table of contents m. mckenzie guidelines on the selection of innovative techniques for the...
TRANSCRIPT
![Page 1: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/1.jpg)
Table of contents
M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures 3A. Žnidarič Optimised assessment of bridges 31E. Denarié Ultra High Performance Fibre Reinforced Concretes (UHPFRC)
for rehabilitation – 1. Motivation and Background 69M. Richardson Guidance on use of surface-applied corrosion inhibitors
Context and Framework of Guidance 97A. Žnidarič Optimised assessment of bridges
Case study 1 - Medno bridge - Soft Load Testing 135A. O’Connor Optimised assessment of bridges
Case study 2 – Danish examples 149JC. Putallaz Ultra High Performance Fibre Reinforced Composites (UHPFRC)
for rehabilitation - 2. Case study – first application 165M. Richardson Guidance on use of surface-applied corrosion inhibitors
Workshop on detailed guidance and Case Studies 197E. Brühwiler Advances in rehabilitation of highway structures Discussion, Summary and Perspectives 233
![Page 2: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/2.jpg)
![Page 3: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/3.jpg)
Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structuresMalcolm McKenzieTRL Ltd, UK
![Page 4: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/4.jpg)
Development Team
• Richard Woodward, TRL Ltd• Team:
Ales Žnidarič ZAG Mark Richardson UCD Emmanuel Denarié EPFL Tomasz Wierzbicki IBDIM Alan O’Connor TCD Professor Joan Casas UPC Ciaran McNally UCD Malcolm McKenzie TRL Bill McMahon TRL
![Page 5: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/5.jpg)
Overview
• Guidelines and innovation• Deteriorating concrete structures• Selecting the ‘best’ rehabilitation option
for a structure• Special procedures for innovative
techniques• Ranking projects when budgets are
limited
GUIDELINES NOT RULES
![Page 6: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/6.jpg)
Guidelines and innovation
• Innovation is an essential part of engineering development
• Materials and techniques are always being improved
• There are acknowledged problems with existing rehabilitation techniques
• Cautious approach aimed at controlling risks and developing experience
• Yesterday’s innovation is today’s tradition
![Page 7: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/7.jpg)
Concrete bridge deterioration
![Page 8: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/8.jpg)
Some deterioration mechanisms
• Reinforcement corrosion• Alkali silica reaction• Freeze/thaw effects• Sulfate attack• Cracking (settlement, thermal)• Overloading• Impact damage
![Page 9: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/9.jpg)
Identification of problem
• Cause• Extent• Importance
based on
• Inspection• Structural Assessment
![Page 10: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/10.jpg)
MAINTENANCE OPTIONS
• Do nothing• Monitor further deterioration
• Carry out remedial treatment• Carry out strengthening
• Replace element or structure
![Page 11: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/11.jpg)
Procedure
Is option innovative
Identify need
Select & rank rehabilitation option
Control risks
Y
Apply TechniqueN
OptionsAvailable
![Page 12: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/12.jpg)
Innovative techniques: additional risk
Lack of a long established track record
Uncertainties in:• Conditions under which they will be effective• Side effects• Long term durability• Implications for future maintenance• Monitoring effectiveness
![Page 13: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/13.jpg)
Balance conflicting Issues
Technical aspects need to be considered along with other relevant factors to meet the needs of current and future customers.
COST TIME ENVIRONMENT
![Page 14: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/14.jpg)
Wallet
Cost of repairs
Running costsImpact on local
economy
Cost of delays
Affordability
Renewal costs
![Page 15: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/15.jpg)
Watch
Time of works User delays
When Life of repair
![Page 16: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/16.jpg)
World
User delays
Raw materials
Energy usage
Transport of materials
Noise
Pollution
Aesthetics
![Page 17: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/17.jpg)
• Rigorous
• Engineering Judgement
Decision making - WWW
![Page 18: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/18.jpg)
Rigorous approach
• Methodology
Convert everything to financial value
Minimise cost over life of structure
• Problems
Conversion to money
Lack of data
Not practicable
![Page 19: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/19.jpg)
Engineering Judgement
• Advantages
Simple to use
Allows engineer to take all factors into consideration
• Problems
Subjective
Decisions could vary
![Page 20: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/20.jpg)
Structured Engineering Judgement
• Formalise the decision making process• Justification of decisions at each stage
• Best option for a structure• Rank individual projects
• Independent review eg via a Workshop
![Page 21: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/21.jpg)
Decision criteria
• Define objectives of the rehabilitation• Define factors to be considered
• Define decision criteria Basis of comparison eg whole life cost Relative importance of each factor Subjective or numerical approach
![Page 22: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/22.jpg)
Select rehabilitation options
• Identify potential options
• Implications of using an innovative technique
• Assessment of options in relation to decision criteria
taking account of any additional actions resulting from innovative procedure
• Recommend option(s)
![Page 23: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/23.jpg)
Assessing innovative techniques
• Desk study of structure and environmental conditions relevant to technique
• Laboratory testing• Feasibility trials
• Cost/time implications
![Page 24: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/24.jpg)
Select technique - 1
Example: Reinforcement corrosion
• Early Stages• Few visible defects• Low levels of chloride• Half-cell potentials mainly passive• Low corrosion currents
• Preventative maintenance• Slow down chloride ingress eg surface
treatment• Corrosion inhibitors to prevent corrosion?
![Page 25: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/25.jpg)
Select technique - 2
Example Reinforced concrete
• Visible defects• Higher chloride levels• More negative half cell potentials• Higher corrosion currents
• Concrete repairs• Electrochemical techniques• Corrosion inhibitors to reduce corrosion
rates??
![Page 26: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/26.jpg)
Prioritise competing projects
• Risk associated with not carrying out maintenance
• What is the consequence of this occurring? Safety Functionality Sustainability Environment
• What is the likelihood of this occurring?
![Page 27: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/27.jpg)
Prioritisation – Scoring
• This comprises three parts:
• Risks averted• Added value• Timing
All ranked on a numerical basis
![Page 28: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/28.jpg)
Procedure
Is option innovative
Identify need
Select & rank rehabilitation option
Control risks
Y
Apply TechniqueN
OptionsAvailable
InspectionAssessment
Innovativetechniques
Decision
User
Experience
![Page 29: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/29.jpg)
Guidelines and innovation
• It is wise to be cautious in the use of innovative techniques
• It is foolish to be over-cautious
• Engineers need to take controlled risks to grow confidence in new techniques
• Today’s innovation is tomorrow’s tradition
![Page 30: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/30.jpg)
THANK YOU FOR
YOUR ATTENTION
![Page 31: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/31.jpg)
Optimised assessment of bridges
Aleš ŽnidaričSlovenian National Building and Civil Engineering Institute
![Page 32: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/32.jpg)
Contents
• General about bridge assessment• Load testing• Traffic loading
Static Dynamic
• Conclusions
![Page 33: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/33.jpg)
Why optimised assessment?
![Page 34: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/34.jpg)
Design vs. assessment
• new bridges are designed conservatively: uncertainty about
increased loading inexpensive to add
capacity
• assessment should be less conservative: expensive to strengthen/replace or post a bridge capacity and loading can be
measured/monitored
![Page 35: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/35.jpg)
Design vs. Assessment
New bridges: high uncertainties:
• conservative capacity • design loading
schemes• design methods
high safety factors unnecessary:
• costly rehabilitation• load limits
Existing bridges: better defined inputs:
• realistic capacity• realistic loading• assessment methods
lower safety factors savings:
• cheaper rehabilitation• posting of bridges
![Page 36: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/36.jpg)
Why optimised assessment?
• to select optimal rehabilitation measures: do nothing protect repair strengthen replace
![Page 37: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/37.jpg)
Assessment of existing bridges
Important factors : condition, level of
damage structural safety:
• carrying capacity• loading (dead, traffic,
dynamic loading)• reliability of data
serviceability (clearances, traffic, obsoleteness)
service life, importance
1. What is the carrying capacity?• age, condition,
drawings…2. What is the real
behaviour?• influence lines• load distributions
3. What is the real loading?• in a country, type of
road, on specific bridge• dynamic amplification5-level assessment
![Page 38: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/38.jpg)
Condition assessment
• Objectives: Detect possible deterioration processes Indication of the condition of:
• structure • its elements • highway structure stock
Ranking the structures Optimisation of budget allocation
![Page 39: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/39.jpg)
Condition assessment
Influencing factors affecting deterioration: Design stage:
• Detailing• Durability• Materials
Construction stage Loadings Maintenance
![Page 40: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/40.jpg)
Condition assessment
D19. Report on assessment of structures in selected countries: condition rating:
• Cumulative• Highest value
4 factors:1. Type of damage and its affect
on the safety, serviceability and/or durability2. Maximum intensity3. Influence of the affected structural member on safety,
serviceability and durability of the whole structure or its component
4. Extent and expected propagation
![Page 41: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/41.jpg)
Condition assessment
Handbook of damages: http://defects.zag.si/ 10 types of damages descriptions:
• affected bridge component• influencing factor: design,
material, construction, overloading, environment and maintenance
• specific influencing factor• additional data or
explanations• photos
Living application
![Page 42: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/42.jpg)
Safety assessment
• to verify that a structure has adequate capacity to safely carry or resist specific loading levels:
R>S
Load testing Live load assessment (static and dynamic)
• How to relate condition and capacity?
R
kSk
RS
![Page 43: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/43.jpg)
Load testing
on bridges that seem to carry out normal traffic satisfactorily, but fail to pass the assessment calculation
the available model of the bridge does not perfectly match with the real bridge itself
to supplement and check the assumptions and simplifications made in the theoretical assessment
To optimise bridge assessment by finding reserves in load carrying capacity
![Page 44: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/44.jpg)
Load testing
benefits: less severe
rehabilitation measures less traffic delays tremendous savings
drawbacks: very costly danger of damaging the
structure
• best candidates: difficult structural modelling lack of documentation
(drawings, calculations,…) when savings are greater than the cost of load test
![Page 45: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/45.jpg)
Load testing
• Types of load test: proof diagnostic soft
![Page 46: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/46.jpg)
Soft load testing - advantages
• the lowest level of load application• uses bridge WIM to provide:
“normal” traffic data information about structural behaviour of the bridge:
• influence lines• statistical load distribution• impact factors from normal traffic.
• “quick&cheap”: no need for pre-weighed vehicles no need to close the traffic
• no risk of overloading and damaging of the structure
![Page 47: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/47.jpg)
BWIM shema
Strain measurementsStrain measurementsStrain measurementsStrain measurements
Axle detectionAxle detectionAxle detectionAxle detection
![Page 48: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/48.jpg)
Soft load testing
• Theoretical vs. measured influence line
![Page 49: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/49.jpg)
Soft load testing – limitations
• not intended to predict the ultimate state behaviour
• validity of bridge assessment is often short-term and depends on the level of safety
• if higher traffic loading is expected, measurements should be extended or replaced by a normal diagnostic load test
• the soft load testing procedure has only been tested and used on bridges shorter than 40 m
• requires an experienced engineer who can realistically evaluate situation
![Page 50: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/50.jpg)
Traffic load modelling
• calibrated notional load models (loading schemes) for: design assessment (rating loading schemes)
• site specific modelling based on traffic data: Monte Carlo simulation simplified models (convolution)
![Page 51: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/51.jpg)
0%
5%
10%
0 10 20 30 40 50 60
GVW (Tonnes)
Fre
qu
en
cy
0%
5%
10%
0 10 20 30 40 50 60
GVW (Tonnes)
Fre
qu
en
cy
0%
5%
10%
0 10 20 30 40 50 60
GVW (Tonnes)F
req
ue
ncy
0%
5%
10%
0 10 20 30 40 50 60
GVW (Tonnes)
Fre
qu
en
cy
Truck histograms from Europe
![Page 52: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/52.jpg)
Truck histograms from Europe
There is an urgent need for effective overload enforcement – better compliance with legal limits will greatly reduce traffic loading on bridges.
![Page 53: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/53.jpg)
Comparison of sites in NL and SI
0,00,10,20,30,40,50,60,70,80,91,0
10 20 30 40
Bridge Length (m)
Ch
ara
cte
risti
c M
om
en
t
NL - Site 1 NL - Site 2NL - Site 3 SI - Site 1SI - Site 2 SI - Site 3
![Page 54: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/54.jpg)
Dynamic Amplification Factor
• problem: combining the extremes of dead load and dynamic effects => very high DAF
• options: codes – conservative modelling – time-consuming and difficult
due to many unknowns measurements – promising, but only
possible since recent development of bridge WIM systems
![Page 55: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/55.jpg)
Dynamic Amplification Factor
Case Study Calculating dynamic amplification for 1000-year extreme loading event: Mura River Bridge, Slovenia 2 lanes, opposing directions extensive Monte Carlo static
load simulation – 10 years identified 100 max-per-
month static loading events
![Page 56: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/56.jpg)
Dynamic Amplification Factor
Case Study• FE model of
bridge and 5-axle articulated vehicles
• Calibrated by site measurement
• Considered edge beam• Found total effect for each
max-per-month event
![Page 57: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/57.jpg)
Dynamic Amplification Factor
Case Study• Max-per-month
Data of static vs. total • Fit to bivariate
extreme value distribution
• Extrapolated the trend to the 1000-year situation
• Dynamics was very small – less than 6%
![Page 58: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/58.jpg)
Dynamic Amplification Factor
SAMARIS experiment: 31-m long span to assess influence
of pavement unevenness
to evaluate DAF for 1000’s of vehicles
upgraded SiWIM system
![Page 59: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/59.jpg)
![Page 60: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/60.jpg)
Dynamic Amplification Factor
-3,5
-3,0
-2,5
-2,0
-1,5
-1,0
-0,5
0,0
0,5
1,0
0 1 2 3 4 5 6
Str
ain
(V
)
Static
Dynamic
-4,0
-3,5
-3,0
-2,5
-2,0
-1,5
-1,0
-0,5
0,0
0,5
1,0
0 0,5 1 1,5 2 2,5 3
Str
ain
(V
)
Static
Dynamic
![Page 61: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/61.jpg)
Dynamic Amplification Factor
-4,0
-3,5
-3,0
-2,5
-2,0
-1,5
-1,0
-0,5
0,0
0,5
1,0
0 0,5 1 1,5 2 2,5 3
Str
ain
(V
)
Static
Dynamic
-4,0
-3,5
-3,0
-2,5
-2,0
-1,5
-1,0
-0,5
0,0
0,5
1,0
0 1 2 3 4 5 6 7 8 9
Str
ain
(V
)
Static
Dynamic
![Page 62: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/62.jpg)
Dynamic Amplification Factor
• Before resurfacing
0,91,01,11,21,31,41,51,61,71,81,92,02,1
0 4 8 12 16 20 24 28 32
Strain (V)
DA
F
One vehicle - Lane 2
One vehicle - Lane 1
MP with a light vehicile
MP of heavy vehicles
Slovene Bridge design code
Sem
i-tr
aile
r 40 t
ons
![Page 63: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/63.jpg)
Dynamic Amplification Factor
• After resurfacing
0,91,01,11,21,31,41,51,61,71,81,92,02,1
0 4 8 12 16 20 24 28 32
Strain (V)
DA
F
One vehicle - Lane 1
One vehicle - Lane 2
MP with a light vehicile
MP of heavy vehicles
Slovene bridge design code
Sem
i-tra
iler
40 t
ons
![Page 64: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/64.jpg)
Dynamic Amplification Factor
Average value Coefficient of variation
100%
102%
104%
106%
108%
110%
112%
0 5 10 15 20 25
Before resurfacing
Af ter resurfacing
0%
2%
4%
6%
8%
10%
12%
0 5 10 15 20 25
Before resurfacing
Af ter resurfacing
![Page 65: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/65.jpg)
Conclusions (1/2)
• Design conservatively, assess optimally• Proper assessment (with monitoring) can:
prove that many existing bridges are safe in their current condition for their current loading: factors from Eurocodes are too high for
assessment of existing bridges• traffic patterns in EU, EEA and CEC are different• carrying capacity is higher than expected
justify optimal rehabilitation measures save a lot of money
![Page 66: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/66.jpg)
Conclusions (2/2)
• soft load testing is proposed as a simpler way of defining real bridge behaviour
• dynamic amplification factors for the extreme load cases are considerably lower than specified in the design codes
• additional topics in the D30: factors required for efficient bridge inspection specifications for diagnostic load test several case studies
![Page 67: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/67.jpg)
Acknowledgment
WP 15 team: ZAG Ljubljana: Igor Lavrič, Jan Kalin UCD Dublin: Prof. Eugene O’Brien, Colin
Caprani, Gavin OConnell, Abraham Getachew
TCD Dublin (now Rambøll): Alan O’Connor UPC Barcelona: Prof. Joan Casas IBDiM Warsaw: Tomasz Wierzbicki
![Page 68: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/68.jpg)
![Page 69: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/69.jpg)
Ultra High Performance Fibre Reinforced Concretes (UHPFRC) for rehabilitation – 1. Motivation and Background
Emmanuel DenariéLaboratory for Maintenance and Safety of Structures Laboratory for Maintenance and Safety of Structures (MCS)(MCS)
![Page 70: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/70.jpg)
OUTLINE
1. Introduction2. UHPFRC materials3. What is proposed?4. Why?5. Validation6. Conclusions7. Acknowledgements
![Page 71: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/71.jpg)
1. Introduction
Road networks = variety of structures, with a variety of sizes, geometries, local conditions, and …common weak zones
![Page 72: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/72.jpg)
Exposures to environmental loads
Most severe = contact with liquid water - XD2, XD3, XA2,3
Reinforced concrete cannot withstand it for a long time !
![Page 73: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/73.jpg)
2. UHPFRC materials
•Ultra compact cementitious matrix•Multilevel fibrous reinforcement•Outstanding mechanical and protective
properties
CEMTECmultiscale® developed by Rossi et al. (2002)
“Selfcompacting” “Ductile as steel”
![Page 74: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/74.jpg)
UHPFRC composition
• Silica fume - SF/C = 0.26 (mass)• Superplasticizer – SP/C = 1 % (mass, dry extract)• Water/Binder = 0.125 to 0.140• Cement: 1051 to 1434 kg/m3
MicrosilicaCement
CEM I 52.5Fine sand
Dmax=0.5 mm
Matrix
![Page 75: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/75.jpg)
UHPFRC composition
• Steel wool + 10 mm/0.2 mm straight fibres • Total dosage 468 - 706 kg/m3 (6 to 9 % Vol.)
Fibrous reinforcement
MicrofibresSteel wool
MacrofibresL=10 mm, D=0.2 mm
CEMTECmultiscale® developed by Rossi et al. (2002)
![Page 76: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/76.jpg)
Fractured surface of UHPFRC with pulled-out steel fibres
10 mm
![Page 77: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/77.jpg)
3. What is proposed ?
Long-lasting, targeted « hardening » of critical zones subjected to severe mechanical and environmental loads
« Apply an everlasting winter coat on bridges »« Apply an everlasting winter coat on bridges »
![Page 78: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/78.jpg)
Concept of application
Cast in place waterproof UHPFRC overlay No thermal treatment, moist curing 8 days
Pavement applied without waterproofing membrane
« An everlasting wintercoat for bridges »« An everlasting wintercoat for bridges »
![Page 79: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/79.jpg)
Concept of application
Combine UHPFRC and rebars to reinforce structures
« An everlasting wintercoat for bridges »« An everlasting wintercoat for bridges »
![Page 80: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/80.jpg)
3. Why ?
• Rehabilitation works are becoming the dominant activity in road construction
Consider impact on a network and society !• Rehabilitations are too often short lived !• Increase load carrying capacity without
increasing deadweight• Limit duration and number of interventions
during service life simplify and shorten !
Combine materials in efficient structures !
![Page 81: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/81.jpg)
4. Validation
• Method of concrete replacementStudy composite UHPFRC-concrete construction
• Consider local conditionsApplication on inclined substrates
• « New material »Test on a wide range of scales of time and
dimensionsProvide guidelines for design and use
• Validate use with existing facilities and tools
![Page 82: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/82.jpg)
Replacement of existing concrete
Successful « Structural rehabilitations » are a major challenge
Major issues:
Processing
Monolithic behaviour
Protective function
Mechanical performance
Durability
![Page 83: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/83.jpg)
Restrained shrinkage
Silfwerbrand (1997)
Stress = stiffness × free strain × degree of restraint
Stiffness: f(Emod, creep/relaxation) material property,Free strain: material property
Degree of restraint: structural property
Typical values: -New layer on bridge deck slab: 0.4 to 0.6
-New layer on stiff beams: 0.6 to 0.8
-New kerb cast on bridge deck: 0.75
-Full restraint: 1.00
Study structural configurations with various degrees of restraint
![Page 84: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/84.jpg)
Summary of R & D worksOngoing studies at MCS-EPFL since 1999.
• Early age and long term behaviour of composite members with UHPFRC
• Composite structural members with UHPFRC, with various geometries: beams, slabs, walls
• Fatigue of composite members with UHPFRC• Tensile behaviour of UHPFRC• Effect of damage on permeability of UHPFRC• Time-dependent behaviour of UHPFRC (creep,
shrinkage)• Combination of UHPFRC with reinforcement bars• Rheological behaviour at fresh state• Numerical modelling and design tools
![Page 85: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/85.jpg)
Range of studies
Creep, shrinkage, permeability
Structural response
Res
ista
nce
![Page 86: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/86.jpg)
Uniaxial tensile response – strain hardening
Modulus of elasticity 30 % higher than normal concretes Tensile strength of matrix 3 to 4 x higher than normal concrete Finely distributed multiple cracking during hardening phase Similarity with yielding of metals (Luders strips)
CEMTECmultiscale®
Mechanical propertiesDenarié et al. (2006)
UHPFRC NC
Compressive strength
[MPa]
160-250 ~ 40
E modulus[GPa]
48-60 ~ 35
Tensile strength
[MPa]
9-20 ~ 3
Strain hardening
[%] 0.05 - 0.2 0
First crack strength
[MPa]
7-16 ~ 3
NC: Normal Concrete
General overview
![Page 87: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/87.jpg)
Structural response
540
150 240 150
f1 f3f2
30
hU
f5f4
30
F F
60 60 60 60120 120
15
ODS U ODS L
3.4
2,5
200
f6 f7UHPFRC
RC
20 20
+
Flexural tests on composite beams with UHPFRC, Habel (2004)
Effect of new UHPFRC layer thickness (hu) Effect of combination of UHPFRC with rebars
![Page 88: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/88.jpg)
Flexural tests on composite beams with UHPFRC, Habel (2004) UHPFRC alone = significant stiffening UHPFRC + rebars = stiffening + increase of load carrying capacity
Structural response
NL: 10 cm
NL: 5 cm
New layer: UHPFRC New layer: UHPFRC + rebars
![Page 89: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/89.jpg)
Analytical modelling
Composite UHPFRC-Concrete structures = multi-layer systems Tensile behaviour of UHPFRC can be taken into consideration Take eigenstresses into consideration for design !
Tensile response of UHPFRC
Habel (2004)
Compression - UHPFRCTension – UHPFRC
UHPFRC
Reinforced
Concrete
![Page 90: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/90.jpg)
Main results of R & D works - 1
• UHPFRC and concrete behave monolithically in composite members, up tp ULS, Habel (2004).
• Interface roughness of 5 mm with wavelength 15 mm is sufficient for monolithic behaviour, Wuest et al. (2005), Herwig et al. (2005)
• UHPFRC exhibit moderate shrinkage (0.6 ‰ after 3 month), and significant viscoelasticity, (creep coeff ~ 0.8) Habel (2004), Kamen et al. (2005), AFGC (2002).
![Page 91: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/91.jpg)
Main results of R & D works - 2
• Under full restraint (worst case), eigenstresses under shrinkage remain moderate (~ 50 % of tensile strength), Kamen et al. (2005)
• Eigenstresses decrease the apparent tensile strength of UHPFRC in composite members, Habel (2004), Clevi (2005), Sadouki et al. (2005) consider for design
• Anisotropic orientation of fibres, function of application consider impact on properties
![Page 92: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/92.jpg)
Main results of R & D works - 3
• Very low transport properties for liquids (sorptivity) and gases, Charron et al. (2004).
• Up to equivalent crack openings of 0.1 mm (strain of 0.1 %) permeability remains very low, Charron et al. (2004), and behaviour under fatigue loading is controlled, Herwig (2005).
• Self-healing capacity for microcracks• Promissing combination of UHPFRC with rebars,
for reinforcement of structures, with no increase of dead weight, Brühwiler et al. (2005), Habel (2004), Wuest et al. (2005).
![Page 93: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/93.jpg)
Geometries of application
P: UHPFRC hu= 15 to 30 mm = Protection
PR: UHPFRC + replacement of corroded rebars (hu~ 50 mm) = Reinforcement
R: UHPFRC + additional rebars (hu>=50 mm) = Reinforcement
Habel et al. (2004)
![Page 94: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/94.jpg)
Recommandation: UHPFRC
Apply UHPFRC where it is worth it! For zones of severe exposure classes (XD2,3, evt. XA2,3)! To improve existing or new structures!
![Page 95: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/95.jpg)
7. Conclusions
«Targeted local hardening» of highway structures, in most critical zones, by using UHPFRC.
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.
Concept has been technically validated on a wide range of scales and duration
![Page 96: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/96.jpg)
Acknowledgements
• UHPFRC team of MCS-EPFL: Prof. Eugen Brühwiler, John Wuest, Aicha Kamen, Andrin Herwig, Dr. Katrin Habel*, Prof. J.P. Charron*, Roland Gysler, Sylvain Demierre,
* Former collaborators of MCS-EPFL
• Partners in Project SAMARIS
Dr. P. Rossi Dr. R. Woodward
![Page 97: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/97.jpg)
Guidance on use of surface-applied corrosion inhibitorsContext and Framework of GuidanceMark RichardsonUniversity College Dublin
![Page 98: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/98.jpg)
Work Package Team
UCD M. Richardson (Team Leader),C. McNally, T. A. Soylev.E. Grimes
ZAG A. Legat
TRL M. McKenzie
Sika P. Mulligan, B. Marazzani, M. Donadio
Cardiff University B. Lark
C-Probe Systems Limited /Structural Healthcare Associates G. Jones
![Page 99: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/99.jpg)
Outline
Background– Methodology, Concept, Motivation
Objectives of SACI in a Maintenance Strategy– Reactive and Proactive Context
Primary Factors Influencing Effectiveness
Framework of Guidance for Specifiers of SACI
![Page 100: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/100.jpg)
Background to SACI
• Methodology
• Concept
• Motivation
![Page 101: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/101.jpg)
Methodology
SACI are applied to mature concrete surfaces where they are absorbed.
Penetrate through the cover concrete by capillary action and diffusion.
Form a protective layer on the reinforcement.
![Page 102: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/102.jpg)
![Page 103: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/103.jpg)
Concept
Before: uncontrolled corrosion activity (existing or future)
After: delay in onset and/or control of corrosion rate
![Page 104: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/104.jpg)
Evans DiagramEvans Diagram
Potential (E)Potential (E)
anodic reactionanodic reaction
cathodic reactioncathodic reaction
Current (I)Current (I)
![Page 105: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/105.jpg)
Potential (E)Potential (E)
E E corrcorr
I I corrcorr
Current (I)Current (I)
![Page 106: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/106.jpg)
After inhibitor applicationAfter inhibitor application
Potential (E)Potential (E)
Current (I)Current (I)
![Page 107: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/107.jpg)
After inhibitor applicationAfter inhibitor application
Potential (E)Potential (E)
E E corrcorr
I I corrcorr
Current (I)Current (I)
![Page 108: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/108.jpg)
Motivation
Benefit of SACI compared to ‘traditional’ repair optionReduce disruption to road users during rehabilitation of structure by time and access efficiency
Sustainability aspect in preventative maintenanceArrest deterioration before it becomes significant and costly to repair
![Page 109: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/109.jpg)
Objectives of SACI in Maintenance Strategy
• Objectives related to overall maintenance strategy
• Specifically consider objectives in ‘Reactive’ and ‘Proactive’ strategies
![Page 110: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/110.jpg)
Reactive Maintenance Strategy
• Inhibitor may be used to reduce (or at least prevent an increase) in the rate of corrosion, thus extending residual service life, unless extent of corrosion is too advanced.
![Page 111: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/111.jpg)
Time
Service life extension
With inhibitor
Without inhibitor
Limit
Deterioration Level
![Page 112: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/112.jpg)
• However in a more general context note that:
Repair occurs when deterioration is apparent and possibly significant
Residual capacity of existing structure may be significantly diminished at time of intervention
![Page 113: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/113.jpg)
Proactive Maintenance Strategy
• Inhibitor may be used to delay the onset of depassivation and thereafter positively influence the rate of corrosion, thus extending residual service life.
![Page 114: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/114.jpg)
Time
Service life extension
With inhibitor
Without inhibitor
Limit
Deterioration Level
![Page 115: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/115.jpg)
• Also in a more general context note that: Measures for performance monitoring of the
structure could be included at time of repair.
Inhibitor may be subsequently reapplied (e.g. a decade later) if performance monitoring indicates it is warranted, before deterioration becomes significant.
![Page 116: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/116.jpg)
Parameter
Time
Resistance Rp,
Corrosion rate, µm/yr
Inhibitor applied
Inhibitor re-applied
![Page 117: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/117.jpg)
Primary Factors Influencing Effectiveness
Effectiveness is influenced by:
Ability of surface to ‘take up’ the inhibitor Ability of inhibitor to penetrate the cover
concrete Ability of inhibitor to form a layer on the
reinforcement Ability of inhibitor to sustain the protective
layer
![Page 118: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/118.jpg)
Appropriateness of SACI
Appropriateness of SACI therefore depends on the following primary factors: Degree of saturation of concrete Permeability characteristics of concrete Corroded state of reinforcement at time of
repair Chloride levels
![Page 119: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/119.jpg)
Degree of saturation of concrete
• State of surface at time of application (initial take-up)
• Surface condition immediately after application (wash out)
• Influence on permeability
![Page 120: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/120.jpg)
Permeability characteristics of concrete
• Ease with which inhibitor may penetrate depends on intrinsic permeability characteristics and degree of saturation
• Permeability also influences ease which other contaminants may enter post-repair (additional protection from suitable coating may be required)
![Page 121: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/121.jpg)
Corroded state of reinforcement
• Inhibitor must form mono-molecular layer on reinforcement
• Ease of formation depends on surface state at time of repair
• Clean or lightly corroded – optimal state
• Heavily corroded – outside inhibitor’s effectiveness window
![Page 122: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/122.jpg)
Chloride levels
• Critical consideration is the relative inhibitor to chloride concentration
• Inhibitor must form a mono-molecular protective layer and displace chloride ions from the reinforcement
• Competitive surface adsorption reaction between inhibitors and chloride ions
• Inhibitors most effective if applied before significant build up of chloride concentration
![Page 123: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/123.jpg)
Framework of Guidance for Specifiers
• Specifiers evaluating or developing a repair strategy based on surface applied corrosion inhibitors are encouraged to view it in the context of a structured approach to deciding on an optimum repair strategy.
• Such a structured approach is presented in SAMARIS Report D31.
![Page 124: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/124.jpg)
Context for Guidance: SAMARIS D31
Determine condition
Rank maintenance option
(Value Management)
Control risks
Apply technique
Select maintenance option
(Value Engineering)Options available
No
Yes
Innovative?
Objectives of maintenance
Identify need
![Page 125: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/125.jpg)
Determine
Rank option
Control risks
Apply technique
Select optionOptions
N
Y
Innov?
Objectives
IdentifySAM
ARIS D
31 G
uida
nce
SAMARIS
D25
a G
uida
nce
![Page 126: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/126.jpg)
Framework of Guidance: D25a
Reference: SAMARIS Report D25a
Summary Flowchart
![Page 127: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/127.jpg)
Yes
Apply technique
No
Initial desk study assessment
Inhibitor potentially
appropriate?
Control of risk to specifier’s
satisfaction?
Re-examine alternative ranked
options
No
Yes
• Overview of guidance flowchart
![Page 128: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/128.jpg)
• Overview of guidance flowchart
Conduct preview and analyse results
No
YesControl of risk to
specifier’s satisfaction?
Define performance criteria for preview
Finalise proposed rehabilitation strategy
![Page 129: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/129.jpg)
• Overview of guidance flowchart
If resources permit conduct post repair monitoring as part of a proactive maintenance strategy and reapply technique if required during residual service life
Control of risk to specifier’s
satisfaction?
Apply technique
Finalise proposed rehabilitation strategy
Re-examine alternative
ranked options
Yes
No
![Page 130: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/130.jpg)
Summary
• Initial Assessment:
• Consider findings, • Balance constraints (funding, time,
urgency, traffic disruption etc.) against control of risk to specifier’s satisfaction,
• Decide: • Go? No go? Go to preview study?
![Page 131: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/131.jpg)
Summary
• Preview Study Assessment (if used): • Consider findings, • Modify proposed strategy if necessary (e.g.
inhibitor + coating rather than inhibitor only),
• Balance constraints (funding, time, urgency, traffic disruption etc.) against control of risk to specifier’s satisfaction,
• Decide: Go? No go?
![Page 132: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/132.jpg)
• Post-repair monitoring• If ‘Go’ consider also follow up monitoring
as part of a proactive maintenance strategy
![Page 133: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/133.jpg)
Further Information
• Follow up presentation • (Guidance on use of surface-applied
corrosion inhibitors: Detailed Guidance and Case Studies)
• SAMARIS Report D25a
![Page 134: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/134.jpg)
![Page 135: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/135.jpg)
Optimised assessment of bridges Case study 1 - Medno bridgeSoft Load TestingAleš ŽnidaričSlovenian National Building and Civil Engineering Institute
![Page 136: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/136.jpg)
Assessment of existing bridges
Important factors: condition, level of
damage structural safety:
• carrying capacity• loading (dead, traffic,
dynamic loading)• reliability of data
serviceability (clearances, traffic, obsoleteness)
service life, importance
1. What is the carrying capacity?• age, condition,
drawings…2. What is the real
behaviour?• influence lines• load distributions
3. What is the real loading?• in a country, type of
road, on specific bridge• dynamic amplification5-level (step-by-step) assessment
![Page 137: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/137.jpg)
Safety assessment
• to verify that a structure has adequate capacity to safely carry or resist specific loading levels:
R>S
Rating factor:
R
kSk
RS
nGd
GGR
RF
![Page 138: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/138.jpg)
Case study – Medno bridge
Structure from 1937: no drawings refurbished in 1997 in very good condition 11.95 m long span total width 8.5 m 5 RC beams 1.35 m apart cross beams above
abutments, at ¼, ½ and ¾ of the span
unknown fixity of supports located on a road with 1150
heavy vehicles ADT posted to 30 tonnes GVW
![Page 139: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/139.jpg)
Carrying capacity
• Assumed characteristics of concrete:
fc = 20 MPa
no information about steel reinforcement: 8 bars from profometer test likely 25 or 28 mm,
assumed 822 mm bars of 240/360 MPa steel
RM = 867.4 kNm
![Page 140: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/140.jpg)
Soft load testing
• to check the assumptions made in the model• bridge WIM used to provide:
normal traffic data (not in this case) information about structural behaviour:
• influence lines• statistical load distribution• impact factors from normal traffic (not in this
case) only 1 pre-weighed vehicle for BWIM
calibration the bridge need not be closed to traffic
![Page 141: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/141.jpg)
BWIM shema
Strain measurementsStrain measurementsStrain measurementsStrain measurements
Axle detectionAxle detectionAxle detectionAxle detection
![Page 142: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/142.jpg)
Soft Load Testing
Soft load testingSimply supportedSimply supportedRF RF << 1.0<< 1.0
![Page 143: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/143.jpg)
Soft Load Testing
Soft load testingSimply supportedSimply supportedRF RF << << 1.01.0
MeasuredMeasuredRF RF >>>> 1 1.0.0
Message:Message:Check, how Check, how bridges really bridges really behave.behave.
![Page 144: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/144.jpg)
Soft Load Testing
Load distribution: normally guestimation bridge WIM evaluates it statistically
![Page 145: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/145.jpg)
± 0
Regular inspection
R factor
Service life
Resistance
Normal Limited
Design
Testing Estimate
= 0.85
Severe
Minor
Bad Good
Redundancy No
Detailed inspection
Yes
No
c = 3.5
c = 2.5
VR = 10% VR = 15% VR = 20% - 0.1
+ 0.1
> 0.95
+ 0.05
0.95
- 0.15
+ 0
- 0.2
No
Average
Yes
No
No Yes
BR×e
R×C×VR
Maintenance
Yes
START
Deterioration
Selection of capacity reduction factor
Capacity reduction factor:
Φ = BR × e -.βc.V
SI procedure accounts for: condition of the structure reliability of data redundancy of structure method of calculation
Medno bridge:Φ = 0.86
![Page 146: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/146.jpg)
Selection of safety factors
Dimensions taken on site:
Safety factor for traffic loading:
WIMEstimated
Estimated
Traffic loading
Rating loading schemes
Lateral loaddistribution
Measured
Q 1.4
Q 1.6
Q Q + 0.2
Q Q - 0.2
Q Q + 0.1
Q Q + 0.1
Estimated
Impact factor
Measured
Service life Limited
Q Q - 0.2
Normal
Yes
Q Q + 0.2
>1000 trucks/day
No
Q = 1.6
G = 1.2
Q = 1.7Q = 1.9
![Page 147: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/147.jpg)
Structural safety of Medno bridge
Calibrated structural model:1. Loading scheme with 2 4-axle rigid 38-ton
trucks, one in each lane:
1.03
28.16.2349.1
7.2352.14.86786.0
nGd
GGR
RF
2. Loading scheme with 81-ton 8-axle vehicle in one lane and rigid 38-ton truck in the other:
1.08
00.15.2469.1
7.2352.14.86786.0
nGd
GGR
RF
Room for further optimisation of analysis
![Page 148: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/148.jpg)
Conclusions
• on Medno bridge soft load testing proved beneficial
• 2004 assessments for special transports for the Slovene Road Administration: 13 posted bridges assessed 11 proved safe even for a
165-tonnes special vehicle with 12 axles
for the rest missing data on carrying capacity
on shorter bridges normal traffic worse than special transports
![Page 149: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/149.jpg)
Optimised assessment of bridges Case study 2 – Danish examplesAlan O’ConnorRambøll
![Page 150: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/150.jpg)
Problem:
1) Lack of load carrying capacity or exceedance of structural/performance limit state due to
– weak bridges– deteriorated/(ing) bridges– Increasing loads
2) Low budgets for strengthening
and/or rehabilitation where required
Idea: 1) Demonstration of higher capacity through Probabilistic safety assessments incorporating better calculation/response models
Principal Motivation:
Cost saving through Budget Optimisation
Problem, idea and motivation
![Page 151: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/151.jpg)
The general approach:
Assessments based upon deterministic
codes for both (a) New bridges and (b) Existing bridges
Generalisation
• Partial safety factor format
• Deterministic Load specification
• Many types of bridges
BenefitEfficient and easy to use
DrawbackCostly in case of lack of capacity may result in unnecessary repair/rehabilitation
Safety approaches for assessment of existing bridges
![Page 152: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/152.jpg)
Concept:
• Not necessarily have to fulfill the requirements of a general code rather the Overall requirement for the safety level must be satisfied on a individual basis
Purpose:
• Cut strengthening or rehabilitation costs without compromising safety level
Method: Probabilistic-based assessment
Site specific modelling of specific conditions/structure:
• Traffic load
• Capacities
• Response Models
Bridge specific “code” is obtained
The individual approach
![Page 153: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/153.jpg)
Decision Process
Yes
Yes
No
No
No
Yes
Assessment from traditional evaluation OK ?
Implement traditional strengthening project
Yes
Assessment from traditional evaluation OK ?
Implement traditional strengthening project
Refinedassessment beneficial?
No
Refined strengthening project
Traditional decision process
New decision process considering refined assessment
Refinedassessment OK ?
![Page 154: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/154.jpg)
Case Studies
Practical experience: The Danish Road Directorate has saved more than $50 million USD Bridge Deterministic Analysis Probability-based as-
sessment Cost Saving
Mio. $US Vilsund Max W = 40 t Max W = 100 t 4 Skovdiget Lifetime ~ 0 years Lifetime > 15 years 15.0 Storstroem Lifetime ~ 0 years Lifetime > 10 years 20.0 Klovtofte Max W = 50 t Max W = 100 t 2 407-0028 Max W = 60 t Max W = 150 t 1.5 30-0124 Max W = 45 t Max W = 100 t 0.5 Nørresø Max W = 50 t Max W = 100 t 0.3 Rødbyhavn Max W = 70 t Max W = 100 t 0.5 Åkalve Bro Max W = 80 t Max W = 100 t 1.0 Nystedvej Bro Max W = 80 t Max W = 100 t 2.0 Avdebo Bro Max W = 80 t Max W = 100 t 2.0
![Page 155: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/155.jpg)
Case Studies - Savings
Savings > $ 4 mio.Savings > $ 4 mio.
Savings > $ 15 ml.Savings > $ 15 ml.
Savings > $ 20 ml.Savings > $ 20 ml.
Savings > $ 0.5 ml.Savings > $ 0.5 ml.
Savings > $ 2 ml.Savings > $ 2 ml.
![Page 156: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/156.jpg)
Case Studies - Savings
Savings > $ 0.Savings > $ 0.33 ml. ml.
Savings > $ 0.5 ml.Savings > $ 0.5 ml.
Savings > $ 1.Savings > $ 1.00 ml. ml. Savings > $ 2.0 ml.Savings > $ 2.0 ml. Savings > $ Savings > $ 22.0 ml..0 ml.
![Page 157: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/157.jpg)
Probability based Maintenance Management
![Page 158: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/158.jpg)
0. Fact-finding 1. Formulation of problem 2. Safety requirements 3. Deterministic models for failure 4. Probability-based safety-model for critical failure modes. 5. Stochastic variables 6. Safety of the non-deteriorated bridge 7. Safety of deteriorated bridge 8. Analysis of repair and rehabilitation options 9. Requirements for the visual appearance of the bridge 10. Cost-optimal management plan using decision analysis to determine optimal rehabilitation options
SAFETY
MANAGEMENT
Practical 10-phase procedure
![Page 159: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/159.jpg)
WestBridge
EastBridge
Post tensioned concrete box-girder bridges12 spans, 220 m longCarries a 4-lane highway
Skovdiget Bridges: Location / OverviewSAVING €20ml.
![Page 160: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/160.jpg)
History
West Bridge East bridge
1965-1967 Construction Construction
1978 Majorrehabilitation
1978-1999 Inspection 4 times Principal Inspectiona year. Load testing every 5 years.every 5 years. Normal M & R
procedure.
Bridge in bad Bridge in good condition. condition.
1998-2000 Implementation ofprobabilistic-based management plan.
![Page 161: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/161.jpg)
Design, Deterioration & Assessment
Poor workmanship during construction: un-injected or poorly injected post-
tensioned cable ducts insufficient and poor drainage area around gulley poorly made
bad waterproofing
Fast Slow Service Emergency Bicycle lane &
lane lane lane lane footway
Gulley
Main girder 3
Main girder 4
Deterministic analysis of bridge & failure modes Main girders, moment and shear failure Shear failure of transverse girders (above
columns) Transverse ribs between main girders 3 and 4 East and west cantilever wing
Identifying areas with most severe deteriorationIdentifying critical combinations
Modelling of stochastic variablesModelling of strengths
concrete, reinforcement steel, cables
Modelling of loads total traffic load dynamic amplification factors transverse distribution of vehicles
Model uncertaintiesPrediction of the deterioration
![Page 162: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/162.jpg)
Calculation of safety allowing for deterioration
Development of the safety index
Maintenance Management OptionsTraffic, repair and information options:Traffic options - Weight restrictions Repair/strengthening - or replacement - options - Minor / major repair - or - strengthening - Preventive actions - ReplacementImprovement of Information level- Inspections to update estimate of current
deterioration - Test loading- Determine actual weight the bridge- Monitoring system- More advanced analysis and response models- Extended routine and special inspections
A Safety-based management plan is established and implemented for Skovdiget WestExtended lifetime > 15 years & Cost savings > €20 millionThe Danish Road Directorate is now using the methodology for other bridgesThe safety level is not compromised
A rational methodology is implemented for practical application
Probabilistic-based assessment of bridges cuts strengthening or rehabilitation costs. The cost savings can be significant
www.vd.dk
![Page 163: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/163.jpg)
Conclusions
• Reliability based assessment of bridges and Probability Based Maintenance Management cuts strengthening or rehabilitation costs
• The safety level is not compromised• A well established
methodology is implemented for practical application
• The cost saving can be millions of € per year
![Page 164: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/164.jpg)
![Page 165: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/165.jpg)
Ultra High Performance Fibre Reinforced Composites (UHPFRC) for rehabilitation - 2. Case study – first applicationJean-Christophe Putallaz SRCE/VSEmmanuel Denarié – MCS/EPFLMCS/EPFL
![Page 166: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/166.jpg)
OUTLINE
1. Rehabilitation strategy2. First application3. Conclusions4. Acknowledgements
![Page 167: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/167.jpg)
Rehabilitation strategy
• Limit costs (construction and life-cycle)• Decrease number and duration of interventions• Provide sufficient durability …… Promote STRATEGY APromote STRATEGY A
![Page 168: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/168.jpg)
2. First application
Creep, shrinkage, permeability
Site application 1 - 2004Structural response
Res
ista
nce
![Page 169: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/169.jpg)
First application
Rehabilitation and widening of the Bridge over river La Morge - Switzerland
Execution: October – November 2004
![Page 170: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/170.jpg)
GEOGRAPHICAL LOCATION
Swiss alps, Valley nearby Sion, 480 m above s.l Secondary road with sustained traffic Heavy salt spraying in winter
![Page 171: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/171.jpg)
Prior to rehabilitation
Downstream kerb Upstream kerb
No waterproofing membrane,Kerbs severely damaged by chloride induced corrosion
![Page 172: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/172.jpg)
Concept of the intervention
Span 10 m No waterproofing membrane
Protective function provided by UHPFRC
Widening of the bridge
Prefabricated UHPFRC kerb downstream
Thin UHPFRC overlay (3 cm) applied on deck
UHPFRC rehab. kerb usptream
Span 10 m
![Page 173: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/173.jpg)
Construction joint for UHPFRC
![Page 174: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/174.jpg)
Prefabricated downstream kerb
![Page 175: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/175.jpg)
Prefabricated kerb in UHPFRC - joint
![Page 176: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/176.jpg)
UHPFRC materials
• Cement CEM I 52.5 (low C3A)• Fine quarz sand (Dmax < 0.5 mm)• Silica fume - SF/C = 0.26• Superplasticizer = 1 % dry extract • Steel wool + 10/0.2 mm steel fibres• Total fibres = 9 % Vol. or 706 kg/m3)
Basis: CEMTECmultiscale® - Rossi et al. (2002)
No thermal curing Protection with plastic sheet + 8 days moist curing
![Page 177: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/177.jpg)
UHPFRC materials
Recipe
Cement[kg/m3]
W/B[--]
W/C[--]
Application
CM22 1410 0.131
0.165
RehabilitationUpstream kerb
CM23 1434 0.125
0.155
Downstream kerb + overlays CM 23: tolerates slope up to 2.5 %
Both recipes are selfcompacting Slump flow ~ 400 mm
![Page 178: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/178.jpg)
Preparation of the UHPFRC
• Concrete plant mixer with 500 to 750 litres capacity • 300 litres UHPFRC pro batch• 3 batches = 900 litres in 45 minutes• 900 litres pro truck - 635 kg steel fibres per truck !
![Page 179: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/179.jpg)
Application on ½ road downstream – october 22, 2004
On the site
![Page 180: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/180.jpg)
Processing of the UHPFRC
The thixotropic, selfcompacting UHPFRC, is handled using simple tools (Photo A. Herzog)
![Page 181: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/181.jpg)
In-situ air permeability testing
Air permeability tests after Torrent et al. (1995)
Extremely low kT values measured on bridge
![Page 182: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/182.jpg)
Comparative uniaxial tensile behaviour
Denarié et al. (2006)
![Page 183: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/183.jpg)
Uniaxial tensile tests on UHPFRC
Test results on 5 specimens, at 28 days
fct = 13.5 MPa (mean)
hardening = 1.5 ‰ (mean)
Denarié et al. (2006)
![Page 184: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/184.jpg)
Cost analysisComparison of three alternatives
A. Executed project with UHPFRC and no waterproofing membrane
B. Similar case with rehabilitation mortar and waterproofing membrane
C. Similar case with cheaper (- 30 %) UHPFRC and no waterproofing membrane
Case Relative construction costs
A 112 %
B 100 %
C 107 %
Realized
![Page 185: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/185.jpg)
The bridge, after first winter
![Page 186: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/186.jpg)
Detail of UHPFRC, after first winter
View of the surface of the prefabricated kerb with UHPFRC, with superficial corrosion of steel fibres tips near to the surface.
UHPFRC cast on site
Prefabricated
![Page 187: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/187.jpg)
Conclusions of first application
UHPFRC CEMTECmultiscale® was easy to produce and cast on site with standard equipments.
Quality of the UHPFRC was verified in-situ and in the laboratory. Excellent properties were achieved.
Waterproofing membrane not necessary with UHPFRC.
Bituminous layer can be applied after 8 days on UHPFRC, instead of several weeks for normal concrete.
Superficial corrosion of steel fibres on UHPFRC skin, is linked to processing.
Although a purely superficial concern, has to be mitigated by adapted processing techniques.
![Page 188: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/188.jpg)
Owner’s point of view
« The main advantages of this technique are:
Shortening of duration of works, quicker reopening of traffic lanes, and longer durability.
Significant savings in terms of reduced traffic disturbances and associated indirect costs.
Reduction of rehabilitation layer thickness and capacity to reinforce without increasing deadweight.
Prevent costly reinforcement of main parts of the structure.
Application by local contractors, with standard equipments. »SRCE - DTEE CANTON DU VALAIS
![Page 189: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/189.jpg)
7. Conclusions
«Targeted local hardening» of highway structures, in most critical zones, by using UHPFRC.
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. Concept has successfully demonstrated its
technical maturity and economical feasibility in a first full scale application.
![Page 190: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/190.jpg)
What is the future ?
Creep, shrinkage, permeability
Site application 2 - 2007
Site application 1 - 2004Structural response
Res
ista
nce
Why not you ?
![Page 191: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/191.jpg)
Partners of the project
Owner:Owner: Département des Travaux Publics du canton du Valais, Sion, Suisse, Département des Travaux Publics du canton du Valais, Sion, Suisse, Service des routes et Cours d'eau, Section du Valais central/Sion, Switzerland.Service des routes et Cours d'eau, Section du Valais central/Sion, Switzerland.
Concept and supervision:Concept and supervision: Laboratory for Maintenance and Safety of Structures, Laboratory for Maintenance and Safety of Structures, Ecole Polytechnique Fédérale de Lausanne (EPFL), SwitzerlandEcole Polytechnique Fédérale de Lausanne (EPFL), Switzerland
Advice for the UHPFRC recipes and processing:Advice for the UHPFRC recipes and processing: Dr. P. Rossi, Laboratoire Dr. P. Rossi, Laboratoire Central des Ponts et Chaussées (LCPC), Paris, France.Central des Ponts et Chaussées (LCPC), Paris, France.
Execution plans and local direction of works:Execution plans and local direction of works: PRA ingénieurs conseil SA, rue PRA ingénieurs conseil SA, rue de la Majorie 9, CH-1950 Sion, Switzerland, de la Majorie 9, CH-1950 Sion, Switzerland,
Production of UHPFRC, realisation of prefabricated UHPFRC kerb and Production of UHPFRC, realisation of prefabricated UHPFRC kerb and reinforced concrete beam:reinforced concrete beam: Proz Frères SA, matériaux de construction, CH-1908 Proz Frères SA, matériaux de construction, CH-1908 Riddes, Switzerland, Riddes, Switzerland,
Contractor:Contractor: Evéquoz SA, rue des Peupliers 16, CH-1964 Conthey, Switzerland, Evéquoz SA, rue des Peupliers 16, CH-1964 Conthey, Switzerland,
![Page 192: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/192.jpg)
Acknowledgements
UHPFRC team of MCS-EPFL: Prof. Eugen Brühwiler, John Wuest, Aicha Kamen, Andrin Herwig, Dr. Katrin Habel*, Prof. J.P. Charron*, Roland Gysler, Sylvain Demierre, *Former collaborators of MCS-EPFL
Partners in Project SAMARIS
Dr. P. Rossi Dr. R. Woodward
Service des Routes et Cours d’Eau – DTEE SRCE – Canton du Valais
![Page 193: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/193.jpg)
Guidance on use of surface-applied corrosion inhibitorsWorkshop on detailed guidance andCase StudiesM. RichardsonUCD
![Page 194: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/194.jpg)
Outline
• Initial Assessment
• Preview Study option
• Post-repair Monitoring option
• Case Study: Assessment and Monitoring – Kingsway Bridge
• Case Study: Post-repair monitoring – Fleet Flood Span Bridge
![Page 195: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/195.jpg)
Initial Assessment
![Page 196: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/196.jpg)
Yes
Apply technique
No
Initial desk study assessment
Inhibitor potentially appropriate
?
Control of risk to specifier’s satisfaction?
Re-examine alternative
ranked options
No
Yes
Summary of Guidance - 1
![Page 197: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/197.jpg)
Issues in Initial Assessment
• Extremes of in-service environmental conditions
• Degree of saturation of concrete• Chloride levels• Permeability and carbonation• Corroded state of reinforcement at
time of repair• Ecological constraints
![Page 198: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/198.jpg)
Issues in Initial Assessment
• Extremes of in-service environmental conditions
• Degree of saturation of concrete• Chloride levels• Permeability characteristics of concrete• Corroded state of reinforcement at
time of repair• Ecological constraints
![Page 199: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/199.jpg)
Issues in Initial Assessment
• Extremes of in-service environmental conditions
• Degree of saturation of concrete• Chloride levels• Permeability characteristics of concrete• Corroded state of reinforcement at
time of repair• Ecological constraints
![Page 200: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/200.jpg)
Extremes of environmental conditions
Environment
IndicativeTemperature
Potential Consequence
Sustained lowtemperatures
≤ -5oC Alteration in the physical nature of the inhibitor, with implications for its mobility in concrete.Temperature limit of –5°C is only applicable for the storage condition.Application to be carried out above +5°C.
Frequent hightemperatures
≥ 40oC Potential loss of volatile material to the atmosphere.Coating the concrete surface may be an option to reduce evaporation loss.
![Page 201: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/201.jpg)
Degree of saturation of concrete
Moisture State
Indicative Example
Possible Consequence
Permanentlysaturated
Elements ofhighwaystructures predominantly below the waterlevel of a lake
Inhibitor take up by absorption would be low.Subsequent penetration would not be assisted by capillary action.
Note: corrosion would be low in these areas if oxygen access is equally restricted.
Frequent and regular wettingcycles
Elements ofcoastal highwaystructures withinthe tidal zone
Potential washout of inhibitor immediately after application.Inadequate concentration at the reinforcement.
![Page 202: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/202.jpg)
Chloride levels
Chloride State
Indicative Free Chloride Ion at
Level at Reinforcement
Possible Consequence
Low ≤ 0.5 % Chloride ion
by mass of cement
Corrosion inhibitor potentially viable as a preventive maintenance strategy before any significant active corrosion takes place.
Moderate
≤ 1 % Chloride ion
by mass of cement
Corrosion inhibitor may be effective if a satisfactory inhibitor to chloride ion concentration ratio is achieved – much depends on existing degree of corrosion.Protective measures to prevent further chloride build up are recommended in chloride-rich environments.
continued …
![Page 203: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/203.jpg)
Chloride levelscontinued …
Chloride State
Indicative Free Chloride Ion at
Level at Reinforcement
Possible Consequence
High 1 – 2 % Chloride ion by mass of cement
Corrosion inhibitor dosage level may have to be increased beyond typical manufacturer’s recommendation and additional protective measures required.May take the technique beyond its recommended effectiveness window, introducing higher risk.
Very high
> 2 % Chloride ion by mass of
cement
Corrosion inhibitor unlikely to be a successful component of the repair strategy.
![Page 204: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/204.jpg)
Permeability and carbonation
Carbonation
State
ConcretePermeability
Possible Consequence
Cover fullycarbonated
Moderate Inhibitor potentially effective.
High Inhibitor potentially effective initially but reservoir may not be retained in concrete reducing effectiveness over time.May need additional measures such as a suitable coating.
![Page 205: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/205.jpg)
Corroded state of reinforcement
continued …
Existing Corrosion Rate
Indicative Corrosion Rate
over a sustained
period
Possible Consequence
Low to Moderate
< 0.5 µA/cm2
< 5 μm/year
Best scenario possible with inhibitor used as part of a proactive preventive maintenance strategy.
Moderate to High
0.5 – 1.0 μA/cm2
5 - 10 μm/year
State of reinforcement is potentially suitable for consideration of corrosion inhibitor treatment.
![Page 206: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/206.jpg)
Corroded state of reinforcementcontinued …
Existing Corrosion Rate
Indicative Corrosion Rate
over a sustained
period
Possible Consequence
High 1.0 - 10 μA/cm2
10 - 100 μm/year
State of reinforcement will depend on corrosion rate lies - effectiveness of the inhibitor correspondingly influenced.Higher risk at higher corrosion rate.Corrosion monitoring recommended in case of higher corrosion rates.
Very High > 10 μA/cm2
> 100 μm/year
Reinforcement may be heavily corroded - corrosion inhibitor is unlikely to be a successful component of the repair strategy.
![Page 207: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/207.jpg)
Ecological constraints
Local environmental or health and safety constraints?
Example: work near drinking water supply source
![Page 208: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/208.jpg)
Preview Study option
![Page 209: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/209.jpg)
Conduct preview and analyse results
No
YesControl of risk to
specifier’s satisfaction?
Define performance criteria for preview
Finalise proposed rehabilitation strategy
Summary of Guidance - 2
![Page 210: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/210.jpg)
Preview Study – Indicative Criteria
Objective Indicative Performance Criteria
Defer the initial time to depassivation
< 5 μm/year loss of steel (or < 0.5 µA/cm2)
Reduce the rate of corrosion
65% reduction from pre-treated levels over a defined time period or ……………
< 5 μm/year loss of steel (or < 0.5 µA/cm2)
Retard incipient action (ring anode)
No increase in loss of steel prefer …………Decrease to < 5 μm/year loss of steel (or < 0.5 µA/cm2)
![Page 211: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/211.jpg)
Post-repair monitoring option
![Page 212: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/212.jpg)
If resources permit conduct post repair monitoring as part of a proactive maintenance strategy and reapply technique if required during residual service life
Control of risk to specifier’s satisfaction?
Apply technique
Finalise proposed rehabilitation strategy
Re-examine alternative
ranked options
Yes
No
Summary of Guidance - 3
![Page 213: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/213.jpg)
If resources permit conduct post repair monitoring as part of a proactive maintenance strategy and reapply technique if required during residual service life
Control of risk to specifier’s satisfaction?
Apply technique
Finalise proposed rehabilitation strategy
Re-examine alternative
ranked options
Yes
No
Summary of Guidance - 3
If resources permit conduct post repair monitoring as part of a proactive maintenance strategy and reapply technique if required during residual service life
![Page 214: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/214.jpg)
Case Study of assessment and monitoring
Kingsway Bridge
Case Study 1
![Page 215: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/215.jpg)
Kingsway Bridge, Warrington, U.K.
Acknowledgement: Warrington Borough Council
• Reinforced concrete• multi-span arch, • 1932
![Page 216: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/216.jpg)
• Main spans, 2 x 26.21m• Reinforced concrete arches• Thickness: 450mm (arch)
1300mm (springings), • Sagging and hogging
bending moments• Drainage route along top
curved surface of arch• Subject to chloride run-off
![Page 217: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/217.jpg)
Environmental conditions Not significant
Degree of saturation Not significant
Chloride levels Typically 0.3% Max. 0.6 –
1.2%
Carbonation 2mm
State of reinforcement Light surface rust
Some pitting
Ecological constraints Over water
![Page 218: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/218.jpg)
![Page 219: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/219.jpg)
Findings from Initial Assessment
• Threat from chloride-induced corrosion.• Chloride-entrained rain and deicing salts
passing through deck and accumulating at crown of arch and later behind springings.
• Surface applied corrosion inhibitors identified as a candidate strategy for rehabilitation.
![Page 220: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/220.jpg)
• Agreement from Warrington Borough Council to allow further investigation including a form of ‘preview’ study of corrosion inhibitors within SAMARIS
• Areas selected:Crown of ArchUnder Arch
• Corrosion inhibitor applied after base measurements
• Monitoring locations established
![Page 221: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/221.jpg)
![Page 222: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/222.jpg)
![Page 223: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/223.jpg)
Corrosion Rates: Crown Arch
0
5
10
15
20
25
30
35
40
6/24
/04
11/3
/04
1/23
/05
2/6/
05
2/20
/05
3/6/
05
3/20
/05
4/3/
05
5/8/
05
5/22
/05
6/5/
05
6/19
/05
9/11
/05
9/25
/05
10/9
/05
10/2
3/05
11/6
/05
11/2
0/05
12/4
/05
12/1
8/05
1/1/
06
C1RC2RC3RC4R
Test Date
Co
rro
sio
n R
ate
(u
m/y
r)
Corrosion Rate Values
C3R Control
C1R Waterproofing
C4R Inhibitor only
C2R Inhibitor plus
waterproofing
![Page 224: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/224.jpg)
Corrrosion Rates: Under Arch
0
4
8
12
16
20
24
6/24
/04
11/3
/04
1/23
/05
2/6/
05
2/20
/05
3/6/
05
3/20
/05
4/3/
05
5/8/
05
5/22
/05
6/5/
05
6/19
/05
9/11
/05
9/25
/05
10/9
/05
10/2
3/05
11/6
/05
11/2
0/05
12/4
/05
12/1
8/05
1/1/
06
F1RF2RF3RF4RF5RF6RX1RX2RX3R
Test Date
Co
rro
sio
n R
ate
(u
m/y
r)Corrosion Rate Values
![Page 225: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/225.jpg)
Case Study: Post-repair monitoring – Fleet Flood Span Bridge
Case Study 2
![Page 226: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/226.jpg)
Concrete repair and corrosion inhibitor treatment to trestles and abutments.
Monitored previously from 2000 to 2002, reactivated 2005.
Fleet Flood Span Bridge
![Page 227: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/227.jpg)
Trestle 1
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
2/14
/00
3/10
/00
3/14
/00
3/16
/00
7/5/
00
11/1
6/00
2/13
/01
4/24
/01
5/21
/02
11/1
6/05
Test Date
Co
rro
sio
n R
ate
(u
m/y
r)
Corrosion Rate Values
0
4
8
12
16
20
24
28
2/14
/00
3/10
/00
3/14
/00
3/16
/00
7/5/
00
11/1
6/00
2/13
/01
4/24
/01
5/21
/02
11/1
6/05
Test Date
Co
rro
sio
n R
ate
(u
m/y
r)
Corrosion Rate Values
0
1
2
3
4
5
6
2/14
/00
3/10
/00
3/14
/00
3/16
/00
7/5/
00
11/1
6/00
2/13
/01
4/24
/01
5/21
/02
11/1
6/05
Test Date
Co
rro
sio
n R
ate
(u
m/y
r)
Corrosion Rate Values
0
2
4
6
8
10
12
14
16
18
2/14
/00
3/10
/00
3/14
/00
3/16
/00
7/5/
00
11/1
6/00
2/13
/01
4/24
/01
5/21
/02
11/1
6/05
Test Date
Co
rro
sio
n R
ate
(u
m/y
r)
Corrosion Rate Values
![Page 228: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/228.jpg)
Trestle 2
0
0.5
1
1.5
2
2.5
3
3.5
4
2/14
/00
3/10
/00
3/14
/00
3/16
/00
7/5/
00
11/1
6/00
2/13
/01
4/24
/01
5/21
/02
11/1
6/05
Test Date
Co
rro
sio
n R
ate
(u
m/y
r)
Corrosion Rate Values
0
0.4
0.8
1.2
1.6
2
2.4
2.8
3.2
3.6
2/14
/00
3/10
/00
3/14
/00
3/16
/00
7/5/
00
11/1
6/00
2/13
/01
4/24
/01
5/21
/02
11/1
6/05
Test Date
Co
rro
sio
n R
ate
(u
m/y
r)
Corrosion Rate Values
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
2/14
/00
3/10
/00
3/14
/00
3/16
/00
7/5/
00
11/1
6/00
2/13
/01
4/24
/01
5/21
/02
11/1
6/05
Test Date
Co
rro
sio
n R
ate
(u
m/y
r)
Corrosion Rate Values
0
0.4
0.8
1.2
1.6
2
2.4
2.8
3.2
3.6
2/14
/00
3/10
/00
3/14
/00
3/16
/00
7/5/
00
11/1
6/00
2/13
/01
4/24
/01
5/21
/02
11/1
6/05
Test Date
Co
rro
sio
n R
ate
(u
m/y
r)
Corrosion Rate Values
![Page 229: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/229.jpg)
North Abutment
1
2
3
4
5
6
7
8
9
10
2/14
/00
3/10
/00
3/14
/00
3/16
/00
7/5/
00
11/1
6/00
2/13
/01
4/24
/01
5/21
/02
11/1
6/05
Test Date
Co
rro
sio
n R
ate
(u
m/y
r)
Corrosion Rate Values
0
5
10
15
20
25
30
35
40
2/14
/00
3/10
/00
3/14
/00
3/16
/00
7/5/
00
11/1
6/00
2/13
/01
4/24
/01
5/21
/02
11/1
6/05
Test Date
Co
rro
sio
n R
ate
(um
/yr)
Corrosion Rate Values
0
10
20
30
40
50
60
2/14
/00
3/10
/00
3/14
/00
3/16
/00
7/5/
00
11/1
6/00
2/13
/01
4/24
/01
5/21
/02
11/1
6/05
Test Date
Co
rro
sio
n R
ate
(u
m/y
r)
Corrosion Rate Values
![Page 230: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/230.jpg)
South Abutment
0
1
2
3
4
5
6
7
8
2/14
/00
3/10
/00
3/14
/00
3/16
/00
7/5/
00
11/1
6/00
2/13
/01
4/24
/01
5/21
/02
11/1
6/05
Test Date
Co
rro
sio
n R
ate
(u
m/y
r)
Corrosion Rate Values
0
5
10
15
20
25
30
35
40
45
2/14
/00
3/10
/00
3/14
/00
3/16
/00
7/5/
00
11/1
6/00
2/13
/01
4/24
/01
5/21
/02
11/1
6/05
Test Date
Co
rro
sio
n R
ate
(u
m/y
r)
Corrosion Rate Values0
1
2
3
4
5
6
7
2/14
/00
3/10
/00
3/14
/00
3/16
/00
7/5/
00
11/1
6/00
2/13
/01
4/24
/01
5/21
/02
11/1
6/05
Test Date
Co
rro
sio
n R
ate
(u
m/y
r)
Corrosion Rate Values
![Page 231: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/231.jpg)
Summary
• Inhibitor effectiveness is very influenced by the state of the reinforcement at time of treatment and the hostility of the chloride environment.
• This inter-relationship makes it difficult to specify precise limits on the effectiveness window but qualitative guidance is proposed.
• Optimal use of inhibitors may be as part of a proactive maintenance strategy and the earlier they are applied the better.
• The use of corrosion monitoring is invaluable in managing such repair strategies
![Page 232: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/232.jpg)
Further Information
• SAMARIS Report D21• Field Studies
• SAMARIS Report D25a• Guidance on use of surface-applied
corrosion inhibitors
![Page 233: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/233.jpg)
Advances in rehabilitation of highway structuresDiscussion, Summary and PerspectivesProf. Eugen BrühwilerMCS/EPFL
![Page 234: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/234.jpg)
… improving the performance !
• apply advanced structural assessment to limit interventions
• improve the structure (not just repair it)• reduce the duration of interventions • reduce life-cycle costs (without increasing the
cost of intervention)
![Page 235: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/235.jpg)
Achieving improved performance …through:• education motivation• applications demonstration• guidelines regulation
![Page 236: Table of contents M. McKenzie Guidelines on the selection of innovative techniques for the rehabilitation of concrete highway structures3 A. ŽnidaričOptimised](https://reader031.vdocuments.us/reader031/viewer/2022032722/56649cdb5503460f949a63e4/html5/thumbnails/236.jpg)