Presentationthe distress of rigid pavement

1. PRESENTATION
DISTRESS OF RIGID PAVEMENT
University of Baghdad
Collage of Engineering
Civil Engineering Dep.
Submitted by:
Ahmed Fahim Rahi
Highway transportation

2. Contain
1.
1.1. Longitudinal ,transverse cracking
1.2. Durability cracking ‘D’
1.3. Corner cracking
1.4. Shrinkage cracking
1.5. Cracking slab
2.
2.1. Faulting
2.2. Joint seal damage
2.3. spalling
3.
3.1. Scaling, map crack
3.2. Polish aggregate
3.3. Popouts
4.
4.1. Blowups
4.2. Punchout
4.3. Patching
4.4. pumping

3. 1.1 Longitudinal, Transverse .
Description:
• occurs in concrete highway and street pavements
• It is characterized by cracks that divide the slab into two or three pieces.
Possible Causes:
• foundation movement (settlements or heaves).
• poor construction techniques.
• underlying pavement layers that are inadequate for the applied load.
• pavement overloads, or repeated loads.
Repaired:
Slabs with a single, narrow crack may be repaired by crack sealing. If More than one
crack generally warrants a full-depth patch .

5. 1.2 Durability “D” Cracking
 Description:
• “D” cracking is progressive deterioration of concrete which occurs as a result of
freeze-thaw.
• While traffic loads do not affect.
• it does diminish the structural integrity of the concrete, along the centerline, and in
the wheelpaths.
 Possible Causes:
 freezing-thawing cycles,
 coarse aggregate composition
 Moisture

6. Repaired
• A full-depth or a partial-depth patch .
• although it does not address the root problem and will not.
• can be made by removing the immediate surface and provide a thin bonded overlay .

7. 1.3 Corner Breaks
 Description:
This type of break is characterized by a crack that intersects the joints at a distance less than, or equal to one-half of
the slab, describing approximately a 45o angle with the direction of traffic, measured from the corner of the slab.
 Possible Causes:
• heavy wheel load repetitions.
• fines are pumped out from under the leave corner.
 Repaired
• Full-depth repair is the solution to refurbish the pavement that suffers corner break.

8. 1.4 Shrinkage Cracking
Description:
Shrinkage cracks are hairline cracks that are usually only a few cm long and do not extend across the entire slab.
They are formed during the setting and curing of the concrete.
do not extend deeper than 6.4 mm from the slab surface.
Possible Causes:
use of high early-strength cement or admixtures that give high heat of hydration.
 Repaired :
• full-depth repair when severe situations.
• means of crack sealants

9. 1.5 Cracking slab:
 Description:
A shattered slab is defined as a slab where intersecting cracks break up the slab into many pieces.
Possible Causes:
This is primarily caused by overloading due to traffic and/or inadequate foundation support.
 Repaired:
• Full-depth patch.

10.  Repaired:
• Full-depth patch.

11. 2.1Faulting
 Description:
• Faulting is a difference in elevation across a joint or crack .
• is a major contributor in JPCP and JRCP, but is not a significant problem for CRCP .
• the average faulting in the pavement section reaches about 2.5 -4 mm .
• Possible Causes:
• Swelling soils, soft foundation. And heavy wheel repetitions.
 Repaired:
• removal of thin top layer of hardened PCC ( 4 to 6 mm).
• if exceeds 12.5 mm used full-depth.
23

12. 2.2 Joint Seal Damage
 Description:
Joint seal damage is any condition that enables incompressible materials such as soil to
accumulate in the joints or that allows infiltration of water.
 Possible Causes:
• Accumulation of materials that prevents the slabs from expanding and may result in
buckling.
• damage include stripping of joint sealant.
• use of the wrong type of sealant
 Repaired :
• cleaning the joint before sealing.
• that existing joint sealant may be replaced with new preformed sealant.

14. 2.3 Spalling
Description: Cracking, breaking or chipping of joint/crack edges. Usually occurs within about 0.6 m of joint/crack
edge on airports and about 0.5 m on roads .
Possible Causes
• Excessive stresses at the joint.
• expansion
• freeze-thaw action or “D” cracking.
• dowels are improperly inserted.
• low quality PCC is used to fill in the last bit of slab volume
• Heavy traffic loading. and expansion
 Repaired :
• Spalling less than 75 mm wide can be repaired with a partial-depth patch.
• Spalling greater than about 75 mm used repaired with a full-depth patch

15. 3.1 Scaling, Map Cracking:
Description:
This distress refers to a network of shallow, fine, or hair-like cracks that extend only through the upper surface of the
concrete.
Possible Causes:
• Construction defects,
• material defects.
• environmental factors.
 Repaired:
• Minor scaling is a cosmetic issue and may not need to repaired.
• Portland cement concrete resurfacing
• Latex modified concrete resurfacing

16. 3.2Polish of aggregate
Description:
• The obvious problem of polished aggregates in pavement is the reduction of skid
resistance,.
• lead to riding discomfort.
• lead to road accidents.
• the protruding rough and angular particles get polished
Possible Causes:
• repeated traffic loads
• wear also contributes to polishing of aggregates
Repaired:
Diamond grinding or an overlay is the solution to the problem

18. 3.3 Popouts
 Description:
• popout is defined as a small piece of pavement that breaks loose from the concrete surface.
• Popouts usually range from approximately 25 to 100 mm in diameter and 13 to 50 mm depth.
• popout may be a singular piece of large aggregate .
• may be clay balls in the concrete mix.
 Possible Causes:
• Poor durability can be a result of a number of items such as:
• Expansive aggregates
• Alkali-Aggregate Reactions
Repaired:
• Isolated low severity popouts may not warrant repair.
• Larger popouts or a group of popouts can be repaired with a partial depth patch.

20. 4.1 Blowups:
Description:
• Blowups normally occur only in thin pavement sections.
• Blowups occur during hot weather because of the additional thermal expansion of the concrete.
• Blowups occur at a transverse crack or joint that is not wide enough.
Possible Causes:
During cold periods (winter) PCC slabs contract leaving wider joint openings. If these openings become
filled with incompressible material (such as or soil), subsequent PCC slab expansion during hot periods
(spring, summer) may cause high compressive stresses.
Repaired: Full-depth patch.

21. 4.2 Punchout
 Description: This distress is a condition that often occurs in CRCP between two closely spaced cracks or
between a crack and a joint with usually 1.5 m wide. The Punchout can take many different shapes and
forms.
 Possible Causes: heavy repeated loads.
• inadequate slab thickness, loss of foundation support.
• compaction is the primary cause
 Repaired:
• full-depth patch.

22. 4.4 Patching
Description:
A patch is defined as an area where the original pavement has been removed and replaced by a filler
material.
Possible Causes:
Loss of support, heavy load repetitions, moisture, and thermal gradients can all cause distress

23. 4.5 Pumping
Description:
The deflection of the slab when loaded may cause pumping, which is characterized by the ejection of
water and underlying material through the joints or cracks in a pavement . As the water is ejected, it
carries particles of gravel, sand, clay, or silt with it, resulting in a progressive loss of pavement support
that can lead to cracking.
Possible Causes:
• Water accumulation underneath the slab.
• Heavy load repetition.
• Pumping near joints indicates poor joint-load transfer, a poor joint seal, and/or the presence of
ground water.
Repaired: A full-depth or a partial-depth patch

25. Functional Distress Contributing Factors *
Pavement
Design
Load Water Temp. Pavement
Materials
Construct.
Roughness
Faulting ** P P P C C N
Heave / swell ** C N P P C N
Settlement ** C C C N N C
Patch deterioration C C C C C C
Surface Polishing N C N N P N
Noise P C N N C P
Surface Defects
Scaling N N C C P P
Popouts N N C C P C
Crazing N N N C C P
Plastic shrinkage
cracks
N N N C C P
. P= Primary Factor C= Contributing Factor N= Negligible Factor
Structural Distresses and Possible
Contributing Factors

26. Structural Distress Contributing Factors *
Pavement
Design
Load Water Temp. Pavement
Materials
Construct.
Cracking
Transverse P P N C C P
Longitudinal P P N C C P
Corner C P C C N N
Intersecting C P C N C N
Joint/Crack Deterioration
Spalling C C N C P C
Pumping C P P N C N
Blow-ups C N N P C N
Joint Seal Damage C C C C P C
Punchout P P C N C N
Durability
D-cracking N N P C P N
ASR N N P C P N
Freeze-thaw damage N N P P P C