ƒ Introduction ƒ Methods for Repair, Protection & Strengthening of RC Structures/bridges as per new Standards BS EN 1504 ƒ Case studies/ Video

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ADVANCEMENTS IN CONCRETE REPAIR
TECHNOLOGIES AND TECHNIQUES
Structural Repair, Protection and Strengthening of RC Structures
European Standards BS EN 1504 Series
Presented by Eng. Joseph Nabih, Sika UAE Refurbishment

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AGENDA
Introduction
Methods for Repair, Protection &
Strengthening of RC Structures/bridges
as per new Standards BS EN 1504
Case studies/ Video

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EXPOSURE AND DAMAGE OF CONCRETE
STRUCTURE
Collapse of a post tensioned bridge due
to corroded steel wires
Erosion and Steel corrosion of concrete piles

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DAMAGE ON CONCRETE BRIDGES
Concrete spalling due to steel corrosion Cracks, water‐bearing

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Volume of corrosion product is approx. 2,5 times bigger than
black steel → delamina on load → spalling!
CORROSION OF STEEL IN CONCRETE

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CORROSION DUE TO CARBONATION ON
BRIDGE BEARING
Reduction of rebar: approx. 2/100 to 2/10 m per year

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PINHOLE ‐ CORROSION CAUSED BY CHLORIDES
Reduction of rebar: approx. 1 to 10 mm per year!!
In carbonated concrete: Reduction of rebar: approx. 2/100 to 2/10 mm per year
Fast, local reduction of cross‐section

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QUALITY AND DURABILITY IN CONCRETE
REPAIR AND PROTECTION:
Clients should use suitably
qualified personnel with
sufficient knowledge of:
‐ Investigation methods
‐ Structural design
‐ Material technology
‐ Deterioration mechanisms
‐ Refurbishment & maintenance

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CONCRETE, DAMAGE
AND DEFECTS
CONCRETE DAMAGE DUE TO
REINFORCEMENT CORROSION
Mechanical
Physical
Chemical
ASSESSMENT SURVEY AND DIAGNOSIS OF
DAMAGE
Stray/Electric
al Current
Carbonation
Chlorides

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CONCRETE, DAMAGE AND DEFECTS
MECHANICALCHEMICALPHYSICAL
‐ Overload- Impact
Abrasion – Erosion- Fire
‐ Thermal
‐ Freeze Thaw
‐ Efflorescence
‐ Salt Crystal Expansion
‐ Erosion
‐ AAR/ASR
‐ Chemical
Exposure
‐ Bacterial action

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CONCRETE DAMAGE DUE TO REINFORCEMENT
CORRSION
CHLORIDESCARBONATION
STRAY/ELECTRIC
CURRENT

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12
ALKALI AGGREGATE REACTION
Reactive Aggregate
CONCRETE, DAMAGE AND DEFECTS

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FREE ‐ SULPHATE ATTACK
Sulphate solutions which react
with calcium hydroxide and
calcium aluminates, (C3A)
CONCRETE, DAMAGE AND DEFECTS

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More than 50%
related to moisture
problem – direct or
indirect
PROBLEMS IN BUILDINGS
Source: CSTB, Belgium
Cracks
Debonding
Thermal Insulation
Deformation
Acoustic
Stability
Maintenance Various
Superficial Degradation
11
10
13
5
4
22 2 24
Corrosion
Hygrothermy
31
4
2
Humidity
Aspect
10

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Structural Cracks!
CONCRETE, DAMAGE AND DEFECTS
CRACKS IN CONCRETE STRUCTURES

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CRACK TYPE:
• Structural or Non structural crack?
• Live or static crack?
• Crack width ?
• Crack substrate Dry, Damp or Wet?
• Crack structure (how deep?)
CRACK CHARACTERISTICS
CRACKS IN CONCRETE STRUCTURES

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TYPES OF
CRACK
Flexure cracks
Shear cracks
Tension cracks
Torsion cracks
CRACKS IN CONCRETE STRUCTURES

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EXAMPLES OF INTRINSIC CRACKS IN HYPOTHETICAL
CONCRETE STRUCTURE
Plastic
settlement
Plastic
settlement
Plastic
settlement
Plastic
shrinkage
Plastic
shrinkage
Plastic
settlement
Plastic
shrinkage
Early therm.
contractionEarly therm.
contraction
Long term
drying
shrinkage
Crazing
Crazing
Long term
drying
shrinkage
Non-Structural Cracks

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CRACKS IN CONCRETE STRUCTURES
CLASSIFICATION OF INTRINSIC CRACKS

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CRACK REPAIR METHODS
Injection
Procedure for filling cracks and cavities under pressure with
drill‐hole (mechanical) or surface packers using the
appropriate injection method.
Injection with drill‐hole (mechanical)
packers is used
when drilling is possible
for low and high pressure injection
Injection with surface packers
Is used
when no drilling is possible
when there is no water
(structural crack repair)
For low pressure injection (<20bar)

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WHAT ARE WE LOOKING FOR ?
• A comprehensive set of standards for Concrete Repair
Implemented by 2009
BS EN 1504 Series
• To be used by specifiers particularly those operating under
public procurement rules

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BS EN 1504:
Products and systems for the protection and repair of concrete structures
Definitions, requirements, quality control and evaluation of conformity
Defects in Concrete
Reinforcement Corrosion

24. THE CORRECT CONCRETE REPAIR AND PROTECTION
PROCEDURE REPAIR PHASES
Information about the
Structure
• History of structure
• Review
documentation
• Condition survey
Process of
Assessment
• Defect diagnosis
• Analysis results
• Root cause
identification
• Structural assessment
Management
Strategy
• Repair options
• Select Principles
• Select Methods
• Health and safety issues
Design of Repair Work
• Definition of performance
• Substrate preparation
• Products
• Application
• Specifications
• Drawings
Repair Work
• Final product selection
• Equipment selection
• Health and safety
assessment
• QA/QC definition
Acceptance of Repair
Work
• Acceptance of testing
• Acceptance of
finishing
• Final documentation
• Maintenance strategy

25. THE PRINCIPLES AND METHODS OF
REPAIR AND PROTECTION FROM EN 1504‐9
Choice of protection & repair principles and methods

26. THE PRINCIPLES AND METHODS OF
REPAIR AND PROTECTION FROM EN 1504‐9
Choice of protection & repair principles and methods

27. THE PRINCIPLES AND METHODS OF
REPAIR AND PROTECTION FROM EN 1504‐9
Choice of protection & repair principles and methods

28. CONCRETE REPAIR & RELATED PRINCIPLES FOR DEFECTS IN
CONCRETE AND REMEDIATION OF REINFORCEMENT CORROSION
Principle 4 Structural Strengthening –
Sika® CarboDur®/SikaWrap®
Principle 10 Cathodic Protection– Sika® MonoTop® 612 or SikaCem® 133
Gunite overlay
Principle 2 Moisture Control
Principle 8 Increasing Resistivity
Principle 9 Cathodic Control
Principle 6 Resistance to Chemicals –
Sikagard® and Sikafloor® Epoxy Coatings
Principle 1 Protection Against Ingress Sikagard® coatings and hyrophobic
impregnations, Sikafloor® deck membranes
Principle 11 Control of Anodic areas – Sika® FerroGard® 903
Principle 5 Physical Resistance
Principle 7 Preserving or restoring passivity – Sika® MonoTop® mortars
Principle 3 Concrete Restoration – Sika® MonoTop® mortars

29. THE METHODS OF REPAIR AND PROTECTION FROM EN 1504‐9
1: PROTECTION AGAINST INGRESS (PI)
Method 1.1 Hydrophobic Impregnation Method 1.2 Impregnation
Method 1.3 Coating Method 1.4 Surface banding of cracks

30. THE METHODS OF REPAIR AND PROTECTION FROM EN 1504‐9
1: PROTECTION AGAINST INGRESS (PI)
Method 1.5 Filling of Cracks Method 1.6 Transferring cracks into joints
Method 1.7 Erection of external panels Method 1.8 Applying membranes

31. THE METHODS OF REPAIR AND PROTECTION FROM EN 1504‐9
2: MOISTURE CONTROL (MC)
Method 2.1 Hydrophobic Impregnation Method 2.2 Impregnation
Method 2.3 Coating Method 2.4 Erecting external panelsmbranes

32. THE METHODS OF REPAIR AND PROTECTION FROM EN 1504‐9
3: CONCRETE RESTORATION (CR)
Method 3.1 Hand‐applied mortar Method 3.2 Recasting with concrete or mortar
Method 3.3 Spraying concrete or mortar Method 3.4 Replacing concrete elements

33. THE METHODS OF REPAIR AND PROTECTION FROM EN 1504‐9
4: STRUCTURAL STRENGTHENING (SS)
Method 4.1 Adding or replacing embedded
or external reinforcing bars
Method 4.2 Adding reinforcement anchored in
pre‐formed or drilled holes
Method 4.3 Bonding plate reinforcement Method 4.4 Adding mortar or concrete

34. THE METHODS OF REPAIR AND PROTECTION FROM EN 1504‐9
4: STRUCTURAL STRENGTHENING (SS)
Method 4.6 Filling cracks, voids or interstices
Method 4.5 Injecting cracks, voids or
interstices
Method 4.7 Prestressing – (post tensioning)

35. THE METHODS OF REPAIR AND PROTECTION FROM EN 1504‐9
7: PRESERVING OR RESTORING PASSIVITY
Method 7.1 Increasing cover with additional
mortar or concrete
Method 7.2 Replacing contaminated or
carbonated concrete.
Method 7.3 Electrochemical realkalisation of
carbonated concrete
Method 7.4 Realkalisation of carbonated
concrete by diffusion

36. THE METHODS OF REPAIR AND PROTECTION FROM EN 1504‐9
7: PRESERVING OR RESTORING PASSIVITY
Method 7.5 Electrochemical chloride extraction

37. THE METHODS OF REPAIR AND PROTECTION FROM EN 1504‐9
11: CONTROL OF ANODIC AREAS (CA)
Method 11.1 Active coating of the reinforcement Method 11.2 Barrier coating of the reinforcement
Method 11.3 Applying corrosion inhibitors
in or to the concrete.

38. PERFORMANCE CHARACTERISTICS DEFINED IN EN 1504‐9

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Class R4 Class R3 Class R2 Class R1
Compressive Strength ≥ 45 MPa ≥ 25 MPa ≥ 15 MPa ≥ 10 MPa
Chloride Ion Content
Adhesive Bond ≥ 2,0 MPa ≥ 1,5 MPa
≥ 2,0 MPa ≥ 1,5 MPa ≥ 0,8 MPa
Carbonation Resistance
(not required if coated)
Not required
Elastic Modulus ≥ 20 GPa ≥ 15 GPa Not required
Restrained shrinkage
Expansion
No
requirement
dK ≤ Control concrete C(0,45)
≤ 0,05% ≤ 0,05%
≥ 0,8 MPa
Max average crack width <0.05mm
No crack width >0.1mm
No delamination
Structural Non-Structural
RequirementItem
Notes:
= For structural strengthening Principle 4
- All intended uses
REPAIR MORTAR CLASSIFICATION
PERFORMANCE REQUIREMENTS

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Structural Strengthening

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FRP GUIDELINES AND CODES

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CarboDur® CFRP Plate Application
CarboDur® CFRP plate
Sikadur®‐30
Primer
Putty
Adhesive
EXTERNAL STRENGTHENING
1‐ PLATE BONDING ( STEEL , CFRP )

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SIKACARBODUR PLATE APPLICATION

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Live Anchorage
CarboDur CFRP Plate
Deviator
Dead Anchorage
EXTERNAL STRENGTHENING PRESTRESSING
WITH CARBODUR PLATE SYSTEM

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CARBOSTRESS® POST‐TENSIONING PROCESS
• Core drilling, block out, concrete surface
• Steel reaction frames
• Cut CarboDur® plate to length
• Temporary support
• Mount CarboStress® anchors
• Place CarboStress® tendon, Hydraulic jack
• Prestress
• Fill with Sikadur®‐41 / 42
• Remove hydraulic jack
• Remove temporary support
• Sikadur®‐30 / 30 LP

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SIKAWRAP® FABRIC DRY APPLICATION
Sikadur®‐330
Primer
Putty
Adhesive
Saturant
Top coat
EXTERNAL STRENGTHENING
3‐ BONDED FABRICS (CARBON, GLASS)
SikaWrap®

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SIKAWRAP APPLICATION

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NEAR SURFACE MOUNTED (NSM)
REINFORCEMENT
1. Cut groove in concrete cover of internal reinforcement
concrete cover
internal steel
reinforcement
2. Fill with Sikadur®‐30/330/300 adhesive
3. Place CarboDur® S plate / CarboDur® BC rod
Design/Calculation:
US: ACI 440.4R‐08
Germany: Guideline DAfStB (November 2011)

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EXTERNAL STRENGTHENING 5 ‐ SHELLS
(FIBERGLASS JACKET)

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TYPICAL AREAS OF APPLICATION 1 ‐ SLABS
Flexural

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TYPICAL AREAS OF APPLICATION 2 ‐ BEAMS
a‐Flexural

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c‐ Flexure & Shear
TYPICAL AREAS OF APPLICATION 2 ‐ BEAMS

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c‐ Flexure & Shear
TYPICAL AREAS OF APPLICATION 2‐ BEAMS

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TYPICAL AREAS OF APPLICATION 3‐ COLUMNS
a ‐ Confinement

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d‐ Corbel Strengthening
TYPICAL AREAS OF APPLICATION 4 ‐ CORBEL

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TYPICAL AREAS OF APPLICATION 5 ‐ WALLS
Shear Wall

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TYPICAL AREAS OF APPLICATION 6 ‐
FOUNDATIONS

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Column to Beam Joints
TYPICAL AREAS OF APPLICATION 7‐ JOINTS

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TYPICAL AREAS OF APPLICATION 8 ‐ OPENINGS
a‐Slab
c‐ Wall
B‐Beams

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TYPICAL AREAS OF APPLICATION 9 –
PIPE REPAIRS
a‐Inside
b‐outside

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Victory Center – Washington, DC
TYPICAL AREAS OF APPLICATION 8 –
BLAST RESISTANCE

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TYPICAL AREAS OF APPLICATION DIFFERENT
SUBSTRATE MATERIALS
Natural Stone
Brickwork Timber
Cast Iron

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TYPICAL AREAS OF APPLICATION DIFFERENT
STRUCTURES

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SIKA IS CAPABLE OF HANDLING ALL
STRENGTHENING APPLICATIONS

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CASE STUDY: STRENGTHENING OF
HOLY HARAM – MAKKAH , KSA

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Sika Solution: Confinement of the Columns using 3500 m2 of
Sika Wrap 230C & Sikawrap 530C
The Problem: Retrofitting for 450 RC columns due to increasing of loads.
40% & 100%
CASE STUDY: STRENGTHENING OF
HOLY HARAM – MAKKAH , KSA

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CASE STUDY: STRENGTHENING OF
HOLY HARAM – MAKKAH , KSA

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CONCLUSION
BASED ON EN 1504 : WHAT DO YOU SPECIFY?
• Minimum performance:
• match properties to the original substrate concrete (like-with-like)
• Additional properties: such as thermal compatibility.
• Specify higher values than the min requirements:
- Higher strength - Lower shrinkage
- Low creep - High chloride ions penetration resistance
• Suppliers of repair systems should reformulate the mortars for compliance with EN 1504
requirements.
• ICRI: Guidelines/technical competence.
• ACI: Guidance/Codes/technical competence
• ASTM: Testing standards/CE equivalence
• ASCE: Technical competence.
• AASHTO: Limited Guidelines/technical competence.
• EN 1504: Coded min performance/process focused, not a guide for assessment & inspection.

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CONTACT US
MOBILE:
+971 50 919 0379
PHONE:
+971 4 439 8200
EMAIL:
jinfo@ae.sika.com

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