Chapter 8Full Depth Concrete Repair
From… Maintenance TechnicalAdvisory Guide (MTAG)
Learning Objectives
1. List benefits of full-depth repairs2. Describe primary design considerations3. List available types of repair materials4. Describe the recommended construction
procedure5. List important quality control activities6. Describe potential construction and
performance problems7. Identify troubleshooting solutions
Chapter 8 – Full Depth Concrete Repair
Presentation Outline
IntroductionDesign considerationsConstructionQuality controlTroubleshooting
Chapter 8 – Full Depth Concrete Repair
Introduction
Cast-in-place concrete repairs that extend the full-depth of the existing slab
Definition
Purpose• Repair localized distress• Preparation for an overlay, as necessary
Chapter 8 – Full Depth Concrete Repair
Candidate Distresses
Transverse cracking (M, H)Longitudinal cracking (M, H)Corner breaks (L, M, H)Spalling (M, H)Blowup (L, M, H)D-cracking (M, H)Deterioration of existing repairs (M, H)
Chapter 8 – Full Depth Concrete Repair
Benefits
Restored rideabilityRestored structural integrityPrevents further deterioration
Chapter 8 – Full Depth Concrete Repair
Limitations
Does not address structural inadequacyNot a long-term solution for material-related distressesWidespread deteriorationCost considerations
Chapter 8 – Full Depth Concrete Repair
Module 8-1
Design, Materials & Specifications
From… Maintenance TechnicalAdvisory Guide (MTAG)
Presentation Outline
IntroductionDesign considerationsConstructionQuality controlTroubleshooting
Chapter 8 – Full Depth Concrete Repair
Design Considerations
Selecting repair boundariesLoad transfer designSelection of repair materialsCuringOpening to traffic
Chapter 8 – Full Depth Concrete Repair
Selecting Repair BoundariesExtent of Deterioration at Joint
Visual deterioration of surface
Dowel bar
ExistingJoint
Actual deterioration at bottom of slab
Chapter 8 – Full Depth Concrete Repair
Selecting Repair BoundariesRepair Dimensions
Minimum dimensions• Use lane-width repairs• Length > 6 ft
Long repairs 12 ft or longer• Provide reinforcement, or• Provide intermediate doweled joint
Chapter 8 – Full Depth Concrete Repair
Selecting Repair BoundariesRepair Recommendations (JPCP)
Some typical distress conditions noted withL = low M = medium H = high
M-H L L M-H L M H
No repair requiredd = 1.8 m (6 ft) minimum
d d ddReplace entireslab-outer lane
d
Chapter 8 – Full Depth Concrete Repair
Selecting Repair BoundariesRepair Recommendations (JRCP)
Some typical distress conditions noted withL = low M = medium H = high
No repair required dReplace entire
slab-outer lanedd ddd
d = 1.8 m (6 ft) minimum
LL
L
ML
HL
HLM-H
L
H
L
L L
L L L LL
M
L
M
L
L
Chapter 8 – Full Depth Concrete Repair
Selecting Repair BoundariesMulti-Lane Considerations
Adjacent lanes can be repaired independently• Matching joints is not essential• Avoid small offsets
If blowups in adjacent lane• Delay until hot weather• Cut pressure relief joints
Chapter 8 – Full Depth Concrete Repair
Load Transfer DesignRecommendations
Mid-depth slabTraffic Direction
Smoothdowels1.5 in dia.12 ft
1 ft typical
Smooth dowelsor deformed rebars
6 ft minimum
Load Transfer DesignDowel Bars
Load Transfer DesignTie Bars
Repair MaterialsRecommendations
PCC mixesRapid strength concrete (RSC)High early strength materialsSpecialty materials
Chapter 8 – Full Depth Concrete Repair
Curing
Curing compoundInsulation blanketsHIPERPAV software
Chapter 8 – Full Depth Concrete Repair
Opening to Traffic
Opening criteria• Minimum strength• Minimum time
Typical strength• 3,500 psi compressive• 400 psi center-point• 250 psi third-point
Chapter 8 – Full Depth Concrete Repair
Typical Item CodesItem Code Description
120090 Construction area signs
120100 Traffic control system
128650 Portable changeable message sign
150846 Remove concrete pavement
150306 Repair spalled concrete
156515 Repair spalled and unsound surface area
401108 Replace concrete pavement (rapid strength concrete
406100 Dowel bar retrofit
413101 Repair corner breaks
413111 Repair spalled joint
413114 Replace joint seal (existing concrete pavement)
413115 Seal joint (existing concrete pavement)
420201 Grind existing concrete pavement
511040 Concrete surface finish
511055 Concrete surface texture
515028 Repair spalled surface area
http://i80.dot.ca.gov/hq/esc/oe/awards/#item_code
Module 8-2
Construction and Inspection
From… Maintenance TechnicalAdvisory Guide (MTAG)
Presentation Outline
IntroductionDesign considerationsConstructionQuality controlTroubleshooting
Chapter 8 – Full Depth Concrete Repair
Construction Procedure
1. Concrete sawing2. Concrete removal3. Repair area preparation4. Load transfer provision5. Material placement6. Curing7. Joint sealing
Chapter 8 – Full Depth Concrete Repair
Concrete SawingConsiderations
Full-depth, diamond-bladed sawing Pressure relief cuts on hot daysLimit traffic loading on sawed pavement to avoid pumpingIf asphalt shoulder present, remove 150 mm (6 in) for form space
Chapter 8 – Full Depth Concrete Repair
Concrete SawingExample Sawcut
Concrete RemovalConcrete Breakup
Concrete RemovalRemoval with a Backhoe
Concrete RemovalLiftout Method
Advantages• Does not disturb subbase• More rapid material removal
Disadvantages• Process requires lifting pins and heavy lifting
equipment
Chapter 8 – Full Depth Concrete Repair
Concrete RemovalPlacement of Lifting Pins
Concrete RemovalLifting of Slab Pieces
Concrete RemovalDisposal of Slab Pieces
Repair Area Preparation
Load Transfer ProvisionDrilling Recommendations
Dowel holes drilled on-center (12 in) at mid-depthDowel holes drilled slightly larger than dowel diameterSmooth steel dowel bars or deformed tie bars can be used
Chapter 8 – Full Depth Concrete Repair
Load Transfer ProvisionGang Drill
Load Transfer ProvisionDowel-Bar Placement
Blow debris and dust from holesPlace grout or epoxy in holesInsert dowel into hole with slight twisting motionInstall grout retention disksGrease protruding dowel ends
Chapter 8 – Full Depth Concrete Repair
Load Transfer ProvisionCleaning Holes
Load Transfer ProvisionInjecting Grout (or Epoxy)
Load Transfer ProvisionDowel-Bar Placement
Load Transfer ProvisionDowel-Bar Placement
Subbase
Repair area
Anchoring materialGrout-retentiondisk (optional)
Hole dia. = d+a
Existing slab
a = 2 mm (1/8 in) for epoxy a = 6 mm (1/4 in) for cement grout
d = dowel diameter
Subgrade Soil
Load Transfer ProvisionArea Prepared with Dowels in Place
Material Placement
Consolidation and level finish are criticalVibrate along edges of repairAvoid addition of extra waterTexture surface to match existing pavement
Chapter 8 – Full Depth Concrete Repair
Material Placement
Material PlacementScreeding
Material PlacementFinishing
Material PlacementTexturing
CuringApplication of Curing Compound
Joint Sealing
Saw and seal as soon as possible after placementFollow the procedures described in Module 4
Chapter 8 – Full Depth Concrete Repair
Special CRCP Considerations
CRCP PavementsCandidate Distresses
Punchouts (L, M, H)Deteriorated transverse cracks (M, H)Longitudinal cracking (M, H)Blowup (L, M, H)D-cracking (M, H)Deterioration of or near repair (M, H)
Chapter 8 – Full Depth Concrete Repair
CRCP PavementsRepair Recommendations
HH
H H Mb a b
Replace as a single area
b a bb a bb a b> 6 ft
a > 6 ft tied steela > 4 ft welded or mechanical connectionb > 18 in
CRCP PavementsSawcut Locations
4 ft - welded or 6 ft tied minimum
Full-depth cutPartial-depth cut
Failure
A
Partial-depth cut
B A
A = 8 in minimum – welded; 24 in minimum – tiedB = 32 in minimum – welded; 24 in minimum – tied
CRCP PavementsRestoring Continuity of Reinforcing Steel
Presentation Outline
IntroductionDesign considerationsConstructionQuality controlTroubleshooting
Chapter 8 – Full Depth Concrete Repair
Quality Control
Similar to conventional PCC pavingVerify repair boundariesMonitor to ensure no damage to surrounding concreteProject inspectionProper curing techniques
Chapter 8 – Full Depth Concrete Repair
Project Checklist
Preliminary Responsibilities • Document review • Project review
Materials Checks • Concrete patch material• Load transfer devices • Other materials • General
Chapter 8 – Full Depth Concrete Repair
Project Checklist
Equipment Inspections • Concrete removal equipment • Patch area cleaning equipment • Testing equipment • Placing and finishing equipment
Others• Weather requirements • Traffic control
Chapter 8 – Full Depth Concrete Repair
Project Checklist
Project Inspection Responsibilities • Concrete removal and cleanup • Patch preparation • Placing, finishing, and curing concrete• Resealing joints and cracks
Cleanup ResponsibilitiesOthers identified in Special Provisions
Chapter 8 – Full Depth Concrete Repair
Presentation Outline
IntroductionDesign considerationsConstructionQuality controlTroubleshooting
Chapter 8 – Full Depth Concrete Repair
Troubleshooting
Construction and performance problemsApproach:
IdentifyProblem
DetermineCause
IdentifySolution
Chapter 8 – Full Depth Concrete Repair
What is wrong here?
Selecting Repair BoundariesWhat is wrong here?
Selecting Repair BoundariesWhat is wrong here?
Selecting Repair BoundariesWhat is wrong here?
TroubleshootingPossible Performance Problems
Problem:Longitudinal cracking in the patch
Potential causes?
Chapter 8 – Full Depth Concrete Repair
TroubleshootingPossible Performance Problems
Problem:Transverse cracking in the patch
Potential causes?
Chapter 8 – Full Depth Concrete Repair
TroubleshootingPossible Performance Problems
Problem:Surface scaling
Potential causes?
Chapter 8 – Full Depth Concrete Repair
TroubleshootingPossible Performance Problems
Problem:Spalling in patch at the transverse or longitudinal joint
Potential causes?
Chapter 8 – Full Depth Concrete Repair
TroubleshootingPossible Performance Problems
Problem:Deterioration adjacent to the patch
Potential causes?
Chapter 8 – Full Depth Concrete Repair
TroubleshootingPossible Performance Problems
Problem:Settlement of the patch
Potential causes?
Chapter 8 – Full Depth Concrete Repair
Troubleshooting Guide – Causes and Solutions
Undercut spallingSaw binds Adjacent slab damage Slab disintegration Patch filled with water Grout flow out of dowel holes Misaligned dowels
Chapter 8 – Full Depth Concrete Repair
Presentation Outline
IntroductionDesign considerationsConstructionQuality controlTroubleshooting
Chapter 8 – Full Depth Concrete Repair
Learning Objectives
1. List benefits of full-depth repairs2. Describe the primary full-depth repair design
considerations3. List available types of repair materials4. Describe the recommended construction
procedure5. List important quality control activities6. Describe potential construction and
performance problems7. Identify troubleshooting solutions
Chapter 8 – Full Depth Concrete Repair
Thank You
Questions?
Chapter 8 – Full Depth Concrete Repair