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Research PUBLICATION NO THE NORDIC CONCRETE FEDERATION 1/2014 PUBLICATION N0. 49 Nordic Concrete Research PUBLICATION NO. 49 1/2014 NORDIC CONCRETE RESEARCH EDITED BY THE NORDIC CONCRETE FEDERATION CONCRETE ASSOCIATIONS OF: DENMARK FINLAND ICELAND NORWAY SWEDEN PUBLISHER: NORSK BETONGFORENING POSTBOKS 2312, SOLLI N - 0201 OSLO NORWAY VODSKOV, JUNE 2014 Preface Nordic Concrete Research is since 1982 the leading scientific journal concerning concrete research in the five Nordic countries, e.g., Denmark, Finland, Iceland, Norway and Sweden. The content of Nordic Concrete Research reflects the major trends in the concrete research. Nordic Concrete Research is published by the Nordic Concrete Federation which also organizes the Nordic Concrete Research Symposia that have constituted a continuous series since 1953 in Stockholm. The Symposium circulates between the five countries and takes normally place every third year. The next symposium, no. XXII, will be held Reykjavik, Iceland 13 - 15 August 2014, in parallel with the ECO-CRETE conference. More information on the research symposium can be found on www.rheo.is. More than 110 papers will be presented. Since 1982, 414 papers have been published in the journal. Since 1994 the abstracts and from 1998 both the abstracts and the full papers can be found on the Nordic Concrete Federation’s homepage: www.nordicconcrete.net. The journal thus contributes to dissemination of Nordic concrete research, both within the Nordic countries and internationally. The abstracts and papers can be downloaded for free. The high quality of the papers in NCR are ensured by the group of reviewers presented on the last page. All papers are reviewed by three of these, chosen according to their expert knowledge. Since 1975, 76 Nordic Miniseminars have been held – it is the experience of the Research Council of the Nordic Concrete Federation, that these Miniseminars have a marked influence on concrete research in the Nordic countries. In some cases, the information gathered during such Miniseminars has been used as Nordic input to CEN activities. The latest Miniseminar concerning Alkali Silica Reactions was held in Riga in an attempt to involve the Baltic countries in our Nordic activities. We look forward to welcome You to the XXII Nordic Concrete Research Symposium in Reykjavik 13. - 15. August 2014. Vodskov, June 2014 Reykjavik, June 2014 Dirch H. Bager Olafur H. Wallevik Editor, Nordic Concrete Research Chairman, Research Council of the Nordic Concrete Federation & Chairman of the Organizing Committee for the XXII Research Symposium PUBLICATION NO. 49 1/2014 CONTENTS 1 Gunvor Marie Kirkelund, Mette Rica Geiker & Pernille Erland Jensen 1 Electrodialytically Treated MSWI APC Residue as Substitute for Cement in Mortar 2 Oldrich Svec, Lars Nyholm Thrane & Henrik Stang 17 Linking the Fibre Orientation Factor with the Mechanical Response of the fibre reinforced Self-compacting Concrete 3 Ya Peng, Klaartje de Weerdt, Bård Pedersen & Stefan Jacobsen 27 Measuring sedimentation and bleeding of fresh paste with hydrostatic pressure 4 Mahdi M. Kioumarsi, Max A.N. Hendriks & Mette R. Geiker 39 Quantification of the interference of localised corrosion on adjacent reinforcement bars in a concrete beam in bending 5 Håvard Nedrelid & Terje Kanstad 59 Shear Resistance of Steel-Fibre Reinforced RC Beams with Small Circular Openings 6 Richard Mc Carthy & Johan Silfwerbrand 73 Is It Possible to Predict Formwork Pressure When Using SCC? – A Field Study 7 Jonas Carlsvärd & Mats Emborg 93 Avoiding undesirable end results of bonded steel fibre concrete overlays – observations from tests and theoretical calculations 8 Björn Täljsten, Gabriel Sas & Thomas Blanksvärd 113 Strengthening of concrete structures with FRP – a guideline 9 Anders Hösthagen, Jan-Erik Jonasson, Mats Emborg, Hans Hedlund & 127 Kjell Wallin Thermal Crack Risk Estimations for Tunnel - Equivalent Restraint Method Correlated to Empirical Observations. 10 Dimitrios Boubitsas & Tang Luping 145 Electrochemical monitoring of Corrosion Initiation of Reinforcement Steel in Concrete and Chloride Threshold Values 11 Martin Persson, Ulf Ohlsson & Mats Emborg 163 Bridge deck concrete overlays – full scale studies 12 Arezou Babaahmadi, Luping Tang & Zareen Abbas 181 Mineralogical, Physical and Chemical Characterization of Cementitious Materials Subjected to Accelerated Decalcification by an Electro-Chemical Method Research Council and Editorial Board of NCR 199 Review Group for NCR 201 1 Electrodialytically Treated MSWI APC Residue as Substitute for Cement in Mortar Gunvor Marie Kirkelund PhD, Researcher Department of Civil Engineering Technical University of Denmark DK – 2800 Lyngby E-mail: [email protected] Mette Rica Geiker PhD, Professor Department of Structural Engineering Norwegian University of Science and Technology Richard Birkelands Vei 1a N – 7491 Trondheim E-mail: [email protected] Pernille Erland Jensen PhD, Associate Professor Department of Civil Engineering Technical University of Denmark DK – 2800 Lyngby E-mail: [email protected] ABSTRACT Air pollution control (APC) residues from municipal solid waste incineration (MSWI) are considered hazardous waste and need pre- treatment prior to possible reuse. Here, two MSWI APC residues, from which the most mobile fraction of heavy metals and salts has been removed by carbonation and/or electrodialytic remediation, were used in Portland cement mortar. Mortar bars with 15 % weight replacement of cement by APC residues showed compressive strengths up to 40 MPa after 28/32 days. Heavy metal and salt leaching from both crushed and monolithic mortars with APC residues was generally similar and comparable to both the reference mortar and mortar with coal fly ash. These results indicate that electrodialytic remediation could be used a pre-treatment method for MSWI APC residues prior to reuse in mortar. Keywords: electrokinetic remediation, mortar, leaching, fly ash, heavy metal 2 1. INTRODUCTION In Denmark municipal solid waste incinerators (MSWI) have air pollution control (APC) systems which generate residues with a high content of salt and leachable heavy metals. Currently, MSWI APC residue is classified as hazardous waste and stabilized and disposed of abroad. Current practice in other countries are either temporary disposal until a treatment method has been found or permanent disposal in hazardous waste landfills, often with pre- treatment (solidification, stabilisation or extraction) of the APC residue [1]. Contrarily to the MSWI APC residue, fly ash from coal combustion is considered a valuable resource to be used in production of cement and as a supplementary cementitious material (SCM) in mortar and concrete. Mortar consists of binder (cement), water and fine aggregate (sand) at a given ratio and is the basis for concrete which is a mix of mortar and coarse aggregate. Up to 5 % of the total global anthropogenic CO2 is emitted by Portland cement production and the replacement of Portland cement by other binders such as industrial by- products have gained increasing interest [2]. MSWI fly ash or APC residues could potentially be used as binder in mortar and concrete [3], but the content of heavy metals restricts/limits this possibility, mainly due to their mobility [4]. Only a few studies have been made where MSWI APC residue is tested for direct reuse in mortar and concrete, most studies report results for fly ash, without the APC products [1]. Pre-treatment of MSWI APC residues prior to reuse has shown to be difficult, as the method should be able to keep the desired material characteristics and treat the contaminants. Generally two approaches are considered when treating heavy metals in MSWI APC residues prior to potential reuse: stabilization or extraction of heavy metals. Stabilization methods include carbonation, thermal treatments or chemical stabilizations, such as stabilization with phosphates, chelating agents or ferrous compounds. In stabilization, the material characteristics are only altered slightly and the heavy metals are still present in the same quantity but are less available [1, 4]. Extraction techniques include different washing and chemical extraction methods. Acid washing is efficient for removing heavy metals, but drastically alters the pH and material characteristics [1, 4]. An electrodialytic (ED) upgrading method, where the mobile fraction of heavy metals is removed by an electric current at the MSWI APC residues’ original alkaline pH, has shown potential for reducing heavy metal and salt leaching and keeping an alkaline pH in the MSWI APC residue both bench [5] and pilot scale [6]. The principle of electrodialytic (ED) upgrading is illustrated in Fig. 1. ED is widely used e.g. for desalination of solutions in industrial scale, but not for suspensions of solid matter. MSWI APC residues in suspension (up to 10% DM) have been subjected to ED. The ED system consists of an ED stack with multiple concentrate compartments (concentrate) and compartments containing the APC residue suspension (diluate). The concentrate and the diluate are pumped through the ED stack and the compartments are separated by ion exchange membranes and anions and cations from the diluate are removed to the concentrate by the applied current. Dewatering is required prior to reuse of the upgraded APC residue as a constituent in construction materials. 3 Diluate Concentrate + + + - 4 3 4 3 4 3 + - - - - 2 1 2 1 2 1 2 Concentrate Diluate Figure 1 – Principle of electrodialytic upgrading of APC residue.1/2- ion exchange membranes, 3- diluate compartments,
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