WP 14 High Performance Fiber Reinforced Cementitious Composites

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 6. 07. 2004 Mid-term assessment London July 5 -6 2004 1

Outline 1. Conceptual approach 2. Properties of UHPFRC 3. Objectives of WP 14 4. Progress at mid term 5. State of the Art Review 6. Protective function 7. Structural response 8. Future works 9. Expected benefits 10. References 6. 07. 2004 Mid-term assessment London July 5 -6 2004 2

1. Conceptual approach Local « hardening » of critical zones subjected to severe mechanical or environmental loads 6. 07. 2004 Mid-term assessment London July 5 -6 2004 3

Motivation 1. Ultra compact HPFRCC (UHPFRC) provide a longterm durability in order to avoid multiple interventions on structures during their service life. 2. 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. 6. 07. 2004 Mid-term assessment London July 5 -6 2004 4

Rehabilitation strategy 6. 07. 2004 Mid-term assessment London July 5 -6 2004 5

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 (lf=10 mm) at a very high dosage: 480 kg/m 3. • Outstanding mechanical properties with significant tensile strain hardening. 6. 07. 2004 Mid-term assessment London July 5 -6 2004 6

Mechanical properties of UHPFRC (CEMTECmultiscale®) NC fcc [MPa] 168 51 Ecc [GPa] 48 38 fct [MPa] 11. 0 3. 4 fct, 1 st [MPa] 9. 1 - Mechanical properties at 28 days (mean values) Habel (2004) NC: normal concrete Tensile behaviour of UHPFRC CEMTECmultiscale® developped by Rossi et al. (2002) 6. 07. 2004 Mid-term assessment London July 5 -6 2004 7

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. ). 6. 07. 2004 Mid-term assessment London July 5 -6 2004 8

Main issues for application • • • Properties in fresh state – processing. Combination with bituminous concrete (adhesivity) 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. 6. 07. 2004 Mid-term assessment London July 5 -6 2004 9

Composite structures Mechanical compatibility with substrate. Material properties + Restraint 6. 07. 2004 Mid-term assessment London July 5 -6 2004 10

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 6. 07. 2004 Mid-term assessment London July 5 -6 2004 11

Milestones Milestone M 4: Identification of most important phenomena for defining main test programme. Results of numerical simulations and preliminary tests available. Date due: Month 6 Milestone M 12: 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 M 18: Choice of on site applications for pilot tests of HPFRCC. Results and interpretation of main test series available. Date due: Month 21 6. 07. 2004 Mid-term assessment London July 5 -6 2004 12

Deliverables D 13: Report on preliminary studies for the use of HPFRCC for rehabilitation of road infrastructure components (Mon. 18) D 18: Test report on laboratory testing of UHPFRC (Mon. 24) D 22: Test report on pilot field trials of UHPFRC (Mon. 30) D 25: Specifications for the use of CI and UHPFRC (Month 33) D 26: Modelling of UHPFRC in hybrid structures (Mon. 33) D 31: Guidelines for the use of UHPFRC WP 12 (Mon. 36) 6. 07. 2004 Mid-term assessment London July 5 -6 2004 13

4. Progress at mid-term 6. 07. 2004 Mid-term assessment London July 5 -6 2004 14

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 6. 07. 2004 Mid-term assessment London July 5 -6 2004 15

6. Protective function b) Measurement of the air permeability a) Air permeability of new layers on composite beams, Habel (2004) 6. 07. 2004 Mid-term assessment London July 5 -6 2004 16

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 6. 07. 2004 Mid-term assessment London July 5 -6 2004 17

Experimental techniques • Uniaxial tensile test • Measurement basis : 100 mm • Specimen unloaded after predefined deformation is reached • Core of f = 100 mm extracted 6. 07. 2004 Mid-term assessment London July 5 -6 2004 18

Permeability of damaged UHPFRC • Damage test • Glycol permeability test • et loading = 0. 25 % • et unloading 0. 13 % 6. 07. 2004 • Source of variability: crack pattern and heterogeneity Mid-term assessment London July 5 -6 2004 19

Tensile limit states for permeability Charron et al. (2004) 6. 07. 2004 Mid-term assessment London July 5 -6 2004 20

Structural application • Hybrid beam made of NC and UHPFRC F F UHPFRC As, UHPFRC = 314 mm 2 50 As, upp = 339 mm 2 150 Deflection 1200 UHPFRC NC 2400 1200 As, low = 1010 mm 2 NC 300 [mm] Habel (2004) Charron (2004) 6. 07. 2004 Mid-term assessment London July 5 -6 2004 21

Structural application (…) • Load limitations • Avoid high creep deformations, sc < 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 6. 07. 2004 Mid-term assessment London July 5 -6 2004 22

Structural application (…) • Load capacity limitations • Avoid high creep deformations, sc < 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 6. 07. 2004 Mid-term assessment London July 5 -6 2004 23

7. Structural response NL: 10 cm NL: 5 cm a) b) Flexural tests on composite beams with UHPFRC: a) without rebars, b) with rebars, Habel (2004). 6. 07. 2004 Mid-term assessment London July 5 -6 2004 24

Crack patterns at peak forces UHPFRC with rebars (r=2%) UHPFRC without rebars Habel (2004) 6. 07. 2004 Mid-term assessment London July 5 -6 2004 25

Proposed geometries for rehabilitation - Habel, (2004) P: protection (hu=10 to 30 mm) PR: protection+ replacement of corroded rebars (hu=30 to 50 mm) R: protection + increase of load carrying capacity with rebars (hu>=50 mm) 6. 07. 2004 Mid-term assessment London July 5 -6 2004 26

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. 6. 07. 2004 Mid-term assessment London July 5 -6 2004 27

Structural tests on composite beams 6. 07. 2004 Mid-term assessment London July 5 -6 2004 28

Structural tests on composite walls 6. 07. 2004 Mid-term assessment London July 5 -6 2004 29

Structural tests on composite slabs 6. 07. 2004 Mid-term assessment London July 5 -6 2004 30

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. 6. 07. 2004 Mid-term assessment London July 5 -6 2004 31

Pilot tests on site 6. 07. 2004 Mid-term assessment London July 5 -6 2004 32

Sensitivity to a slope Tolerance to 3 to 5 % slopes for current mixes 6. 07. 2004 Mid-term assessment London July 5 -6 2004 33

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. 6. 07. 2004 Mid-term assessment London July 5 -6 2004 34

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. 6. 07. 2004 Mid-term assessment London July 5 -6 2004 35