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Defects of Pavement
Tutor:
Asst. Prof. Pradeep Kumar Shrestha
Department of Civil Engineering
IOE, Tribhuvan University
2019-02-09
Submitted BY:
Sulav Sigdel
Roll No: 072BCE171
2. Introduction
• Generally it is observed that after the opening of newly constructed road or well
maintained or newly widened road which is very good in the terms of level of
service, but it is after some time with the use of traffic volume and constantly
changing weathers, especially after monsoon or in monsoon the road quality is
decorated at every use of traffic and after some time it gets completely decorated
with uneven crack, pot holes, ruts, crack etc…. This problem is very much common
in every road. Hence the quality and level of service is dropped down drastically as
the road user increases but maintenance is overlooked.
• Pavements fail prematurely because of many factors. There are four primary
reasons pavements fail prematurely, like failure in design, failure in construction,
failure in materials, failure in maintenance.
• Here for case study we will pick one cluster of Kathmandu city, the capital of Nepal.
In the case study we will find the problems, causes and remedies.
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3. Types of Pavement Structure
• Flexible pavements :- Flexible pavements are those, which on the whole
have low or negligible flexural strength & are rather flexible in their structural
action under the loads.
• Rigid pavements:- Rigid pavements are those which possess noteworthy
flexural strength or flexural rigidity.
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4. Pavement Failure
Pavements fail prematurely because of many factors. When boiled down to the basics,
there are four primary reasons pavements fail prematurely:
• Failure in design
• Failure in construction
• Failure in materials
• Failure in maintenance
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5. Case Study
• Kathmandu is a capital city of Nepal. Nepal extends into
India in the East, west ans south whereas inot China in
the North.
• The portion of road selected lies in Bagmati Corridor(at
kupandole). The map is attached below.
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6. 1. Fatigue cracking (alligator cracking):-
Fatigue cracking is commonly called alligator
cracking. This is a series of interconnected
cracks creating small, irregular shaped pieces
of pavement. It is caused by failure of the
surface layer or base due to repeated traffic
loading (fatigue).
Fix: Because a structural failure is taking place
the only possible solution to alligatoring is to
perform a full-depth patch.
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7. 2. Longitudinal cracking:-
Longitudinal cracks are long cracks that run
parallel to the canter line of the roadway.
These may be caused by frost heaving or
joint failures, or they may be load induced.
Understanding the cause is critical to
selecting the proper repair.
Fix: Less severe cracks measuring 1/2 inch
or less can be sealed to prevent moisture
from entering into the sub grade. More
severe cracks should be fixed by removing
the cracked pavement layer and replacing it
with an overlay.
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8. 3. Pot holes:-
Small, bowl-shaped depressions in the
pavement surface that penetrate all the way
through the asphalt layer down to the base
course. They generally have sharp edges and
vertical sides near the top of the hole.
Potholes are the result of moisture infiltration
and usually the end result of untreated
alligator cracking. As alligator cracking
becomes severe, the interconnected cracks
create small chunks of pavement, which can
be dislodged as vehicles drive over them. The
remaining hole after the pavement chunk is
dislodged is called a pothole.
Fix: Full depth replacement patch
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9. 4. Raveling:-
Raveling is the on-going separation of aggregate
particles in a pavement from the surface downward or
from the edges inward. Usually, the fine aggregate
wears away first and then leaves little "pock marks" on
the pavement surface. As the erosion continues, larger
and larger particles are broken free and the pavement
soon has the rough and jagged appearance typical of
surface erosion.
Fix: apply a thin hot-mix overlay. Other solutions could
include: sand seal, chip seal, slurry seal or micro-
surfacing.
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10. 5. Rutting:-
Ruts in asphalt pavements are channelized
depressions in the wheel-tracks. Rutting results from
consolidation or lateral movement of any of the
pavement layers or the subgrade under traffic. It is
caused by insufficient pavement thickness; lack of
compaction of the asphalt, stone base or soil; weak
asphalt mixes; or moisture infiltration.
Fix: if rutting is minor or if it has stabilized, the
depressions can be filled and overlaid. If the
deformations are severe, the rutted area should be
removed and replaced with suitable material.
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11. 6. Slippage Cracks:-
Slippage cracks are crescent-shaped cracks or
tears in the surface layer(s) of asphalt where the
new material has slipped over the underlying
course. This problem is caused by a lack of
bonding between layers. This is often because a
tack coat was not used to develop a bond between
the asphalt layers or because a prime coat was
not used to bond the asphalt to the underlying
stone base course. The lack of bond can be also
caused by dirt, oil, or other contaminants
preventing adhesion between the layers.
Fix: all of the areas exhibiting the “stretch marks”
will need to be removed and will require a partial
or full depth patch.
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12. 7. Edge cracking:-
Edge cracks travel along the inside edge of a
pavement surface within one or two feet. The
most common cause for this type of crack is
poor drainage conditions and lack of support
at the pavement edge. As a result underlying
base materials settle and become weakened.
Heavy vegetation along the pavement edge
and heavy traffic can also be the instigator of
edge cracking.
Fix: The first stepin correcting the problem is
to remove any existing vegetation close to the
edge of the pavement and fix any drainage
problems. Crack seal/fill the cracks to prevent
further deterioration or remove and reconstruct
to full depth fixing any support issues.
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13. Problem
From my case study on this road, the most common problem is aligator
cracking and longitudnal cracking. Main reason of road cracking is lack of
drainage systems and improper construction.
Reasons of Problem
1. Traffic:- Traffic is the most important factor influencing pavement
performance. The performance of pavements is mostly influenced by the
loading magnitude, configuration and the number of load repetitions by heavy
vehicles.
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14. 2. Rainfall:- The result of moisture ingress is the lubrication of particles, loss of
particle interlock and subsequent particle displacement resulting in pavement
failure.Average rainfall of amreli city is 552mm.
3. Construction quality:- failure to obtain proper compaction, improper moisture
conditions during construction, quality of materials, and accurate layer
thickness (after compaction) all directly affect the performance of a pavement. •
Maintenance:- pavement performance depends on what, when, and how
maintenance is performed. No matter how well the pavement is built, it will
deteriorate over time based upon the mentioned factors.
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15. Solution
Crack repairs are the proper and timely maintenance of cracks using
sealing or filling techniques to extend pavement life. Crack repairs are very
cost effective if done properly. A crack repair program begins by
determining if crack repairs are suitable for the type of distress
1. Sealing versus filling:-
2. 2. Asphalt resurfacing:-
3. 3.Rejuvenation:-
4. 4. Infrared repair:-
5. 5.Fog seal (PASS):-
6. 6. Chip seal:-
7. 7. Self-adhering waterproofing membranes:-
8. 8. Shallow surface repair (pothole):-
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16. Conclusion
• The pavement should be designed with precise future forecasting.
• The pavement should be constructed as per design only.
• The pavement should be maintained periodically...i.e. on the maintenance
concept of routine, Periodic & complete maintenance.
• The road user should be as per consideration only...if the nature of traffic
changes due to unexpected growth of the area than it should be well
maintained.
• There should not be any delay in maintenance.
• The nature of traffic plays vital role for the life span of pavement so at the
time of designing assumption of the future traffic is very much important.
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