WP 14

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WP 14 High Performance Fiber Reinforced
Cementitious Composites for Rehabilitation

• WP leader Dr. E. Denarié, MCS-EPFL (CH)
• Contractors MCS-EPFL (CH), Prof. E. Brühwiler
• Dr. K. Habel, Dr. J.P. Charron, A. Kamen, J.
  Wuest,
• R. Gysler, S. Demierre
• LCPC (France), Dr. P. Rossi
• TRL (UK), Dr. R. Woodward

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Outline

• Conceptual approach
• Properties of UHPFRC
• Objectives of WP 14
• Progress at mid term
• State of the Art Review
• Protective function
• Structural response
• Future works
• Expected benefits
• References

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1. Conceptual approach
Local  hardening  of critical zones subjected
to severe mechanical or environmental loads
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Motivation

• Ultra compact HPFRCC (UHPFRC) provide a long-term
  durability in order to avoid multiple
  interventions on structures during their service
  life.
• Ultra compact HPFRCC materials can be applied
• as thin watertight overlays ,
• as repair or reinforcement layers, with a
  thickness from 20 to 50 mm, alone or combined
  with reinforcement bars,
• for prefabricated elements such as curbs,
• in critical zones such as transitions from
  joints to the main structural elements.

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Rehabilitation strategy
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2. Ultra compact HPFRCC (UHPFRC)

• Ultra compact cementitious matrix.
• Excellent resistance towards ingress of water,
  gases and detrimental substances such as chloride
  contaminated water.
• Self-compacting.
• Reinforcement with short steel fibers (lf10 mm)
  at a very high dosage 480 kg/m3.
• Outstanding mechanical properties with
  significant tensile strain hardening.

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Mechanical properties of UHPFRC
UHPFRC (CEMTECmultiscale) NC
fcc MPa 168 51
Ecc GPa 48 38
fct MPa 11.0 3.4
fct,1st MPa 9.1 -
Mechanical properties at 28 days (mean values)
NC normal concrete
Habel (2004)
Tensile behaviour of UHPFRC
CEMTECmultiscale developped by Rossi et al.
(2002)
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3. Objectives of WP 14

• Demonstrate applicability and advantages of
  HPFRCC materials for the rehabilitation of
  concrete road infrastructure components
  (including aspects of global Life-Cycle-Cost in
  relation with WP 12).
• Make a first step towards the optimisation of
  these materials for rehabilitation.
• Provide guidelines for use of these materials and
  their further optimisation (numerical simulation
  tools, test methods, limit states for design,
  etc.).

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Main issues for application

• Properties in fresh state processing.
• Combination with bituminous concrete
  (adhesivity).
• Early age and long term behavior.
• Mechanical compatibility with substrate.
• Physico-chemical compatibility with substrate.
• Protective function - effect of damage on
  transport properties.
• Influence of geometry of element to be repaired.
• Statistical distribution of properties.
• Test methods and compliance criteria.
• Modelling of mechanical behavior.
• Design methods.

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Composite structures

• Mechanical compatibility with substrate.
• Material properties Restraint

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Tasks

• WP 14 is divided into 5 tasks, as follows
• 14.1 Preliminary Study
• 14.2 Testing
• 14.3 Interpretation modelling
• 14.4 Numerical parameter study
• 14.5 Specifications documents for application

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Milestones

• Milestone M4 Identification of most important
  phenomena for defining main test programme.
  Results of numerical simulations and preliminary
  tests available. Date due Month 6
• Milestone M12 Selection of materials for main
  test series of HPRFCC. Preliminary test results
  and conclusion concerning materials for the main
  tests available. Date due Month 12
• Milestone M18 Choice of on site applications for
  pilot tests of HPFRCC. Results and interpretation
  of main test series available. Date due Month 21

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Deliverables

• D13 Report on preliminary studies for the use of
  HPFRCC for rehabilitation of road infrastructure
  components (Mon.18)
• D18 Test report on laboratory testing of UHPFRC
  (Mon.24)
• D22 Test report on pilot field trials of UHPFRC
  (Mon.30)
• D 25 Specifications for the use of CI and
  UHPFRC (Month 33)
• D26 Modelling of UHPFRC in hybrid structures
  (Mon.33)
• D31 Guidelines for the use of UHPFRC ? WP 12
  (Mon. 36)

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4. Progress at mid-term
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5. State of the art Review

• Relevant documents (scientific, technical, norms,
  guidelines, etc.) from following countries were
  taken into consideration
• France, Switzerland, Belgium, Canada
• Germany, Austria
• United Kingdom, USA
• Italy
• Japan, China
• Denmark, Sweden, Norway

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6. Protective function

b) Measurement of the air permeability
a) Air permeability of new layers on composite
beams, Habel (2004)
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Serviceability of UHPFRC

• Assess the influence of cracking on the
  permeability of a UHPFRC
• Suggest serviceability limit states for an UHPFRC
  according to exposure conditions
• Optimise composite UHPFRC-concrete structures

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Experimental techniques

• Uniaxial tensile test
• Measurement basis 100 mm
• Specimen unloaded after predefined
• deformation is reached
• Core of f 100 mm extracted

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Permeability of damaged UHPFRC

• Glycol permeability test
• Source of variability crack pattern and
  heterogeneity

• Damage test
• et loading 0.25
• et unloading ? 0.13

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Tensile limit states for permeability
Charron et al. (2004)
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Structural application

• Hybrid beam made of NC and UHPFRC

Habel (2004) Charron (2004)
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Structural application ()

• Load limitations
• Avoid high creep deformations, sc lt 0.5 fc
• Protect reinf. bars against corrosion, ss limited
  BAEL, 1999

• Use NC specifications
• for UHPFRC
• conservative design
• benefits provided by
• UHPFRC not optimal

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Structural application ()

• Load capacity limitations
• Avoid high creep deformations, sc lt 0.5 Fc
• Protect reinf. bars against corrosion, ss limited
  by permeability

• Use UHPFRC limits
• suggested in this study
• design less conservative
• better use of UHPFRC
• potential

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7. Structural response
NL 10 cm

NL 5 cm

• Flexural tests on composite beams with UHPFRC a)
  without rebars, b) with rebars, Habel (2004).

b)
a)
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Crack patterns at peak forces
UHPFRC with rebars (r2)
UHPFRC without rebars
Habel (2004)
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Proposed geometries for rehabilitation - Habel,
(2004)
P protection (hu10 to 30 mm) PR protection
replacement of corroded rebars (hu30 to 50 mm)
R protection increase of load carrying
capacity with rebars (hugt50 mm)
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8. Future works

• Structural response (ongoing)
• Three types of composite members walls, slabs
  and beams, to test the application of UHPFRC as
  protective or reinforcing layer.
• Three kinds of action effects Effect of
  autogenous shrinkage at early age until 3 month,
  effect of sustained creep loads (3 to 9 month),
  effect of fatigue loading (age 3 month, duration
  1 month - 15 million cycles).
• Main parameters monolithic behaviour of the
  composite members and avoidance of transverse
  cracking.

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Structural tests on composite beams
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Structural tests on composite walls
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Structural tests on composite slabs
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Pilot tests on site

• Application of UHPFRC for the rehabilitation of
  the deck and curbs of a road bridge in
  Switzerland ? october 2004.
• Determination of the best surface treatment of
  UHPFRC at fresh test to guarantee adhesivity with
  bituminous concrete.

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Pilot tests on site
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Sensitivity to a slope
? Tolerance to 3 to 5 slopes for current mixes
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9. Expected benefits

• Targeted local hardening of highway structures,
  in most critical zones.
• Simplification of the construction process.
• Reduction of the dead loads (superstructure and
  pavement).
• ?Increase of the performance of existing and new
  structures (protection and reinforcement).
• ?Dramatic decrease of the number and severity of
  interventions during service life.

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10. References

1. Charron, J.P., Denarié, E. Brühwiler, E.
   Permeability of UHPFRC under high stresses.
   Proceedings, RILEM Symposium, Advances in
   Concrete Through Science and Engineering, March
   22-24, 12 p., Chicago, USA, 2004.
2. Habel K. Structural behaviour of composite
   UHPFRC-concrete elements, Doctoral thesis,
   Swiss Federal Institute of Technology, Lausanne,
   Switzerland, 2004, to be published.
3. Rossi P., Development of new cement composite
   material for construction, Proceedings of the
   International Conference on Innovations and
   Developments In Concrete Materials And
   Construction,, University of Dundee, Ed. by R. K.
   Dhir, P. C.Hewlett, L. J. Csetenyi, pp 17-29,
   Dundee, Scotland, September, 2002.