of depleted opencast lignite mines. Furthermore, they are used in underground mining, for surface recultiva-tion, soil beneficiation, cement production and as addition to concrete. FGD gypsum is used in the gypsum and cement industry and increasingly as fertilizer and soil conditioner.

The utilisation of the calcareous fly ash from lignite fired power plants is depending on their chemical, miner-alogical and physical properties. These properties are influenced by the power plant technology, the source of coal as well as the type of coal feed. A constant product quality is of greatest importance for utilisation in hydraulic binders, cement and concrete.

The paper deals with the utilisation of calcareous fly ash from lignite fired power stations in Germany, exist-ing fields of application and results of recent research work regarding their utilisation in blended cement.

Keywordslignite, calcareous fly ash, properties, reactivity, utilisation, reclamation, mine fill, soil beneficiation, blended cement, concrete

6Development Fly Ash Utilization in Turkey and Contribution of ISKEN to the Market

Dr. S. Uyanik*, M. Topeli

* Iskenderun Enerji retim ve Ticaret A.S,., Budak Sokak No:4 06700 Gaziosmanpas,a ANKARA - TRKIYE, phone: +90(312) 455 2 455, fax: +90(312) 455 2 456, e-mail: isken@isken.com.tr, mehmet.topeli@isken.com.tr

AbstractTurkey is demonstrating a sustainable economic growth, and has already become the 16th largest economy in the world (Turkey at a Glance > Facts and Figures > Economic Outlook). Turkeys power consumption per capita also exceeded the world average with an average growth rate of around 8%. In order to satisfy this increasing demand, the installed capacity is amounted to 53.000 MW and approximately 12.000 MW of this amount is based on lignite and imported hard coal. Consequently, around 24 million tons of fly ash is produced per year, which is an opportunity for supply. However, fly ash utilization has not reached to satis-factory levels yet. But, as being the largest cement manufacturer in Europe, the country has started appreci-ating the value of the product and finally it is accepted as a by-product, not anymore a waste. Our company (ISKEN) is the pioneer in Turkey in terms of fly ash marketing and certification. ISKEN Sugz PP, which is an imported coal-fired power plant with an installed capacity of 2 x 660 MW, has been in operation since November 2003. Nearly 350.000 tons of fly ash is being handled per year resulting from 3,3 million tons of imported hard coal consumption. ISKEN is not only the first imported coal-fired power plant but also a pioneer in the area of by-product utilization in Turkey. The fly ash of ISKEN has been certified according to EN 450 since 2005. The quality of the fly ash and efforts of ISKEN to maintain it are highly appreciated by the customers and nearly 100% of the production has been taken by them.

This article shall provide an overview about the development of fly ash market in Turkey and the contribu-tion of ISKEN to that market. Turkey has a great interest in coal for power production in an economical and environmentally friendly way. Consequently, utilization of coal combustion products (CCP) will continue to be important in the future.

KeywordsTurkey, Fly Ash, ISKEN, Cement Industry,

7Coal ash management - retrospective and perspective

K. Szczygielski

Ecotech Group, Poland

AbstractCoal - this inconspicuous mineral has accompanied mankind throughout its existence from ancient times when people were but an idea in some higher entitys mind up till now. What is more it is surely going to be a part of our lives much farther into the future [12]. This black rock provided our ancestors with heat and electricity and even nowadays it is still one of main energetic resources known to us. Burning this fossil fuel satisfies 30, 3% of worlds total energy consumption as well as contributes to 40, 2% of worlds electricity demand.

Burning coal in order to produce heat and electricity runs in boilers especially designed for this purpose. The process of burning coal generates residues often referred to as coal ashes[2]. These Coal Combustion By-Products consist of fly ash, bottom ash and slag [12]. Coal ash is mainly made up of minerals and other non-combustible natural materials mixed in with the coal when it is mined from the earth. In some cases, the ash might include nitrogen or sulfur compounds captured by air emissions-control equipment, these air emissions compounds may be collected and managed separately or co-mingled with coal ash. Depending on the plant and process, these ashes have different but manageable properties [13].

Miscellaneous physical and chemical characteristics of Coal Combustion Byproducts, negative social ap-proach towards secondary materials emerging usually from peoples ignorance and lobbing from produc-ers of traditional materials such as cement and lime makes management of CCPS as well as the process of implementing certain solutions to introduce them to market economies an interesting and complex problem [9]. This lecture is about to bring the issue of Coal Combustion Byproducts vertically integrated develop-ment to the fore.

8Statistical analysis as a key for the selection of suitable fractions of lignite fly ashes towards their further exploitation

S. Tsimas 1, A. Moutsatsou2, M. Zervaki2, C.A. Drosou2, O. Karakasi2, A. Papadopoulos2, I. Masavetas2, E. Tsimas2, G. Vardaka2, A. Karamberi2, K. Vavyloni2

1 National Technical University of Athens, Iroon Polytechneiou 9, Zografou Campus, Athens, Greece, tel: +30 210 772 3095,

fax: +30 210 772 3188, e-mail: stangits@central.ntua.gr 2 National Technical University of Athens, Iroon Polytechneiou 9, Zografou Campus, Athens, Greece

AbstractThe application rate of European lignite Ashes in the construction sector is still very low compared with relevant hard coal ashes. This fact must be mainly attributed to their intrinsic characteristics and specifically to the fluctuations in sulfates as well free calcium oxide contents. These characteristics exclude generally lig-nite ashes from the relevant European Standard (EN 450-1) even though numerous literature findings clearly demonstrate that selected qualities of them provide very good durability properties and consequently can be used in special concrete applications. In order to establish general criteria for the selection of the suitable quantities of fly ashes of Ptolemais region, a statistical analysis of the fluctuations of these parameters for the four power stations and for a temporal period of 10-20 years has been made. The very useful results, which will help Public Power Corporation to proceed to the preselection project in a definite power station, are discussed in the frame of this paper.

KeywordsHCFA, CaOf, SO

3, Statistical analysis, Preselection

9European Product Standards update on status and changes with relevance to CCPs

A.-J. Feuerborn1, A. Saraber2, J. van den Berg2

1 European Coal Combustion Products Association e.V (ECOBA), EU, e-mail: info@ecoba.org2 Vliegasunie b.v., The Netherlands, email: asaraber@vliegasunie,nl; jvdberg@vliegasunie.nl

AbstractThe utilisation of Coal Combustion Products (CCPs) in Europe is based on requirements in standards and national legislation which are subject to regular revision by CEN or national authorities. The European standard EN 450-1 has recently been revised and will be published soon. The revision result particularly in the increase of the maximum amount of co-combustion materials, the deletion of the lower limit value of the categories for LOI classes B and C as well as modifications for require-ments of parameters and for test pro-cedures, especially regarding wet and dry sieving. Also the standards for hydraulic road binders (EN 13282) and hydraulically bound mixtures (EN 14227) are under revision.

With the revision of the aggregate standards also the essential requirement No 3 (ER3) on Hygiene, Health and the Environment will be implemented in product standards. An overview of the work on harmonised test procedures for the emission of regulated dangerous substances (RDS) will be given. The aggregates standards will be the first to implement respective parameters for RDS. The industry is requested to prepare data bases to allow proper evaluation of construction products, i.e. also CCPs used as e.g. aggregates.

The Construction Products Regulation (CPR) is partly in force by April 24, 2011 and will be fully imple-mented by 1 July 2013. With this final implementation the essential requirement ER 3 and ER 10 have to be considered in the next revision of product standards. Furthermore, the producers have to declare the performance of their products.

Keywordscoal combustion products, fly ash, FGD gypsum, standardization, EN 450, EN 13282, EN 14227, CPR

10

Justification for the standardization of calcareous fly ash in Europe

I. Papayianni

Aristotle University of Thessaloniki

AbstractCalcareous fly ash is produced mainly in Central and Eastern European countries, where lignite or subbitu-minus coal is burnt for energy production, and constitutes around 50% of the total fly ash output in Europe. It is often characterized by its high free lime and sulphate contents and its use as an admixture for concrete in the European market is not allowed since there are no European Standards prescribing its use in concrete. However, according to the EN 197-1, this marginal material may be used after proper testing, by which suit-ability of calcareous fly ash for blended cement production is controlled.

In the present paper, a reference is made to the history and frame of existing standards on the use of cal-careous fly ash, by which up to nowadays the material is handled and marketed. The background for the constitution of the Hellenic Technical Specifications is highlighted. Then, based mostly on Greek experience, successful applications are presented, including also some economic considerations. They concern mainly plain concrete structures and pilot projects whose technical characteristics were in particular improved by the addition of this ash. What is definitely proved, is that calcareous fly ashes possess a strength potential as cementitious and pozzolanic materials and could prove beneficial for concrete, provided that they will meet the limit values of a regulatory frame addressing these fly ashes as a separate category of European fly ashes. An indicative list of possible applications of standardized calcareous fly ash is given. Furthermore, considering the future infrastructure projects programmed to be implemented for the next decade in Greece, a draft pre-estimation is made if local calcareous fly ash is used in combination with Portland cement in the cementitious system of concrete works. By projecting this consideration to the wider Eastern European area it can be proved that calcareous fly ash could be a profitable material resource.

KeywordsCalcareous fly ash, European Standards

11

Separation Technologies 17 Years of Commercial Experience in Fly Ash Processing

J.D. Bittner, S.A. Gasiorowski2, F.J. Hrach and W. Lewandowski1

Separation Technologies, LLC Technical Center, 101 Hampton Avenue, Needham Massachusetts, USA1Presenting author email: Laddy_Lewandowski@gmx.de Tel: +49 172 66 041412Corresponding author email: sgasiorowski@titanamerica.com Tel:603-523-7024

AbstractSeparation Technologies, LLC (ST), part of the Titan Cement Group, has developed an electrostatic benefi-ciation technology to reduce the carbon content of coal fly ash, producing a consistent, low loss on ignition (LOI) ash for use as a substitute for cement in concrete applications. The environmentally friendly process eliminates wet processing and required drying of the final material. The process operates at high capacity up to 40 tonnes per hour by a compact machine. Energy consumption is low, approximately 1 kWh/tonne of material processed. Since the only potential emission of the process is dust, permitting is typically relatively easy. Fly ash with carbon levels greater than 20% have been used to produce a concrete grade ash with a con-trolled carbon content of 2 0.5%, virtually eliminating fly ash related air entrainment problems in concrete. A carbon rich product is simultaneously produced and returned to the utility boiler to recover the fuel value of the carbon. Since 1995, this triboelectric process has been extensively used for the beneficiation of coal fly ash with eighteen separators in place and over 100 machine-years of operation at locations in the North America and Europe. Over 10 million tons of low carbon content ProAsh fly ash has been sold to concrete and cement producers in these market areas.

ST has also developed a process that removes ammonia from fly ash. The process can reduce the ammonia concentration on contaminated ash containing up to 3,000 mg NH

3 / kg (ppm) to less than 50 mg / kg. Com-

mercial operations are currently processing 50 tons per hour of contaminated ash.

The technical details of the carbon separation and ammonia removal processes will be discussed. STs newest project in Poland will be highlighted. This project includes a wet-to-dry ash collection conversion and an ST carbon separator.

KeywordsFly Ash, NOx, LOI, SNCR, SCR, Ammonia

12

Characterization of Coal ash from a Captive Power plant for Potential End uses

U. Kant1, V.K. Saxena1*, A. Sarkar2, A.K. Varma3 and K.K. Mishra4

1Department of Fuel & Mineral Engineering,2Department of Applied Chemistry, Indian School Of Mines,Dhanbad-826004,India 3Department of Applied Geology, Indian School Of Mines,Dhanbad-826004,India 4Central Institute of Mining and Fuel Research, Barwa Road, Dhanbad-826001,India

AbstractCoal ash (fly ash and bottom ash) collected from a local captive power plant (Jamadoba Power Plant, Tisco, Dhanbad, India production 10MW/day) was characterized in respect of their physico-chemical, morpho-logical and mineralogical properties. Bulk densities, specific gravities, water holding capacities, pH were determined for as received, Fe enriched and Fe depleted fly ash and bottom ash. Mineralogical characteristics were obtained by carrying out XRD analysis (CoK and CuK) of all the above mentioned samples. Particle size analysis of all the samples was carried out using Laser based particle size analyzer (Fritsch). Morphologi-cal properties were assessed using Scanning Electron Microscope. FTIR spectra were determined for all the samples including the feed coal. In addition to the various instrumental analysis carried out for the ash sam-ples, sieve analysis and flotation of selected size fraction (+212m) were carried out. Analysis of the results obtained yielded some important information. The bottom ash samples were large fused masses (Fig.1) of irregular shape and much larger than those of fly ash samples. Mineralogical analysis revealed the presence of quartz as the principal phase. Additionally strong intensity bands were observed for hematite and magnetite in case of Fe-enriched fly ash fractions. Flotation experiments revealed that one particular fraction (+212 m) has high carbon content, which indicates that this fraction can be enriched to a fraction which has the potential for reuse as domestic fuel. Other fractions having lower carbon content may have other utilization channels like road stabilization, brick making, in the making of cement etc.

Fig. (a)Bottom ash Fig.(b)Fly ash. Fig (c)Fe enriched ash

KeywordsFly ash, Characterization, FBC coal ash, SEM, FTIR, XRD, flotation, End uses

13

Life Cycle Cost Analysis of road pavement with Greek High Calcium Fly Ash Roller Compacted Concrete

L. Apostolakaki1, I. Papayianni 2

1 MSc Civil Engineer, e-mail: l.apostolakaki@gmail.com2 Professor, Laboratory of Building Materials, Aristotle University of Thessaloniki, Greece, e-mail: papayian@civil.auth.gr

AbstractRoad pavement construction is a very high capital investment, usually of public funds. It should be based on economic and environmental protection criteria. Therefore, Life Cycle Cost Analysis is necessary for select-ing the most suitable for the case design of pavement. In Greece, until now, the experience in construction of rigid pavements is very limited. Flexible asphalt pavements dominate although the great inclinations, the hot climate in summer and longer service life of concrete favor concrete pavements. The main hamper is the relatively great initial cost of construction and the reluctance of contractors to change traditionally used asphalt. However, Greek fly ash, which is specified in the 2007 Hellenic Specifications for its use in plain concrete, could be used in replacing a great volume of cement in roller compacted concrete (RCC) pavement reducing the initial cost of concrete road construction. This offers new perspectives for a low cost concrete road by using RCC.

In this study, an effort is made on economic evaluation of two alternatives, which differ in the type of pavement. Specifically, the purpose of this study is to examine and compare the cost between flexible and unreinforced rigid pavement, which are designed for greek roads with high traffic, and in particular heavy vehicles. Furthermore, it examines alternatives for the composition of concrete for rigid pavement (use only traditional cement and use of fly ash as a partial replacement of cement), and also for anti-skidding layer ma-terials. The methodology for analyzing pavement costs takes into account, not only the initial construction cost, but also the maintenance and reconstruction cost, the user cost and the salvage value of the materials, during a standard analysis period. The method for conducting this economic analysis is known as Life Cycle Cost Analysis (LCCA) and uses basic concepts of engineering economics. The analysis comes to very use-ful conclusions about the cost of rigid pavements, especially for the alternatives in which fly ash is used as a partial replacement of cement. In combination with other factors and results of other studies, they will lead the decision maker to the final choice of the appropriate solution for the particular case.

Keywordslife cycle cost, high calcium fly ash, rigid pavement.

14

Investigating Techniques for Evaluating Fly Ash Behaviour in Air-entrained Concrete

G.M. Sadiqul Islam1, M.J. McCarthy2, L.J. Csetenyi3 and M.R. Jones4

1 Division of Civil Engineering, University of Dundee, Dundee, DD1 4HN, Scotland, UK, e-mail: g.m.s.islam@dundee.ac.uk2 Division of Civil Engineering, University of Dundee, Dundee, DD1 4HN, Scotland, UK, e-mail: m.j.mccarthy@dundee.ac.uk3 Division of Civil Engineering, University of Dundee, Dundee, DD1 4HN, Scotland, UK, e-mail: l.csetenyi@dundee.ac.uk4 Division of Civil Engineering, University of Dundee, Dundee, DD1 4HN, Scotland, UK, e-mail: m.r.jones@dundee.ac.uk

AbstractThe paper describes research from a study carried out to investigate techniques for evaluating fly ash influ-ences on air-entrainment in concrete and covers the potential of dye adsorption tests, i.e. using methylene blue (MB) and acid blue 80 (AB80), in this role. The MB test is essentially that given in BS EN 933-9 (nor-mally used for the assessment of fines in sand) and involves visual determination of an endpoint, while the AB80 test (similar to those used for examining activated carbon) is spectroscopic and, therefore, instrument-based. Following the determination of suitable procedures for the tests, their evaluation with fly ashes cover-ing a range of properties is described through comparisons against parameters including, loss-on-ignition and specific surface area (measured by N

2 adsorption). Relationships are presented that examine the dye ad-

sorption of fly ash with respect to the air-entraining admixture demand to achieve a target air content range (5.0 1.0%) in corresponding concretes. These indicate strong correlations for the materials used. Consid-eration is given to how the dye adsorption tests could be applied in air-entrained fly ash concrete production.

Keywordsfly ash, air-entrainment, dye adsorption tests, loss-on-ignition, specific surface area, admixture demand, concrete.

15

Utilization of Coal Gasification Slag COLLECTED FROM IGCC AS FINE AGGREGATE FOR CONCRETE

Y. Ishikawa

Senior Researcher, Dr. Eng., Chigasaki Research Institute, Electric Power Development Co., Ltd. (Jpower), 1-9-88 Chigasaki, Chigaski-City, Kanagawa, 253-0041, Japan

AbstractThe Integrated coal Gasification Combined Cycle (IGCC) has received a lot of attention in recent years from the viewpoint of reducing CO2 emissions. IGCC is basically different from conventional pulverized coal-fired thermal power generation systems; electricity is generated by a combined cycle using gas turbines and steam turbines. Thus, it is said that IGCC is much more efficient than a conventional coal-fired power plant. In IGCC, the by-product is collected not as coal ash but as coal gasification slag. Coal gasification slag has a tremendous amount of potential for effective use in the field of concrete production because no hazardous material leaches from it and it is simple to handle compared with coal ash.

This paper describes how the aggregate test and concrete test were conducted on coal gasification slag in order to examine whether coal ash slag can be used as a fine aggregate for concrete. The results of these tests showed that concrete made from slag has almost the same compressive strength as concrete in which natural sand is used. In addition, the drying shrinkage rate and freeze-thaw resistance, which are values related to the durability of concrete, of such slag concrete did not show any difference from those of concrete made with natural sand. From these experimental results, it can be concluded that coal gasification slag has a possibility for use in structural concrete.

KeywordsCO

2 emissions, IGCC, effective use, coal gasification slag, fine aggregate

16

Utilisation of lignite fly ash in oil sorption and energy saving during clinker production

O.K. Karakasi1, A. Moutsatsou2

1 Laboratory of Inorganic and Analytical Chemistry, National Technical University of Athens, Greece, e-mail: o.k.karakasi@gmail.com2 Laboratory of Inorganic and Analytical Chemistry, National Technical University of Athens, Greece, e-mail: angst@central.ntua.gr

AbstractThe present study aims at developing an environmental application of lignite fly ash, which constitutes the main by-product of power production by lignite combustion and whose greater amount remains unutilised. In particular, its application in oil spill cleanup and the further utilisation of the resultant oil-fly ash mixtures in energy saving during clinker production has been investigated. For the amelioration of the floating ability and the oil sorption capacity of lignite fly ash, the mixing with a cheap, light and porous agricultural by-prod-uct, such as sawdust, has been applied. The addition of 30-50% w/w sawdust results not only in amelioration of the behaviour of lignite fly ash when added to oil spill in marine environment, by contributing to better floating and total oil removal, but also in increase in its oil sorption capacity by up to 50-80%. The higher calorific value of the resultant oil-lignite fly ash-sawdust mixtures rising up to that of oil and bituminous coal encourages their utilisation as alternative fuels in cement industry. The remaining after their combustion ash varies from 18 to 58% w/w and its chemical and mineralogical composition differentiates slightly from the initial one. Analyses showed that it is enriched in Al

2O

3, SiO

2, reactive SiO

2, Fe

2O

3, CaO, CaO

f and SO

3. An

increase in phases, such as anhydrite, gehlenite, gismondine, portlandite, and a decrease in lime and calcite are observed. However, the change observed in its composition is not expected to change the composition of clinker produced.

Keywordslignite fly ash, sawdust, oil, sorbent, energy, clinker

17

Quantification and Qualification of High Lime Fly Ash by Efficiency Factor: Mechanical and Durability Aspects

D. Aponte, M. Barra, E. Vzquez

Department of Construction Engineering, E.T.S. Ingenieros de Caminos, Canales y Puertos (Civil Engineering School), Universitat Politcnica de Catalunya. Spain, e-mail: diego.fernando.aponte@upc.edu

AbstractThis paper presents a study of the cementing efficiency of high lime fly ash with regards to mechanical and durability properties. The investigated variables were the rate of the incorporation of fly ash, the cement type, the water/cement ratio, and the curing age of the mix. An extensive experimental campaign was con-ducted in order to determine the compressive strength and chlorides penetration. A test which simulates the penetration of chloride ion in concrete (multi-regime method) has been conducted, in order to determine the chloride diffusion coefficient in a non-steady-state. Two cementing efficiency factors were determined; (i) in terms of the compressive strength, (ii) in terms of the chlorides diffusion coefficient. Both of them have been determined in relation to the water/cement ratio. The result shows that the cementing efficiency is strongly influenced by the water/cement ratio. Concerning durability, greater efficiency values than those observed in relation to the compressive strength have been found.

Keywordshigh lime fly ash, cementing efficiency, k value, durability, chloride diffusion.

18

Use of calcareous fly ash in SCC

E. Anastasiou, I. Papayianni

Aristotle University of Thessaloniki

AbstractThe robustness of self-compacting concrete (SCC) mixtures is usually sensitive to alterations in the mixture constituents, which is also the case when using high volumes of calcareous fly ash as binder. In the present report, calcareous fly ash was used as 30% and 50% by mass of the total binder without changing the water to binder ratio. The expected loss of workability due to the increased water demand of calcareous fly ash was compensated by adjusting the dosages of the admixtures (superplasticizer and viscosity modifying agent). Slump flow, L-Box and segregation resistance tests were carried out on the fresh mixtures, showing that ro-bust SCC can be produced with the addition of high volumes of calcareous fly ash. Mechanical characteristics of the test mixtures were also measured, showing adequate strength development, comparable to that of the reference concrete, while shrinkage deformations were reduced when higher volumes of calcareous fly ash were used.

KeywordsCalcareous fly ash, self-compacting concrete

19

The high-calcium fly ash as a component of self-compacting concrete

T. Ponikiewski1, J. Goaszewski2

1 Department of Material Engineering and Building Processes, Silesian University of Technology, Gliwice, Poland, e-mail: Tomasz.Ponikiewski@polsl.pl2 Department of Material Engineering and Building Processes, Silesian University of Technology, Gliwice, Poland, e-mail: Jacek.Golaszewski@polsl.pl

AbstractIn the paper the basic influence trends of different composition and properties High Calcium Fly Ash (HCFA) on fresh mixture properties of Self-Compacting Concrete. HCFA was used as a replacement for a part of cement in the mixture (2 types of fly ashes, also activated by grinding) or as an additive to cement (also in combination with other additives as F-class ash and ground granulated blast furnace). Primary and secondary effects of admixtures action were investigated in the first place: rheology (using rheometrical test). Discus-sion about the results covers mechanism of high - calcium fly ashes (C-class) influence on effectiveness of admixtures. The research has shown the negative influence of raw calcium fly ash (without grinding) added to concrete mix on its rheological properties and workability. Activation of fly ash (by grinding) improves its properties, and becomes positive as an additive to concrete mixes. Without a doubt, in many cases the prob-lem is the loss of workability, but it does not concern cement composites. The current state of knowledge is not sufficient to effectively control of SCC mixtures with HCFA. Further research is needed, especially taking into consideration the impact which the changeable physical and chemical properties of HCFA and cement type have. The possibility of applying calcium fly ash as a partial replacement for cement in concrete and other cement components has been ascertained. An analysis on the effect of HCFA content on the proper-ties of selected concretes of the new generation is the subject of this article. The paper presents test results for the self-compacting concrete SCC modified by HCFA, SCC mixes with cement modified by HCFA, high performance self-compacting concrete HPSCC modified by HCFA, and FRSCC mixes modified by selected types of steel and synthetic fibers. The results include studies on samples belonging to classes of slump flow SF, classes of viscosity T

500, the compressive strength tests:

cm,28. The concrete mix was tested with a varying

amount of lime fly ash lime (10-20-30%), as equivalent of cement. The studies have confirmed the possibil-ity of using HCFA in new generation concretes while maintaining the assumed technological parameters for concrete mixtures, especially their workability.

Keywordscalcareous fly ash, self-compacting concrete, rheology, steel fibers

20

Using Fly Ash to Achieve Low Embodied CO2 Concrete

M.D. Newlands1,, M.R. Jones2, M.J. McCarthy3 and L Zheng4

1 Division of Civil Engineering, University of Dundee, Dundee, DD1 4HN, Scotland, UK, e-mail: m.d.z.newlands@dundee.ac.uk 2 Division of Civil Engineering, University of Dundee, Dundee, DD1 4HN, Scotland, UK, e-mail: m.r.jones@dundee.ac.uk3 Division of Civil Engineering, University of Dundee, Dundee, DD1 4HN, Scotland, UK, e-mail: m.j.mccarthy@dundee.ac.uk4 Division of Civil Engineering, University of Dundee, Dundee, DD1 4HN, Scotland, UK, e-mail: l.zheng@dundee.ac.uk

AbstractTwenty-first century design is increasingly being influenced by the specification of carbon-critical materi-als. The use of fly ash (FA) will, therefore, be an ever more important contributor to this requirement. This paper describes research carried out, aimed at developing practical guidance on how to exploit FA to achieve low embodied CO

2 in concrete susceptible to corrosion induced by chloride ingress and carbonation. Data

is presented for concretes with, (i) high FA contents, (ii) FA ternary cement combinations and (iii) coarse FA materials. The initial part of the paper establishes the effect that these have on the durability properties, making comparisons with those of reference Portland cement and conventional FA concretes. It is shown that care has to be taken to adjust the concrete mix constituent proportions in order to match the properties of the references mixes. The paper quantifies the embodied CO

2 of the concretes, using recently agreed UK

figures for the various constituent materials. It is also shown that in some cases there is a need to optimise and balance embodied CO

2 and durability performance.

KeywordsEmbodied CO

2, high fly ash contents, fly ash ternary cement combinations, coarse fly ash, durability perfor-

mance, material selection.

21

Creating High-Value Eco-Friendly Materials from Industrial Coal Combustion Ash

C. Tang1, N. Thawornsak1, S. Samrankrang1, O. Jullaphan2, M. Chareonpanich2

1 Siam Research and Innovation Co. Ltd, SCG Cement, Thailand, e-mail: clarenct@scg.co.th2 Department of Chemical Engineering, Kasetsart University, email: fengmtc@ku.ac.th

AbstractThailand is one of the largest industrialized countries in Southeast Asia and its coal-combustion ashes are mainly generated for either energy utilization or manufacturing purposes. Being one of the leading industrial conglomerates in Thailand and ASEAN, SCG is committed towards sustainable care for the environment and communities via resource and waste management system. In order to significantly reduce the conventional landfilling of coal combustion ashes as our entire organization is expected to achieve the target of Zero-waste to Landfill by 2012, we have developed a number of high-value eco-friendly materials for building construction applications. This paper will discuss on the present state of our industrial coal combustion ash and the challenges to effectively use coal ashes as conventional building materials. Some of the novel techni-cal solutions to transform these waste ashes into high-value eco-friendly materials such as commercial-grade sodium silicate, zeolites A and lightweight aggregates for precast hollow-core concrete applications are fur-ther presented here.

Keywordscoal ash, sodium silicate, zeolite A, lightweight aggregate, precast concrete.

22

Integrated solutions on providing the consumer properties of ash and improvement of environmental and economic characteristics of power plant operation at burning hard coal of the unsteady quality in power boilers

V.Y. Putilov, A.V. Arkhipov, I.V. Putilova

National Research University Moscow Power Engineering Institute, Moscow, Russia

AbstractInfluence of technologies of pulverized coal combustion in power boilers on loss on ignition (L.O.I.) in fly ash and NO

X emissions is considered. In the paper attention is paid to burning of Kuznetsky coal of the main

ranks in different boilers of steam capacity of 50 to 950 t/h. At combustion of design Kuznetsky coal at these power plants L.O.I. in fly ash can reach 25 % that exceeds the standards for using fly ash by 5 times despite of the fact the standards for unburnt carbon are mostly met. By that, specific emissions of nitrogen oxides without implementation of expensive DeNO

x measures make up to 1600 mg/m3 that is also several times

more than the normative values. The paper contains the basic technical solutions and recommendations on arrangement of effective pulverized staged combustion of Kuznetsky coal of unsteady quality for maximum reduction of L.O.I. in fly and bottom ash as well as for achievement of specific nitrogen oxides emissions below the norms without constructing the costly DeNOx installations.

Keywordspower plant, slag-tap boiler, dry-bottom boiler, fly ash, L.O.I., hard coal, Kuznetsky coal, NO emissions

23

Use of New Industrial By-products and Mixtures for Reducing the Environmental Cost of Constructions

J. Tapali1, S. Demis2 and V.G. Papadakis31

1 Civil Engineer MSc., PhD candidate, Department of Environmental and Natural Resources Management, University of Western Greece, Agrinio, Greece2 Invited Lecturer, Department of Civil Engineering, University of Patras, Patras, Greece3 Associate Professor, Department of Environmental and Natural Resources Management, University of Western Greece, Agrinio, Greece

AbstractThe building sector in Greece occupies prime position within the industrial / technical activities. However, given the fact that the construction sector produces more than 35% of all the greenhouse emissions, on European level, emphasis is given on adaptation of energy and emissions reducing solutions by the construc-tion industry. Utilization of supplementary cementitious materials (SCM) in concrete design, for example, is a very promising first step in reducing considerably the fixed environmental footprint. On this note, the aim of this study is twofold. To evaluate the environmental contribution of each concrete component and to provide the best possible mix design configuration, by using analytical models developed by the authors, in terms of low environmental cost, concrete compressive strength and service life estimation under harsh environments.

It is hoped that the outcomes of this study will provide the basis for the establishment of an optimum, bal-anced approach, between sustainability and durability. It was proved that such a balance can be achieved through extended use of industrial by-products and their various mixtures in the concrete mix, reducing in this way the fixed environmental emissions without minimizing the long-term safety and durability of the structure.

KeywordsIndustrial by-products, Concrete, Constructions, Environmental cost, Software, Supplementary cementing materials.

1 To whom all correspondence should be addressed: Prof. V.G. Papadakis, Department of Environmental and Natural Resources Manage-ment, University of Western Greece, Seferi str. 2, GR-30100, Agrinio, Greece, email: vgp@psp.org.gr

24

Aspects concerning the applicability of the efficiency k-factor in the case of calcareous fly ash

I. Papayianni, E. Anastasiou

Aristotle University of Thessaloniki

AbstractAlthough there is much scepticism about the quantification of the influence of an addition on concrete per-formance by using a single k-factor, it seems that it serves as a convenient engineering tool for estimating the contribution of additions to the strength development. According to EN 206-1, Annex E, the efficiency k-factor could be used for siliceous fly ash, ground granulated blastfurnace slag (ggbs) and silica fume, for which relevant European Standards already exist. The k-factor values for fly ash range from 0.2 to 0.4. The literature on calcareous fly ash efficiency factor or factors is very limited and many questions should be an-swered before any efficiency consideration, such as: Which type of calcareous fly ash are we discussing? As it is known, this material is reactive and cannot be used as inert filler, mainly due to free lime and sulphate contents. Furthermore, fineness plays an important role on its performance in concrete and it possesses self-cementing properties and often increases the water demand of the concrete mixture in which it is added. In this paper, the whole problem relating to calcareous fly ash addition in concrete is addressed. Based on long term experience on the use of calcareous fly ash as a separate constituent of the binding system in the mixer, k-factors are given which are in the range of certain limits concerning chemical composition and fineness. By replacing up to 40% of cement with these calcareous fly ashes, the efficiency k-factor seems to be around unity. In addition, the performance of high volume of these fly ashes in concrete is given by presenting ex-perimental results concerning strength development over quantity of fly ash and water to cementitious ratio.

Keywordsk-factor, calcareous fly ash

25

Fly Ash Radioactivity Measurements in Electric Power Industry of Serbia Thermal Power Plants

D. Kisic1, S. Miletic2, S, Jovanovic3, I. Grzetic4

1 Public Enterprise Electric Power Industry of Serbia, Serbia, e-mail: dragica.kisic@eps.rs2 Public Enterprise Electric Power Industry of Serbia, Serbia, e-mail: sasa.miletic@eps.rs3 Public Enterprise Electric Power Industry of Serbia, Serbia, e-mail: suncica.jovanovic@eps.rs4 University of Belgrade, Faculty of Chemistry, Serbia, e-mail: grzetic@chem.bg.ac.rs

AbstractSerbian thermal power plants (TPPs) produce siliceous fly ash from lignite in the quantity of approximately 6 million tons per year. The potential market for the use of fly ash is operational, but for the time being, only used by cement producers. Fly ash radioactivity could be one of the major points of concern when larger use of fly ash is planned, particularly in the Serbian construction industry.

Radioactivity measurements have been conducted regularly for decades. This paper presents the results of a ten-year fly ash radioactivity measurements at the Nikola Tesla B TPP located in Obrenovac.

In addition, the paper compares the natural radionuclides coal content data coming from the Kolubara Basin and ash created as the coal combustion by-product in the Nikola Tesla B TPP boilers. Following the obtained results indicating the 26Ra, 232Th, 40K content and joint concentration of all artificial radionuclides, it may be concluded that TPP ash and slag are environmentally friendly. Moreover, they may be used in the construc-tion industry since they meet the legal criteria defining the radionuclides content.

Following the obtained natural radionuclides content results it may be concluded that the Nikola Tesla B TPP ash may be disposed into the environment. Ash may be used also in the construction industry (civil engi-neering). In building construction applications, ash share as the additive to other building materials depends from its physical and chemical characteristics, as well as from the radionuclides activity: 266Ra, 232Th and 40K.

KeywordsSerbian power plants, fly ash, radioactivity measurements, natural radionuclides, 238U, 232Th, construction industry.

26

Alkaline Activation as a procedure for the transformation of fly ashes into cementitious materials.PART I. FUNDAMENTALS

I. Garca-Lodeiro1, A. Fernndez-Jimnez1 and A. Palomo1

1 Instituto Eduardo Torroja (CSIC), Madrid (Spain), e-mail: iglodeiro@ ietcc.csic.es

AbstractThe reaction of a solid aluminosilicates with a highly concentrated aqueous alkali hydroxide or silicate solu-tion produces a synthetic alkali aluminosilicate material generically called a geopolymer, after Davidovits, but probably more appropriately referred to as an example of what is more adequate termed as gel N-A-S-H. These materials can provide comparable performance to traditional cementitious binders in a range of ap-plications, but with the added advantage of significantly reduced Greenhouse emissions.

Depending on the raw material selection and processing conditions, alkali activated products can exhibit a wide variety of properties and characteristics, including high compressive strength, low shrinkage, fast or slow setting, acid resistance, fire resistance and low thermal conductivity. Despite this wide variety of commonly boasted attributes, these properties are not necessarily inherent to all alkaline silicoaluminous formulations.

Some general aspects to be remarked of this chemical process (alkaline activation), when applied to the case of fly ashes are: kinetics diversity, complexity of chemical reactions, different microstructure formations, etc... This paper summarizes the fundamental aspects about alkaline activation of fly ashes; it means authors describe the mechanisms governing the main chemical transformation of fly ashes into hardened and com-pact cementitious materials.

Keywords fly ash, alkali activation, geopolymer, mechanisms of reaction, microstructure

27

Alkaline Activation as a procedure for the transformation of fly ashes into cementitious materials.PART II. IMMOBILISATION OF TOXIC AND HAZARDOUS ELEMENTS

S. Donatello1, A. Fernndez-Jimnez2, and A. Palomo3

1 Eduardo Torroja Institute (CSIC), Serrano Galvache N 4, 28033 Madrid, Spain, email: shanedonatello@ietcc.csic.es2 Eduardo Torroja Institute (CSIC), Serrano Galvache N 4, 28033 Madrid, Spain, email: anafj@ietcc.csic.es3 Eduardo Torroja Institute (CSIC), Serrano Galvache N 4, 28033 Madrid, Spain, email: palomo@ietcc.csic.es

AbstractIn this study, the potential of alkali activated fly ash cements to immobilise metals that are generally not well immobilised in Portland cements was examined. A class F fly ash was activated with a solution of 8M NaOH to form a hardened cementitious paste. Prior to activation, fly ashes were doped with either: i) 5000 mg/kg (0.5%) Hg2+ as HgCl

2, ii) 10000 mg/kg (1.0%) Cs+ as CsOH.H

2O or iii) 10000 mg/kg (1.0%) As3+ as

NaAsO2. Mechanical strengths of the pastes were measured and the degree of metal immobilisation in pastes

was determined by TCLP leaching tests. Finally, a study of the crystalline phases and paste microstructure was carried out to determine the fate of immobilised metals in the AAFA matrix.

Microstructural analysis of Hg doped pastes showed a strong correlation between Hg and S, implying that formation of highly insoluble HgS or Hg

2S precipitates is an important immobilisation mechanism. How-

ever, the coexistence of HgO could not be entirely ruled out. In Cs doped pastes, it is proposed that Cs+ ions are associated with the N-A-S-H gel and zeolites formed in AAFA cements, suggesting that Cs is mainly chemically bound rather than physically encapsulated. With As doped pastes, generally poor performance was observed, both with and without the addition of Fe

2O

3 in an attempt to improve immobilisation.

Keywordsfly ash, alkali activation, geopolymer, zeolite, Cesium, Mercury, Arsenic, TCLP, leaching.

28

Alkaline activation-induced conversion of fly ash into an effective binderPART III. REDUCING THE CLINKER CONTENT

A. Fernndez-Jimnez1, I. Garcia-Lodeiro1 and A. Palomo1

1 Instituto de Ciencias de la Construccin Eduardo Torroja (IETcc C.S.I.C.), Serrano Galvache N 4, 28033 Madrid, Spain; email anafj@ietcc.csic.es

AbstractThe present paper contains a discussion of the environmental issues surrounding binders used in construc-tion in general and an introduction to fly ash activation technology and certain basic concepts about hybrid cements (binders with a very low clinker factor and high fly ash content). In the authors opinion, such technology may soon become highly enough developed to bridge the gap between portland cement and the cements of the future.

A good deal of research is still required on low portland clinker, high aluminosilicate content binders, how-ever. This paper reports on mechanical strength development in several such hybrids and on the mineralogi-cal and microstructural development of the reaction products, which were observed to constitute a mix of C-A-S-H and (N,C)-A-S-H gels.

Keywordsfly ash, alkali activation, clinker factor, hybrid cements, geopolymer

29

Alkaline Activation as a procedure for the transformation of fly ashes into cementitious materials. PART IV. OTHER APPLICATIONS

A. Fernndez-Jimnez1 , C. Varga and A. Palomo1

1 Instituto de Ciencias de la Construccin Eduardo Torroja (IETcc C.S.I.C.), Serrano Galvache N 4, 28033 Madrid, Spain; e-mail: anafj@ietcc.csic.es and palomo@ietcc.csi.es

AbstractIn general terms it is widely acknowledged that the alkali activation of fly ashes can produce a material with similar cementing features than those of Ordinary Portland Cement. Actually, the alkali activation of fly ashes is a singular procedure in which the dark grey powder originating from coal power plants is mixed with certain alkaline activators (alkaline dissolution); and then cured at a certain temperature to form solid hardened materials. The alkaline activation of fly ashes is consequently of great interest regarding the devel-opment of new and environmentally friendly binding materials with similar or superior properties to those of other well known binders.

The present paper discusses the fundamental technological aspects for producing high quality alkali cement using alkali activated fly ash as the main raw material. The resulting material exhibits a series of properties and characteristics of interest, including: high early age flexural and compressive strengths, rapid or slow setting, low drying shrinkage and so on. Due to their good technical properties and durability, as well as the ease with which these materials can be adapted (for manufacturing purposes) to existing facilities, these new cements are particularly suitable for: i) The precast industry; (ii) As protective coatings of materials with no capacity of fire resistance; (iii) Production of lightweight materials.

Keywordsfly ash, alkali activation, geopolymer, lightweight materials, fire protection

30

Effect of sintering conditions on the production of ceramics from lignite fly and bottom ashes

V. Karayannis1, E. Katsika2, A. Moutsatsou2

1Department of Pollution Control Technologies, Technological Education Institution (TEI) of West Macedonia, Kila 50100, Kozani.2Laboratory of Inorganic and Analytical Chemistry, School of Chemical Engineers NTUA, 9 Iroon Polytechniou Str., 15773 Athens.

AbstractThe current study aims at the extension of field application of lignite combustion by-products due to their considerable silica and alumina content. Fly/bottom ash mixtures were prepared and Powder Metallurgy processing techniques were applied, and then their microstructure and physico-mechanical properties were studied, in order to assess whether the chemical, mineralogical and morphological characteristics of these ashes render them suitable starting materials for ceramics development. The role of silica, with its different mineralogical structures, is highlighted here, while the absence of gehlenite in the sintered materials leads to promising results concerning their strength.

KeywordsSiliceous fly ash, bottom ash, sintering, ceramics

31

High strength Portland cement free cementitious mortar

S. Aydn1, B. Baradan2

1 Dr. Assistant, Department of Civil Engineering, Dokuz Eyll University, Buca 35160, Izmir, Turkey, e-mail: serdar.aydin@deu.edu.tr2 Prof. Dr., Department of Civil Engineering, Dokuz Eyll University, Buca 35160, Izmir, Turkey, e-mail: bulent.baradan@deu.edu.tr

AbstractThe aim of this study is to product a fly ash based binder without Portland cement. Type C fly ash was activat-ed by NaOH with different molar ratios and cured in three different curing conditions (standard, steam and autoclave). Flexural and compressive strength values of mixtures were compared with conventional Portland cement mortars. In the second stage of this study, mechanical properties of fly ash based binders were im-proved by using silica fume and ground granulated blast furnace slag. Test results showed that the low early strength of FA based geopolymer can be improved by slag replacement and high performance geopolymer mortars can be produced by autoclave curing. Incorporation of fly ash by 50% ground granulated blast fur-nace slag and 10% silica fume was significantly increased the mechanical properties of autoclaved mortars. Drying shrinkage and swelling of geopolymer mortars were similar to Portland cement mortar. Both steam curing methods were effective in terms of reducing drying shrinkage and swelling of geopolymer mortars.

Keywordsgeopolymer, fly ash, ground granulated blast furnace slag, silica fume, thermal treatment, mechanical proper-ties, dimensional stability.

32

Use of calcareous fly ash for improving mechanical and physical characteristics of soils

I. Papayianni, M. Papachristoforou, E. Stavridakis

Aristotle University of Thessaloniki

AbstractStabilization of soil is an old and well known process for improving soils of low load bearing capacity, high moisture content and swelling when sub bases or embankments are to be constructed in areas with weak soil deposit. Among stabilizers, lime and cement are widely used for modifying Atterberg limits, increasing density and CBR (California Bearing Ratio) as well as fly ashes as fly ash according to ASTM D 5239-98. Calcareous fly ashes may contribute to soil stabilization by entering free lime and cementing characteristics into soil. Other geotechnical applications such as face symmetrical or hard fill dam constructions could also be benefited from self-cementing fly ash character. In this paper, fly ash samples of different origin in rela-tion to chemical composition and fineness are tested to determine the calcareous fly ashes influences on soil mechanic and physical characteristics. They are added in a soil categorized s CL type at percentages 0, 10, 15 and 20% by mass of the total mixture and the Proctor density, CBR as well as swelling deformation after moist curing are measured. Furthermore, the resistance of the stabilized soil mixture to wet cycling accord-ing to relevant test method is estimated by measuring the loss of material after cycling. Based on the results, it seems that calcareous fly ash is an ideal stabilizer improving impressively the characteristics of soil. CBR values are increased from 100 to 200%, swelling is limited and resistance to wet cycling is increased. Taking into account the large volume of soil materials handled in geotechnical work that are mentioned, calcareous fly ash especially of high lime content, seems to be an attractive stabilizer.

KeywordsCalcareous fly ash, soil stabilization

33

The Effect of Aqueous Solutions Treatments on Coal Fly Ash Surface and Its Interactions with Trace Elements

R.N. Lieberman1, H. Cohen1, 2

Department of Biological Chemistry, Ariel University Center at Samaria, Ariel, 40700 Israel, phone: 00972-54-7776499,

fax: 00972-8-9200749, email: hcohen@ariel.ac.il; roynl@ariel.ac.il

Chemistry Department, Ben-Gurion University of the Negev, Beer Sheva, Israel email: hcohen@bgu.ac.il

AbstractThe Coal fly ash in Israel is produced via combustion of pulverized bituminous coals in utilities. The bulk of coal fly ashes produced in Israel stems from South African and Columbian bituminous coals, therefore these fly ashes were the subject of the present study. Recently, it was observed that fly ash can serve as an efficient scrubber and fixation reagent to acidic wastes.

Three possible modes of interaction were observed: cation exchange, chemical bonding and electrostatic adsorption of very fine precipitate at the fly ash surface. In order to better understand these interactions, treatments of the fly ashes with aqueous solutions (neutral and acidic) have been carried out. The coal fly ashes were washed with acidic (0.1M HCl) and neutral (Treion Deionized Water Columns (UPDI)) solutions, subsequently changing the properties of the surface of the fly ash particles. Surface analysis by SEM and EDAX of the treated and untreated fly ashes have demonstrated that the treated fly ashes have changed ap-preciably its interactions with transition metal ions (e.g Cd2+, Cu2+).

Keywordsfly ash, aqueous solutions, structural changes, matrix SEM, Hydrochloride acid, transition metal ions.

34

Modification of surface properties of South African coal fly ash for industrial filler applications

L. van der Merwe1, L. Prinsloo2, R. Kruger3, L. Mathebula1

1 Department of Chemistry, University of Pretoria, Pretoria, 0002, South Africa, e-mail: liezel.vandermerwe@up.ac.za2 Department of Physics, University of Pretoria, Pretoria, 0002, South Africa, e-mail: linda.prinsloo@up.ac.za3 Richonne Consulting, PO Box 742, Somerset Mall, 7137, South Africa, e-mail: richonne@mweb.co.za

AbstractFillers are generally used in polymers and rubber to reduce their production costs and to improve certain physical characteristics of these products. The morphology and particle size of fly ash make it suitable for application as filler in polymers and rubbers, but its application is hindered by the lack of compatibility between the inorganic surface of the ash and the organic matrix of the polymer or rubber. Another concern is the agglomeration between fly ash particles, which has an adverse effect upon its application as filler. In order to meet some of the demands of the coal fly ash, polymer and rubber industries; the chemical and physi-cal properties of the coal fly ash surface need to be chemically modified in order to add functionality to its surface, before its application as filler will be profitable.

In this study, South African coal fly ash was treated under different conditions with an anionic and cationic surfactant, with the aim to modify the surface and physical properties of the ash. Although the overall chemi-cal composition of the SLS and CPC modified coal fly ash investigated in this study was not altered exten-sively, significant changes could be observed in its physical properties.

Surface and physical properties of the untreated and treated fly ash were studied by scanning electron micros-copy (SEM) and transmission electron microscopy (TEM) in order to determine the extent of interaction between the SLS and fly ash surface. Fourier Transform Infrared spectroscopy (FT-IR) was used to establish if any changes on the fly ash surface has occurred due to the various treatments.

Keywordscoal fly ash, surface modification, sodium lauryl sulphate, cetyl pyridium chloride

35

Extraction of Alumina from Coal Fly Ash Generated from Inner-Mongolia Chinese Coal

Xiaoting Liu1, Baodong Wang2, Lijun Zhao3, Qi Sun4,*

1 National Institute of Clean-and-Low-Carbon Energy (NICE), P.O. Box 001 Shenhua NICE, Future Science & Technology City, Beijing, 102209, China, email: liuxiaoting@nicenergy.com2 National Institute of Clean-and-Low-Carbon Energy (NICE), P.O. Box 001 Shenhua NICE, Future Science & Technology City, Beijing, 102209, China, email: wangbaodong@nicenergy.com3 National Institute of Clean-and-Low-Carbon Energy (NICE), P.O. Box 001 Shenhua NICE, Future Science & Technology City, Beijing, 102209, China, email: zhaolijun@nicenergy.com4,* National Institute of Clean-and-Low-Carbon Energy (NICE), P.O. Box 001 Shenhua NICE, Future Science & Technology City, Beijing, 102209, China, email: sunqi@nicenergy.com

AbstractGenerated during the combustion of coal for energy production, coal ash is an industrial by-product and an environmental pollutant recognized by all. Continuous research is conducted to identify opportunities for the ultilization of fly ash. However, it hasnt been well and fully utilized throughout the world for quite some time. Coal fly ash from Inner-Mongolia Guohua Junggar Power Plant typically contains 50% alumina, 40% silica, 3% lime, 1.5% titania, and 1.5% hematite. Due to the availability of high quantity of alumina in fly ash and large quantities of alumina imported by China, an alumina extraction from fly ash project, funded by Chinese Ministry of Science and Technology (MOST) and Shenhua Group, was initiated by NICE. An improved alkali lime sintering method has been developed for alumina extraction. Alumina product suitable for alumina electrolysis, with a valuable by-product white carbon black, can be produced from high alumina fly ash of Junggar by this novel process.

Keywordshigh alumina fly ash, alumina extraction, sinter.

36

Pressure infiltration technique for the synthesis of A356 Al/high-Ca fly ash composites

G. Itskos1, 3, P.K. Rohatgi2, A. Moutsatsou1, N. Koukouzas3, C. Vasilatos4 and J.D. Defow2

1 Laboratory of Inorganic and Analytical Chemistry, School of Chemical Engineering, National Technical University of Athens, Zografou Campus, GR-157 80, Athens, Greece2 College of Engineering and Applied Science, Materials Department, University of Wisconsin, Milwaukee, WI 53211, USA3 Centre for Research and Technology Hellas, Institute for Solid Fuels Technology and Applications, 357-359 Mesogeion Avenue, GR-152 31, Halandri, Athens, Greece4 Department of Economic Geology & Geochemistry, Faculty of Geology and Geoenvironment, National & Kapodistrian Univer-sity of Athens, Panepistimioupolis, Ano Ilissia, GR-157 84, Athens, Greece

AbstractIn the present paper eight types of A356 Al-fly ash composites were synthesized using pressure infiltration technique, by utilizing Class C fly ash (FA). Actually, such a strongly calcareous FA was for the first time used in MMCs-manufacturing by liquid metal infiltration techniques. After testing their mineralogy and chemis-try, certain FA size-fractions were used for the fabrication of the composites and their particular properties were linked to the level of the successful synthesis of the materials, the development of their microstructure and their wear strengths. The effect of using ground FA particles on the structure of composites and their tribological performance was also investigated through this study. It was concluded that using fine FA par-ticles can strongly advantage the properties of composites and that grinding of fly ash facilitates MMCs-manufacturing by pressure infiltration and it also advantages their wear properties.

KeywordsMetal Matrix Composites (MMCs), lignite fly ash, liquid metal infiltration, wear, compression strength

37

The effect of sintering processes of lignite calcareous ashes on the production of ceramics

A.K. Moutsatsou1, V.G. Karayannis2, E.L. Katsika1, Ch. Drossou1

1 Laboratory of Inorganic and Analytical Chemistry, School of Chemical Engineers, NTUA, Athens, Greece, e-mail: angst@central.ntua.gr2 Department of Pollution Control Technologies, Technological Educational Institute of West Macedonia, Kozani, Greece, e-mail: vkarayan@kozani.teikoz.gr

AbstractTwo-step sintering (TSS) and microwave (MW) heating process are two new techniques, promising ap-proaches to obtain effectively densified ceramics. TSS is characterized by the absence of the final stage of grain growth occurring upon the conventional sintering and by the development of nanograin microstruc-ture. MW energy offers many advantages for effective and rapid, thus eco-friendlier and economic sintering of materials over conventional processing. This process, by its selective and volumetric heating, can reduce the sintering time considerably, enhance the solidification efficiency and improve physical and mechanical properties. In the present research, compacts prepared from lignite combustion Class-C ashes originated from West Macedonia Greece were sintered employing the aforementioned alternative sintering proce-dures and compared to similar specimens that were conventionally sintered. The ceramic microstructures obtained were characterized by means of XRD and SEM-EDX analysis, as well as by density measurements conducted using the Archimedes method. The effectiveness of the solidification process was thoroughly stud-ied and is discussed here, and the specific microstructural features attained are compared between each other and evaluated in relation to the sintering method applied. The results show that the valorization of lignite calcareous ashes into ceramic materials is feasible through different sintering techniques.

Keywordssintering, lignite calcareous ashes, two-step sintering, microwave, ceramics.

38

Development of ferrocement matrix by using calcareous fly ash and ladle furnace slag as pozzolanic admixtures

I. Papayianni, M. Papachristoforou

Aristotle University of Thessaloniki

AbstractFerrocement is defined as reinforced mortar with multiple layers of steel mesh encapsulated in mortar ma-trix. It is widely used for housing units, flat or corrugated roofing sheets as well as other structural compo-nents. Ferrocement seems to be an alternative for supporting photovoltaic cells. Mortar is usually injected and therefore, fluidity of it is the important criteria for the design of the mortar mixture apart from the required strength. According to ACI 599-1R5, the mortar mixture is a rich in cement mixture in which poz-zolanic admixtures are added to replace part of fine aggregates. In addition, synthetic fibres may be used to increase toughness and contribute to elongation of service life of ferrocement applications. In this paper, the experimental work concerning the development of ferrocement matrix with addition of fly ash, ladle furnace slag and synthetic fibers is presented. The two pozzolanic admixtures were added at 10, 15 and 20% of cement mass while the polypropylene fibres content was 0.7, 0.8 and 0.9% by volume of the total mixture. Super plasticizer of carboxylic origin was also used. The properties of fresh mortar measured were apparent specific density and plasticity immediately and one hour after mixing. The hardened mortar matrix was test-ed by determining characteristic compressive strength fc (by using cylindrical 15x30cm specimens) as well as flexural strength and static modulus of elasticity at 28-d age. Additionally, fracture energy was measured ac-cording to JCI-S-001-2003 Standard. The 28-d age early shrinkage deformation of concrete matrix with and without fibers was also measured. Based on results, it seems that fly ash addition contributes to 23% strength increase in comparison to control plain cement mixture. A characteristic compressive strength of 50 MPa is achieved in mixtures with 10 and 15% fly ash by mass of cement of the same level of fluidity with the control mixture. Fracture energy is also higher while early shrinkage is reduced. The addition of ladle furnace slag influences very positively the plasticity while the 28-d strength ranges around the control mixture strength.

KeywordsCalcareous fly ash, ladle furnace slag, ferrocement

39

CO2 optimized cement based on synthetic slag made

of fly ash

A. Buchwald1 and J.A.L.M. Wiercx2

1 ASCEM B.V., The Nederlands, e-mail: a.buchwald@ascem.nl2 ASCEM B.V., The Nederlands, e-mail: j.wiercx@ascem.nl

AbstractAlkali-activated materials harden under the reaction of an alkaline source and a raw material reactive in such way. Different raw materials are suitable for the reaction. The use of secondary raw materials such as granulated blast furnace slags and fly ashes are favoured due to environmental aspects such as CO

2 emission

and resource consumption. A disadvantage of the use of secondary resources is their limited availability or the variability of different batches.

Therefore the ASCEM cement technology goes a different way: a synthetic glass is produced under the use of fly ash and correcting materials. The advantage of this is the production of a high reactive glass with a stable quality. That glass can easily be dissolved by a lower need of hydroxide concentration compared to the fly ash. The reactive glass is milled and mixed to 50 % with fly ash as filler as well as with a dry activator. The paper gives an overview over the principle production process, some key properties and data about ecologi-cal and economic aspects compared to ordinary Portland cement.

Keywordsfly ash, alkali-activated binders, secondary resources, low CO

2 cement.

40

Bituminous Coal Fly ash as a Potential Scrubber Reagent for Low Activity Radioactive Wastes

R.N. Liberman1, G. Segev 1, 2 and H. Cohen1, 3

Department of Biological Chemistry, Ariel University Center at Samaria, Ariel, 40700 Israel, phone: 00972-54-7776499, fax: 00972-8-9200749, email: hcohen@ariel.ac.il ; roynl@ariel.ac.il

Israel Atomic Energy Commission, Tel-Aviv, Israel.

Chemistry Department, Ben-Gurion University of the Negev, Beer Sheva, Israel email: hcohen@bgu.ac.il

AbstractThe most abundant fossil fuel for power generation in Israel is bituminous coal (more than 50% of the electri-cal power in 2011). The main waste produced during the combustion is fly ash (~10% residues). The fly ashes produced in Israel are Class F, thus when exposed to water a highly basic solution results (pH> 10.5), which is the result of the very low sulfur and phosphorus content in the bituminous coals used. Fly ashes are used commercially worldwide mainly as aggregates or as partial cement substitutes in the construction industry. The fact that the Israeli fly ash is highly basic may indicate its feasibility as a chemical scrubber for acidic wastes, which can be used as an efficient scrubber and a fixation reagent for these wastes. Furthermore it has been proved, that trace elements are trapped at the surface of the fly ash particle and also that the scrubbed waste product can serve as a partial substitute to sand and cement for concrete production. Bricks produced using the aggregate as a partial sand substitute, have proved to be strong enough according to the concrete standards and the fixation of the trace element in the concrete was excellent (checked via the improved TCLP1311, the European Directive EN12457-2 and the CAL WET methods). Subsequently, fly ash might be a potential efficient fixation reagent for radionuclides.

The feasibility of the fly ash as a potential fixation reagent for radionuclides has been studied via simulation experiments in aqueous solutions containing cesium ions, Cs+, divalent strontium, Sr2+ and Ce3/4+ as simula-tion reagents to the radionuclides (e.g Cs137, Sr90, and actinides). The fixation mechanisms are discussed in detail.

Keywordsfly ash, radioactive wastes, trace elements, cesium, strontium, cerium

41

Fly-ashes from fluid combustion as an alternative binder for cold recycling and stabilized base courses in pavement structures

J. Suda1, J. Valentin2, M. Faltus3

1 Czech Technical University in Prague, Faculty of Civil Engineering, Department of road structures, email: jan.suda@fsv.cvut.cz2 Czech Technical University in Prague, Faculty of Civil Engineering, Department of road structures, email: jan.valentin@fsv.cvut.cz3 Technical University in Ostrava, Faculty for mining and geology, Institute of mining engineering and safety, email: geologicus@seznam.cz

AbstractIn road construction sector in the present the focus is laid on technologies and techniques, which allow decreasing energy demand necessary for production. At the same time attention is paid to decreasing con-struction costs related to new structures or pavement rehabilitation works. In the Czech Republic in this connection the development during last ten years was oriented in increased extend on cold in-place recy-cling techniques. Certain positive potential of this group of techniques is the possibility to use energetic by-products in a form of alternative binders or fillers. These by-products, coming from coal combustion, have a relatively broad range of possible applications especially like alternative substitutes of normally used hy-draulic binders (cement, lime) in cold recycling mixes. Within the experimental activities of Faculty of Civil Engineering CTU in Prague usually used cement was replaced by fly-ashes or inorganic loose binder obtained by mechanical activation of fly-ash coming from fluid combustion. With respect to limited knowledge of behavior and properties of mixes if an alternative solution is used, it is necessary to specify correctly newly designed mixes. For assessed mixes basic volumetric properties, as well as strength and deformation charac-teristics were determined. Within the evaluation of particular performance characteristics the influence of different aggregate grading on strength properties was assessed as well. From the expected use leaching tests were done for selected mixes as well as combined water and frost susceptibility tested. So far gained results are presented in the paper.

KeywordsFly-ash from fluid combustion, mechanical activation, cold recycling techniques, indirect tensile strength, stiffness, water sensitivity, leaching, diffusive test

42

High Volume of Calcareous Fly Ash for the Production of a Hydraulic Binder for Road Pavements

C. Charalampidou1, M. Chaniotakis2, I. Papayianni1, S. Tsimas3

1 Laboratory of Building Materials, Civil Engineers Department, Aristotle University of Thessaloniki 2Titan Cement S.A.,3Laboratory of Inorganic and Analytical Chemistry, Chemical Engineers Department, National Technical University of Athens

AbstractThe construction of road pavement with concrete seems very advantageous from technical point of view es-pecially for heavy load transportations. However, the use of concrete pavement often results in higher initial cost in comparison to asphalt one though the service life of concrete road is generally longer.

The development of a commercial low cost hydraulic binder of adequate strength capacity will contribute to the reduction of the initial cost of concrete pavement.

In the paper, an effort in this direction is described. Fly ashes of different compositions in terms of free lime and sulfate content are blended at laboratory with clinker and other mineral admixtures so as in the mixed systems the fly ash to be at least 50% and the clinker 20%. Limestone filler and natural local pozzolan were used as additions. A series of mixes produced at a laboratory mill were tested to find the optimum blending for required mortar 28-d strength of 30MPa. Apart from strength development the volume stability was also measured. Remarks concerning the grindability of the fly ash are made as well as comments about the relationship of fly ash composition and strength results.

Although the capacity of existing laboratory mill was limited and did not correspond to the real blended po-tential of the constituents, it seems that by achieving a fineness R45 value of 2-10% a 28-d strength level of 40 2 MPa was obtained in mixes where 60% of clinker was replaced by calcareous fly ash. These strength values were obtained even though the water demand was greater compared to that of the control mixture. For mixed systems in which 70% clinker was replaced, this strength level was achieved at 90 days. In mixtures where 80% of clinker was replaced by calcareous fly ash a strength level of 30 2 MPA was developed at 90 days. Net fly ashes mixes of R45 2-5% showed a 28d strength of 10-20 MPa. Based on this research, the production of a high volume fly ash hydraulic binder seems feasible and a new field of exploitation of calcare-ous fly ash is opened.

Keywordshigh volume fly ash hydraulic binder, calcareous fly ash, cement, clinker, pozzolan, limestone

43

Construction of a pilot road with high volume calcareous fly ash binder

I. Papayianni1, E. Chaniotakis2, E. Anastasiou1, C. Leptokaridis2

1 Aristotle University of Thessaloniki, 2 TITAN Cements S.A.

AbstractA new hydraulic binder developed by TITAN Cements was tested for the construction of a pilot road as a demonstration project. The binder, which consisted of about 50% calcareous fly ash, was used to produce roller compacted concrete (RCC) of C25/30 strength level. The concrete mixture was developed by test mixtures using a suitable aggregate gradation and water to binder ratio of 0.50. The maximum aggregate size was 16 and 31.5 mm, while cement content was 280 kg/m3 or 300 kg/m3 and plasticizer was also added. The workability of the test mixtures was measured by the Vebe test and compaction factor using a compaction hammer, while the results showed that sufficient strength levels were achieved with 280 kg/m3 and 31.5 mm maximum aggregate size. Following the test mixtures, the pilot road was constructed by using the concrete mixture with the best results regarding workability and strength. Workability loss due to transportation times and factors affecting compaction by roller drums were recorded and adjustments were made to the final mixture. A finisher was used to place the concrete in two layers and 10t roller drums were used for compac-tion, while joints were sawed within 24h of the placement. In order to assess the performance of the concrete pavement, cores were drilled and tested in the laboratory. The drilled cores showed satisfactory strength levels but poor connection between the two concrete layers. It seems that a properly compacted single layer RCC pavement using the new hydraulic binder can achieve the required strength levels.

Keywordshydraulic road binder, calcareous fly ash, RCC pavement

44

Durability Properties of High Performance Fiber Reinforced Cementitious Composites Incorporating High Volumes of Fly Ash

M. Sahmaranb, M. Tokyaya

a Department of Civil Engineering, Gaziantep University, Gaziantep, Turkey, e-mail: sahmaran@gantep.edu.trb Department of Civil Engineering, Middle East Technical University, Ankara, Turkey, e-mail: mtokyay@metu.edu.tr

AbstractThis paper discusses the influence of the high volumes of fly ash on the fire and frost resistance and micro-structure of the Engineered Cementitious Composites (ECC). Composites containing two different contents of fly ash as a replacement of cement (55 and 70% by weight of total cementitious materials) are examined. For frost resistance, mixtures are exposed to the freeze and thaw cycles up to 300 cycles in accordance with ASTM C666, Procedure A. For fire resistance, mixtures are exposed to the temperatures up to 800 oC for one hour. Fire and frost resistance of the mixtures are determined in terms of the residual ultrasonic pulse ve-locity and mass loss. The air-void characteristics of mixtures are also studied using linear transverse method. The role of fly ash is discussed through the analysis of microstructure. The microstructural characterization is examined before and after exposure to frost and fire deterioration by using scanning electron microscopy. Results indicate that frost resistance of ECC mixtures containing no entrained air is worsened, but fire resist-ance of ECC mixtures is improved with the addition of fly ash.

KeywordsEngineered Cementitious Composites (ECC); Durability; Fly Ash.

45

Alumina-rich Glass Cement from Lignite Coal Ash

Dr. A. Wolter, Clausthal-Zellerfeld

Clausthal University of Technology, Institute of Nonmetallic Materials, Germany, Cement and Building Materials Department

AbstractLime-rich coal ashes can provide a chemical composition which is located between the well known blast furnace slag (BFS), the calcium alumina cement (CAC) and the conventional portland clinker (PC). From the phase diagram CaO-SiO2-Al2O3 it can easily be derived that any composition with a lower CaO content than clinker and a higher alumina content than blast furnace slag, if crystallized, would lead to non-hydraulic phases like gehlenite - except special compositions which are investigated currently as calcium alumina sulfate / belite cements (but not shown here).

From a technological point of view, however, it seems to be attractive to investigate the melting of such compositions and to save the glassy state by rapid cooling. F.W. LOCHER has investigated a huge number of such glasses regarding their hydraulic behaviour and strength potential. He published his results in 1958, from which the background of figure 1 is derived.

LOCHER did his trials mainly with the scope to identify new and better performing blast furnace slag com-positions. Therefore he did not involve SO3 and iron oxide contents in his raw mix, which are at very low levels in BFS. However, at high amounts they may be present in coal ashes. The alkali content in his glasses was also kept at low levels.

Some European lignite coal ashes are containing high amounts of calcium and aluminium oxides, sulfates and alkalis, in particular if additional calcium oxide was added for the dry SO2 scrubbing. If such lignite ashes shall be molten and converted into glass cement, the calcium sulfate decomposition and SO2 volatilization goes up sharply. Therefore the tentative process diagram, shown in figure 2, must comprise an additional flue

Fig. 1:

Optimum alumina rich glass composition for sulfate-induced hardening, at 5 % MgO.The acceptable melting temperature area is marked in yellow, i.e.

46

gas desulfurization stage.

On the other hand, the triggering of the hardening process by sulfate seems to be promising in alumina-rich glasses, so the recovered calcium sulfate can be utilized as a set regulating and strength accelerating agent in the final product.

The melting temperature can be estimated at 150 K above the range of clinker burning because the additional components, i.e. iron oxide, alkalies, MgO and minor constituents, will all tend to lower the actual melting temperature range. After the melting stage, the glassy constitution of the material can only be preserved, if the cooling occurs very fast.

Conventional blast furnace slag cooling with excess water (granulation) is not favourable for alumina-rich glasses, because its hydraulic reactivity is probably much higher. The remaining water content in the wet sand would complicate the materials handling and reduce or destroy the hydraulic potential.

Therefore the flow of alumina-rich glass will be micronized by nozzle spray. The fine glass spheres which would result from that can be cooled extremely fast by radiation losses. It is obvious that current state of alumina-rich glass cement development is at a suggestion level. Some process steps must be developed com-pletely new. However, if the CO2 burden of conventional clinker burning becomes too costly, it will become more and more attractive to substitute clinker by other hydraulic materials, but in composition terms still remaining within the well known and proven CaO-SiO2-Al2O3-Fe2O3 scheme of common cements. The potential of alumina-rich glasses ranges from artificial slag composition to new material classes. If the pro-duction process can be developed and performed in an economical way, the market potential of alumina-rich glass cement could be very promising.

The tonnage/y of suitable lime-rich coal ashes in Europe is estimated to amount at least at that of BFS. Today they are mostly dumped, because without chemical adjustments and due to lacking of a proven micronizing process at high temperatures such coal ashes do not develop sufficient hydraulic activity. Much research work has still to be done in identifying the optimum compositions, the process steps for melting, quenching and micronizing, as well as the AGC performance in mortar and concrete.

Fig. 2:

Principle process sketch of alumina-rich glass cement production by melting and hot micronizing