12th_PhD_Symposium_in_Prague,_Czech_Republic_–_FIB_Proceedings_2018.pdf

Proceedings of
The 12th
International
PhD Symposium
in Civil Engineering
Czech Technical University in Prague
Prague, Czech Republic
August 29-31, 2018
Edited by
Alena Kohoutková, Jan L. Vítek, Michaela Frantová, Petr Bílý
© fédération internationale du béton (fib). This document may not be copied or distributed without prior permission from fib.
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Symposium Sponsors
BASF Construction Chemicals
http://careers.construction-chemicals.basf.com
VALBEK-EU, a.s.
http://www.valbek.eu/en/
BETOTECH, s.r.o.
http://www.betotech.cz/
Červenka Consulting s.r.o.
https://www.cervenka.cz/products/atena/
Metrostav a.s.
https://www.metrostav.cz/en/
Pontex Consulting Engineers, Ltd.
http://www.pontex.cz/
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Alena Kohoutková
Jan L. Vítek
Michaela Frantová
Petr Bílý
(Eds.)
Proceedings of
The 12th
fib International
PhD Symposium
fib
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Proceedings of
The 12th
fib International
PhD Symposium
29-31 August 2018, Prague, Czech Republic
Edited by
Alena Kohoutková
Jan L. Vítek
Michaela Frantová
Petr Bílý
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VI
Note by the editors
This book was carefully produced. However, no liability or responsibility of any kind (including
liability for negligence) is accepted by the editors, the authors, the Scientific Committee and the
Organizing Committee. Statements, data, illustrations or other issues may be inaccurate or incorrect.
This publication is available on Internet under the following Creative Commons license
Some rights reserved
Published: http://creativecommons.org/licenses/by-nc-nd/4.0/
Print on Demand
ISBN 978-80-01-06401-6
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VII
Greetings
The fib is delighted to have its 12th
International PhD Symposium in Civil Engineering hosted at
the Czech Technical University in Prague in the Czech Republic.
This is a special event for the fib, which was masterminded by Honorary President György Balázs for
PhD students supervised by professors.
The fib is at the forefront of scientific development at the international level. It focuses on the study of
scientific and practical matters capable of advancing the technical, economic, aesthetic and
environmental performance of concrete construction. Its objectives could be summarised in the
following ideas: Stimulation of research and synthesis of findings, transfer into design and
construction practice, dissemination by publications, conferences, etc., production of
recommendations and codes.
The International PhD Symposia in Civil Engineering fit perfectly in the mission and objectives of the
fib and were created intentionally with many differential and specific characteristics.
Research carried out by PhD students supervised by professors constitutes the forefront of the
scientific development. The fib International PhD Symposium in Civil Engineering provides a unique
forum to the participants, who have already started their scientific work but who have not yet
submitted their theses, to present their ongoing results to the international audience and to obtain
advice on how to continue and complete their dissertations. For this reason, the programme includes a
substantial compulsory discussion time for each presentation in order to guarantee exchanges between
the PhD students and the numerous professors, from all over the world, who participate in the
conference.
The PhD International Symposium in Civil Engineering was also created with the ambition to make
the fib known to younger engineers to include them in our fib activities. Young engineers, researchers,
designers and constructors will be the next leaders and, potentially, the next contributors to the fib
technical activities. The fib is a non-profit association based on voluntary work. Throughout its
history, it has benefitted from contributions from the most prominent engineers from all over the
world. The fib needs your contribution and leadership to maintain alive its objectives and high
technical level production. For this reason, the fib International PhD Symposium in Civil Engineering
has been organised, from the beginning, at a minimum cost to allow young engineers to participate
and to develop their professional network and to help expand the fib family with new members.
I would like to express my sincere gratitude to the organisers of the 12th fib International PhD
Symposium in Civil Engineering: The Faculty of Civil Engineering, The Klokner Institute of the
Czech Technical University in Prague and the ČBS – Czech Concrete Society (the Czech fib national
group). I would especially like to thank Prof. Jan Vítek.
Hugo Corres Peiretti
President of the International Federation for Structural Concrete (fib)
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IX
Preface
A long-standing tradition of the fib, the PhD Symposia started in 1996. They were established by
Prof. Balázs in Budapest to support young researchers and practitioners. Since then, the fib National
Groups have already organised eleven symposia. The PhD symposia have become highly-recognised
events, boasting the participation of international experts attending the symposia as PhD students'
supervisors or keynote speakers. A two-year interval between each symposium allows for a thorough
preparation of the event and for a sufficient amount of new information. The symposia are exclusively
organised at universities. This allows for a relaxed and friendly atmosphere, which befits the young
generation.
The 12th fib Symposium will be held in Prague, again in Europe after two overseas symposia in
Quebec (2014) and Tokyo (2016). Two organisations are involved in the preparation: The Czech
Technical University in Prague and The Czech Concrete Society (representing the national fib group).
The symposium will take place at the Faculty of Civil Engineering of the Czech Technical University
in Prague.
The organisers were surprised by the high number of students interested in participating in the
symposium. The organisers received a lot of abstracts after the first deadline. The organisers were
unsure whether they would be able to organise the symposium as it usually is. However, we have
received less full papers than anticipated. We were thus able to organise the event as planned.
Nevertheless, there will be some differences in the organisation, as the number of papers is rather
high. The scientific committee decided to divide the papers into a group of oral presentations and
posters. This is new, as no poster session was organised at the past symposia. The scientific
programme is divided into 4 parallel sessions over three days.
It is also important to note that the scientific programme will be enriched by three excellent speakers
who will cover the current topics of civil engineering. Prof. E. Brühwiler from Lausanne will speak
about new materials. Prof. J. Strásky from Brno will show the effect of prestressing on structural
behaviour, and finally, Prof. H. Corres, president of the fib, will focus his presentation on conceptual
design. All three topics – new materials, new technologies and conceptual design – are crucial and
include the other recently-discussed phenomena like structural performance and safety, aesthetics,
economy, sustainability, etc.
The symposium, as a platform for sharing experience, cannot be organised without a social
programme. The welcome reception, as well as the informal conference dinner, will contribute to
facilitating networking between young participants. I am delighted that the fib Young Member Group
will participate in the organisation of the PhD Symposium for the first time in Prague. They will
contribute to evaluation of presentations and awarding the Best Paper Presentation.
Last but not least, it is a great pleasure for me to express my gratitude to all the sponsors who
contributed to the organisation of the symposium. Without their support, it would be very difficult to
keep the scientific level as well as the social standard of the previous symposia.
Finally, let me wish to all participants – especially PhD students – an interesting event. I hope that
this Symposium will remain in their memories as the beginning of their progress in scientific work
and perhaps also in the fib activities. The international environment may also help in developing
relations between participants and contribute to the mutual understanding of different cultures and
countries, which is also one of the roles and strengths of the fib.
Jan L. Vítek
Czech Technical University in Prague and Metrostav a.s., Prague
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XI
Scientific Committee
Jan L. Vítek (Czech Republic) – chair
Andrej B. Ajdukiewicz (Poland)
Pedro A. de Oliveira Almeida (Portugal)
György L. Balázs (Hungary)
Joseé Bastien (Canada)
Vladimír Benko (Slovakia)
Konrad Bergmeister (Austria)
Hans-Dieter Beushausen (South Africa)
Francesco Biasioli (Italy)
Petr Bílý (Czech Republic)
Mikael Wimpffen Braestrup (Denmark)
Abraham Sánches Corriols (Germany)
Manfred Curbach (Germany)
Radim Čajka (Czech Republic)
Avraham N. Dancygier (Israel)
Frank Dehn (Germany)
Wit Derkowski (Poland)
Vyacheslav R. Falikman (Russia)
Michael N. Fardis (Greece)
David Fernández-Ordóñez (Switzerland)
Ludovít Fillo (Slovakia)
Stephen Foster (Australia)
Michaela Frantová (Czech Republic)
Hans-Rudolf Ganz (Switzerland)
Fabrice Gatuingt (France)
Petr Hájek (Czech Republic)
Jaroslav Halvonik (Slovakia)
Steinar Helland (Norway)
Nico Herrmann (Germany)
Sung Gul Hong (Korea)
Dick A. Hordijk (Netherlands)
Gintaris Kaklauskas (Lithuania)
Milan Kalný (Czech Republic)
Akio Kasuga (Japan)
Alena Kohoutková (Czech Republic)
Jiří Kolísko (Czech Republic)
Vladimír Křístek (Czech Republic)
Xilin Lu (China)
Koichi Maekawa (Japan)
Riadh S Al-Mahaidi (Australia)
Giuseppe Mancini (Italy)
Antonio Marí (Spain)
Aurelio Muttoni (Switzerland)
Harald S. Müller (Germany)
Takafumi Noguchi (Japan)
Josef Novák (Czech Republic)
Tor Ole Olsen (Norway)
Alessandri Palermo (New Zealand)
Peter Paulík (Slovakia)
Hugo Corres Peiretti (Spain)
Martin Petřík (Czech Republic)
Marco Di Prisco (Italy)
Radomír Pukl (Czech Republic)
Koji Sakai (Japan)
Johan Silfwerbrand (Sweden)
Jiří Stráský (Czech Republic)
Alfred Strauss (Germany)
Fernando Stucchi (Brazil)
Luc Taerwe (Belgium)
Jean-Michel Torrenti (France)
Lucie Vandewalle (Belgium)
Sherif Yehia (United Arab Emirates)
Yamei Zhang (China)
Bin Zhao (China)
Miloš Zich (Czech Republic)
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XII
Organizing Committee
Alena Kohoutková (Czech Republic) – chair
Petr Bílý (Czech Republic)
David Čítek (Czech Republic)
David Fernández-Ordóñez (Switzerland)
Michaela Frantová (Czech Republic)
Petr Hájek (Czech Republic)
Petra Johová (Czech Republic)
Jiří Kolísko (Czech Republic)
Šárka Nenadálová (Czech Republic)
Josef Novák (Czech Republic)
Martin Petřík (Czech Republic)
Michal Števula (Czech Republic)
Jiří Vích (Czech Republic)
Jan L. Vítek (Czech Republic)
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XIII
Participating Universities
University of Tebessa
Algeria
TU Wien
Austria
University of Innsbruck
Austria
University of Natural Resources and Life
Sciences (BOKU), Vienna
Austria
Ghent University
Belgium
KU Leuven
Belgium
Vrije Universiteit Brussel
Belgium
Brno University of Technology
Czech Republic
Czech Republic
University of Pardubice
Czech Republic
VŠB – Technical University of Ostrava
Czech Republic
Aalto University
Finland
Ecole Centrale de Nantes
France
Université de Nantes
France
Université de Pau et des Pays de l'Adour
France
University of Angers
France
University of La Rochelle
France
University of Toulouse
France
RWTH Aachen University
Germany
Technische Universität Braunschweig
Germany
Technische Universität Darmstadt
Germany
Technische Universität Dresden
Germany
Technische Universität München
Germany
TU Dortmund University
Germany
Budapest University of Technology and
Economics
Hungary
Széchenyi István University
Hungary
Harbin Institute of Technology
China
Tongji University
China
Tsinghua University
China
Indian Institute of Technology Madras
India
Indian Institute of Technology Roorkee
India
National Institute of Technology Rourkela
India
Politecnico di Milano
Italy
Politecnico di Torino
Italy
Roma Tre University
Italy
University of Bergamo
Italy
University of Padova
Italy
University of Salerno
Italy
The University of Tokyo
Japan
Yokohama National University
Japan
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XIV
Universiti Sains Malaysia
Malaysia
Norwegian University of Science and
Technology (NTNU), Trondheim
Norway
University of Agder
Norway
Cracow University of Technology
Poland
Lodz University of Technology
Poland
Lublin University of Technology
Poland
Rzeszow University of Technology
Poland
Silesian University of Technology
Poland
Wrocław University of Science and
Technology
Poland
University of Beira Interior
Portugal
Technical University of Cluj-Napoca
Romania
Universitatea Politehnica Timișoara
Romania
Singapore ETH Centre
Singapore
Slovak University of Technology in
Bratislava
Slovakia
Technical University of Košice
Slovakia
University of Žilina
Slovakia
Seoul National University
South Korea
Ulsan National Institute of Science and
Technology (UNIST)
South Korea
Universitat Politècnica de Catalunya
Spain
Chalmers University of Technology
Sweden
École Polytechnique Fédérale de Lausanne
Switzerland
ETH Zurich
Switzerland
Middle East Technical University
Turkey
O.M. Beketov National University of Urban
Economy in Kharkiv
Ukraine
Imperial College London
United Kingdom
University of Cambridge
United Kingdom
University of Leeds
United Kingdom
University of Arkansas
United States
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XV
Table of Contents
Note by the editors ................................................................................................................VI
Greetings..............................................................................................................................VII
Preface ..................................................................................................................................IX
Scientific Committee..............................................................................................................XI
Organizing Committee..........................................................................................................XII
Participating Universities .....................................................................................................XIII
List of Papers................................................................................................................... XVII
Advanced materials............................................................................................................1
Innovative structures and details ....................................................................................177
Structural analysis and design........................................................................................273
Strengthening and repair................................................................................................837
Monitoring and structural assessment............................................................................945
Durability and life assessment......................................................................................1063
Sustainability and life cycle management.....................................................................1217
Index of Authors ...............................................................................................................1275
Previous fib International PhD Symposia..........................................................................1279
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XVII
List of Papers
Advanced materials 1
Effect of metakaolin on mechanical properties of cement paste exposed to elevated temperatures
Nabil Abdelmelek and Éva Lublóy.................................................................................................... 3
Characteristics of cement pastes incorporating different amounts of unprocessed waste fly ash
(UWFA)
Mohammed Abed and Rita Nemes ................................................................................................ 11
Post-fire assessment of mechanical properties of polypropylene-fibered reactive powder concrete
using non-destructive testing methods
Muhammad Abid, Xiaomeng Hou, Wenzhong Zheng and Shuomang Shi...................................... 19
Behaviour of concrete at elevated temperatures with respect to shear failure
Naser Alimrani and György L. Balázs............................................................................................. 27
Opportunities for biodegradable straw-based thermal insulations
Dániel Csanády and Olivér Fenyvesi ............................................................................................. 35
Monotonic and cyclic pull-out behaviour of 3D and 5D hooked-end steel fibres from a concrete
matrix
Maure De Smedt, Kristof De Wilder, Els Verstrynge and Lucie Vandewalle ................................... 43
Tensile response of ultra-high performance steel fiber reinforced concrete under moderate strain
rates
Veronika Goglin, Götz Hüsken, Peter Wossidlo, Ralf Häcker, Hans-Carsten Kühne
and H.J.H. Brouwers...................................................................................................................... 51
Influence of limestone addition to cement on rheological properties of mortars
Małgorzata Gołaszewska and Zbigniew Giergiczny........................................................................ 59
Self-healing properties of sulfur composites with expansive agents
Seongwoo Gwon and Myoungsu Shin............................................................................................ 65
Experimental and numerical study of the behaviour of post installed anchors in FRC
Viktor Hlavička and Éva Lublóy...................................................................................................... 71
The effect of the setting accuracy on the load bearing capacity of plate glass columns
András Jakab and Salem G. Nehme ............................................................................................. 79
Numerical modelling of cement-graphene composites
Małgorzata Krystek, Leszek Szojda and Marcin Górski.................................................................. 87
Lowering environmental impact from ultra high performance concrete, utilizing industrial by-
products
Ingrid Lande Larsen, Rein Terje Thorstensen and Katalin Vertes................................................... 93
Effect of sodium hydroxide concentration and alkaline activator ratio on the mechanical
properties of fly ash-based geopolymer binders
Adrian Lăzărescu, Henriette Szilagyi, Adrian Ioani and Cornelia Baeră........................................ 101
Influence of nanosilica on the mechanical properties and durability of cementitious materials
Gerlinde Lefever, Dimitrios G. Aggelis, Nele De Belie, Didier Snoeck
and Danny Van Hemelrijck........................................................................................................... 109
Evolution of micro-mechanical properties of cement and fly-ash composite measured by
nanoindentation over one year period
Jiří Němeček, Veronika Koudelková and Jiří Němeček ................................................................ 117
A preliminary study into the effect of superplasticisers on the dispersion of graphene materials in
cement
Ioanna Papanikolaou, Chrysoula Litina and Abir Al-Tabbaa......................................................... 123
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XVIII
Experimental investigations on bond behavior of pre-tensioned carbon fiber reinforced polymer
tendons
Sophia Perse and Josef Hegger...................................................................................................131
Some possibilities of the composition of ternary binders
David Pytlík, Markéta Bambuchová and Vlastimil Bílek ................................................................139
Strength and microstructure of tungsten mining waste-based hybrid alkaline material: Effect of
activators
Naim Sedira and João Castro-Gomes ..........................................................................................145
Comparitive study of bond behaviour for different FRP and steel bars
Sandor Solyom and György L. Balázs ..........................................................................................153
Effect of the addition of polypropylene fibers on the rheological behaviour of fresh fluid
cementitious materials
Fariza Sultangaliyeva, Hélène Carré, Christian La Borderie and Nicolas Roussel ........................161
Experimental research on textile reinforced concrete for the development of design tools
Patrick Valeri, Miguel Fernández Ruiz and Aurelio Muttoni...........................................................169
Innovative structures and details 177
Modelling and experimental verification of flexural behaviour of textile reinforced
cementitious composite sandwich renovation panels
Matthias De Munck, Jolien Vervloet, Michael El Kadi, Svetlana Verbruggen, Jan Wastiels,
Olivier Remy and Tine Tysmans...................................................................................................179
Influence of head-size on concrete cone capacity: a comparison for two cast-in solutions
Giuseppe Di Nunzio, Angelo Marchisella and Giovanni Muciaccia................................................187
Push-out shear tests for timber-UHPC composite footbridge
Milan Holý and Lukáš Vráblík .......................................................................................................195
Numerical modeling of a composite wood-UHPFRC structure
Petr Kněž and Petr Bouška ..........................................................................................................203
Diagrid structures as innovative retrofit solutions for existing reinforced concrete buildings
Simone Labò, Chiara Passoni, Alessandra Marini, Andrea Belleri and Paolo Riva .......................211
Experimental evaluation of concrete beam with corrugated section under four-point bending test
Chong Yong Ong, Kok Keong Choong and Mirzakhid Miralimov ..................................................221
Deformation of a 3D printed polyurethane formwork during concrete pouring
Elodie Paquet, Philippe Poullain, Benoı̂t Furet and Sébastien Garnier..........................................229
A study for an effective arrangement of shear reinforcements in pier cap designs
Jae-Hyun Park, Jun-Long An and Jae-Yeol Cho...........................................................................237
Structural behaviour of carbon reinforced slab elements made of ultra-high performance concrete
Philipp Preinstorfer, Benjamin Kromoser and Johann Kollegger...................................................245
Kinked rebar: a novel configuration for improving the collapse resistances of the reinforced
concrete frame structures
Hanlin Qiang and Peng Feng .......................................................................................................251
Numerical analysis of bond between UHPC and steel reinforcement
Veronika Steinerová and Miroslav Černý......................................................................................257
Composite glass – UHPC footbridge
Lucie Vošahlíková and Klára Machalická......................................................................................265
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XIX
Structural analysis and design 273
Investigations on influence factors on shear in structural components without shear reinforcement
Viviane Adam and Josef Hegger.................................................................................................. 275
Bond slip parameters of RILEM beam specimen after exposure to fire
Mohammad Suhaib Ahmad, Pradeep Bhargava and N.M.Bhandari ............................................. 285
Evaluation of shear transfer capacity of reinforced concrete exposed to fire
Subhan Ahmad, Pradeep Bhargava and N.M. Bhandari............................................................... 291
Three-dimensional nature of contact between fibre and cement matrix considering
the principles of contact mechanics
Anna Antonova, Marika Eik, Jouni Punkki and Jari Puttonen........................................................ 299
Punching shear resistance of flat slabs with openings – experimental testing
Tomáš Augustín, Ľudovít Fillo, Jaroslav Halvonik and Marián Marčiš .......................................... 305
Sustained load and time to failure of fastening systems
Ioannis Boumakis, Marco Marcon, Krešimir Ninčević and Roman Wan-Wendner ........................ 311
Multiphase simulations of experimental tests on the hygric behaviour of concrete
Andreas Brugger, Peter Gamnitzer and Günter Hofstetter ........................................................... 319
Analysis of selected adhesive joint types by FEM
Arkadiusz Bula, Jacek Hulimka and Marcin Kozłowski ................................................................. 327
Shear strength of thin-walled concrete members with micro-reinforcement
Daniel Busse and Martin Empelmann .......................................................................................... 337
Combining finite element analyses and mechanical models for the assessment of reinforced
concrete slabs
Raffaele Cantone, Miguel Fernández Ruiz, Beatrice Belletti and Aurelio Muttoni ......................... 345
Some developments in limit analysis of RC structures and structural elements
Elisa Conti and Pier Giorgio Malerba ........................................................................................... 353
Load-bearing capacity and deformation behaviour of carbon-textile reinforced concrete members
Redouan El Ghadioui, Tilo Proske and Carl-Alexander Graubner ................................................ 363
Fibre textile reinforced cementitious composites: experimental investigation and modelling
of three point bending tests on short beams
Michael El Kadi, S. Verbruggen, J. Vervloet, M. De Munck, J. Wastiels, D. Van Hemelrijck
and T. Tysmans........................................................................................................................... 371
Semi-discrete analytical beam model for fibre reinforced concrete beams
Mária Erdélyiné Tóth and Anikó Pluzsik ....................................................................................... 379
Assessment of influencing parameters on transmission length of prestressed concrete
Nicola Fabris, Flora Faleschini, Mariano Angelo Zanini and Carlo Pellegrino ............................... 387
Design equations from empirical and semi-empirical resisting models: a reliability-based
approach
Diego Gino, Gabriele Bertagnoli, Paolo Castaldo and Giuseppe Mancini..................................... 397
Comparison of modelling of hardness testing with DEM and FEM
Zoltán Gyurkó and Rita Nemes.................................................................................................... 405
Application of effective crack model in analysis of fracture response of chevron-notched
core-based concrete specimen
Petr Halfar, Petr Frantík, Iva Rozsypalová, Petr Daněk, Hana Šimonová
and Zbyněk Keršner..................................................................................................................... 413
Load-bearing performance of concrete beams with basalt fibre reinforced polymer (BFRP) rebars
Sebastian Hofmann, Carl-Alexander Graubner and Tilo Proske................................................... 419
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XX
Testing of multi-layer concrete-based structures loaded by contact blast
Alena Horska, Josef Fladr and Alena Kohoutkova........................................................................427
The nexus of column stiffness and lateral displacement in seismic design
Helga Iozan-Toth, Attila Puskás and Vasile Păcurar.....................................................................433
Numerical analyses of concrete composite T-shaped beams with variously arranged interface
Łukasz Jabłoński..........................................................................................................................441
Evaluation of the (UHP)FRC slab contact blast resistance with numerical simulation using
LS-DYNA
Ondřej Janota and Marek Foglar..................................................................................................449
Diagonal cracking load of concrete members without shear reinforcement
Sara Javidmehr and Martin Empelmann.......................................................................................457
Development of non-uniform corroded RC member simulation based on rigid body spring model
Punyawut Jiradilok, Kohei Nagai and Koji Matsumoto ..................................................................467
The influence of the composite bridge exploitation on the behavior of the structure subjected
to a dynamic load
Michał Jukowski, Ewa Błazik-Borowa, Janusz Bohatkiewicz, Jarosław Bęc
and Mateusz Hypki.......................................................................................................................477
A numerical insight on the behaviour of prestressed concrete members exposed to natural fires
Nataša Kalaba and Patrick Bamonte............................................................................................485
FEA simulation and probability approach of the road barrier crash tests
Michal Kalinský and Jana Marková...............................................................................................493
Numerical prediction of ballistic limit and failures of plain concrete slabs
Kamran Kamran and Mohammad Ashraf Iqbal.............................................................................503
Investigation of the bond properties between textile reinforced concrete and extruded
polystyrene foam
Panagiotis Kapsalis, Jolien Vervloet, Eleni Tsangouri, Svetlana Verbruggen,
Dimitrios Aggelis, Tine Tysmans and Thanasis Triantafillou .........................................................511
Influence of concrete cover thickness on shear strength of concrete glass fiber reinforced
polymer beams without stirrups
Monika Kaszubska and Renata Kotynia .......................................................................................521
Experimental investigation of the bond between SAS 670/800 reinforcement bars and high-
strength concrete in a pull-out test
Magda Kijania-Kontak and Andrzej Winnicki.................................................................................529
Strain-based safety evaluations of nuclear spent-fuel transport casks in drop events
SeungPil Kim, Myoungsu Shin and Chanyoung Kim.....................................................................537
Nonlinear analysis of reinforced concrete elements of the example of the existing RC
two – way slab floor
Joanna Kujda, Izabela Skrzypczak and Lidia Buda-Ożóg .............................................................545
Numerical model of the approach slab with gap functionality
Kamil Laco and Viktor Borzovič ....................................................................................................553
Experimental investigation of bond behaviour under repeated loading
Yasmin Lemcherreq and Thomas Vogel.......................................................................................561
Experimental verification of a method in development for predicting the punching shear
strength of flat slabs
Lukáš Lyčka and Petr Štěpánek ..................................................................................................567
Comparison of post-installed and cast-in rebars under monotonic and cyclic loads
Angelo Marchisella and Giovanni Muciaccia.................................................................................575
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XXI
Bottle-shaped stress field solution for partially loaded reinforced concrete blocks
Tomislav Markić and Walter Kaufmann........................................................................................ 583
On the criterion of the limit state for concrete
Hammoud Mohammad, Valeriy Shmukler, Petro Reznik and Olena Petrova................................ 593
Numerical simulation for horizontal tunnels with vertical alignment affected by static and
dynamic loads
Jaafar Mohammed and Eva Hrubesova ...................................................................................... 601
Development of three-dimensional strut-and-tie models for structural concrete components
Salma Mozaffari, Masoud Akbarzadeh and Thomas Vogel .......................................................... 609
Advanced reliability and sensitivity analysis of prestressed concrete girders failing in shear
Lukáš Novák, Lixia Pan, Ondřej Slowik and Drahomír Novák....................................................... 617
On the mechanical response of a fibre reinforced concrete redundant structure;
the redistribution factor
Ali Pourzarabi, Matteo Colombo and Marco di Prisco................................................................... 625
Assessment of existing shear strength models for reinforced concrete deep beams
Kondalraj Ramakrishnan and G. Appa Rao.................................................................................. 633
Numerical analysis of the partial collapse of a twin-tubes tunnel
Ahmed Rouili, Mabrouk Touahmia and Youcef Djerbib ................................................................ 641
Probabilistic models for shear bond strength of clay and fly ash bricks
Santosini Sahu, Pradip Sarkar and Robin Davis .......................................................................... 649
Analytical model verification for FRP and synthetic fibre reinforced concrete beams
Peter Schaul and György L. Balázs.............................................................................................. 657
Implementation of the critical shear crack theory to predict punching failure in the analysis of RC
layered-shells
Andri Setiawan, Robert Vollum and Lorenzo Macorini.................................................................. 665
Creep and shrinkage effects on reinforced concrete walls: Experimental study
Najeeb Shariff and Devdas Menon............................................................................................... 673
Influence of transverse reinforcement on the cracking behaviour of reinforced concrete
panels subjected to uniaxial tension
Muhammad K. Shehzad and John P. Forth.................................................................................. 681
Stochastic analysis of precast structural members failing in shear
Ondřej Slowik, Drahomír Novák, Alfred Strauss and Bernhard Krug ............................................ 689
Large scale tests on prestressed concrete beams subjected to bending, shear and torsion
Eva Stuppak and Reinhard Maurer .............................................................................................. 697
Safety concept for non-linear finite element analysis
Remus Tecusan and Konrad Zilch ............................................................................................... 705
Experimental study of elastic modulus using standard tests and optical measurements
Marcin Tekieli, Magda Kijania-Kontak and Andrzej Winnicki......................................................... 715
Modern experimental research techniques for a consistent understanding of aggregate interlocking
Max Tirassa, Miguel Fernández Ruiz and Aurelio Muttoni............................................................ 723
Case study: Price comparison of three post-tensioned flat slabs beside classic flat slabs from
three existing structures/under construction
Iosif Tőrők, Attila Puskás and Jácint Virág ................................................................................... 731
Transfer length of GFRP rebars for pretensioned elements
Adrián Valašík, Vladimír Benko and Anton Sivčák........................................................................ 739
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XXII
Overview and new insights into the modeling of the force transfer in the end zones of
pretensioned concrete girders
Kizzy Van Meirvenne, Wouter De Corte, Veerle Boel and Luc Taerwe .........................................747
Experimental Verification of Long-term Behaviour of Concrete Structures
Radek Vasatko and Jan L. Vitek...................................................................................................755
Design and experimental investigation of textile reinforced cement sandwich panel ends.
Jolien Vervloet, Petra Van Itterbeeck, Brendan Murray, Svetlana Verbruggen,
Michael El Kadi, Matthias De Munck, Jan Wastiels and Tine Tysmans.........................................763
Tests of shear capacity of deck slabs under concentrated load
Radoslav Vida and Jaroslav Halvonik...........................................................................................773
Numerical study on effect of steel fibres on the shear strength of reinforced concrete squat shear
walls with opening
Sivaguru Viswanathan and G. Appa Rao......................................................................................781
Design of concrete structures using structural optimization based on the stress field method
Qianhui Yu, Aurelio Muttoni and Miguel Fernández Ruiz..............................................................791
Impact behavior of RC beam considering various momentum of drop weight
Yong Jae Yu and Jae-Yeol Cho ...................................................................................................799
Numerical simulation of concrete pumping pressure loss
Yong Yuan, Yaxin Tao and Weijiu Cui..........................................................................................807
A stochastic model for the capacity estimation of non-seismically designed beam-column joints
Özgür Yurdakul, Onur Tunaboyu, Ladislav Routil and Özgür Avşar..............................................813
Influence of basalt mesh induced by increase of heterogeneity of cement composites on its
resistance under near-field blast
Jakub Zíma and Marek Foglar......................................................................................................821
Ultimate compressive strain in lightweight aggregate concrete beams
Jelena Zivkovic and Jan Arve Øverli.............................................................................................829
Strengthening and repair 837
Behaviour of torsionally strengthened reinforced concrete beam-column joints with carbon
fibre reinforced polymer dheets
Sarmad Ali and John Forth...........................................................................................................839
Shear resistance of concrete-to-concrete interface without reinforcement
Đorđe Čairović, Martin Zlámal, Petr Štěpánek, José Maria Raposo and Eduardo Júlio.................847
Strengthening infilled RC frames against biaxial seismic action
İsmail Ozan Demirel, Ahmet Yakut and Barış Binici......................................................................855
Tensile behaviour of textile reinforced mortar composite systems with flax fibres
Giuseppe Ferrara and Enzo Martinelli ..........................................................................................863
Post – installed shear reinforecement in flat slabs
Ondrej Keseli, Juraj Bilčík and Marián Marčiš...............................................................................871
Shear strengthening of structures with carbon reinforced concrete
Sebastian May, Alexander Schumann and Manfred Curbach.......................................................879
Behaviour of perforated rectangular columns wrapped with bi-directional glass fibre
reinforced polymer reinforcement
Darya Memon, Jayaprakash Jaganathan and Stijn Matthys..........................................................887
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XXIII
Technology of additional shear reinforcement for strengthening foundation slabs and its
long-term monitoring
Jan Novacek and Milos Zich ........................................................................................................ 895
Load transfer in horizontally prestressed masonry wall
Robin Peknik, Ladislav Klusacek, Zdenek Bazant, Michal Pozar and Petr Duchac....................... 901
Textile reinforced concrete composites for existing structures: performance optimization
via mechanical characterization
Marco C. Rampini, Giulio Zani, Matteo Colombo and Marco di Prisco.......................................... 907
Concrete screws as a post-installed punching reinforcement under static and cyclic loads
Matthias Spiegl, Rupert Walkner and Jürgen Feix........................................................................ 915
Strengthening of reinforced concrete bridges by post-tensioning
Adam Svoboda and Ladislav Klusáček ........................................................................................ 923
Strengthening of hybrid steel-concrete shear walls using high performance steel fiber
reinforced cementitious composites
Viorel Todea, Valeriu Stoian, Sorin-Codruț Floruț, Dan Adrian Popescu....................................... 931
Evaluation for shear strength of biaxial RC slab-column connections with ultra high
performance fiber-reinforced concrete overlay
Hyun-Soo Youm, and Sung-Gul Hong.......................................................................................... 937
Monitoring and structural assessment 945
Effects of moisture contents on the diffusion of ultrasound in concrete
Eunjong Ahn and Myoungsu Shin................................................................................................ 947
Performance analysis of distributed optical fiber sensors on reinforced concrete elements
under fatigue testing
António Barrias, Joan R. Casas and Sergi Villalba....................................................................... 953
Experimental evaluation of longitudinal resistance of continuously welded rail on bridges
Filip Bláha and Marek Foglar ....................................................................................................... 961
Concept of repair and proposals for reconstruction of the vault structures of Liben Bridge
Marek Blank and Petr Bouška ..................................................................................................... 971
Influence of materials knowledge level on the assessment of the shear strength characteristic
value of existing RC beams
Angelo Forte, Silvia Santini, Gabriele Fiorentino, Davide Lavorato,
Alessandro Vittorio Bergami and Camillo Nuti.............................................................................. 979
Check of resistance to fatigue on existing prestressed concrete bridges by monitoring
Jens Heinrich and Reinhard Maurer............................................................................................. 987
Assessment of one-way slab bridges with bent-up bars as shear reinforcement
Tobias Huber, Patrick Huber and Johann Kollegger..................................................................... 995
Evaluation of fair-faced concrete surfaces using digital image processing
Kitti Károlyfi and Ferenc Papp.................................................................................................... 1003
Verification of in-use concrete bridge’s safety inspection methodology
with decommissioned bridges
Joo-Hyung Lee, Nankyoung Lee, Minyeong Kim and Jae-Yeol Cho........................................... 1011
Reliability of industrial chimneys affected by carbonation-induced corrosion
Jan Mlcoch and Miroslav Sykora................................................................................................ 1019
Static and dynamic load tests of Libeň bridge over Vltava river in Prague with comparisson to
FEA model results
Jan Mourek and Petr Bouška..................................................................................................... 1025
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XXIV
Partial problems during long-term monitoring of concrete bridges after reconstruction
Martin Olsak, Ladislav Klusacek and Radim Necas.................................................................... 1033
Anchorage capacity of corroded smooth reinforcement bars in existing reinforced structures
Samanta Robuschi, Karin Lundgren, Ignasi Fernandez, Kamyab Zandi
and Mathias Flansbjer................................................................................................................ 1039
Comparison of energy dissipation devices in response reduction of blast-induced
vibration of buildings
Deepak Kumar Sahu, Robin Davis, Pradip Sarkar and Sanjaya Ku. Patro ................................. 1047
SHM system of a cable styed bridge as a data source for probabilistic durability assessment
Marco Teichgraeber, Jan Biliszczuk and Paweł Hawryszków ..................................................... 1055
Durability and life assessment 1063
Numerical study of the effect of moisture on chloride and carbon dioxide transport in concrete
Mohamad Achour, Ouali Amiri, François Bignonnet and Emmanuel Rozière.............................. 1065
Corrosion of glass used for radioactive waste disposal influenced by environmental parameters
Ali Al Dabbas and Katalin Kopecskó........................................................................................... 1071
Specification of new sulfate resistant blended cements through performance testing
Sonia Boudache, Emmanuel Rozière, Ahmed Loukili and Horacio Colina .................................. 1079
Gas diffusivity test method development: effect of cement paste saturation degree
and concrete specimen thickness
Mouna Boumaaza, Bruno Huet, Philippe Turcry, Christoph Gehlen,
Abdelkarim Aït-Mokhtar and Detlef Heinz................................................................................... 1087
Analysis of the influence of chloride exposure conditions and material properties
on the convection zone depth and the corresponding chloride content
A. El Farissi, Ph. Turcry, A. Younsi, A. Aït-Mokhtar, A. Aït-Alaïwa and Ph. Gotteland................. 1095
The influence of concrete composition on its modulus of elasticity: comparison
of experiment and values from Eurocode 2
Romana Halamová, Dalibor Kocáb and Tomáš Vymazal............................................................ 1103
Quantitative evaluation of effects of crack control methods for NATM tunnel lining
concrete by 3D finite element method
Keitai Iwama and Akira Hosoda.................................................................................................. 1111
The use of supplementary cementitious materials to reduce calcium oxychloride formation:
A review of the literature
Casey Jones and W. Micah Hale................................................................................................ 1121
FEM and RBSM numerical analyses of concrete wall under long-term exposure
to neutron irradiation
Yuliia Khmurovska and Petr Stemberk ....................................................................................... 1129
Qualification methodology for durability of concrete subject to an environnement
with corrosion induced by carbonation
Nadare Matoiri Chaibati, Abdessamad Kobi, David Bigaud and Horacio Colina.......................... 1137
Effect of carbonation on dimensional change of cement paste
Kiyofumi Nakada and Takafumi Noguchi.................................................................................... 1145
Influence of through and surface cracks on transport of water vapor in concrete
Ryohei Ohara and Takumi Shimomura....................................................................................... 1153
Multi-model approach to assess the ultimate flexural capacity of existing concrete bridges
Marco Proverbio and Ian F.C. Smith........................................................................................... 1159
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XXV
Bio-based self-healing concrete: A review
Hana Schreiberová, Alena Kohoutková, Petr Bílý and Pavla Ryparová...................................... 1169
Effect of water contents of recycled concrete aggregates on carbonation kinetic
Marie Sereng, Assia Djerbi, Othman Omikrine-Metalissi, Patrick Dangla
and Jean-Michel Torrenti ........................................................................................................... 1177
Transformation of accelerated corrosion tests results for the prediction
of the reinforcement corrosion in practice
Miroslav Strieška, Peter Koteš and Miroslav Brodňan................................................................ 1185
Effects of delayed ettringite formation on reinforced concrete structures
Yvan Thiebaut, Stéphane Multon, Alain Sellier, Laurie Lacarrière, Laurent Boutillon,
Djemal Belili, Lionel Linger, François Cussigh and Sofiane Hadji ............................................... 1193
Comparison of properties of recycled concrete aggregate with natural aggregate
Tomáš Trtík, Petr Bílý, Josef Fládr and Jitka Vašková................................................................ 1201
Numerical simulation of early age thermal stress in durable RC bridge slab utilizing blast
furnace slag concrete with expansive additive
Arifa Zerin, Akira Hosoda, Satoshi Komatsu and Kosuke Kashimura ......................................... 1207
Sustainability and life cycle management 1217
Variant design of concrete structure in relation to durability of the structure and
environmental impacts
Anna Horáková, Alena Kohoutková and Iva Broukalová............................................................. 1219
Efficiency investigation on electro-kinetic decontamination for concrete waste originated
from nuclear power plants
Chanyoung Kim, Sungyeol Choi, Seungpil Kim and Myoungsu Shin.......................................... 1227
Study on performance characteristics of pervious concrete made of various types
of locally available aggregate
Marek Kováč, Alena Sičáková and Karol Urbán......................................................................... 1235
Experimental measurement of water absorption by model recycled concrete aggregates
immersed in a filler or cement paste
Houda Maimouni, Sébastien Remond, Florian Huchet, Patrick Richard, Vincent Thiery
and Yannick Descantes ............................................................................................................. 1243
Performance prediction of concrete torrent control structures in Austria
Roman Paratscha and Alfred Strauss ........................................................................................ 1251
Effect of PP fibres on flexural behaviour of concrete with RCAs – A preliminary study
Brecht Vandevyvere, Zeger Sierens, Miquel Joseph, Paul Jonckheere, Luc Decraemer
and Jiabin Li............................................................................................................................... 1259
Influence of cement replacement by admixture on mechanical properties of concrete
Roman Chylík and Karel Šeps ................................................................................................... 1267
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Advanced materials
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Proc. of the 12th fib International PhD Symposium in Civil Engineering
Aug 29 to 31, 2018, Czech Technical University in Prague, Prague, Czech Republic
3
Effect of metakaolin on mechanical properties of
cement paste exposed to elevated temperatures
Nabil Abdelmelek and Éva Lublóy
Budapest University of Technology and Economics (BME)
Muegyetem rkp. 3, 1111 Budapest, Hungary
Abstract
Concrete is a composite material consisting mainly of mineral aggregates bound by a matrix of
hardened cement paste. Strength reduction of high strength concrete during and after fire may be
different from that of normal strength concrete. Our intention was directed to evaluate effect of
metakaolin (MK) as supplementary cementitious materials (SCMs) in cement paste on surface
cracking and residual compressive strength at elevated temperatures. An extensive experimental study
was carried out to analyze the post-heating characteristics of hardened cement paste subjected to
temperatures up to 900 °C with varied values of MK and water/binder (w/b) ratio. In the experiments
specimens were exposed to given maximal temperatures and then cooled down to room temperature.
Tests were carried out at room temperature. Present studies included analysis of surface cracking,
compressive strength.
1 Introduction
Concrete can be exposed to elevated temperatures during fire or when it is applied by furnaces and
reactors. The behaviour of a concrete structural members exposed to fire is dependent on physical,
thermal, and mechanical deformation properties of concrete of which the member is composed. The
deterioration processes influence the durability of concrete structures and may result in undesirable
structural failures. Therefore, preventative measures such as choosing the right materials should be
taken to minimize the harmful effects of high temperature on concrete. The high temperature
behaviour of concrete is greatly affected by material properties, such as the properties of the
aggregate, the cement paste, and the bond between the aggregate, as well as the thermal compatibility
of the aggregate and cement paste [1].
On the other hand, the related studies show that hardened cement paste plays a key role in this
deterioration process. Loss in structural quality of concrete, especially the strength and fracture
generally exhibits a complex dependency on the developed phase composition and pore structure of
hardened cement paste [2] [3].
The quest for the development of high strength (HSC) and high performance concretes has
increased considerably in recent times because of the demands from the construction industry. As a
relevant result, in the last three decades, (SCMs) such as fly ash (FA), silica fume (SF) and ground
granulated blast furnace slag (GGBS) have been judiciously utilized as cement replacement materials
as these can significantly enhance the strength and durability characteristics of concrete in
comparison with ordinary Portland cement (OPC) [4].
2 Influence of metakaolin (MK)
2.1 MK at ambient temperatures
Recently, MK has been added to the list of commercial pozzolans, and thought of as being an
excellent material for producing high performance concrete. It is gaining popularity due to its
consistent composition and production, light colour, and rapid pozzolanic reaction [5]. In addition to
that, Poon et al [6]-[8] have shown a lot of interest in MK as it has been found to possess both
pozzolanic and micro filler characteristics. It has also been used successfully for the development of
HS self-compacting concrete using mathematical modelling [9]. In a related, MK or calcined kaolin
produced by calcinations has the capability to replace SF as an alternative material [10].
MK is a thermally activated aluminosilicate material obtained by calcining kaolin clay within the
temperature range of 700 – 850C [11]-[13]. It contains typically 50 – 55% SiO2 and 40 – 45% Al2O3
and is highly reactive. It has been reported that the replacement of cement by 5 –15% MK results in
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12th
fib International PhD Symposium in Civil Engineering
4 Advanced materials
significant increases in compressive strength for high-performance concretes and mortars at ages of
up to 28 days, particularly at early ages [14] and [15]. The replacement also results in improved
concrete durability properties, including the resistance to chloride penetration, freezing and thawing,
and deicing salting scaling [14] and [16].
2.2 MK at high temperatures
Initially, MK concretes showed an increase in compressive strength at 200 °C. This increase may
probably be due to the hydration of unhydrated MK particles, which were activated as a result of the
temperature rise. Since the hydration in MK concrete is slowed down after 14 days due to the
blocking of capillaries [17].
Despite high losses during heating, the HSC showed better strength recovery as compared to the
normal strength concretes (NSC). For 600 °C, the HSC regained 66 – 93% of their original strength
after 56 days, while it was 61 – 85% for NSC. Similarly for 800 °C, these values were 34 – 79% for
HSC’s and 31 – 56% for NSC’s. Dinakar et al [10] investigated the effect of incorporating MK on the
mechanical and durability properties of HSC for a constant water/binder (w/b) ratio of 0.3. MK
mixtures with cement replacement of 5, 10 and 15 % were designed for target strength and slump of
90 MPa and 100 ± 25 mm. From the results, it was observed that 10 % replacement level was the
optimum level in terms of compressive strength. Beyond 10 % replacement levels, the strength was
decreased but remained higher than the control mixture. Compressive strength of 106 MPa was
achieved at 10 % replacement.
The compressive strength recovery was faster and more enhanced after water re-curing, as
compared to the air re-curing. On the average, the water re-cured specimens regained l5 – 20% more
strength than the air re-cured specimens. The compressive strength recovery was better after 600 °C
than 800 °C [18]. In a related context, the Mercury Intrusion Porosimetry (MIP) test results highlight
pore structure coarsening, and show an increase in porosity at elevated temperatures, which are the
major reasons of strength and durability losses [19].
Despite the high strength loss, most MK concretes still had lower porosities as compared to the
corresponding SF, FA, and pure OPC concretes. The only exception was HS-MK20. The latter’s
sample dense microstructure at 20 °C (with the lowest porosity and smallest average pore size), was
changed to a relatively open one with the highest porosity and largest average pore size after heating
at 800 °C. The average pore diameters of most MK concretes (except HS-MK10) were larger than the
other concretes, which in combination with internal cracking might have caused more strength and
durability losses at all temperatures above 200 °C [18].
2.3 Previous studies
Poon [18] pointed out that NC and HSC mixes incorporating 0 – 20% MK were prepared and exposed
to a series of high temperatures till 800 °C. The residual compressive strength, porosity and pore size
distribution were determined. It was found that after an increase in compressive strength at 200 °C,
the MK concrete suffered a more severe loss of compressive strength and permeability-related
durability than the corresponding SF, FA, and pure OPC concretes at higher temperatures. Explosive
spalling was observed in both normal and high strength MK concretes, and the frequency increased
with higher MK contents.
Morsy et al [20] studied the effects of high temperatures up to 800 °C on the mechanical
properties and microstructure of cement mortars with nanometakaolin (NMK) and (w/b) ratio of 0.6.
It was found that after an initial increase in compressive strength at 250 °C for the mortar specimens,
the strength decreased considerably at higher temperatures. The replacement of OPC by 5% NMK in
cement mortar hydrated at ambient temperature increases the compressive and flexural strengths of
cement mortar and they pointed experimentally that the higher the compressive and flexural strengths
results were obtained from the specimens containing 15% NMK, as compared with other replacement
percentages considered in this study for all thermal treatment, with increase of temperature from 250
to 800 °C [20].
In context of spalling, Chan et a1 [21] found that moisture content and strength are the two main
factors governing thermally induced explosive spalling of concrete. The results showed that no
spalling would occur if either strength or moisture content is below a certain threshold value, which
was found to be 60 MPa or 62%.
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Effect of Metakaolin on mechanical properties of cement paste exposed to elevated temperatures
Nabil Abdelmelek and Éva Lublóy 5
The results also indicate that MK concrete is highly prone to spalling as compared to SF, FA, and
pure OPC concretes.
The obvious reason is the dense pore structure, in particular, the small pore size of MK concretes,
which held the vapour pressure of steam and resulted in explosive spalling. It is interesting to note
that FA concrete showed no spalling at all, despite the moisture content and compressive strength of
the specimens exceeded the threshold values specified by Chan et al [21].
3 Experimental details
An experimental program was designed to analyse the post-heating characteristics of hardened
cement paste subjected to temperatures up to 900 °C. Major parameters of our study were the
different dosages (0, 3, 6, 9, 12 or 15 m %) of supplementary material (MK) of the binder (as
replacement of cement) and the value of maximum temperature (20, 50, 150, 300, 400, 500, 800, 900
°C). In the experiments specimens were exposed to the given maximal temperatures and then cooled
down to room temperature. Tests were carried out at the present study to analyse compressive
strength.
Table 1 Experimental matrix with detailed varied parameters.
Amount of
MK (m %)
Water to binder (w/b) ratio
0.3 0.35 0.4
0 % Series 1 (S1): MK0% Series 2 (S2): MK0% Series 3 (S3): MK0%
12 % Series 7 (S7):MK12% Series 12 (S12):MK12% Series 17 (S17):MK12%
15 % Series 8 (S8):MK15% Series 13 (S13):MK15% Series 18 (S18):MK15%
3.1 Materials
Cement of the specimens was OPC (CEM I 42,5 N) and ordinary MK supplementary material was
used. Ratio of (w/b) were (0.3, 0.35, and 0.4) for each category in addition to 2 g/kg of liquid
superplasticizer was applied also for each. Cubic form cement paste specimens were used with the
size of 30 mm for compressive strength test.
3.2 Curing and heating regimes
The way of mixing was mixing of the dry binder (Cement + Metakaolin) during 30 seconds and
adding the water in two times after that the casting and compaction of specimens. The specimens
were demolded 24 h after the casting and placed in a water tank at 20 °C. After 7days of water curing,
they were transferred to an environmental chamber maintained at 20 °C and normal humidity. At an
age of 90 days, the specimens were heated in a furnace (20, 50, 150, 300, 400, 500, 800 and 900 °C).
Our experimentally applied heating curve was similar to the standard fire curve up to 800 °C.
Specimens were kept for three hours at the actual maximum temperature levels. Specimens were then
slowly cooled down in laboratory conditions for further observations. During the heat load a program
controlled electric furnace was used. Residual compressive strengths were measured for specimens
after cooled down to the room temperature, then the average values of the measurements were chosen
and analysed.
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12th
4 Results and discussions
Residual compressive strength in function of temperature with varied ratio of MK is presented in
Figures (1, 2 and 3).
Relative residual compressive strength of cement paste specimens are shown in Figures (4, 5 and
6). Relating to the concrete composition and the maximum temperature of thermal load, following
conclusions can be drawn as following comments:
Concerning residual compressive strength of MK specimens, two different regions were observed
20-400 °C and 400 - 900 °C. Increasing of strength followed by decrease is the main feature describe
both regions. MK specimens showed a slight increase in compressive strength at normal temperature
up to 50°C for all amounts of MK (Fig 1, 2 and 3), however highest values were related to w/b = 0.3
(Fig. 1).
Fig. 1 Effect of the amount of MK on compressive strength of concrete at elevated
temperatures with w/b=0.3.
Fig. 2 Effect of the amount of MK on compressive strength of concrete at elevated temperatures
with w/b= 0.35.
The strength starts to slightly decrease till the temperature reaches 150 °C attributed to loss of
moisture and evaporable water (intensive dehydration in the temperature interval between 60 and 180
°C). The strength increase again up to 300 °C which attributed to the hydration of unhydrated MK
grains in the microstructure particles as a result of the temperature rising. Unlike specimens contained
MK, all pure cement specimens with 0% MK showed continuous decrease.
0,00
50,00
100,00
150,00
0,00 200,00 400,00 600,00 800,00 1000,00
compressive
strength
[N/mm
2
]
maximum temperature [°C]
S1
S4
S5
S6
S7
S8
0
20
40
60
80
100
0,00 200,00 400,00 600,00 800,00 1000,00
compressive
strength
[N/mm
2
]
S2
S9
S10
S11
S12
S13
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Fig. 3 Effect of the amount of MK on compressive strength of concrete at elevated temperatures
with w/b= 0.4.
From 50 to 400 °C specimens with (w/b= 0.3) showed relatively higher strength than other specimens
with different (w/b) ratio. Most of the specimens maintained their original compressive strength for
the different (w/b) ratio, whereas compressive strength loss was observed in specimen S3 (MK0%-
0.4). Neither spalling nor cracking were observed at this temperature in specimens.
Fig. 4 Effect of the amount of MK on relative compressive strength of concrete at elevated
temperatures with w/b= 0.3.
After 400 °C, the MK specimens showed significant reduction in compressive strength for all of S1,
S2, S3, S4, S5, S9, S10, S14, and S18. For S1, S2 and S3 reduction related to these specimens with
MK= 0% can be attributed to decomposition of calcium hydroxide (CH). Specimens with MK
between 3% and 6% (S4, S5, S9, S10, S14, S18) behave slightly as MK= 0% indicating the small
effect of MK specimens that have MK ratio below 6% in increasing compressive strength. At
temperatures between 800 and 900 °C. The results showed that at high MK (15%) content, specimens
suffered more loss. This severe strength loss could be due to the very dense pore structure of MK
concrete which might enhance the build-up of vapour pressure upon heating and resulted in spalling
and cracking.
0,00
20,00
40,00
60,00
80,00
100,00
0,00 200,00 400,00 600,00 800,001000,00
compressive
strength
[N/mm
2
]
S3
S14
S15
S16
S17
S18
0,00
0,50
1,00
1,50
0,00 200,00 400,00 600,00 800,00 1000,00
reletive
compressive
stregth
[-]
S1
S4
S5
S6
S7
S8
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Fig. 5 Effect of the amount of MK on relative compressive strength of concrete at elevated
temperatures with w/b= 0.35.
Fig. 6 Effect of the amount of MK on Relative compressive strength of concrete at elevated
temperatures with w/b = 0.4.
Best performances through all specimens that showed high compressive strength at low temperatures
and remain relatively stable at high temperatures were given by (MK= 12% for w/b= 0.35 and 0.4),
(MK= 9% for w/b= 0.3) and (MK=0% for w/b= 0.35). In case of cement stone prepared with MK
containing binder (to 12 m% related to the mass of cement) the strength increased due to the
temperature of 800 °C. Addition of MK was found to be unfavourable for fire resistance of concrete
at early ages (at age of 28 days). This could be explained by the different rate of pozzolanic reaction
of the SCMs.
Fig. 7 The compressive strength for the different mixes as a function of maximum temperature
(averages of 5 measurements).
0,00
0,50
1,00
1,50
0,00 200,00 400,00 600,00 800,00 1000,00
reletive
compressive
stregth
[-]
S2
S9
S10
S11
S12
S13
0,00
0,50
1,00
1,50
0,00 200,00 400,00 600,00 800,00 1000,00
reletive
residuel
compressive
stregth
[-]
S3
S14
S15
S16
S17
S18
0
50
100
0 200 400 600 800 1000
compressive
strength
[N/mm2]
the maximal temperature [°C]
M=0% M=3% M=6% M=9% M=12%
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Fig. 8 Relative residual compressive strength for the different mixes as a function of maximum
temperature (averages of 5 measurements).
To conclude results for both compressive strength and relative compressive strength, each five
measurements were set as one value as illustrated in Figures 7 and 8.
5 Conclusions
The use of MK as a recent material in the construction industry, proves to be very useful to modify
the properties of concrete. An extensive experimental study was carried out to analyses the post-
heating characteristics of hardened cement paste subjected to temperatures up to 900 °C.
Two main regions were observed in results i.e. 20 - 400 °C and 400 - 900 °C. Increasing of
strength followed by decrease is general feature that describes both regions. At the first region,
specimens with MK ratio 9% and 12% showed relatively high compressive strength. All specimens
showed significant decrease in strength during heating after 400 °C, however both MK specimens
with 9% and12% showed slightly less decrease than others.
Relating to w/b ratio namely at 0.35, presence of MK ratio, except for lower than 6%, was
observed to keep its relative residual strength above 50% after temperatures reach 400 up to 900
whereas other w/b ratio do not generally kept their strength. From abovementioned results it could
mainly be concluded that specimens with MK 9% and 12% with (w/b) ratio equals 0.35 is the most
favorable.
Acknowledgements
Authors acknowledge the support by the Hungarian Research Grant NVKP_16-1-0019 “Development
of concrete products with improved resistance to chemical corrosion, fire or freeze-thaw”.This was
supported by the János Bolyai Resarch Scholarship of the Hungarian Academy of Siences.
References
[1] Abdelmelek, Nabil, and Éva Lublóy. 2017. “Improved fire resistance by using different
dosages of metakaolin.” 12th Central European Congress on Concrete Engineering 2017
Tokaj: 240–246.
[2] Bournazel, J. P., and M. Miranville. 1997. “Durability of concrete: the crossword between
chemistry and mechanics.” Cem. Concr. Res. 27:1629–1637.
[3] Vydra, V., F. Vodak,, O. Kapickova, and S. Hoskova, 2001. “Effect on temperature on
porosity of concrete for nuclear safety structures.” Cem. Concr. Res. 31:1023–1026.
[4] Neville, A. M. 1997. ”Concrete with particular properties.” In Properties of concrete (pp.
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[5] Caldarone, M.K, K. A. Gruber, R. G. and Burg. 1994. “High-Reactivity Metakaolin: A New
Generation Mineral Admixture.” Conc. Int. 16(11):37–40.
[6] Poon, C. S., L. Lam, S. C. Kou, Y. L. Wong, and R. Wong. 2001. “Rate of pozzolanic
reaction of metakaolin in high-performance cement pastes.” Cement and Concrete Research
31(9):1301–1306.
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residual
compressive
strength
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the maximal temperature [°C]
M=0% M=3% M=6% M=9% M=12%
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[7] Wild, S., and J. M. Khatib. 1997. “Portlandite consumption of metakaolin cement Pastes and
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Properties of High Strength Concrete.” International Journal of Concrete Structures and
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UK (1993):1799-1811.
[12] Sabir, B. B, S. Wild, and J. M. Khatib. 1996. “On the workability and strength development
of metakaolin concrete.” R.K Dhir, T.D Dyer (Eds.), Concrete for Environmental
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Adv. Cem. Based Mater. 1(4):161-168.
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generation mineral admixture.” Concr. Int. 16:37-40.
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for high-performance mortars.” Cem. Concr. Res. 28(6): 803-809.
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silicate pozzolanic material and its use in concrete.” Cem. Concr. Res. 25(8):1713-1725.
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[18] Poon, Chi-sun. 2003. “Deterioration and Recovery of Metakaolin Blended Concrete
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High-Strength Concrete and Normal-Strength Concrete after Exposure to High
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[21] Chan, S. Y. N., G. F. Peng, and M. Anson. 1999. “Fire Behavior of High-Performance
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Proc. of the 12th fib International PhD Symposium in Civil Engineering
Aug 29 to 31, 2018, Czech Technical University in Prague, Prague, Czech Republic
11
Characteristics of cement pastes incorporating
different amounts of unprocessed waste fly ash
(UWFA)
Mohammed Abed and Rita Nemes
Department of Construction Materials and Technologies,
Budapest University of Technology and Economics (BME),
Műegyetem rkp. 3, Budapest 1111, Hungary,
Abstract
Although modified fly ash is one of the most usable materials as a supplementary cementitious mate-
rial (SCM) however, unprocessed waste fly ash (UWFA) is rarely used for the same purpose. In the
literature, it proved its efficiency in certain aspects when it is used as a SCM in the desired amount. In
this study, different amounts of UWFA in cement paste as SCM have been investigated as an attempt
to produce green binder, which is useful for sustainable construction applications. From zero to up to
60% by mass replacement amounts of cement by UWFA has been conducted. Consistency, compres-
sive strength, and the activity index of UWFA from seven to ninety days old specimens have been
examined through 7, 28 and 90, where the optimum UWFA replacement was up to 30%, in which the
activity index still increased to the end of test period (90 days), also when up to 30% of UWFA used
instead of cement; a very close strength to the 100% cement paste have been getting.
1 Introduction
Global warming is a recognized phenomenon, whereas the construction industry is one of the most
industries that contribute to increased carbon emissions, especially production of Portland cement,
where production of one ton of Portland cement releases one ton of CO2 into the atmosphere. Since
cement is the major source of strength of concrete (which is the second highest used material in our
plant after fresh water) and the most expensive component as well, it is mandatory to minimize envi-
ronmental impact and carbon footprint by incorporating the use of wastes materials as a SCM, such as
fly ash, in building construction [1]-[5].
The term fly ash used is usually express the treated or modified fine fly ash. Fly ash is an indus-
trial by-product derived from coal combustion in thermal power plants, which considered one of the
most complex materials that can be characterized besides, it is one of the most abundant of anthropo-
genic materials [6]. In fact, it has been exhaustively discussed by researchers as SCM and in fact
served the most common SCM, therefore it has been widely used in modern concrete due to several
well-known effects on concrete. For instance, improving the workability, prolonging sitting time,
reducing the total heat generation, decreasing density, enhancing the durability more or less, and
consolidating long age mechanical properties in general. However, the degree of effect of fly ash on
the properties of concrete and the hydration products depend highly on the particle morphology and
differences of compositions of fly ash. Thus, the main reason of existence some differences in results
between researchers that they usually use different fly ash from different resource’s [7]-[10].
The worldwide utilization rate of fly ash in concrete is considered very little, and to improve the
properties of concrete, many investigations on incorporating large volume (>45%) of modified fly ash
in concrete have been done and named high volume fly ash (HVFA). HVFA concrete for structure
applications was developed by the Canadian Center for Mineral and Energy Technology (CANMET)
in 1985 concrete [11]. Regarding the literature, the inclusion of HVFA in the matrix has a positive
effect on some properties and a negative effect on others. It is therefore imperative to investigate and
develop a concrete incorporating large volumes of UWFA to increase considerably the utilization of
fly ash [12], [13].
Improper disposal has become an environmental concern and resulted in a waste of recoverable
resources like water and soil pollution, disrupt ecological cycles and pose environmental hazards.
Despite already aggressive efforts have been undertaken recently to recycle fly ash in road base con-
struction, soil amendment, zeolite synthesis, and use as a filler in polymers.
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More than 300 individual minerals and 150 mineral groups have been identified in various coal ash
samples[14]-[16], so the European Standards set a number of requirements and process for treat
UWFA before its use to optimize its fineness, reduce its water demand or to improve other properties
in general. This process as classification, selection, sieving, drying, blending, grinding, or carbon
reduction often involves a series of costly and energy consuming mechanical and physical applica-
tions [17]. UWFA is not suitable for use in construction applications due to its high carbon content
and large particle size [18]. There is a very limited information about the utilization of UWFA, thus
[19]-[21] and the current literature as well suggest that incorporating UWFA as a replacement of
cement in paste, mortar or even concrete would improve its mechanical and durability properties. A
limited number of researchers has investigated UWFA, and they have been used different expressions
to express the raw fly ash without any modifications, those expressions like unprocessed fly ash, low
quality fly ash, reject fly ash, and waste fly ash. Here the basic methodologies and conclusions for a
number of researchers approached the UWFA topic:
1) Hamood et al [21] investigated the utilization of different replacement amounts of UWFA in-
stead of cement in mortar mixtures and concluded that the increasing of replacement amount
of UWFA reduced flowability, ultrasonic pulse velocity in the early age testing up to 28 days,
the compressive strength at early age up to 90 days, and the drying shrinkage. However, it
improves the long-term compressive strength and ultrasonic pulse velocity up to 30% re-
placement of cement by UWFA. They recommended utilizing the UWFA in different con-
struction and civil engineering applications like cement-based materials for road construction
and self-compacting concrete.
2) Poon et al [18] studied the pozzolanic properties of UWFA blended cement pastes and found
that the higher but not excessive water-to-binder (w/b) ratio can enhance the reactivity of
UWFA, the paste with a higher w/b ratio of 0.35 had higher strength values than a similar
paste prepared with a lower w/b ratio of 0.28. This can be attributed to the absorption of
UWFA compared with normal fine fly ash, that what they observed from scanning electron
microscope (SEM). Since SEM showed more hydration products and denser microstructure
for the paste prepared with higher w/b ratio. Under the same conditions, UWFA was difficult
to react than normal fine fly ash and requires a higher pH value to be activated little reaction
occurred between UWFA and cement at 7 days of hydration but Significant amounts of reac-
tion only appeared after 28 days of hydration.
3) Snelson and Kinuthia [19], [20] investigated the physical, mechanical and durability charac-
teristics of concrete and cement paste using UWFA by preparing reference mixtures made of
just Portland cement and others with different replacements amount by UWFA. They agreed
with the possibility of utilizing the UWFA in concrete works. They also mention that caution
should, however, be taken to avoid excessive cement replacement, as the excessive reduction
in strength may compromise sulfate resistance
According to the literature, the incorporating of UWFA in concrete is not discussed from all aspects
especially the activation behavior of the binder itself with time. This paper studied the effect of paste
by incorporating different amounts of UWFA on physical, fresh and hardened properties in different
ages, while special emphasis has been placed UWFA on determining the maximum replacement
amount that could be achieved ascending activation index.
2 Expermintal work
This experimental work was examined as an initial phase to PhD work for producing green self-
compacting high performance concrete using different waste materials and recycled concrete aggre-
gate, one of these waste materials is UWFA. Whereas the response of mortar systems and concrete
systems depend greatly on the properties of paste Materials especially the in self-compacting
ones[22], [23].
2.1 Materials
The performance of six groups of paste mixtures containing 0, 15, 30, 40, 50, and 60% by mass
UWFA of total binder weight were examined, with a w/b ratio of 0.35. A plain cement paste without
the addition of fly ash was prepared at the same w/b ratio as a reference. The composition of mixtures
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Characteristics of cement pastes incorporating different amounts of unprocessed waste fly ash (UWFA)
Mohammed Abed and Rita Nemes 13
shown in Table 1. Paste mixtures were tested for their fresh and engineering properties including
consistency and compressive strength.
Table 1 Mixtures proportions of cement paste.
Name of
mixture
Weight (g) Percentage (%) Water
(g)
w/b
(%)
Superplasticizer
(ml)
Cement UWFA Cement UWFA
G0 1500 0 100 0 525 35 0
G15 1275 225 85 15 525 35 0.4
G30 1050 450 70 30 525 35 0.5
G40 900 600 60 40 525 35 1
G50 750 750 50 50 525 35 2
G60 600 900 40 60 525 35 4
The cement used throughout the experimental program was CEM I strength class 42.5 N that com-
plies with the requirements of EN 197-1:2000 to eliminate the effect of mineral admixtures on the test
[24]. The fly ash used in this experimental work was UWSF that was collected from a coal power
station in Hungary. The UWFA collected from Visonta coal-fired thermal power station and delivered
to the laboratory for use in the testing program. Table 2 shows the physical properties and chemical
composition of cement and UWFA in accordance with the EN standard [25], [26]. The mixing water
used for the reference was tap water that complies with the requirements of EN 1008:2002 [27]. To
achieve the same flowability for the mixtures and produce a workable paste with the same w/b ratio a
considerable amount of High range water reducing admixture (HRWRA) “Sika ViscoCrete-5 Neu”
superplasticizer was a modified polycarboxylates aqueous solution has been used in the present study.
This type of admixtures reduces the water dosage of a concrete mixture for the desired slump class.
Table 2 Chemical compositions and physical properties of cement and UWFA.
Measured property
CEM I 42.5 N
UWFA
(Visonta)
Physical
Density (g/ml) 3.02 2.15
Specific surface area (cm2
/g) 3326 4323
Chemical
(% by mass)
Loss on ignition 3 1.95
Insoluble part in dilute hydrochloric acid and
sodium carbonate
0.26 49.72
SiO2 19.33 43.02
CaO 63.43 15.07
MgO 1.45 3.14
Fe2O3 3.42 14.17
Al2O3 4.67 15.6
SO3 2.6 3.56
Chloride content 0.04 0.02
Free CaO 0.71 0.37
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2.2 Mixing and method
Mixing was carried out in accordance with EN 196-1 [28], for a total mixing time of four and a
half minutes partitioned in three stages, using a KM250 Kenwood Chef Major mixer, between each
stage the mixture manually homogenized to achieve the highest homogeneity. The pastes were cast
and compacted to produce (40×40) mm specimens, which vibrated using a vibrating table, to make 18
paste specimen for each mixture type. Casted specimens were covered with plastic sheets and placed
in temperature room (20 °C ± 2 °C) for 24 h until demoulding. Thereafter, specimens were cured for
7, 28 and 90 days by wrapping them using cling film. 18 samples in each group were tested; average
values are reported. A total of 108 samples were prepared (6 samples × 3 ages × 6 mixtures). The
consistency of fresh mixtures was obtained using the flow table, then for each testing age, the com-
pressive strength for six specimens (40x40) mm have been examined.
3 Results and discussion
3.1 Consistancy
For achieving the same flowability for all the groups of pastes it was necessary to use superplasticiz-
er, whereas the workability decreased with increasing the UWFA amount, moreover decreased signif-
icantly when a high amount of UWFA. In the beginning, the flowability for G0 was determined and
recorded 235 mm, then for other mixtures superplasticizer added to achieve flowability in the same
range of the reference mixture. The reduction in flowability may be due to the high surface area and
high unburned carbon content of the UWFA, which absorbs hydration water resulting in less worka-
bility [21], [29]. Fig. 1 shows the increasing of superplasticizer demand with increasing UWFA
amount as a result of decreasing the flowability for the same w/b ratio.
Fig. 1 Impact of UWFA on flowability and superplasticizer dosage.
3.2 Density
The apparent density has been measured for all specimens during different ages and the average
values reported in fig. 2, it goes without reason that the density will be decreased by increasing the
amount of UWFA due to its lower density comparing to cement. Fig. 2 illustrated the decreasing of
density by increasing the dosage of UWFA.
Fig. 2 Impact of UWFA on average density
0
1
2
3
4
5
G0 G15 G30 G40 G50 G60
0
50
100
150
200
250
300
Superplastisizer
dosage
(ml)
Mixture group
Flowability
(mm)
Flowability (mm)
Superplastisizer demand (ml)
0,000
0,500
1,000
1,500
2,000
2,500
G0 G15 G30 G40 G50 G60
Avergae
density
g/cm
3
Mixture Group
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Characteristics of cement pastes incorporating different amounts of unprocessed waste fly ash (UWFA)
Mohammed Abed and Rita Nemes 15
3.3 Compressive strength
Fig. 3 presents the compressive strength of the paste mixes at 7, 28 and 90 days the compressive
strength generally decreased when UWFA was included, and the greatest compressive strength was
achieved for the mortar mix with 0% UWFA. Nevertheless, the increase of strength with time for the
paste groups incorporated UWFA is higher than reference one, plus the strength up to 30% replace-
ment by UWFA are very close to the strength of the reference. It is an indication of the possibility of
increasing the long-term compressive strength for pastes incorporating up to 30% of UWFA to be
higher than the reference. That is exactly in accordance with what [21] observed in their study, which
his results after 365 days showed a significant improvement in the compressive strength for all mixes
that contained UWFA and this may be due to the positive impact of the pozzolanic activities of fly
ash particles on long-term strength development [30], [31].
Fig. 3 Impact of UWFA on compressive strength
3.4 Activity index
Activity index is expressed by the ratio of the strength of cement paste mixture containing SCM
replacement and strength of reference mixture with just cement, and it is express the hydration rate of
the SCM [32]. The activity indices are presented in fig. 4 for all mixtures groups in different ages. It
shows that with increasing the age of specimens incorporating UWFA the activity index increase,
thus the main reason for getting higher compressive strength for UWFA specimens. It is clear that the
most valuable replacement of cement by UWFA is up to 30% where the activity index is more than
0.9 after 90 days. It is clear the positive effect of increasing UWFA replacement up 30% in the activi-
ty index since the activity index increase with age. Whereas the behavior of activation for the pastes
with more than 30% UWFA show optimum activation index after 28 and the start to decrease.
Fig. 4 Impact of UWFA on activation index
4 Conclusion
Using unprocessed waste fly ash (UWFA) as a supplementary cementatious materials (SCM) will not
just decrease the cement consumption and its energy needed for production, but also will eliminate a
series of costly and energy consuming mechanical and physical applications generated to treat
0,0
20,0
40,0
60,0
80,0
100,0
G0 G15 G30 G40 G50 G60
Compressive
strength
MPa
Mixture Group
7 days 28 days 90 days
0,00
0,20
0,40
0,60
0,80
1,00
1,20
G0 G15 G30 G40 G50 G60
Activity
indecies
Mixture Group
7 days 28 days 90 days
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