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Chapter 8 Full Depth Concrete Repair. From… Maintenance Technical Advisory Guide (MTAG). Learning Objectives. List benefits of full-depth repairs Describe primary design considerations List available types of repair materials Describe the recommended construction procedure

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chapter 8 full depth concrete repair

Chapter 8Full Depth Concrete Repair

From… Maintenance Technical

Advisory Guide (MTAG)

learning objectives
Learning Objectives
  • List benefits of full-depth repairs
  • Describe primary design considerations
  • List available types of repair materials
  • Describe the recommended construction procedure
  • List important quality control activities
  • Describe potential construction and performance problems
  • Identify troubleshooting solutions
presentation outline
Presentation Outline
  • Introduction
  • Design considerations
  • Construction
  • Quality control
  • Troubleshooting
introduction
Introduction
  • Definition

Cast-in-place concrete repairs that extend the full-depth of the existing slab

  • Purpose
    • Repair localized distress
    • Preparation for an overlay
candidate distresses
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)
benefits
Benefits
  • Restored rideability
  • Restored structural integrity
  • Prevents further deterioration
limitations
Limitations
  • Does not address structural inadequacy
  • Not a long-term solution for material-related distresses
  • Widespread deterioration
  • Cost considerations
design materials specifications

Module 8-1

Design, Materials & Specifications

From… Maintenance Technical

Advisory Guide (MTAG)

presentation outline9
Presentation Outline

  • Introduction
  • Design considerations
  • Construction
  • Quality control
  • Troubleshooting
design considerations
Design Considerations
  • Selecting repair boundaries
  • Load transfer design
  • Selection of repair materials
  • Curing
  • Opening to traffic
selecting repair boundaries extent of deterioration at joint
Selecting Repair BoundariesExtent of Deterioration at Joint

Visual deterioration of surface

Existing

Joint

Dowel bar

Actual deterioration at bottom of slab

selecting repair boundaries repair dimensions
Selecting Repair BoundariesRepair Dimensions
  • Minimum dimensions
    • Use lane-width repairs
    • Length > 1.8 m (6 ft)
  • Long repairs (>3.7 m [12 ft] long)
    • Provide reinforcement, or
    • Provide intermediate doweled joint
selecting repair boundaries repair recommendations jpcp

Some typical distress conditions noted with

L = low M = medium H = high

M-H

L

L

M-H

L

M

M

d

d

d

d

d

d

No repair required

Replace entire

slab-outer lane

d = 1.8 m (6 ft) minimum

Selecting Repair BoundariesRepair Recommendations (JPCP)
selecting repair boundaries repair recommendations jrcp

L

L

L

H

L

L

L

L

L

L

L

L

M

L

L

M

L

L

H

L

M-H

L

L

H

M

Some typical distress conditions noted with

L = low M = medium H = high

d

d

d

d

Replace entire

slab-outer lane

d

d

d = 1.8 m (6 ft) minimum

Selecting Repair BoundariesRepair Recommendations (JRCP)

No repair

required

selecting repair boundaries multi lane considerations
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 cooler weather
    • Cut pressure relief joints
load transfer design recommendations
Load Transfer DesignRecommendations

Traffic Direction

Mid-depth slab

Smooth dowels

or deformed rebars

Smooth

dowels

38 mm

(1.5 in) dia.

0.6 m

(2 ft)

3.7 m

(12 ft)

0.3 m (1 ft) typical

1.8 m (6 ft) minimum

repair materials recommendations
Repair MaterialsRecommendations
  • PCC mixes
  • Rapid set cement (RSC)
  • Regulated set portland cement (RSPC)
  • Proprietary materials
curing
Curing
  • Curing compound
  • Insulation blankets
  • HIPERPAV software
opening to traffic
Opening to Traffic
  • Opening criteria
    • Minimum strength
    • Minimum time
  • Typical strength
    • 13.8 MPa (2,000 psi) compressive
    • 2.1 MPa (300 psi) center-point
    • 1.7 MPa (250 psi) third-point
typical item codes
Typical Item Codes

http://i80.dot.ca.gov/hq/esc/oe/awards/#item_code

construction and inspection

Module 8-2

Construction and Inspection

From… Maintenance Technical

Advisory Guide (MTAG)

presentation outline24
Presentation Outline

  • Introduction
  • Design considerations
  • Construction
  • Quality control
  • Troubleshooting

construction procedure
Construction Procedure
  • Concrete sawing
  • Concrete removal
  • Repair area preparation
  • Load transfer provision
  • Material placement
  • Curing
  • Joint sealing
concrete sawing considerations
Concrete SawingConsiderations
  • Full-depth, diamond-bladed sawing
  • Pressure relief cuts on hot days
  • Limit traffic loading on sawed pavement to avoid pumping
  • If asphalt shoulder present, remove 150 mm (6 in) for form space
concrete removal breakup and cleanout method
Concrete RemovalBreakup and Cleanout Method
  • Advantages
    • Efficient breakup of concrete
    • Rapid removal of concrete onto trucks
  • Disadvantages
    • Greatly disturbs subbase
    • Potential to damage slab
concrete removal liftout method
Concrete RemovalLiftout Method
  • Advantages
    • Does not disturb subbase
    • More rapid material removal
  • Disadvantages
    • Disposal of large concrete pieces
    • Process requires lifting pins and heavy lifting equipment
load transfer provision drilling recommendations
Load Transfer ProvisionDrilling Recommendations
  • Dowel holes drilled on 305 mm (12 in) centers at mid-depth
  • Dowel holes drilled slightly larger than dowel diameter
  • Smooth steel dowel bars or deformed tie bars can be used
load transfer provision dowel bar placement
Load Transfer ProvisionDowel-Bar Placement
  • Blow debris and dust from holes
  • Place grout or epoxy in holes
  • Insert dowel into hole with slight twisting motion
  • Install grout retention disks
  • Grease protruding dowel ends
load transfer provision dowel bar placement42
Load Transfer ProvisionDowel-Bar Placement

Existing slab

Grout-retention

disk (optional)

Anchoring material

Hole dia. = d+a

Repair area

d = dowel diameter

a = 2 mm (1/8 in) for epoxy

Subbase

a = 6 mm (1/4 in) for cement grout

Subgrade Soil

material placement
Material Placement
  • Consolidation and level finish are critical
  • Vibrate along edges of repair
  • Avoid addition of extra water
  • Texture surface to match existing pavement
joint sealing
Joint Sealing
  • Saw and seal as soon as possible after placement
  • Follow the procedures described in Module 3-1
crcp pavements candidate distresses
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)
crcp pavements repair recommendations
CRCP PavementsRepair Recommendations

H

H

H

M

H

b a b

Replace as a single area

> 1.8 m

b a b

b a b

b a b

a > 1.8 m (6 ft) tied steel

a > 1.2 m (4 ft) welded or mechanical connection

b > 46 cm (18 in)

crcp pavements sawcut locations
CRCP PavementsSawcut Locations

1.2 m (4 ft) - welded or 1.8 m (6 ft) tied minimum

A

B

A

Failure

Partial-depth cut

Full-depth cut

Partial-depth cut

A = 200 mm (8 in) minimum – welded; 610 mm (24 in) minimum – tied

B = 810 mm (32 in) minimum–welded; 610 mm (24 in) minimum – tied

presentation outline57
Presentation Outline

  • Introduction
  • Design considerations
  • Construction
  • Quality control
  • Troubleshooting

quality control
Quality Control
  • Similar to conventional PCC paving
  • Verify repair boundaries
  • Monitor to ensure no damage to surrounding concrete
  • Project inspection
  • Proper curing techniques
project checklist
Project Checklist
  • Preliminary Responsibilities
    • Document Review
    • Project Review
  • Materials Checks
    • Concrete patch material
    • Load tranfer devices
    • Other materials
    • General
project checklist60
Project Checklist
  • Equipment Inspections
    • Concrete Removal Equipment
    • Patch Area Cleaning Equipment
    • Testing Equipment
    • Placing and Finishing Equipment
  • Others
    • Weather Requirements
    • Traffic Control
project checklist61
Project Checklist
  • Project Inspection Responsibilities
    • Concrete removal and cleanup
    • Patch preparation
    • Placing, finishing, and curing concrete
    • Resealing joints and cracks
  • Cleanup Responsibilities
presentation outline62
Presentation Outline

  • Introduction
  • Design considerations
  • Construction
  • Quality control
  • Troubleshooting

troubleshooting

Identify

Problem

Determine

Cause

Identify

Solution

Troubleshooting
  • Construction and performance problems
  • Approach:
troubleshooting possible performance problems
TroubleshootingPossible Performance Problems
  • Problem:

Longitudinal cracking in the patch

  • Potential causes?
troubleshooting possible performance problems69
TroubleshootingPossible Performance Problems
  • Problem:

Transverse cracking in the patch

  • Potential causes?
troubleshooting possible performance problems70
TroubleshootingPossible Performance Problems
  • Problem:

Surface scaling

  • Potential causes?
troubleshooting possible performance problems71
TroubleshootingPossible Performance Problems
  • Problem:

Spalling in patch at the transverse or longitudinal joint

  • Potential causes?
troubleshooting possible performance problems72
TroubleshootingPossible Performance Problems
  • Problem:

Deterioration adjacent to the patch

  • Potential causes?
troubleshooting possible performance problems73
TroubleshootingPossible Performance Problems
  • Problem:

Settlement of the patch

  • Potential causes?
troubleshooting guide causes and solutions
Troubleshooting Guide – Causes and Solutions
  • Undercut spalling
  • Saw binds
  • Adjacent slab damage
  • Slab disintegration
  • Patch filled with water
  • Grout flow out of dowel holes
  • Misaligned dowels
presentation outline75
Presentation Outline

  • Introduction
  • Design considerations
  • Construction
  • Quality control
  • Troubleshooting

learning objectives76
Learning Objectives
  • List benefits of full-depth repairs
  • Describe the primary full-depth repair design considerations
  • List available types of repair materials
  • Describe the recommended construction procedure
  • List important quality control activities
  • Describe potential construction and performance problems
  • Identify troubleshooting solutions
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