Designing and Building with UHPFRC E-Book

Jacques Resplendino

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 960

Veröffentlichungsjahr: 2013

Beschreibung

This book contains the proceedings of the international workshop "Designing and Building with Ultra-High Performance Fibre-Reinforced Concrete (UHPFRC): State of the Art and Development", organized by AFGC, the French Association for Civil Engineering and French branch of fib, in Marseille (France), November 17-18, 2009. This workshop was focused on the experience of a lot of recent UHPFRC realizations. Through more than 50 papers, this book details the experience of many countries in UHPFRC construction and design, including projects from Japan, Germany, Australia, Austria, USA, Denmark, the Netherlands, Canada... and France. The projects are categorized as novel architectural solutions, new frontiers for bridges, new equipments and structural components, and extending the service life of structures. The last part presents major research results, durability and sustainability aspects, and the updated AFGC Recommendations on UHPFRC.

Leseprobe

Contents

Foreword

UHPFRC’09 Scientific Committee

UHPFRC’09 Sponsors

PART I Genesis of a New Construction Material

Chapter 1 Introduction: What is a UHPFRC?

1.1. The basis of UHPFRC mix-design

1.2. The main UHPFRC available on the market

1.3. Brief history of the development of UHPC

1.4. The main features of UHPC

1.5. UHPFRC: a material that needs to revolutionize the technologies of design and implementation

1.6. UHPFRC and sustainable development issues

1.7. Conclusion and outlook

1.8. Bibliography

Chapter 2 UHPFRC: Science-driven Material Engineering Can Provide Sustainable Solutions

2.1. Introduction

2.2. Historical overview of concrete technology

2.3. The scientific concepts that have changed concrete technology

2.4. Current, economic, social and environmental challenges

2.5. Conclusion

2.6. Bibliography

Chapter 3 UHPFRC Development: Review of a Determining Application

3.1. Introduction

3.2. Context of repair works at Cattenom

3.3. Possible solutions

3.4. Chinon prototype

3.5. Material specifications

3.6. Codes

3.7. The Cattenom nuclear power plant renovation project

3.8. Quality control of the production process

3.9. The CIVAUX power plant renovation project

3.10. Conclusion

3.11. Bibliography

Chapter 4 UHPFRC Development: Experience with Ductal® Over the Past Two Decades

4.1. Introduction

4.2. Technology of UHPFRC

4.3. Main applications explored in the past two decades

4.4. Conclusion

4.5. Bibliography

Chapter 5 UHPFRC Development: The Experience of BSI® Applications

5.1. Introduction

5.2. First structural application: EDF nuclear power plants

5.3. Bourg-lès-Valence road bridges

5.4. Millau Viaduct toll-plaza canopy

5.5. Aqueduct along the high-speed rail bridge over Canal de l’Ourcq

5.6. ITE® beam

5.7. Architectural applications

5.8. Structural applications in construction

5.9. Applications to structural repair and reinforcement

5.10. Conclusion

5.11. Bibliography

PART II Novel Architectural Solutions

Chapter 6 The Enrico Navarra Gallery

6.1. General features

6.2. Structural gauging

6.3. Realization on the jobsite

6.4. Figures

6.5. Conclusion

6.6. Bibliography

Chapter 7 UHPFRC – A Material for Perforated Panels and Lattice Work: Controlling Shrinkage in Order to Experiment with Various Shapes

7.1. Introduction

7.2. Technology and applications for Ductal® UHPFRC

7.3. Perforated panels made of Ductal®: examples of applications

7.4. Discussion and prospects

7.5. How UHPFRCs connect structures and architecture

7.6. Conclusions

7.7. Bibliography

Chapter 8 The Jean Bouin Stadium

8.1. General features

8.2. Making of the UHPFRC roofing

8.3. Figures

8.4. Conclusion

8.5. Bibliography

PART III New Frontiers for Bridges

Chapter 9 The Passerelle des Anges Footbridge

9.1. General overview

9.2. Working design

9.3. Aeroelastic behavior

9.4. Precasting of the segments and decking

9.5. Installation

9.6. Conclusion

9.7. Bibliography

Chapter 10 Gärtnerplatz – Bridge over River Fulda in Kassel: Multispan Hybrid UHPC-Steel Bridge

10.1. Introduction

10.2. Advantages of UHPC for bridge construction

10.3. First UHPC bridge projects in Germany

10.4. Conceptual design of the Gäertnerplatzbruecke

10.5. Final design and execution

10.6. Additional investigations

10.7. Discussion, conclusions and acknowledgments

10.8. Bibliography

Chapter 11 Construction of the PS34 UHPFRC Bridge

11.1. BCV®: UHPFRC

11.2. General description of the PS34 bridge

11.3. Completion

11.4. Conclusion

11.5. Bibliography

Chapter 12 The Innovation and Application of UHPFRC Bridges in Japan

12.1. Introduction

12.2. Material performance of UHPFRC

12.3. Durability

12.4. Application of UHPFRC bridges

12.5. Toyota city gymnasium footbridge

12.6. Tokyo monorail girder

12.7. Ground support equipment (GSE) bridge

12.8. The mass production of slabs in Haneda Runway D

12.9.Conclusions

12.10.Bibliography

Chapter 13 Perspective on UHPCs from a Specialist Construction Company

13.1. Introduction

13.2. UHPC design and production in Australia

13.3. Australia and New Zealand project examples

13.4. Prospective applications and challenges to overcome

13.5. Concluding remarks

13.6. Bibliography

Chapter 14 Road Bridge “Wild”: Application of the UHPFRC Precast Segmental Construction Method for an Arch Structure

14.1. Introduction

14.2. The “Road Bridge – Wild” pilot project

14.3. Assembly and erection of the arch

14.4. Design and detailing

14.5. Full-scale test

14.6. Final comments for further applications and continuative research

14.7. Conclusions

14.8. Bibliography

Chapter 15 UHPC in the US Highway Infrastructure

15.1. Introduction

15.2. UHPC deployment

15.3. FHWA research efforts

15.4. Discussion and conclusion

15.5. Bibliography

Chapter 16 ITE® Beams, a Cost-effective Enduring Alternative to Filler-beam Decks

16.1. Applications of filler-beam decks

16.2. The ITE® beam

16.3. Comparison with conventional filler-beam construction

16.4. Pinel bridge – first application of ITE® beams

16.5. Detailed design

16.6. Conclusion

16.7. Summary of main figures and features

Chapter 17 UHPFRC Waffle Deck Concept for a Bridge at Livron-Loriol

17.1. General context

17.2. Generic design study

17.3. Experimental program for validation

17.4. Application to the Livron-Loriol composite bridge project

17.5.Conclusions

17.6. Acknowledgements

17.7. Bibliography

Chapter 18 UHPFRC Prototype for a Flexible Modular Temporary High-speed Railway Bridge

18.1. Motivation

18.2. Idea and concept

18.3. The flexible modular temporary bridge

18.4. Assembling and erection

18.5. Design and structural detailing

18.6. Special features in structural design and detailing with UHPFRC

18.7. Conclusion

18.8. Bibliography

Chapter 19 Effective use of UHPC for Deep Foundation Piles

19.1. Introduction

19.2. UHPC pile section design

19.3. Production of piles

19.4. Laboratory testing

19.5. Field testing

19.6. Summary and conclusions

19.7. Acknowledgements

19.8. Bibliography

Chapter 20 Design of Prestressed UHPFRC Girder Bridges According to Canadian Highway Bridge Design Code

20.1. Introduction

20.2. Mechanical properties of UHPFRC

20.3. Design approach for prestressed UHPFRC girders

20.4. Illustrative example – slab a on prestressed UHPFRC girders bridge

20.5. Conclusions

20.6. Bibliography

PART IV New Equipment and Structural Components

Chapter 21 CRC: Precast Applications of UHPFRC

21.1. Introduction

21.2. CRC properties

21.3. Structural applications

21.4. Production

21.5. Discussion

21.6. Bibliography

Chapter 22 Contribution of UHPFRCs in the Treatment of Thermal Bridges

22.1. Context and challenges of the study

22.2. Description of the thermal breaker

22.3. Tests carried out to characterize the properties of the breaker

22.4. Results and discussion

22.5. Conclusion

22.6. Bibliography

Chapter 23 UHPFRC Sunshades: An Elegant Solution for Regulating Heat Input in Buildings

23.1. Introduction

23.2. Ductal® UHPFRC technology: how it contributes to new sunshade design

23.3. The reason Ductal® is the most relevant material for sunshades

23.4. Nantes police headquarters: cable-stayed Ductal® sunshades

23.5. Results and discussion

23.6. Conclusions

23.7. Bibliography

Chapter 24 Investigation of UHPFRC Slabs under Blast Loads

24.1. Introduction

24.2. Previous research

24.3. Continuing and new research

24.4. Example of an existing application

24.5. Concluding remarks

24.6. Bibliography

Chapter 25 Experience with Prefabricated UHPFRC in the Netherlands

25.1 Introduction

25.2 Development of UHPFRC at Hurks Beton

25.3. Applications of UHPFRCs

25.4. Conclusions

25.5. Bibliography

Chapter 26 Precast Bridge Parapets in Ultra High Performance Fiber-reinforced Concrete

26.1. Introduction

26.2. Conception of parapets

26.3. Experimental program

26.4. Experimental results

26.5. Discussion

26.6. Conclusions

26.7. Acknowledgements

26.8. Bibliography

Chapter 27 Using UHPFRC for Complex Façade Elements

27.1. Introduction

27.2. Concrete technology

27.3. Experimental study

27.4. Tests results

27.5. Conclusions

27.6. Bibliography

Chapter 28 Innovative Field Cast UHPC Joints for Precast Bridge Decks. Design, Prototype Testing and Projects

28.1. Introduction

28.2. The solution

28.3. Characteristics of the UHPC jointing material technology

28.4. Testing

28.5. Design considerations for durability of the joint

28.6. Construction/installation

28.7. Conclusion

28.8. Bibliography

Chapter 29 The High Performance Cementitious Material (HPCM), a Cousin of UHPFRC for Long-life Pavement

29.1. Introduction

29.2. Design of the HPCM complex

29.3. Plain mortar tests

29.4. Cracking tests

29.5. Surface resistance tests

29.6. Miscellaneous

29.7. The way forward: two new projects to continue the development of HPCM

29.8. Conclusion

29.9. Bibliography

Chapter 30 Performance of UHPC Crossarms for High-voltage Transmission Lines

30.1. Introduction

30.2. Experimental program

30.3. Conclusions

30.4. Bibliography

Chapter 31 Structural Evaluation of Hybrid FRP-UHPC Bridge Girders

31.1. Introduction

31.2. Experimental program

31.3. Analytical work

31.4. Fatigue tests

31.5. Conclusions

31.6. Bibliography

Chapter 32 Museum of European and Mediterranean Civilizations (MuCEM): The Owner’s Ambition

32.1. Project background

32.2. Project evolution

32.3. Financing

32.4. Program

32.5. Owner’s point of view regarding UHPFRC use

32.6. Planning

Chapter 33 Museum of European and Mediterranean Civilizations (MuCEM): High UHPFRC Content Structure Design

33.1. Introduction

33.2. Structure description

Chapter 34 Museum of European and Mediterranean Civilizations (MuCEM): Experimentation and Modeling of Straight and Y-shaped UHPFRC Prestressed Columns Under the Action of an Off-centered Vertical Load

34.1. Introduction

34.2. Definition of the experimental program

34.3. Modeling of the test

34.4. Conclusion and prospects

PART V Extending the Life of Structures

Chapter 35 Seismic Retrofitting of Bridge Piers with UHPFRC Jackets

35.1. Introduction

35.2. Failure mode of rectangular bridge piers and research objectives

35.3. Description of the proposed retrofitting technique

35.4. Concrete mixes

35.5. Large-scale specimen design

35.6. Test set-up and loading condition

35.7. Specimen behavior

35.8. Conclusion, recommendations and acknowledgements

35.9. Bibliography

Chapter 36 Application of Ultra-high-strength Fiber-reinforced Concrete for Irrigation Channel Repair Works

36.1. Introduction

36.2. Overview of UFC

36.3. Abrasion resistance test

36.4. Roughness coefficient measurement

36.5. Overview of the Hosokawa river tunnel repair work project [MAT 07]

36.6. UFC panel production

36.7. UFC panel installation

36.8. Conclusion

36.9. Bibliography

Chapter 37 Using UHPFRC for Structural Reinforcement of Buildings and Civil Works

37.1. Introduction

37.2. Scope of UHPFRC application

37.3. Anti-abrasion linings

37.4. Architectural transformation of buildings

37.5. Structural reinforcement

37.6. Conclusion

37.7. Bibliography

PART VI Major Research Results

Chapter 38 Ultra High Performance Concrete for Prestressed Elements. Interest of Creep Prediction

38.1. Introduction

38.2. Experiments

38.3. Analytical models

38.4. Conclusions

38.5. Bibliography

Chapter 39 Rheology of Fiber-reinforced Cementitious Materials: Basic Concepts and Application to UHPFRC

39.1. Main concepts of FRC rheology

39.2. Application to UHPFRC

39.3. Bibliography

Chapter 40 Behavior of UHPFRC at High Temperatures

40.1. Introduction

40.2. Concrete mixes and main properties

40.3. Experimental program

40.4. Tests procedure and experimental settings

40.5. Results and discussion

40.6. Conclusions

40.7. Bibliography

Chapter 41 Ant Colony Optimization for Ultra High Performance Concrete Structures

41.1. Introduction

41.2. UHPC

41.3. Ant colony optimization

41.4 Algorithm

41.5. Case study

41.6. Discussion

41.7. Conclusions

41.8. Bibliography

Chapter 42 Investigation of Biaxial Stress States of UHPC Bridge Girders through Small Panel Testing and Finite Element Analysis

42.1. Introduction

42.2. Test specimens

42.3. Small panel testing

42.4. Experimental testing results

42.5. Finite element analysis of UHPC panels

42.6. Discussion

42.7. Conclusions

42.8. Bibliography

Chapter 43 An Overview of Research Advances from 2002 Concerning UHPFRC, in View of Updating the AFGC Recommendations

43.1. Context

43.2. UHPFRC mix-design and behavior in its fresh state

43.3. Casting, early-age behavior and tests

43.4. Structural behavior and modeling

43.5. Structural applications and dedicated experimental research programs

43.6. Other (possibly non-structural) applications and results

43.7. Conclusions: advances and research needs

43.8. Bibliography

PART VII Durability and Sustainability

Chapter 44 An Example of UHPFRC Recycling

44.1. Introduction

44.2. Choice of crushing method

44.3. Evaluation of recycled sand properties

44.4. Recycling of sand in high-quality concrete

44.5. Recycling of fibers in Ceracem®

44.6. Conclusions

44.7. Bibliography

Chapter 45 Ultra High Performance Concrete and its Contribution to Sustainable Development

45.1. Introduction

45.2. Sustainable construction

45.3. Intrinsic performance of the material

45.4. Description of the lifecycle assessment of the “fresh” material

45.5. Application of the LCA to a structure

45.6. Acknowledgements

45.7. Bibliography

Chapter 46 Field Experience of UHPFRC Durability in an Air Cooling Tower

46.1. Context: UHPFRC girders in a nuclear power plant

46.2. Investigations after 10 years of exposure

46.3. Conclusions

46.4. Acknowledgements

46.5. Bibliography

PART VIII Updated AFGC Recommendations

Chapter 47 Ultra High Performance Concrete: New AFGC Recommendations

47.1. Introduction

47.2. Major research and feedback from the 2002 recommendations

47.3. Main changes compared to the 2002 recommendations

47.4. Conclusion

47.5. Bibliography

Chapter 48 New AFGC Recommendations on UHPFRC: Chapter 1 – Mechanical Characteristics and Behavior of UHPFRC

48.1. Introduction

48.2. The new recommendations

48.3. Bibliography

Chapter 49 New AFGC Recommendations on UHPFRC: Chapter 2 – Design

49.1. Introduction

49.2 Fiber orientation (K-coefficient)

49.3 Strain hardening behavior

49.4. Concrete cover adapted for UHPFRC

49.5. Shear stress

49.6. Shear between concrete cast at different times

49.7. Passive reinforcement anchorage length

49.8. Load transfer tests for post-tensioning anchorages

49.9. Bibliography

Chapter 50 New AFGC Recommendations on UHPFRC: Chapter 3 – Durability

50.1. Introduction

50.2. Durability indicators of UHPFRCs

50.3. UHPFRC behavior under extreme temperatures

50.4. UHPFRC and delayed ettringite formation

50.5. Bibliography

Chapter 51 Ultra High Performance Concrete and Sustainable Development: Synthesis of Available Data

51.1. Introduction

51.2. Environmental impact of UHPFRC mixes and manufacturing

51.3. Environmental impact and cost of UHPC structures over their whole lifespan

51.4. New possibilities for retrofitting or repairing existing structures

51.5. Social aspects of sustainable development

51.6. Recyclability

51.7. Bibliography

List of Authors

Index

Author Index

French Summaries

First published 2011 in Great Britain and the United States by ISTE Ltd and John Wiley & Sons, Inc.

Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitted under the Copyright, Designs and Patents Act 1988, this publication may only be reproduced, stored or transmitted, in any form or by any means, with the prior permission in writing of the publishers, or in the case of reprographic reproduction in accordance with the terms and licenses issued by the CLA. Enquiries concerning reproduction outside these terms should be sent to the publishers at the undermentioned address:

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The rights of François Toutlemonde and Jacques Resplendino to be identified as the authors of this work have been asserted by them in accordance with the Copyright, Designs and Patents Act 1988.

Library of Congress Cataloging-in-Publication Data

Designing and building with UHPFRC / edited by Jacques Resplendino, François Toutlemonde.

p. cm.

Includes bibliographical references and index.

ISBN 978-1-84821-271-8 (hardback)

1. Concrete construction. 2. Fiber-reinforced concrete. I. Resplendino, Jacques. II. Toutlemonde, François, 1965- III. Title.

TA683.D374 2010

624.1'8341--dc22

2010038377

British Library Cataloguing-in-Publication Data

A CIP record for this book is available from the British Library

ISBN 978-1-84821-271-8

Foreword

Over 330 participants attended the international workshop “Designing and Building with UHPFRC: State of the Art and Development”, organized by AFGC, the French Association for Civil Engineering and French branch of fib (fédération internationale du béton), in Marseille (France), November 17-18, 2009. The event focused on the experience gained from many recent ultra-high performance fiber-reinforced concrete (UHPFRC) realizations, presented the updated AFGC Recommendations on UHPFRC, and took advantage of the workshop taking place in Marseille by presenting the MUCEM project, an outstanding exhibition building, with varied innovative structural and decorative applications of this material, which is to be erected on Marseille harbor by 2013.

While UHPFRC has deserved special sessions in scientific conferences from the mid-1990s, especially in the series of International Symposia on the Utilization of High Strength/High Performance Concrete which took place in Paris (France) 1996, Sherbrooke (Canada) 1999, Leipzig (Germany) 2002, Washington DC (USA) 2005, and Tokyo (Japan) 2008, as well as the dedicated symposia held in Kassel (Germany) in 2004 and 2008, it was felt necessary to demonstrate, especially to contractors, architects, designers and owners, the growing expansion of UHPFRC applications, and to share the technical experience gained in designing and building with this material.

Through more than 50 presentations, many countries shared their experience, including projects from Japan, Germany, Australia, Austria, USA, Denmark, the Netherlands, Canad and France. These projects, collected for stimulating further creativity using UHPFRC, could be categorized as renewed architectural opportunities, structures of extended spans and limits, new equipment and components for building and civil structures, and applications for strengthening and reinforcement. The economic feasibility and interest of UHPFRC has been demonstrated mainly for (foot)bridges, outstanding buildings, large pre-cast series and special (high added value) applications. Furthermore, the safety and durability of UHPFRC projects have also been confirmed by recent advances in research, especially concerning fire resistance and durability. As highlighted during the workshop, UHPFRC has benefitted from a fruitful science-based approach of material optimization and civil engineering, which should continue to drive concrete innovation. This may encourage further promising applications, provided the required additional research efforts are carried out, including:

− structural strengthening and the possibility of lighter new buildings in a seismic context;

− use of UHPFRC in sandwich / composite elements for construction;

− wider use of UHPFRC in durability-related applications (pavements, sewage, water, etc.).

In terms of general needs for the development of UHPFRC, the workshop helped identify a number of desired advances that concern the whole concrete technology and community:

− development of rational tools for optimization of casting processes and fiber placement control, which is also under development for SCC;

− development of clarified tools for evaluation of CO2 print and sustainability, and effective possibilities of favoring global cost-effective offers (with lower maintenance costs);

− development of a reasonably updated frame for design and order including possible creativity;

− special information and education for designers, checkers, contractors, owners, assistants, even over a relatively small market sector, which still represents a challenge, although the Marseille workshop may have been the first step!

Since the presentations made during the workshop have been available in English sometimes only in a short version, the UHPFRC’09 workshop organizers have decided to publish the full-length contributions in an edited English version of the Workshop Proceedings, so that the present state-of-the art of UHPFRC projects and realizations can be made available worldwide in a reference book. The technical content of the present book should be of special benefit to:

− researchers, scientists, teachers and research engineers, for the development and dissemination of sound knowledge and scientific evidence gained in UHPFRC applications, as detailed herein, on which they can base safe and sustainable use of this material;

− architects and designers, who can use it to imagine creative, safe, durable and worthy UHPFRC applications, which represent a new frontier of cement materials use and building art;

− owners and contractors, who can rely on successful experience described herein for taking the risk of non-conventional, technically demanding, yet possibly outstanding UHPFRC solutions.

Thanks to the effort of the UHPFRC’09 Scientific Committee and the help of Nadget Berrahou and Jocelyne Jacob at AFGC, it is our honor and pleasure to have collected and edited these contributions, and to provide these Proceedings as a comprehensive reference work for the future of UHPFRC.

François ToutlemondeVice-chairman of UHPFRC’09 scientific committee

Jacques ResplendinoChairman of UHPFRC’09 international workshop

October 2010

UHPFRC’09 Scientific Committee

Jacques RESPLENDINO,

DIRMéd, MEEDDM

, chair

France

Dr François TOUTLEMONDE,

LCPC

, vice-chair

France

Prof. Franz Josef ULM,

MIT

, vice-chair

USA

Bendt AARUP,

CRC Technology

Denmark

Prof. Paul ACKER,

Lafarge

France

Laurent BOUTILLON,

Vinci

France

Prof. Eugen BRÜHWILER,

EPFL

Switzerland

Prof. Myriam CARCASSES,

Paul Sabatier University

France

Danièle CHAUVEL,

EDF

France

Dr Christian CLERGUE,

Vicat

France

Prof. Ekkehard FEHLING,

Kassel University

Germany

Bernard FOURÉ,

Consultant

France

Dr Hans Rudolf GANZ,

VSL

Switzerland

Prof. Ian GILBERT,

University of New South Wales

Australia

Dr Benjamin GRAYBEAL,

FHWA

USA

Prof. Makoto KATAGIRI,

Taiheiyo Cement Corporation

Japan

Pierre MARCHAND,

Sétra / LCPC

France

Prof. Bruno MASSICOTTE,

Ecole Polytechnique de Montréal

Canada

Dr Pierre PIMIENTA,

CSTB

France

Prof. Karl Heinz REINECK,

Stuttgart University

Germany

Dr Pierre ROSSI,

LCPC

France

Dr Patrick ROUGEAU,

CERIB

France

Prof. Yasuhiko SATO,

University of Hokkaido

Japan

Prof. Lutz SPAROWITZ,

Graz Technical University

Austria

Yoshihiro TANAKA,

Taisei Corporation

Japan

Thierry THIBAUX,

Eiffage

France

Prof. Joost WALRAVEN,

TU-Delft

The Netherlands

The members of the UHPFRC’09 Scientific Committee are gratefully acknowledged for the time and expertise devoted to selecting the papers, and reviewing and suggesting amendments for improvement of the contributions collected in this book.

UHPFRC’09 Sponsors

AFGCAssociation française de génie civil − French Association for Civil Engineering, French branch of fib, IABSE and RILEM

fibfédération internationale du béton − International Federation for Structural Concrete

MEEDDM / CGDDMinistère de l’écologie, de l’énergie, du développement durable et de la mer / Commissariat général au développement durable − French Ministry in charge of sustainable development

EFBEcole française du béton − French foundation for knowledge on concrete

CERIBCentre d’études et de recherches de l’industrie du béton − Research center for precast concrete industry

Eiffage TP

Lafarge

Vicat

VSL

The financial support of the UHPFRC’09 Sponsors enabled the organization of the international workshop in Marseille 17-18 November 2009, with over 330 attendees, thus collecting the valuable information provided in this book.

PART I

Genesis of a New Construction Material

Chapter 1

Introduction: What is a UHPFRC?

After recalling the definition of ultra high performance fiber-reinforced concretes (UHPFRC), this chapter details the basic elements of their composition. It presents the main products available on the market and provides a brief history of the development of these concretes. Then the chapter details the main features of UHPFRC, highlighting what distinguishes them from conventional concrete: heat treatment, delayed effects, compressive and tensile strength, performance in terms of sustainability and quality of the faces. The chapter analyzes the changes in design and implementation technology necessitated by UHPFRC development and ends with a presentation of the interest in these materials as part of sustainable development.

UHPFRC 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, if possible, overcome the use of passive reinforcement. UHPFRC differ from high performance and very high performance concretes in that:

– the systematic use of fibers ensures that the material is not brittle and can allow us to avoid any classical active or passive reinforcements;

– their compressive strength is generally greater than 150 MPa;

– their mix-design with a high binder content leads to the absence of any capillary porosity;

– the direct tensile strength of the matrix is systematically higher than 7 MPa.

The aim of UHPFRC development is to achieve high tensile strengths through participation of the fibers, 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 subjected, dispense with conventional reinforcement. In general, we remove any traditional passive reinforcement cage in order to keep just the main passive or active reinforcement bars required when the resistance to major forces cannot be provided by the fibers.

1.1. The basis of UHPFRC mix-design

In ordinary concretes, the ratio of water to binder (W/B) is in the order of 0.4 to 0.6. To obtain a high performance concrete, the W/B ratio has to be decreased to below 0.4 (0.3 to 0.35). This reduction is possible thanks to the addition of an admixture (superplasticizer), which allows deflocculating binder, and cement with minimal amounts of water. In a high-performance concrete, if we wish, we can complement the W/B reduction with an extension of the granular spectrum through ultra-thin micrometer-sized additions (generally consisting of silica fume), 5 to 10 times smaller than the size of the cement particles. To obtain UHPFRC, we should further decrease the W/B ratio to below 0.25 (about 0.16 to 0.2). This decrease is generally obtained through a significant increase in the binder amount, and a quantity of water substantially the same as in conventional concrete. We should also add a large quantity of ultra-thin addition (typically silica fume) amounting about 20% of the cement mass. The UHPFRC aggregate size is also very small compared to ordinary concrete – the largest grain size is of the order of millimeters – and particular attention is given to the nature of the aggregates, which must present sufficient mechanical strength to avoid being the weak points of the mixture. The resulting material is extremely compact and has quite remarkable mechanical and durability performance.