Heft 19 No.19
S c
h r i
f t e n
r e i h
e B a u
s t o
f f e
u n d M
a s s
i v b a
u
S t r u
c t u
r a l M
a t e
r i a
l s a n
d E n g
i n e e
r i n
g S e
r i e s
U N I K A S S E L
V E R S I T A T
Ultra-High Performance Concrete and
Nanotechnology for High Performance
Edited by
M. Schmidt
E. Fehling
Heft 19
No. 19
Proceedings of Hipermat 2012 3
rd International Symposium on UHPC and
Nanotechnology for High Performance Construction Materials Kassel,
March 7–9, 2012
Edited by M. Schmidt E. Fehling
C. Glotzbach S. Fröhlich
Die Deutsche Nationalbibliothek verzeichnet diese Publikation in
der Deutschen Nationalbibliografie; detaillierte bibliografische
Daten sind im Internet über http://dnb.d-nb.de abrufbar
ISBN print: 978-3-86219-264-9 ISBN online: 978-3-86219-265-6 URN
urn:nbn:de:0002-32656
© 2012, kassel university press GmbH, Kassel
www.uni-kassel.de/upress
Herausgeber
Prof. Dr.-Ing. habil. M. Schmidt Prof. Dr.-Ing. E. Fehling
Universität Kassel Universität Kassel Fachbereich Bauingenieur-
Fachbereich Bauingenieur- und Umweltingenieurwesen und
Umweltingenieurwesen Institut für Konstruktiven Ingenieurbau
Institut für Konstruktiven Ingenieurbau Fachgebiet Werkstoffe des
Bauwesens Fachgebiet Massivbau und Bauchemie Kurt-Wolters-Str. 3
Mönchebergstr. 7 D-34125 Kassel D-34125 Kassel Tel. +49 (561) 804
2656 Tel. +49 (561) 804 2601 Fax +49 (561) 804 2803 Fax +49 (561)
804 2662
[email protected]
[email protected] www.uni-kassel.de/fb14/massivbau
www.uni-kassel.de/fb14/baustoffkunde
Ultra-High Performance Concrete (UHPC), one of the recent
breakthroughs in concrete
technology, impresses us with its high durability and a compressive
strength comparable to that
of steel. It permits the design of sustainable concrete structures
such as wide-span bridges,
filigree shells and high-rise towers and allows for spectacular
architectural designs.
In 2004 and 2008, two International Symposia on UHPC took place at
the University of Kassel,
organized by the Department of Structural Materials and
Construction Chemistry and the
Department of Structural Engineering. Since then, the set of
knowledge about the Ultra-High
Performance Concrete has been substantially widened and its
practical application has rapidly
increased worldwide. New researchers and users of UHPC have joined
the community and
broadened the scope of its potential.
This conference as well has substantially grown since 2008. In
2012, about 130 speakers presented their impressions, research, and
practical experience. It also attracted the attention
of many international standardization bodies.
Even though the material is already highly developed, it is still
possible to increase its potential
even further using recent advancements in nanotechnology and
colloidal chemistry. Nowadays,
the reactions of binders can be studied at the nanoscale, synthetic
nanoparticles of various
oxides can significantly improve microstructure and reaction
potential. This knowledge gives
rise to many new possibilities that allow developing impregnable
ceramics or multifunctional
materials. They can, for example, carry agents for environmental
protection, provide additional
self-healing potential, and act as part of heating or cooling
measures. As nanotechnology provides many new and auspicious
approaches to improve the performance of construction
materials and to open up new applications, the 3rd International
Symposium on UHPC
extended its focus towards nano-optimized construction materials
and its recent advancements.
This additional aspect led us to establish the new conference name
HiPerMat, derived from
High Per formance Construction Materials.
This volume thus contains more than 120 contributions from many
research disciplines that are
influenced by High Performance Materials and UHPC in particular:
material sciences, structural
engineering, environmental engineering, nanotechnology, chemistry,
architecture, codification,
and economy. A design adequate to the materials and to the
construction of durable and sustainable high performance structures
receives special attention.
We hope that our conference, Hipermat 2012, has once more
contributed to the development of
modern and progressive buildings and materials for construction and
will continue to do so in
the future.
Prof. Dr.-Ing. habil. Michael Schmidt Prof. Dr.-Ing. Ekkehard
Fehling
8/15/2019 HiPerMat 2012 Kassel
Chairmen
Prof. Mouloud Behloul
Prof. Françoise de Larrard Lafarge, F
Prof. Marco di Prisco
Politecnico di Milano, I
Prof. Harald Müller Karlsruhe University of Technology, D
Prof. Aurelio Muttoni
EPFL Lausanne. CH
Prof. Jan Vitek
Prof. Alphose Zingoni
Symposium organizers
The Path to Ultra-High Performance Fiber Reinforced Concrete
(UHP-FRC): Five
Decades of Progress
Naaman, Antoine E.
Michael Schmidt
17
State of the art of design and construction of UHPFRC structures in
France
Jacques Resplendino
Theresa Ahlborn, Eric Steinberg
43
On the way to international design recommendations for Ultra High
Performance Fibre
Reinforced Concrete
Ehsan Ghafari, Hugo Costa, Eduardo Júlio, António Portugal, Luisa
Durães
71
Genady Shakhmenko, Aleksandrs Korjakins, Patricija Kara, Janis
Justs, Inna Juhnevica
79
Cavitation Treatment of Nano and Micro Filler and Its Effect on the
Properties of UHPC
Janis Justs, Genady Shakhmenko, Viktors Mironovs, Patricija
Kara
87
Nanoparticles as accelerators for cement hydration Gerrit Land,
Dietmar Stephan
93
Christoph Glotzbach, Dietmar Stephan, Michael Schmidt
101
Investigation the Effects of Nano-Silica Colloidal Solutions on
Properties of Mortars
Ali Akbar Ramezanianpour, Shabnam Firoozmakan, Hamed Bahrami
Jovein
109
Ali Akbar Ramezanianpour, Mahdi Mahdikhani, S. Sina Yousefian
Moghaddam, Morteza Nikravan, S.Rahimeh Mousavi
117
A comparison between the pozzolanic reactivity of nanosilica
sols and pyrogenic nanosilicas
Hesam Madani, Alireza Bagheri, Parhizkar Tayebe
125
http://slidepdf.com/reader/full/hipermat-2012-kassel 11/1056
Fluid Catalytic Cracking Residue additions such an alternative to
Silica Fume in
UHPFRC
133
Photocatalysis
visible light irradiation
Shuai Yuan, Meihong Zhang, Jianping Zhang, Yin Zhao, Zhuyi Wang,
Liyi Shi
141
Nanoparticles
147
Synthesis of Photoactive Silica Spheres with Titania Nano Coating
as Potential Nano-
Composites for Mortar and Concrete
Sameena Kamaruddin, Dietmar Stephan
161
Jeffrey Chen, Matthieu Horgnies
Andreas Winzenburg, Rüdiger Faust
Raw Materials, Mixtur e Compositi ons and Fresh Concrete
Synergistic Effect of Rce Husk Ash and Fly Ash on Properties of
Self-Compacting High
Performance Concrete
187
Proportioning Optimization of UHPC Containing Rice Husk Ash and
Ground Granulated
Blast-furnace Slag
197
Per Fidjestol, Rein Terje Thorsteinsen, Paul Svennevig
207
Control of Rheology, Strength and Fibre Bond of UHPC with Additions
– Effect of
Packing Density and Addition Type
Dirk Lowke, Thorsten Stengel, Peter Schießl, Christoph Gehlen
215
Influences on Repeatability and Reproducibility of Testing Methods
for Fresh UHPC
Susanne Fröhlich, Michael Schmidt
Hybrid Intensive Mixer with integrated Rheometer for High
Performance Concrete
Harald Garrecht, Christian Baumert, Andreas Karden
233
Influence of vacuum mixing on the mechanical properties of
UHPC
Jeroen Dils, Geert De Schutter, Veerle Boel, Egon Braem
241
Definition of three levels of performance for UHPFRC-VHPFRC with
available materials
Esteban Camacho, Juan Ángel López, Pedro Serna
249
Incorporating Coarse Aggregate
257
UHPC composites based on glass fibers with high fluidity,
ductility, and durability Jeffrey Chen
265
Concrete (UHPFRC)
273
Effect of Heat Treatment Method on the Properties of UHPC
Detlef Heinz, Liudvikas Urbonas, Tobias Gerlicher
283
Hydration and Early Ag e
Modeling Cement Hydration Kinetics using the Equivalent Age Concept
Xueyu Pang, Dale P. Bentz, Christian Meyer
291
Mechanical Properties of Ultra-High Performance Concrete (UHPC) at
Early Age
Harald Budelmann, Jens Ewert
Andina Sprince, Aleksandrs Korjakins, Leonids Pakrastinsh,
Genadijs Shakhmenko, Girts Bumanis
309
Shrinkage Behavior of Ultra High Performance Concrete at the
Manufacturing Stage
Sungwook Kim, Jungjun Park, Dooyeol Yoo, Youngsoo Yoon
317
Creep and shrinkage prediction for a heat-treated Ultra High
Performance Fibre-
Reinforced Concrete
325
Creep Behavior of UHPC under Compressive Loading with Varying
Curing Regimes
Jason C. Flietstra, Theresa M. Ahlborn, Devin K. Harris, Henrique
de Melo e Silva
333
Mitigation of early age shrinkage of Ultra High Performance
Concrete by using Rice Husk
Ash
341
Durability
Microstructure of Ultra High Performance Concrete (UHPC) and its
Impact on Durability
Jennifer C. Scheydt, Harald S. Mueller
349
Computer Modeling and Investigation on the Chloride Induced Steel
Corrosion in
Cracked UHPC
Marine Performance of UHPC at Treat Island
Michael David Arthur Thomas, Brian Green, Ed O'Neal, Vic Perry,
Sean Hayman, Ashlee Hossack
365
Evaluation of Durability Parameters of UHPC Using Accelerated Lab
Tests
Julie Pierard, Bram Dooms, Niki Cauberg
371
Bond Strength between UHPC and Normal Strength Concrete (NSC) in
accordance with
Split Prism and Freeze-Thaw cycling tests.
Miguel A. Carbonell, Devin K. Harris, Sarah V. Shann, Theresa M.
Ahlborn
377
Concretes with Improved Acid Resistance
Ricarda Tänzer, Dietmar Stephan, Michael Schmidt
385
Tension and Bending
Direct and Flexural Tension Test Methods for Determination of the
Tensile Stress-Strain
Response of UHPFRC
395
Experimental and Analytical Analysis of the Flexural Behavior of
UHPC Beams
Eric T. Visage, K. D. S. Ranga Perera, Brad D. Weldon, David V.
Jauregui, Craig M. Newtson, Lucas Guaderrama
403
Characterization of the Fracture Behavior of UHPC under Flexural
LoadingEric L. Kreiger, Theresa Ahlborn, Devin K. Harris, Henrique
A. de Melo e Silva
411
Johannes Gröger, Nguyen Viet Tue, Kay Wille
419
Tests on the Flexural Tensile Strength of a UHPFRC subjected to
Cycling and Reversed
Loading reversed loading
427
Flexural Model of Doubly Reinforced Concrete Beams Using Ultra High
Performance
Fiber Reinforced Concrete
Simone Stürwald, Ekkehard Fehling
Niki Cauberg, Julie Pierard, Benoit Parmentier, Olivier Remy
451
Charles Kennan Crane, Lawrence F. Kahn
459
Numerical Study on the Shear Behavior of Micro-Reinforced UHPC
BeamsMartina Schnellenbach-Held, Melanie Prager 469
Experimental Investigations on I-Shaped UHPC Beams with Combined
Reinforcement
under Shear Load
Ultimate Shear Strength of Ultra High Performance Fibre Reinforced
Concrete Beams
Florent Baby, Joël Billo, Jean-Claude Renaud, Cyril Massotte,
Pierre Marchand, François Toutlemonde
485
Guido Bertram, Josef Hegger
Experimental Investigations on UHPC Structural Elements Subject to
Pure Torsion
Ekkehard Fehling, Mohammed Ismail
Changbin Joh, Jung Woo Lee, In Hwan Yang, Byung-Suk Kim
509
Martin Empelmann, Vincent Oettel
Guido Bertram, Josef Hegger
Ekkehard Fehling, Paul Lorenz, Torsten Leutbecher
533
Effect of adding micro fibers on the pullout behavior of high
strength steel fibers in UHPC
matrix
Seung Hun Park, Dong Joo Kim, Gum Sung Ryu, Kyung Taek Koh
541
Literature Review on the Behaviour of UHPFRC at High
Temperature
Pierre Pimienta, Jean-Christophe Mindeguia, Alain Simon, Mouloud
Behloul, Roberto Felicetti, Patrick
Bamonte, Pietro G. Gambarova
Sung-Gul Hong, Sung-Hoon Kang, Eo-Jin Lee, Soo-Min Jeong
557
Elevated Temperatures Richard Way, Kay Wille
565
Behaviour of Ultra High Performance Concrete (UHPC) in Case of
Fire
Dietmar Hosser, Björn Kampmeier, Dirk Hollmann
573
583
Ultra High Performance Concrete Structures under Aircraft Engine
Missile Impact
Markus Nöldgen, Ekkehard Fehling, Werner Riedel, Klaus Thoma
593
Material Models
A Triaxial Fatigue Failure Model for ultra high performance
concrete (UHPC)
Jürgen Grünberg, Christian Ertel
Ludger Lohaus, Nadja Oneschkow
Mechanical Behaviour of Ultra High-Performance Fibrous-Concrete
Beams Reinforced
by Internal FRP Bars Emmanuel Ferrier, Laurent Michel, Philippe
Lussou, Bruno Zuber
619
Fatigue Behaviour of plain and fibre reinforced Ultra-High
Performance Concrete
Ludger Lohaus, Kerstin Elsmeier
Kenneth K. Walsh, Eric P. Steinberg
639
Composite Structures and Connection Technol ogy
Design Models for Composite Beams with Puzzle Strip Shear Connector
and UHPC
Joerg Gallwoszus, Josef Hegger, Sabine Heinemeyer
647
Josef Hegger, Nguyen Viet Tue, Janna Schoening, Martina
Winkler
655
Benjamin A. Graybeal, Matthew Swenty
663
V.H. Perry, Peter Seibert
Petr Hajek, Magdalena Kynclova, Ctislav Fiala
679
Hasan Han, Steffen Grünewald, Joost Walraven, Jeroen Coenders,
Pierre Hoogenboom
685
Joerg Gallwoszus, Josef Hegger, Sabine Heinemeyer
693
Application of Steel Shares as Shear Connectors in Slender
Composite Structures
Wolfgang Kurz, Jürgen Schnell, Susanne Wiese
701
Structural Behaviour and Load-Bearing Capacity of Reinforced Glued
Joints of UHPC-
Elements
709
Adhesion of fine-grained HPC and UHPC to Steel and
Glass
Joachim Juhart, Bernhard Freytag, Gerhard Santner, Erwin
Baumgartner
717
725
Ultra High Performance Spun Concrete Columns with High Strength
Reinforcement
Corinna Mueller, Martin Empelmann, Helmut Lieb, Florian Hude
733
Experimental analysis and numerical simulation of
Ultra-High-Performance Concrete
tube columns with a steel sheet wrapping for large sized truss
structures
Ludger Lohaus, Jürgen Grünberg, Nick Lindschulte, Sven
Kromminga
741
Lionel Moreillon, Joanna Nseir, René Suter
749
Pierre Marchand, Florent Baby, Waël Al Khayer, Mohammed Attrach,
François Toutlemonde
757
765
Analytical and experimental investigations on the
introduction of compressive loads in
thin walled elements made of UHPFRC by the use of implants
Jan Mittelstädt, Werner Sobek
Load-Bearing Behaviour of Sandwich Strips with XPS-Core and
Reinforced HPC-
Facings
781
APPLICATIONS
Microstructural Optimization of High-Strength Performance Air
Hardened Foam Concrete
Bernhard Middendorf, Armin Just
UHPC Under Intensive Autoclave Cycles for Energy Storage Water
Tanks.
Mohamed Abd Elrahman, Bernd Hillemeier
799
Ultra-High Performance Concrete for Drill Bits in Special
Foundation Engineering
Hursit Ibuk, Karsten Beckhaus
807
Effect of Fibres on Impact Resistance of Ultra High Performance
Concrete
Sandy Leonhardt, Dirk Lowke, Christoph Gehlen
811
On the way to micrometer scale: applications of UHPC in machinery
construction
Bernhard Sagmeister
825
Sewer pipes and UHPC - Development of an UHPC with earth-moist
consistency Michael Schmidt, Torsten Braun, Heiko Möller
833
Development of an Ultra-High Performance Concrete for precast spun
concrete columns
Thomas Adam, Jianxin Ma
841
Infrastructure
Whiteman Creek Bridge – A Synthesis of Ultra High Performance
Concrete and Fibre
Reinforced Polymers for Accelerated Bridge Construction
Wade Francis Young, Jasan Boparai, Vic Perry, Brent Archibald,
Sameh Salib
849
Current Research on Ultra High Performance Concrete (UHPC) for
Bridge Applications in Iowa
Sri Sritharan, Sriram Aaleti, Dean Bierwagen, Jessica Garder, Ahmad
Abu-Hawash
857
R&D Activities and Application of Ultra High Performance
Concrete to Cable Stayed
Bridges
Byung-Suk Kim, Seungwook Kim, Young-Jin Kim, Sung Yong Park,
Kyung-Teak Koh, Changbin Joh
865
Structural Performance of Prestressed UHPC Ribbed Deck for
Cable-Stayed Bridge
Sung Yong Park, Keunhee Cho, Jeong Rae Cho, Sung Tae Kim, Byung Suk
Kim
873
Bernhard Freytag, Günter Heinzle, Michael Reichel, Lutz
Sparowitz
881
Practical Use of Fibre-reinforced UHPC in Construction - Production
of Precast Elements
for Wild-Brücke in Völkermarkt
Structural Design and Preliminary Calculations of a UHPFRC Truss
Footbridge
Juan Angel López, Esteban Camacho, Pedro Serna Ros, Juan Navarro
Gregori
897
Behaviour of an Orthotropic Bridge Deck with a UHPFRC Topping Layer
Pierre Marchand, Fernanda Gomes, Lamine Dieng, Florent Baby,
Jean-Claude Renaud, Cyril Massotte, Marc Estivin, Joël Billo,
Céline Bazin, Romain Lapeyrere, Dominique Siegert, François
Toutlemonde
905
Benjamin Scheffler, Michael Schmidt
913
"Whitetopping" of Asphalt and Concrete Pavements with thin layers
of Ultra-High-
Performance Concrete - Construction and economic efficiency
Cornelia Schmidt, Michael Schmidt
Application of Ultra-High Performance Concrete (UHPC) as a
Thin-Topped Overlay for
Concrete Bridge Decks Sarah V. Shann, Devin K. Harris, Miguel A.
Carbonell, Theresa M. Ahlborn
929
Assessment of a UHPFRC based bridge rehabilitation in
Slovenia, two years after
application
937
Structural Health Monitoring of the Gaertnerplatz Bridge over the
Fulda River in Kassel
Based on Vibration Test Data and Stochastic Model Updating
Michael Link, Matthias Weiland
945
Life-Cycle Cost Analysis of a UHPC-Bridge on Example of two Bridge
Refurbishment
DesignsSiemon Piotrowski, Michael Schmidt
957
Material performance control on two large projects: Jean-Bouin
stadium and MUCEM
museum
Innovative design of bridge bearings by the use of UHPFRC
Simon Hoffmann, Hermann Weiher
Study on the Application of UHPC for Precast Tunnel Segments
Norbert Randl, Arnold Pichler, Walter Schneider, Joachim
Juhart
981
Architectural Concrete with UHPC for facades and interior
design - recent application in
Germany
The First Architectural UHPC Façade Application in North
America
Peter J. Seibert, Vic H. Perry, Gamal Ghoneim, Gerald Carson,
Rafaat El-Hacha, Ignacio Cariaga, Don Zakariasen
997
Rogier Friso van Nalta, Tommy Bæk Hansen
1005
Precast thin shells made of UHPFRC for a large roof in a waste
water treatment plant
near Paris
1011
Off-shore Foundations
Design of Grouted Connections for Offshore Wind Energy Converters
and Composite
Structures using UHPC
1027
As part of the conference bag, you received a storage device containing the online version of this volume. You can
access all the information in this book, skim through it via a fulltext search, filter the contributions, and get further
information on the authors and the visitors of HiPerMat 2012.
To access the online proceedings, all you need is a recent web browser and a PDF viewer, you can use any operating
system. Just plug the USB storage device into a compatible computer and open the file start.html in its root
directory.
On the USB stick, you will find one additional contribution:
Grouted Connections with HPC and UHPC for Offshore Wind Power
Plants - Material
Properties and Quality
The Path to Ultra-High Performance Fiber Reinforced Concrete
(UHP-FRC): Five Decades of Progress
Antoine E. Naaman1, Kay Wille2
1: Department of Civil and Environmental Engineering, University of
Michigan, Ann Arbor, Michigan, USA 2: Department of Civil &
Environmental Engineering, University of Connecticut, Storrs,
Connecticut, USA
Following the onset of modern developments of fiber reinforced
concrete in the early 1960’s, there has
been a continuous search for its improved performance. One can thus
follow such progress in milestones
along four inter-related paths: one path for the cementitious
matrix, another for the fiber, the third for the
interface bond between fiber and matrix, and the forth for the
composite itself. After identifying some key
milestones for each path, over a period of five decades, leading to
today’s ultra-high performance fiber
reinforced concretes (UHP-FRCs), the composition and key mechanical
properties of newly designed
UHP-FRC mixtures obtained without heat or pressure curing while
using materials available on the US
market are described. Record breaking performance in direct tension
(in terms of strength, ductility, and
fracture energy) is reported and sets limits to exceed in the
future.
Keywords: bond strength, ductility, fiber reinforced concrete,
fracture energy, high strength, high
performance, steel fibers, tensile testing, ultra-high
performance.
1 Introduction
The past five decades mark the modern development and broad
expansion of fiber reinforced
cement and concrete composites, which has led to today extensive
applications and market
penetration worldwide. Their success is due in part to significant
advances in the fiber
reinforcement, the cementitious matrix, the interface bond between
fiber and matrix,
fundamental understanding of the mechanics of the composite, and
improved cost-
effectiveness. Ultra-high performance cement or concrete (UHPC)
composites are very brittle and, as such,
often compared to ceramics. Adding fibers to an UHPC matrix in
order to improve its toughness
and ductility, has led to the terminology used here, that is:
“ultra high performance fiber
reinforced cement or concrete composite” or UHP-FRC
composite.
It is strongly believed that high performance and ultra-high
performance fiber reinforced
cement composites are emerging materials well suited for use in the
next generation of
infrastructure. There is real need to tailor-design these
composites to satisfy certain demands
on strength, toughness, durability, ductility, and fracture energy.
These include demand for
combined axial and bending resistance at the base of columns in
high rise buildings, demand
for high rotational capacity, demand for combined plastic shear and
plastic bending
deformations at the base of shear walls, high shear and bending
resistance at the continuous
supports in long-span bridges, and, blast and impact resistant
structures. Clearly high
performance mechanical properties are needed. UHP-FRC composites
seem to be also
particularly suitable in thin products applications, such as panels
and cladding, where they
could be used as stand-alone material. Enhanced durability
properties could fulfill the need for
structures with longer lifetime, less maintainance and
repair.
Combined properties of interest to civil engineering applications
include strength, toughness,
energy absorption, stiffness, durability, freeze-thaw and corrosion
resistance, fire resistance,
tightness, appearance, stability, construct-ability, quality
control, and last but not least, cost and
user friendliness.
High strength and high performance concrete, high performance fiber
reinforced concrete
(HPFRC), ultra-high performance concrete (UHPC), and ultra-high
performance fiber reinforced
concrete (UHP-FRC) have been addressed in numerous investigations
in the US and abroad [1-
52]. A recent review of their definitions, if available, can be
found in Ref. [23]. For the purpose
of this paper and with the intent of providing extremely brief
definitions until technical committees working on these materials
provide some, the following definitions are suggested:
Ultra high performance concrete (UHPC) is a hydraulic
cement-based concrete with a
compressive strength at least equal to 150 MPa, etc.
Ultra-high performance fiber reinforced concrete (UHP-FRC)
is a UHPC with fibers added
in order to significantly improve a particular mechanical property
(or properties), etc.
The additive “etc…” suggests that these short definitions could be
qualified by one or a
combination of attributes, such as adopted by some researchers [19,
20]. For UHPC, these
attributes include, for instance, a minimum water to binder ratio,
a minimum cement content, a
minimum packing density or a minimum level of durability
performance. For UHP-FRC the
composite can be qualified by whether it is strain-softening or
strain-hardening in tension [12,13], or whether it is
deflection-softening or deflection-hardening in bending, as well as
by a
minimum level of ductility, toughness or fracture energy. Other
attributes may be imposed
depending on particular applications; examples include
permeability, electrical conductivity,
resistance to chloride penetration, volume stability (shrinkage or
expansion), etc.
How a recommended level of performance is achieved in practice
should be of less interest
to a general definition. Thus UHPC could be obtained using heat
curing or pressure curing or
none at all; it may necessitate the use of a particular mineral
additive or a polymer additive, or a
special mixing procedure.
Whether a single or multiple attributes are used, reference to
broadly acceptable standard
tests procedures and specimen dimensions is needed to help clearly
identify a particular
composite.
3 Chronological Developments: Five Decades of Progress
It is difficult to put specific limits at technical advances and
progress on a particular subject, not
only in terms of time but also geographic location. However, one
can point out certain
milestones that helped improve the performance of cement and
concrete composites in general
and somehow started a trend. For UHP-FRC, these milestones can be
followed along four
paths and their combination, namely, the cement matrix, the fiber,
the bond at the interface
between fiber and matrix, and the resulting composite.
3.1 Concrete Matrix and Fiber
In Table 1, the authors list in chronological order key advances
related to the concrete matrix
(2nd column) and the fiber (3rd column) since the 1960’s,
mostly as encountered in the Europe
and the US. It is likely that a similar evolution took place
elsewhere around the world, but with
some slight delay (or advance) in adoption or implementation. Table
1 is self-explanatory.
3.2 Progress Leading to Ultra High Performance Fiber Reinforced
Concrete
It has been a common aspiration for researchers dealing with cement
and concrete composites
to race for increasing compressive strength. In the early 1970’s
very high compressive
strengths of up to 510 MPa were reported from testing small
specimens prepared under special
conditions with vacuum, heat and pressure curing [24, 25]. In the
early 1980’s the addition of
special polymer and the use of very low water to cement ratios led
to what was described as
micro-defect-free cement with a compressive strength exceeding 200
MPa [26]; no pressure or
4
The Path to Ultra-High Performance Fiber Reinforced Concrete
(UHP-FRC): Five Decades of Progress
heat curing was needed. Such discoveries, however, while
illustrating the potential of the
material, did not translate into easily implemented applications.
In Tables 2, the authors
summarize various milestones related to numerous such composites
developed since the
1970’s. Widely used acronyms are highlighted. Table 2 covers the
period from 1970 to 2011. It
gives the approximate date of introduction, the range of
compressive strength reported, the
reference, the name and/or acronym used for the material developed,
if any, and the special
conditions applied to achieve the reported properties. Related
references can be found in the
reference list [24 to 49] Note that Table 2 is by no means
exhaustive; it covers what the
authors consider key developments in the US and Europe. The
emphasis is on materials that
have led to ultra-high performance concrete and ultra-high
performance fiber reinforced
concrete as understood at time of this writing.
Table 1: Chronological Advances in the matrix and fibers since the
196 0’s.
Decade Cementitious Matrix and Concrete Fiber
1970’s
Better understanding shrinkage, creep, porosity, …
High strength concrete to 50 MPa in practice
Development of water reducers
Smooth steel fibers; normal strength
1980’s
Increased development of chemical additives: HWRA,
etc…
Increased utilization of fly ash and silica fume, and other
mineral additives, etc…
Increased flowability (flowable concrete)
Reduction in W/C ratio;
High-Strength-Concrete terminology: up to 60 MPa; special
high strength: up to 80 MPa; exotic high strength (special
aggregate and curing): up to 120 MPa
High-Performance-Concrete terminology: high-strength-
concrete with improved durability properties.
Deformed steel fibers: normal and high strength
Low-modulus synthetic fibers (PP, nylon, etc..)
Increased use of glass fibers
Micro fibers
1990’s
Increased use of supplementary cementitious materials as
cement replacement
UHPC: application of concept of high packing density;
addition of fine particles; low porosity; lower water to
cementitious ratio;
Self consolidating concrete; self compacting concrete;
New steel fibers with a twist (untwist during pull-
out)
PVA fibers with chemical bond to concrete
Improved availability of synthetic fibers
2000’s
UHPC: improved understanding of high packing density;
application of nanotechnology concepts
Ultra high strength steel fibers: smooth or
deformed with diameters as low as 0.12 mm and strengths up to 3400
MPa
Carbon nano-tubes; carbon nano-fibers
…???...
http://slidepdf.com/reader/full/hipermat-2012-kassel 25/1056
Table 2: Developments in high str ength high performance
cement composites from the 1970’s to date (in the
US and Europe).
1972 230 Yudenfreund, Skalny, et al.
Paste; vacuum mixing; low porosity; small specimens.
1972 510 Roy et al. (US)
Paste; high pressure and high heat; small specimens.
1981 200 Birchall et al. (UK)
MDF (Micro-Defect-Free) Paste; addition of polymer; bending
strength up to 150 MPa
1981- 1983
DENSIT; COMPRESSIT Mortar and concrete; normal curing; use of
microsilica
1980’ all
DSP (Densified Small Particles)
Improved particle packing; use of microsilica; use of
superplasticizers;
1980’s Up to 120 Many researchers worldwide (Shah; Zia;
Russell; Swamy; Malier; Konig; Aitcin; Malhotra)
High Strength Concrete; High Performance Concrete (HSC; HPC)
Concrete with special additives and aggregates for structural
applications; use of superplasticizers; normal curing; better
durability
1980’s
(US)
fractions of steel fibers (8% to 15% by volume)
1987 Up to 140 Bache (Denmark)
CRC (Compact Reinforced Concrete)
Concrete with high volume of steel fibers used with reinforcing
bars
1987 Open range Naaman (US)
HPFRCC (High Performance Fiber Reinforced Cement Composites)
Mortar and concrete with fibers leading to strain-hardening
response in tension
1991 Open range Reinhardt and Naaman (Germany, US)
HPFRCC (First International Workshop)
1992 Open range Li and Wu (US)
ECC (Engineered Cementitious Composites)
1994 In excess of
1995 Up to 800 Richard & Cheyrezy RPC (Reactive Powder
Concrete)
Paste and concrete; heat and pressure curing; particle
packing
1998 and later
DUCTAL 90 o C heat curing for 3 days; steel
fibers up to 6% (commercially available)
2000 and later
CEMTEC; CEMTEC-multi-scale
Early 2000
UHPC and UHP-FRC Many formulations based on DUCTAL
2005 Up to 140 Karihaloo (UK)
CARDIFRC Optimized particle packing and mixing procedure
2005 Up to 200 Jungwirth (Switzerland)
CERACEM Formulation similar to DUCTAL, larger fibers, larger
aggregates
2004 Open range >150
First International Symposium on UHPC
Many formulations similar to DUCTAL with and without heat curing;
with and without fibers.
2005 Open Schmidt et al. (Germany)
Sustainable Building with UHPC
2008 Open range >150
Second International Symposium on UHPC
Many formulations similar to DUCTAL with and without heat curing;
with and without fibers.
2011 >150 Accorsi & Meyer (US) UHPC Workshop First US
Workshop
2011 Up to 290 Wille & Naaman
(US-Germany)
UHP-FRC No heat curing; optimized packing;
record direct tensile strength 2011 ACI UHPC Committee 239 First
meeting: Oct. 2011
Also: PCI working group
2012 Open range >150
6
The Path to Ultra-High Performance Fiber Reinforced Concrete
(UHP-FRC): Five Decades of Progress
German Research Program: Sustainable Building with UHPC
4 Summary of Key Mechanical Properties Achieved to Date
This section provides a summary of the composition, mixing
procedure, and key mechanical
properties achieved using particular UHP-FRC composites developed
by the authors and their
collaborators. Several references can be consulted for additional
details [44 to 52].
4.1 Mixture Composition
Examples of mixture compositions for UHPC and UHP-FRC composites
developed by the
authors in prior investigations [45, 48] are provided in Table
3. The ratio for each material is
given by weight of cement. The compressive and tensile strengths
observed from tests are
given in the last rows of the table. A typical composition of UHPC
by volume is illustrated in Fig.
1 and is compared to a conventional normal concrete (NC) with the
same air content. It can be
observed that the paste phase in UHPC is more than 2.5 times that
of NC while the inert
particle phase is much smaller to essentially compensate for the
difference. A description of the
particle sizes of the various materials used and some of their
recommended characteristics are
shown in Fig. 2. The average particle size of each material is
compared in Fig. 3 to the ideal theoretical particle sizes that
would optimize packing density [44]; the theoretical particles
sizes
are shown as distribution functions around average diameters
d 1, d 2 , d 3, … where d 1 is
assumed to be equal 0.5 mm, and the other diameters are derived for
optimum packing.
Table 3: Examples of mixtures developed for UHPC and UHP-FRC.
Type UHPC UHP-FRC
Cement 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00
Silica Fume 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25
Glass Powder 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25
Water 0.220 0.195 0.190 0.180 0.212 0.200 0.185-0.195 0.18-0.20
0.207
Superplasticizer a 0.0054 0.0108 0.0108 0.0114 0.0054
0.0108 0.0108 0.0108 0.0108
Sand A 0.28 0.30 0.31 1.05 0.27 0.28 0.29 0.92 0.76
Sand B c 1.10 0.71 0.72 0.00 1.05 0.64 0.67 0.00 0.00
ratio Sand A/B 20/80 30/70 30/70 100/0 20/80 30/70 30/70 100/0
100/0
Fiber 0.00 0.00 0.00 0.00 0.15/0.25 0.22 0.18-0.27 0.22-0.31
0.71
Fiber Vol.% 0 0 0 0 1.5/2.5 2.5 2.0-3.0 2.5-3.5 5 e /8
]28,[' d cube f c MPa 194 207
220-240 232-246 207/213 219 227-261 251-291 270 e
/292 f
g ; 6.9-7.8
g ; 7.4-8.5
g ; 8.2-9.0
e
d non vibrated, non surface cut; e twisted (T)
fiber;
f straight (S) fiber;
failure
7
Figure 1: An example of mix proportions by volume comparing UHP-FRC
with normal concrete (NC).
Figure 2: Materials used in the mixtures developed and their
particular characteristics [Ref. 48].
4.2 Mixing Procedure
In UHPC, the number of ingredients is higher and the fineness of
the particles is smaller
compared to normal strength concretes. Therefore, it is important
that all particles, especially
the very fine ones, are uniformly distributed. Because very fine
particles tend to agglomerate
and form chunks, the minimal shear force for breaking these chunks
can be reduced by keeping
the particles dry; it is thus recommended to mix all dry particles
first before adding the water
and high –range water reducing (HRWR) additives.
In this investigation [45, 48], silica fume was first mixed with
all the sand for about 5 minutes,
similar to [40]. Afterwards, cement and glass powder were added and
mixed dry for at least
another 5 minutes before water was added. The whole amount of HRWR
was added at once
after the water. The UHPC became fluid after approximately 5
minutes of adding the water and
HRWR. Fibers, if any, were then added during the following 5 min. A
horizontal pan mixer
8
The Path to Ultra-High Performance Fiber Reinforced Concrete
(UHP-FRC): Five Decades of Progress
(capacity of around 60 Liter, 1.8 kW), with constant mixing speed
(60 rpm), was sufficient for
mixing the UHPC described in this research.
10 100 1000
3
Figure 3: Comparison between particle sizes of materials used with
theoretical sizes (di) obtained to optimize
packing density [Ref. 44].
Figure 4: Comparison of compressive strength of UHPC and UHP-FRC
mixtures developed versus existing
data reported in the technical literature [Ref. 48].
4.3. Compressive Strength and Stress-Strain response
The average compressive strength at 28 days (using 50 mm cube
specimens) of the various mixtures described in Table 4 is compared
to equivalent cubic compressive strengths of various
UHPC composites reported in the technical literature. It can be
observed that they compare
9
http://slidepdf.com/reader/full/hipermat-2012-kassel 29/1056
very favorably to existing data, particularly given the fact that
they were obtained with no heat
treatment, no special mixer, and using materials commercially
available on the US market.
Details can be found in [45, 48].
4.4 Bond Stress-Slip at the Fiber-Matrix Interface
In order to optimize the response of UHP-FRC after first
percolation cracking, that is, to
essentially improve simultaneously its post-cracking tensile
strength, the corresponding strain capacity, and its fracture
energy, a thorough attempt was made to optimize the bond at the
fiber
to matrix interface, and to use deformed steel fibers of tensile
strength as high as can be
practically obtained from manufacturers of steel wires. The
objective was to achieve the highest
possible bond without failing the fiber. Extensive pull-out tests
were then carried-out on single
fibers with different characteristics [50, 51]. Examples of bond
shear stress versus slip curves
obtained using smooth brass-coated steel fibers embedded in various
matrices are shown in
Fig. 5. The shear stress was obtained from the pull-out load and
the embedded length of fiber at
the slip considered. It can be observed that even with smooth
fibers, very high local shear
stresses of up to 30 MPa can be obtained; unlike what is observed
with conventional concrete,
this behavior seems to be particular to UHPC and is likely due to
the very dense transition zone around the fiber and the very fine
particles it contains. Details of the study can be found in
Ref.
[50].
Figure 6 illustrates for a given fiber, the influence of the twist
ratio on the pull-out load versus
slip response. Thus the higher the twisted ratio, the higher the
maximum pull-out load, up to a
level where the fiber fails. Tensile stresses exceeding 3000 MPa
are induced in the fiber. On
the right side of Fig. 6, the photograph shows the damage on the
surface of the fiber where the
brass coating is abraded, likely due to the compactness of the zone
around the fiber and the
presence of glass powder.
Figure 5: Typical bond stress versus relative slip relationships
using different matrices [Ref. 50].
4.5 Tensile Response
Examples of stress-strain curves obtained from specimens tested in
direct tension are shown in
Figs.7 and 8. Figure 7 compares the tensile stress strain response
of UHP-FRC composites
using premixed twisted steel fibers with typical data reported in
the literature from Ductal and
Ceracem [16, 35, 36, 37, 41]. It can be observed that for about the
same fiber content, the
composite tensile strength is about doubled, and the strain at peak
stress is about tripled. Note that, to the best of the authors
knowledge, test series T12-1% (using high strength twisted
steel
fibers with an equivalent diameter of 0.12 mm) gives the highest
tensile strength (15.9 MPa) per
10
The Path to Ultra-High Performance Fiber Reinforced Concrete
(UHP-FRC): Five Decades of Progress
unit volume of composite recorded to date in the technical
literature and also the highest strain
capacity, for any fiber reinforced cement composite using
discontinuous fibers [49].
Figure 6: Typical effect of twist ratio of a steel fiber on its
pull-out load versus slip response [Ref. 49].
Figure 8 also provides a comparison of the response of various
UHP-FRC composites in
tension. In particular, it shows the best results obtained in Ref.
[49], for a composite using a
Sifcon (slurry infiltrated fiber concrete) process, and an
composite using a hybrid fiber mixture.
Although the fiber content by volume is 5.5% and 6%
respectively, to the best of the authors
knowledge, the post-cracking tensile strength achieved (about 37
MPa) and its corresponding
strain capacity are the highest so far reported in the technical
literature for a fiber reinforced
cementitious matrix subjected to direct tension. The tensile
post-cracking strains at peak stress
(Figs. 7 and 8) exceeding in some cases 1% are also the highest
observed to date for steel
fiber reinforced cement composites.
Similarly, to the best of the authors knowledge, the energy
absorption capacity g obtained per 1% volume fraction
of steel fibers for series T12 1% (Fig. 7) is the highest value
(g = 128
kJ/m3) achieved to date for a cement composite with discontinuous
fibers. It exceeds at least 5
times the energy values reported by other researchers for UHP-FRC
composites [49].
Figure 7: Comparison of tensile stress-strain response of UHP-FRCs
developed with composites from other
researchers [Ref. 49].
Figure 8: Tensile stress-strain response curves showing highest
tensile strengths recorded to date [Ref. 49].
4.6 Fracture Energy Figure 9 illustrates typical values of fracture
energy obtained from direct tensile tests of different
UHP-FRC-B (Table 3) varied by amount and type of fiber [47]. How
the average fracture energy
Gf (in kJ/in2) of each test series was calculated is
described in Ref. [47]. It comprises the
dissipated energy per unit volume during strain hardening
g f,A, the dissipated energy per unit
ligament area Gf,A to open one crack up to
pc and the dissipated energy per unit
ligament area
Gf,B to completely separate the critical (localized) crack
during softening.
The values shown in Fig. 9 are among the highest reported in the
technical literature and
exceed the values of comparable UHP-FRC by a significant margin
[47]. For instance, test
series UHPFRC-T1-1.5 obtained with no heat curing shows
Gf = 31 kJ/m2, that is,
Gf = 20.67 kJ/m2 per 1% volume of fibers. In comparison,
a fracture energy of 40 kJ/m2 is reported by Richard and
Cheyrezy (1995) for Reactive Powder Concrete using 2.5 %
steel
fibers with 90°C thermal treatment; that is equivalent to 16 kJ/m 2
per 1% volume of fiber.
Figure 9: Examples of fracture energy values obtained for some of
the UHP-FRC developed [Ref. 47].
12
The Path to Ultra-High Performance Fiber Reinforced Concrete
(UHP-FRC): Five Decades of Progress
5 Concluding Remark
This paper summarized in a first part some historical developments
since the 1960’s that led to
ultra-high performance (UHPC) and ultra-high performance fiber
reinforced concrete (UHP-
FRC) as we understand them at time of this writing. The second half
of the paper was devoted
to describing key information on several UHPC and UHP-FRC mixtures
that led to composites
with record breaking tensile properties. Indeed by combining an
ultra-high strength cementitous matrix and very high strength fine
diameter steel fibers with tailored bond properties, tensile
strength up to 37 Mpa, strain at maximum stress up to 1.1%, and
energy absorption capacity
prior to softening up to 304 kJ/m3 were realized for the
composite. These values exceed by a
significant margin the current tensile properties of UHP-FRC
reported in the technical literature.
Multiple cracking with crack spacing as small as 1 mm and crack
widths as small as 4 microns
prior to localization of tension failure were observed.
Today the technical challenge for the use of ultra high performance
fiber reinforced concrete
in structural applications is not through increased compressive
strength (which can easily be
made to exceed 200 MPa) but rather through an increased combination
of tensile strength,
tensile ductility and energy absorption capacity. Moreover, on the
practical side, the challenge is to achieve the desired properties
for design, in both the fresh and hardened state, at least
cost. Technically the record-breaking results mentioned above on
tensile strength shall be
exceeded in the future, but the real success of the composite in
practice will greatly depend on
its cost-benefit ratio in a given application.
References
The following list of references is very limited due to space
limitation and does not do justice to the
thousands of studies available at time of this writing.
[1] Russel, H.G., “ACI Defines High Performance Concrete,” Concrete
International , Feb. 1999, pp. 56-
57.[2] Naaman, A.E., and Reinhardt, H.W., “Proposed Classification
of FRC Composites Based on their
Tensile Response “ Materials and Structures, Vol. 39, page 547-555,
2006.
[3] Naaman, A.E., "High performance fiber reinforced cement
composites," Proceedings of the IABSE
Symposium on Concrete Structures for the Future, Paris, France,
September 1987, pp. 371-376.
[4] Reinhardt, H.W., and Naaman, A.E., Editors, "High Performance
Fiber Reinforced Cement
Composites," RILEM, Vol. 15, E. & FN Spon, London,
1992, 565 pages.
[5] Naaman, A.E., and Reinhardt, H.W., Editors, "High Performance
Fiber Reinforced Cement
Composites: HPFRCC 2,” RILEM, No. 31, E. & FN Spon, London,
1996, 505 pages.
[6] Naaman, A.E., and Reinhardt, H.W., "Characterization of High
Performance Fiber Reinforced
Cement Composites," in "High Performance Fiber Reinforced Cement
Composites - HPFRCC 2 ,'
A.E. Naaman and F.W. Reinhardt, Editors, RILEM Pb. 31, E. and
FN Spon, England, 1996; pp. 1 -24.
[7] Reinhardt, H.W., and Naaman, A.E.,, Editors, "High
Performance Fiber Reinforced Cement Composites - HPFRCC
3," RILEM Proceedings, PRO 6, RILEM Pbs., S.A.R.L.,
Cachan, France,
May 1999; 666 pages.
[8] Naaman, A.E., and Reinhardt, H.W., Editors, "High Performance
Fiber Reinforced Cement
Composites - HPFRCC 4," RILEM Proc., PRO 30, RILEM
Pbs., S.A.R.L., Cachan, France, June
2003; 546 pages.
[9] Reinhardt, H.W., and Naaman, A.E.,, Editors, "High
Performance Fiber Reinforced Cement
Composites - HPFRCC 5," RILEM Proceedings, PRO 53,
RILEM Pbs., S.A.R.L., Cachan, France,
June 2007; 518 pages.
[10] Parra-Montessinos, G., Reinhardt, H.W., and Naaman, A.E.,
“High Performance Fiber Reinforced
Cement Composites, HPFRCC6 ,” Rilem Bookseries, Springer,
2011, 559 pages.
[11] Naaman, A.E., and Reinhardt, H.W., “Setting the Stage: toward
Performance Based Classification of
FRC Composites,” in High Performance Fiber Reinforced Cement
Composites (HPFRCC-4), A.E. Naaman and H.W. Reinhardt, Editors,
RILEM Publications, Pro. 30, June 2003, pp. 1-4.
13
http://slidepdf.com/reader/full/hipermat-2012-kassel 33/1056
[12] Naaman, A.E., and Reinhardt, H.W., “High Performance Fiber
Reinforced Cement Composites
(HPFRCC-4): International RILEM Report,” Materials and Structures,
Vol. 36, Dec. 2003, pp. 710-
712. Also same in Cement and Concrete Composites, Vol. 26, 2004,
pp. 757-759.
[13] de Larrard, F.; Sedran, T., 1994, “Optimization of ul
tra-high-performance concrete by the use of a
packing model,” Cement and Concrete Research, Vol. 24, pp.
997 – 1009.
[14] Richard, P.; Cheyrezy, M., 1995, “Composition of reactive
powder concretes,” Cement and Concrete
Research, Vol. 25, No. 7, pp. 1501-1511.
[15] Richard, P., “Reactive powder concrete: a new ultra -high
strength cementitious material,” Proceedings of the 4
th International Symposium on Ultilisation of
High-Strength/High-Performance
Concrete, F. de Larrard and R. Lacroix, Editors, Presses des Ponts
et Chaussees, Paris, France,
1996, pp. 1501-1511.
[16] Schmidt, M.; Fehling, E.; Geisenhanslüke, C. (Editors): "Ultra
High Performance Concrete (UHPC )",
Proceedings of the International Symposium on UHPC, Kassel
University Press GmbH, Germany,
September 2004, 868 pages.
[17] Fehling, E, Schmidt, M., and Sturwald, S., Editors, “Ultra
High Performance Concrete (UHPC)”,
Proceedings of Second International Symposium on Ultra High
Performance Concrete, Kassel
University Press, GmbH, Germany, May 2008, 902 pages.
[18] Rossi, P, 2000, “Ultra-high Performance Fibre Reinforced
Concrete (UHPFRC): An Overview,” in
Proceedings of Fifth RILEM Symposium in Fibre-Reinforced Concretes
(FRC) - BEFIB’ 2000 , pp. 87
– 100.
[19] Rossi, P., “Ultra High Performance Concretes – A Summary
of the Curren t Knowledge,” Concrete
International , February 2008, pp. 31-34.
[20] Naaman, A.E., "New Fiber Technology: Cement, Ceramic and
Polymeric Composites," Concrete
International , Vol. 20, No. 11, July 1998.
[21] Naaman, A.E., "Fibers with Slip-Hardening Bond," in High
Performance Fiber Reinforced Cement
Composites - HPFRCC 3,' H.W. Reinhardt and A.E. Naaman, Editors,
RILEM Pro 6, RILEM
Publisations S.A.R.L., Cachan, France, May 1999, pp. 371-385.
[22] Naaman, A.E., “Half a Century of Progress Leading to Ultra
High Performance Fiber Reinforced
Concrete,” Rilem Proceedings PRO 81, Strain Hardening Cementitious
Composites (SHCC2 -Rio),
2 nd
International Rilem Conference, Edited by R.D. Toledo Filho,
F.A. Silva, E.A.B. Koenders, and
E.M.R. Fairbrairn, December 2011, Parts I: Overall Review, Part II:
Tensile Stress Strain Response, pp. 17-36.
[23] Yudenfreund, M.; Skalny, J.; Mikhail, R. S.; Brunauer, S.,
1972, “Hardened Portland Cement Pastes
of Low Porosity, II. Exploratory Studies. Dimensional Changes,”
Cement and Concrete Research,
Vol. 2, No. 3, May, pp 331-348.
[24] Roy, D. M.; Gouda, G. R.; Bobrowsky, A., 1972, “Very high
strength cement pastes prepared by hot
pressing and other high pressure techniques,” Cement and Concrete
Research, Vol. 2, pp. 349 –
366.
[25] Birchall J.D.; Howard A.J., Kendall K., 1981, “Flexural
strength and porosity of cements,” Nature
289, pp. 388 – 390.
[26] Bache, H. H., 1981, “Densified cement/ultrafine particle
-based materials, ” 2nd Int. Conference on
Superplasticizers in Concrete, Ottawa, Canada, 10-12 June.
[27] Hjorth, L., 1983, “Development and application of high-density
cement-based materials,” Phil. Trans. R. Lond ., A 310, pp.
167 – 173.
[28] Bache, H.H., “Compact Reinforced Concrete: Basic Principles,”
Aalborg Portland Cement -og
Betonlaboratoriet, CBL Report No. 41, 1987.
[29] Lankard, D., “Slurry Infiltrated Fiber Concrete (SIFCON):
Properties and Applications,” Very High
Strength Cement-Based Materials, J. F. Young, Editor,
Materials Research Society, Symposia
Proceedings Volume 42, Pittsburgh, Pennsylvania, 1985, pp.
277-286.
[30] Homrich, J., and Naaman, A.E., "Stress-Strain Properties of
SIFCON in Uniaxial Compression and
Tension," Report No. UMCE 87-7, Department of Civil Engineering,
University of Michigan, Ann
Arbor, October 1987, 138 pp. Also published as
AFWL-TR-87-115, August 1988.
[31] Naaman, A.E., and Homrich, J.R., "Tensile Stress-Strain
Properties of SIFCON," ACI Materials
Journal , Vol. 86, No. 3, May-June 1989, pp. 244-251.
[32] Naaman, A.E., "SIFCON: Tailored properties for structural
performance," in High Performance Fiber Reinforced Cement
Composites, RILEM Proceedings 15, E. and FN SPON, London, 1992,
pp.18-
38.
14
The Path to Ultra-High Performance Fiber Reinforced Concrete
(UHP-FRC): Five Decades of Progress
[33] Li, V.C., & H.C. Wu, "Conditions for pseudo
strain-hardening in fiber reinforced brittle matrix
composites," J. Applied Mechanics Review , V.45, No. 8,
August, pp. 390-398, 1992.
[34] Behloul, M., “Tensile Behavior of Reactive Powder Concrete,” 4
th
International Symposium on the
Utilization of High Strength High Performance Concrete, Paris,
France, 1996, pp. 1375-1381.
[35] Orange, G., Dugat, J., and Acker, P. “DUCTAL: New Ultra H igh
Performance Concretes. Damage,
Resistance and Micromechanical Analysis,” BEFIB 2000, Fifth RILEM
Symposium on Fiber-
Reinforced Concretes (FRC), Ed. By P. Rossi and G.
Chanvillard, Lyon, 2000, pp. 781-790.
[36] Chanvillard, G., and Rigaud, S., “Complete
Char acterization of Tensile Properties of Ductal UHPFRC
According to the French Recommendations,” in High Performance Fiber
Reinforced
Cement Composites (HPFRCC-4), A.E. Naaman and H.W. Reinhardt,
Editors, RILEM Publications,
Pro. 30, June 2003, pp. 95-113.
[37] Ulm, F.-J.; Acker, P., 2008, “Nanoengineering UHPC Materials
and Structures,” in Fehling, E,
Schmidt, M., and Sturwald, S., Editors, “Ultra High Performance
Concrete (UHPC)”, Proceedings of
Second International Symposium on Ultra High Performance Concrete,
Kassel University Press,
GmbH, Germany, May 2008, pp. 3-9.
[38] Graybeal, B.A. and Davis, M., “Cylinder or cube: strength
testing of 80 to 200 MPa (11.6 to 29 ksi)
ultra-high-performance fiber-reinforced concrete.” ACI
Materials Journal , Vol. 105, No. 6, 2008, pp.
603 –609.
[39] Benson, D.S.P., and Karihaloo, B.L., “CARDIFRC
– Development and Mechanical Properties,“ Part
I, Magazine of Concrete Research, Vol. 57, 2005, pp. 347-352. See
also Part III, Vol. 57, 2005, pp.
433-443.
[40] Jungwirth, J., 2006, “Zum Tragverhalten von zugbeanspruchten
Bauteilen aus Ultra-Hochleistungs-
Faserbeton,“ EPF Lausanne, Ph.D. thesis, 2006.
[41] Accorsi, M., and Meyer, C., „Ultra High Performance
Concrete Workshop,“ Columbia University,
New York, Jan. 2011; unpublished report.
[42] Kim, D.J., Naaman, A.E., and El-Tawil, S., “High Tensile
Strength Strain-Hardening FRC
Composites with Less Than 2% Fiber Content,” in Proceedings of 2nd
International Symposium,
Ultra High Performance Concrete (UHPC), Edited by E. Fehling, M.
Schmidt and S. Sturwald,
Universitat-Kassel, Germany, March 2008, pp. 169-176.
[43] Naaman, A.E., and Wille, K., “Some Correlation Between High
Packing Density, Ultra-High
Performance, Flow Ability, and Fiber Reinforcement of a Concrete
Matrix; BAC2010 – 2
nd
Iberian Congress on Self Compacting Concrete, University of
Minho – Guimaraes, Portugal. July 1-2, 2010 ,
Proceedings Edited by J. Barros, J. Sena-Cruz, R.M. Ferreira, and
A. Camoes, pp. 3-18.
[44] Wille, K., Naaman, A.E., and Parra-Montesinos, G. “Ultra High
Performance Concrete with
Compressive Strength Exceeding 150 MPa: A Simpler Way,” ACI
Materials Journal , Vol. 108, No.
No. 1, Jan. – Feb., 2011, pp. 46 – 54.
[45] Wille, K., Kim, D. and Naaman, A. E., “Strain-Hardening
UHP-FRC with Low Fiber Contents”,
Materials and Structures, published online Aug. 4th 2010, in
Journal Vol. 44, No. 3, 2011, pp. 583.
[46] Wille, K. and Naaman, A. E., “Fracture Energy of UHPFRC under
Direct Tensile Loading”,
FraMCoS-7 International Conference, Jeju, KOREA, May
23-28, 2010. Electronic Proceedings.
[47] Wille, K., Naaman, A.E., and El-Tawil, S., and
Parra-Montesinos, G., “Ultra-high performance
concrete and fiber reinforced concrete: achieving strength and
ductility with no heat curing,”
Materials and Structures, accepted for publication. 2011. [48]
Wille, K., Naaman, A.E., and El-Tawil, S. “Optimizing Ultra-High
Performance Fiber Reinforced
Concrete: Mixtures with Twisted Fibers Exhibit Record Performance
under Tensile Loading,”
Concrete International , Vol. 33, No. 9, Sept. 2011, pp.
35-41.
[49] Wille, K., and Naaman, A.E., “Bond-Slip Behavior of Steel
Fibers Embedded in Ultra High
Performance Concrete,” Proceedings of 18 European Conference on
Fracture and Damage of
Advanced Fiber-Reinforced Cement-Based Materials,
Contribution to ECF 18, Dresden, V.
Mechtcherine & M. Kaliske (eds.), Aedificatio Publishers,
Freiburg, September 2010, pp.99-111.
[50] Wille, K. and Naaman, A.E., “Pull-Out Behavior of High
Strength Steel Fibers Embedded in UHPC ,”
ACI Materials Journal , accepted for publication, in
press.
[51] Wille, K., and Parra-Montesinos, G., “Effect of Beam Size,
Casting Method and Support Conditions
on the Flexural Behavior of Ultra High Performance Concrete,”
ACI Materials Journal , in press,
2012.
[52] Zia, P., Leming, M.L., and Ahmad, S.H., “High Performance
Concretes, A State -of-the-Art Report,”
Strategic Highway Research Program, National Research Council,
Report No. SHRP-C/FR-91-103,
Washington, D.C., 1991.
Michael Schmidt
Institute of Structural Engineering, University of Kassel,
Germany
In Germany, a 12 Mio. € Research Program on UHPC has just been fin
ished. It started in 2005, covering
a wide range of topics related to UHPC. The program was funded by
the German Research Foundation
(DFG) and coordinated by the University of Kassel. More than 20
research institutes were involved. Its
purpose was to elaborate the basic knowledge necessary to
draft reliable Technical Standards covering
materials, material adequate design principles and innovative
construction and fitting technologies to
make UHPC a reliable, commonly available, economically favorable,
regularly applied material. This
paper describes the intention and the background of the
program, and it gives an overview over the
topics being dealt with and the results recently available. It is
part of a series of articles during this
conference presenting some topics of the program in more
detail.
Keywords: Ultra-High Performance Concrete, materials, design,
construction, state-of-the-art
1 Introduction
In Germany, a comprehensive 12 Mio. € Research Program on UHPC is
practically completed
covering a wide range of topics related to UHPC. The program was
funded by the German
Research Foundation (DFG) and coordinated by the University of
Kassel. More than 20
research institutes were involved, striving to elaborate the basic
knowledge necessary to draft
reliable technical standards covering both materials and design
principles to make UHPC a
reliable, commonly available, economically favorable, and regularly
applied material. The fields
of interest that the individual research projects concerned
themselves with include the suitability
and performance of raw materials including cements, inert or
reactive mineral fillers, artificial
nanoparticles, and improved plasticizers. Basic research on
appropriate mix designs for
different applications, the rheological specifics of the fresh
concrete and its hydration were
evaluated as well as the time dependent strength and deformation
behavior of hardened UHPC
with and without fibers. Also involved were scientists and
engineers working on adequate
design and construction procedures including new appropriate
technologies to build high
performance light and slender and thus sustainable
structures.
The Program was subdivided in 8 main topics, each being coordinated
by a working group
combining several intertwined projects:
Time-Dependent Behavior (shrinkage, creep)
Failure and Fatigue Behavior
Design and Construction
Testing The paper will present the overall aims and visions
of this project as well as the background
aspects that led to its installation, and the main results
elaborated from 2005 to 2011. In 2009,
the last of three two-year-periods of research was started,
primarily consisting of projects
researching design and construction. This contribution is a
“keynote” introduction to a series of articles at this
conference
presenting some results of the last research period in more detail
[10-16].
17
2 Objectives and technical background
The most notable characteristic of Ultra-High Performance Concrete
(UHPC) is its extremely
dense microstructure resulting in a steel-like compressive strength
of about 180 to 250 MPa
combined with a significantly improved durability. The structural
density results primarily from a
high packing density of fine and ultra-fine particles ≤ 125 μm
in the cement matrix, and a
comparatively low w/c-ratio of about just 0.20. The technological
basis was already laid by Bache [1] in Denmark in the 1980s.
Among
others, Okamura et. al contributed to the theoretical
background of particle optimization [2,3,4].
The large scale practical application did not begin until the 1990s
when new
superplasticizers based on polycarboxylate ethers (PCE) with a
significantly improved
performance were developed. For about 10 years, dry mixed UHPC
products have been
commercially available and have already been successfully applied
for bridges and other
visually and technically appealing, spectacular structures in
several countries.a, e.g. for the very
first bridge made of UHPC in Sherbrook in Canada.
The first German large scale application was the
“Gaertnerplatzbridge” in Kassel [5,6] built in
2007 (Figure 1). This very slender structure consists of a 3D steel
truss in combination with longitudinal girders and deck slabs, both
made of prefabricated, prestressed, fiber-reinforced
UHPC elements. Due to the high adhesive tensile strength of the
material, the slabs were glued
to the girders with an epoxy resin without any additional
mechanical fitting device [7]. The
bridge has been intensively monitored since its construction. This
data is used to validate the
assumptions that had to be made concerning the mechanical behavior
of the material, the
design and the load-bearing behavior of the whole structure in
practice. Up to now, the
collected data comply with the expectations.
Figure 1: Gaertnerplatzbridge in Kassel, under construction (left)
and in use (right) – a hybride bridge of
132 m span, longitudinal girders and deck plates fitted by gluing
with an epoxy resin mortar. Slab
thickness 85 mm only.
Apart from a small number of pilot projects, the application
of UHPC has been restricted due to
the fact that neither the material itself nor the material-specific
design of the structures are
covered by technical standards that already exist for ordinary or
even high performance concrete, e.g. the European Standard EN 206
or the design codes for concrete structures.
Thus, each application requires a single case approval from the
Building Authorities.
18
http://slidepdf.com/reader/full/hipermat-2012-kassel 39/1056
was discovered that the real shape and the texture of the fine
particles may significantly
increase the “effective” surface of the particle mix. Considering
this fact allows for a much better
theoretical optimization of the packing density and gives a much
better correlation between the
packing density, the water demand, the flowability, and the
viscosity of the fresh concrete
compared to conventional models and algorithms merely based on
spherical particles.
Microstructure
Electron microscopy investigations by Möser [10] using a
NanoSEM microscope confirmed that
the hydrate phases in UHPC are significantly shorter owing to the
high packing density, the low
w/c ratio of about 0.20 only and the high superplasticizer content
of UHPC. Figure 3 gives an image showing some unhydrated
microsilica particles surrounded by dense CSH-phases.
Table 1: Working groups inside the priority program and their
individual research topic.
Working group # of projects
Raw materials, rheology,
processing,
sustainability
4 - Influence of shape and texture of fine grains and of
interparticle forces on packing density and rheology
- Life cycle inventory on UHPC - UHPC with low-energy
binders - Optimization of the mixing process
Hydration and
microstructure
2 - Characterization of the microstructure - Micro- and
nanostructure of UHPC with nanotubes and
pyrogene SiO2
- Reduction of crack formation by internal curing
- Shrinkage-reducing chemical admixtures -
Time-dependent stress-strain behavior - Early age cracking
and durability - Autogenous shrinkage and
microstructure
Fiber efficiency and
conventional
reinforcement
3 - Load-bearing capacity of elements reinforced with fibers
and bars under tension and bending
- Ductility of UHPC with fibers and nanoparticles -
Self-compacting UHPC with fiber meshes
Strength and
deformation
2 - Fatigue under uni- or multiaxial loads - Modelling
of multiaxial strength
Durability 4 - Resistance to freezing and deicing
agents
- Resistance to chemical attacks (acid, sulphate) -
Fire safety of UHPC under load - Corrosion of steel fibers
and influence on the
microstructure
Design, construction,
and application
11 - Prestressed beams - Performance of steel fitting
elements for hybrid structures
(UHPC/steel) - Loadbearing of extensively loaded columns
- Fitting of elements by gluing - Thin fiber-reinforced
UHPC layers on conventional
concrete structures - UHPC under transverse (biaxial)
forces
- Anchorage and overlapping joints of reinforcing bars
- UHPC/steel pipes for truss structures - Thin-walled
pipes - Structural connection of precast elements -
Miniaturized fitting devices for slender slabs
Testing 2 - Adjusted test procedures for rheology and
strength - Fiber distribution and orientation
20
Sustainable Building with Ultra-High-Performance Concrete
(UHPC) – Coordinated Research Program in Germany
Due to the dense matrix, the modulus of elasticity is significantly
higher compared to ordinary
concrete. As a rule, the UHPC matrix shows brittle rupture. To
prevent uncontrolled cracking,
steel fibers are of great importance for nearly all applications of
UHPC. Usually, high strength
steel fibers are used to provide the brittle material with
sufficient ductility, and they improve its
tension and bending tension strength up to about 15 to 40 MPa
respectively. Thus UHPC
members are able to carry tension forces even without additional
reinforcing bars. For the
realization of wide-span structures, fibers can be combined with
non-prestressed or prestressed
reinforcement in the tensile zone. As a result of the interaction
of both types of reinforcement,
the stiffness of tensile members with mixed reinforcement is
significantly improved as
exemplified in Figure 4.
Figure 3: Matrix of UHPC, (left) compared to ordinary concrete
(right). SEM pictures of same scale.
Leutbecher [12] developed a mechanical model, which combines the
mechanical relationships
of the crack formation of reinforced concrete and the stress-crack
opening-behavior of the fiber-
reinforced concrete considering the equilibrium of internal and
external forces and the
compatibility of deformations. Experimental results confirmed that
crack distribution and thus
the crack width can obviously be controlled much more effectively
by a combination of fibers
and rebars than exclusively by high fiber content.
Figure 2: Interparticle forces between silica surfaces without
(grey) and with four superplasticizers measured with AFM with
different designed polymer-structures in nN [11].
Quartz
particle
UHPC
Matrix
21
17 mm); (a) stress-strain-relationship, (b) contribution of fiber
concrete [12].
Multiaxial strength
At the TU Dresden, behavior under multiaxial stress was
examined [13]. The tests were
performed in a triaxial test machine, as shown in Figure
5, which compressive or tensile forces
can be introduced with in all three spatial directions
independently. The results indicated that
the multiaxial strength – related to the uniaxial
strength – is considerably smaller than at normal
concrete. There was, for example, no strength increase whatsoever
in some stress ratios under
biaxial compression, compared to the uniaxial strength ( Figure 6).
Despite a steel fiber
content of up to 2.5 volume percent, UHPC exhibits very brittle
behavior under uniaxial and biaxial compression. An all-side
confinement due to increasing pressure components in both
lateral directions works against the progressive crack growth and
so it leads to increasing
strength, to increasingly ductile behavior and to an early
indication of failure (Figure 7). Related
to the uniaxial strength the strength increase of UHPC under
triaxial compression is smaller
than for normal concrete.
Figure 5: Triaxial experimental setup. Figure 6: Strength under
biaxial compression.[13]
22
-500
-400
-300
-200
-100
0
-30 -25 -20 -15 -10 -5 0 5 10 15
s 1/s 3 =
s 2/s 3 =
0.17
0.12
0.09
Stress s 3 [MPa]
(edge length 10 cm)
s 1 s 2
Figure 7: Stress-strain-behavior on compressive meridian
( s 1 = s 2 >
s 3 ).[13]
Shear Capacity
In the following projects [14,15], special design aspects
were investigated: the anchorage
behavior of strands in UHPC, and the shear behavior. This knowledge
is required basically for
an economic and safe design of material adequate slender
pretensioned beams. Due to the
high tensile strength of fiber-reinforced UHPC, the height of such
a beam can be reduced to
approx. 50 %. The remaining dead load amounts about 1/3 compared to
normal strength
concrete and the steel fibers serve as shear reinforcement. The
fiber action is illustrated in
Figure 8 by the red tensile forces in the simplified shear model.
Nevertheless additional shear
reinforcement – in solid beams as well as in beams with
openings – leads to further increase of
the shear capacity.
Figure 8: Crack pattern [14], simplified shear model and additional
shear reinforcement [15].
23
Ultra-High Performance Concrete (UHPC) is a high performance
material with steel-like
compressive strength of about 200 MPa and – reinforced
with steel fibers – significantly
increased tensile, bending, and shear strength, therefore allowing
for much lighter, longer
lasting and even more economic concrete structures – it
is sustainable material. To endorse
widespread and regular use of this material, the German Research
Foundation (DFG) funded an 12 Mio. € research program. About 20
research institutes were investigating in about 40
projects open scientific and technical questions covering the best
fitting raw materials, their
mixing and processing, rheological aspects and the specifics of the
hydration process, as well
as strength and deformation behavior of UHPC under uni- and
multiaxial static and dynamic
loads, and the resistance to chemical and frost attacks. The wide
arc of topics ends in the load-
bearing behavior of differently reinforced UHPC members and the
development of new fitting
technologies for slim precast elements. In the end, the research
results provided a safe
foundation to develop Technical Regulations for UHPC, enabling
concrete producers to create
mixtures and structural members using regionally available raw
materials, and to allow
designers and construction companies to build safe, long lasting,
and economic UHPC structures.
References
[1] Bache, H. H., “Densified cement/ultra fine particle based
materials”, 2nd International Conference on
Superplasticizers in Concrete, Ottawa, Canada, June 10-12,
1981.
[2] Okamura, H., Kazumasa, O., “Mix Design of Self -Compacting
Concrete”, Proc. of JSCE,V. 25, No. 6,
1995, pp. 107-120.
[3] Geisenhandlüke, C., Schmidt, M., “Methods for Modelling and
Calculation of High Density Packing
for Cement and Fillers in UHPC”, Proc. of the 1st International
Symposium on UHPC, Sept. 2004, Kassel University Press, pp.
303-312.
[4] Teichmann, T., Schmidt, M., “Influence of the packing density
of fine partickles on structure, strength
and durability of UHPC”, Proc. of the 1st International Symposium
on UHPC, Sept. 2004, Kassel
University Press, pp. 313-323.
[5] Fehling, E., Bunje, K., Schmidt, M., Schreiber, W., “The
Gärtnerplatzbrücke, Design of First Hybrid
UHPC-Steel Bridge across the River Fulda in Kassel, Germany”, Proc.
of the 2nd Inter nat. Symp. on
UHPC, March 05-07, 2008, Kassel, pp.581-588.
[6] Schmidt, M., Jerebic, D., “UHPC: Basis for Substainable
Structures – the Gaertnerplatz Bridge in
Kassel”, Proc. of the 2nd Internat. Symp. on UHPC, March 05-07,
2008, Kassel, pp. 619-625.
[7] Krelaus, R., Freisinger, S., Schmidt, M., “Adhesive Bonding of
UHPC Structural Members at the
Gaertnerplatz bridge in Kassel”, Proc. of the 2nd Internat. Symp.
on UHPC, March 05-07, 2008, Kassel, pp. 597-604.
[8] Wiens, U., Schmidt, M., “State of the Art Report on Ultra High
Performance Concrete of the German
Committee for Structural Concrete (DAfStb)”. Proc. of the 2nd
Internat. Symp. on UHPC, March 05-
07, 2008, Kassel, pp. 629-637.
[9] Fehling, E., Schmidt, M., Stürwald, S. (eds.), „Ultra -High
Performance Concrete – Proc. of the 2nd
International Symposium on UHPC“, Structural Materials and
Engineering Series, V. 10, Kassel
University Press, March 2008 – available online
under www.upress.uni-
kassel.de/publi/abstract.php?978-3-89958-376-2
[10] Möser, B., Pfeiffer, C., “Microstructure and Durability of
Ultra-High Performance Concrete”, Proc. of
the 2nd Internat. Symp. on UHPC, March 2008, pp. 417-424.
Sustainable Building with Ultra-High-Performance Concrete
(UHPC) – Coordinated Research Program in Germany
[11] M. Schmidt, M., Stephan, D., Krelaus, R., Geisenhanslüke, C.:
“The promising dimension in building
and construction: Nanoparticles, nanoscopic structures and
interface phenomena pt.1,” Cement
International, V. 5, 2007, pp. 86-100.
[12] Leutbecher, T., Fehling, E., “Crack Formation and Tensile
Behaviour of UHPC Reinforced with a
Combination of Rebars and Fibres”, Proc. of the 2 nd
Internat. Symp. on UHPC, March 2008, pp. 497-
504. [13] Curbach, M., Speck, K., “Ultra-High Performance Concrete
under Biaxial Compression”, Proc. of the
2 nd
Internat. Symp. on UHPC, March 2008, pp. 477-484.
[14] Bertram, G., Hegger, J., “Anchorage Behavior of Strands in
Ultra-High Performance Concrete,
Proceedings”, 8 th
Concrete, Tokyo, Japan in 2008, CD S3-3-6.
[15] Bertram, G., Hegger, J., “Pretensioned Concrete Beams made
of Ultra-High Performance Concrete”,
Proceedings, International fib Symposium, London, The United
Kingdom in 2009, CD (Mon 1600-
1730 D2).
http://slidepdf.com/reader/full/hipermat-2012-kassel 46/1056
State of the art of design and construction of UHPFRC structures in
France
Jacques Resplendino
Chief engineer, Chairman of the AFGC working group on UHPFRC,
President of the AFGC Mediterraneen delegation, Director South Est
SETEC TPI Vitrolles, France
After a fast reminder of the main caracteristics and
compositions of UHPFRC, the paper makes a fast
presentation of the new AFGC recommendations on UHPFRC by
emphasizing the evolutions which
benefit from experience feedback and from researches made on the
last decade.The presentation
continues by a general presentation of diverse recent realizations.
Every project will be presented by
trying to emphasize two essential points: the specific points of
the design which justified the use of
UHPFRC, the delicate points of the realization which bring out of
the fields of traditional structures.
The article ends by a synthesis of the technological breaks
engendered by these materials as long in the
methods of conception than in the processes of implementation;
breaks which impose on the engineers
and the designers to go out of the reflexes attached to the
traditional reinforced or prestressed concrete
structures.
Keywords: AFGC recommendations, design method, construction
process
1 Introduct ion – What is an Ultra High Performence Fiber-Reinfor
ced
Concrete (UHPRFC)
Ultra High Performance Fiber-Reinforced Concrete are materials with
a cement matrix, and a
characteristic compressive strength between 150 MPa and 250 MPa.
They contain steel fibers,
in order to achieve ductile behavior in tension and overcome if
possible the use of passive
reinforcement.
UHPFRC differ from high performance and very high performance
concretes: - the systematic use of fibres ensures that the material
is not brittle and can allow to avoid
any classical active or passive reinforcements,
- their compressive strength generally greater than 150 MPa,
- their composition with a high binder content that leads to the
absence of any capillary
porosity,
- their direct tensile strength of the matrix systematically higher
than 7 MPa.
The aim of UHPFRC development is to achieve high tensile strenths
through the
participation of the fibres which provide tensile strength after
the cement matrix has cracked.
When the tensile strength is sufficiently high, it may be possible,
depending on the way the
structure works and the way the loads to which it is subject, to
dispense with conventional
reinforcement.
In general, one removes any traditional passive reinforcement cage
in order to keep only the
main passive or active reinforcement bars required when the
resistance to major forces cannot
be provided by the fibers.
2 Major research and feedback from the 2002 recommendations
Reinforcement in the need to produce proofs o f convenience
To use UHPFRC structural material, the AFGC recommendations
introduced in 2002 the
concept of suitability tests to validate the methodologies of
implementation. The principle of these tests was to perform a
suitability test upstream of the actual structure: realize a
specimen
representative of the real structure, made of the same materials
and following the same
procedures as those proposed for the execution of the actual
structure.
27
http://slidepdf.com/reader/full/hipermat-2012-kassel 47/1056
In the case of industrialized products, the process corresponds to
the phase of development of
industrial production processes. During completion of real
structures, we were able to measure
how this approach was valid and necessary, including when companies
in charge of the
construction were very experienced in the use of UHPFRC. Indeed,
these suitability tests lead
almost invariably to optimize implementation process initially
planned, or to adapt the original
design when technological and/or economical aspects prevent an
adjustment of the process.
Sometimes suitability tests lead to slightly change the formula to
better control the rheology of
the material.
Confirmation of the relevance of the K coefficient phil
osophy
The influence of the UHPFRC implementation on the tensile strength
of the material in the
actual structure is dealt with in the recommendations through a
coefficient noted K that weights
the theoretical behavior laws issu from laboratory tests. This
coefficient is determined from the
results of flexural tests performed on specimens sawn in the
element built for suitability test
described above. This notion of K coefficient validated though
suitability test does not exist in
Eurocodes but has been introduce in the last draft of the fib Model
Code (MC2010 final draft
september 2011, article 5.6.7). This notion is essential for
UHPFRC, and shall be taken into account in any fiber-reinforced
concrete in which the structural strength is provided by the
fibers.
Fire behavior UHPFRC
Many recent tests [3] [4] (CERIB, CSTB) have determined for several
UHPFRC materials all
temperature mechanical properties in order to achieve numerical
simulations of fire resistance
(thermal conductivity, specific heat, thermal expansion,
compression and tensile strength,
Young's modulus). The new recommendations make a synthesis of these
tests and provide
values in order to make a first preliminary design of a UHPFRC
structure subject to precise
specifications of stability under fire.The UHPFRC behaviour under
high tempatures depending
strongly of the material, the recommandations remind that for a
final design one must
absolutely use the actual behaviour law of the material used to
build the structure.
Punching resistance
Several recent research on punching [5] [6] [7] [8] allow to
propose formulations in accordance
with the philosophy of Eurocodes.
Abrasion
The new version of the recommendations provides the main results of
abrasion tests (CNR test)
made under the realization of hydraulic works. The results confirm
the interest of UHPFRC used
as a shield in case of strong mechanical stresses.
Shear resistance
In the context of drafting the new guidelines, a compilation of all
existing international literature
on shear testing was performed. In addition, LCPC performed 12
additional tests beams made
with two different materials, with or without active and/or passive
reinforcement.
The entire investigation on the reported results and additional
testing campaign has allow to
adjust and consolidate the formula proposed in the
recommendations.
Tensile strength
Numerous tests were conducted to examine the tensile behavior of
traditionnal reinforced
UHPFRC (tension stiffening) [9] [10].
The new recommendations have been improved to better integrate the
research results.
These considerations have led to distinguish:
28
http://slidepdf.com/reader/full/hipermat-2012-kassel 48/1056
State of the art of design and construction of UHPFRC
structures in France
- UHPFRC with a hardening characterictic law in direct tension
(only very few material are
hardening in pure tension knowing that this requires a very high
fiber content),
- UHPFRC with a hardening average law in direct tension, but with a
softening