The document discusses maintenance of roads and flexible pavements. It describes the requirements of a good pavement including sufficient thickness to distribute wheel loads, structural strength, adequate friction, a smooth surface, and long design life. It then discusses the necessity of road maintenance to prevent accidents, maintain components in good working condition, and increase road life. Various types of defects in flexible pavements are described such as cracks, rutting, shoving, and potholes. Causes and treatments of these defects are provided. Maintenance techniques for flexible pavements like patching potholes, ruts, and conducting surface treatments are outlined.

1. Maintenance and Road Repairs
Prof. Hole G.R.
Civil Engineering Department
J.S.Polytchnic, Hadapsar.

2.  Maintenance of road reduces petrol consumption and
wear and tear of vehicles.
 Also provide comfort to passenger.
Introduction

3.  Sufficient thickness to distribute the wheel load stresses to a safe value
on the sub-grade soil.
 Structurally strong to withstand all types of stresses imposed upon it.
 Adequate coefficient of friction to prevent skidding of vehicles.
 Smooth surface to provide comfort to road users even at high speed
 Produce least noise from moving vehicles.
 Dust proof surface so that traffic safety is not impaired by reducing
visibility.
 Impervious surface, so that sub-grade soil is well protected, and
Long design life with low maintenance cost.
Requirement of Good Pavement

4. To prevent accidents.
To maintain all the components of road in better
working condition ex. Pavement,shoulder,drains etc.
To provide safe and convenient movement of
passenger.
To maintain road in best possible condition for
smooth driving.
To increase life of road.
To keep safety for road users.
Necessity of Maintenance Of Highway

5. Flexible pavements
Flexible pavements will transmit wheel load stresses to the lower layers by
grain-to-grain transfer through the points of contact in the granular structure
(see Figure 1).
Figure 1: Load transfer in granular structure.
Causes of Failure Flexible Pavement

6.  Excessive load application.
 Inadequate stability.
 Loss of course materials.
 Loss of binding action between highway materials.
 Use of low quality material in different layers.
 Inadequate wearing course.
 Inadequate Strength of material.
 Inadequate drainage of rainwater from different layers.
 Improper compaction of layers of flexible pavement.
 Environmental factors like heavy rain, frost action etc.
Failure of Flexible Pavement can be caused by
following reason:

7. A. Subgrade Failure of flexible Pavements:
• Failure of subgrade soil is due to :
1.Improper compaction of subgrade soli.
2.Improper drainage in subgrade or inadequate camber to subgrade layer.
Types of Failure of Flexible Pavement

8.  Failure of wearing course is due to:
1.Improper bonding between top course
highway material.
2.Less quantity of binding material is
used during construction.
3. Aggregates used in wearing course
is not clean which affects binding .
B.Wearing Course Failure:

9.  Failure of Base Course Due to:
1.Improper Drainage.
2.Heavy Load.
3.Improper Compaction.
4.Material used is of low
quality in base course.
C. Failure of Base Course:

10. a) Cracks
b) Rutting and Shoving
c) Pot Holes and Patching
Types Of Defects Of Flexible Pavement

11. Following are types of cracks observed in flexible pavement
alligator Cracking
Longitudinal Cracking
Block Cracking
Edge Cracking
Centre Cracking
A.Cracks:

12. General Description:
 Series of interconnected cracks.
 Many sided, sharp angled, usually longest side < 1 feet.
 Initially appears a longitudinal crack.
Causes:
 Ageing of binder or initial over heating leads to brittleness of binder.
 Inadequate pavement thickness or excessive overloading or both.
 Unstable subgrade or lower layers.
Treatment:
 cracks should be filled with low viscosity binder.
 Slurry seal or sand bituminous premix patching can be used to fill
wide cracks.
 cut back or an emulsified bitumen or fog seal can be broomed into the
cracks and lightly filled with sand to prevent the picking up of the
binder by the traffic.
1. Alligator Cracking

13. General Description:
 These cracks are relatively parallel to pavement center line, may appear
either at the joint between the pavement and the shoulder or at the joint
between two paving lanes.
Causes:
 variation in temperature.
 week joint between adjoining layers of the pavement.
Treatment:
Treatment depends on whether pavement remains structurally sound or not,
if structurally sound then treatment is done as follow:
 Fill cracks with bituminous binder.
 A slurry seal or sand
 bituminous premix patching for wide
cracks.
2. Longitudinal Cracking

14. General Description:
 These cracks appear as interconnected cracks forming blocks of square or
rectangular shape on pavement Surface.
 The size of the block cracking varies from 1000 sq.cm to 10000 sq.cm
Causes:
The possible causes are summarized as below:
 Inadequate pavement thickness and unstable condition of subgrade and lower
layers.
 Shrinkage of bituminous layer itself with age.
 Ageing and brittleness of binding material.
Treatment:
The block cracking should be repaired by laying a interface treatment followed
by giving surface layer as per original existing surface
3. Block Cracking

15. General Description:
These are fairly continuous cracks, parallel to and usually up to 0.5m from the
edge of pavement. Edge cracks if not repaired in time lead to edge breaking
and lane to shoulder drop off and separation occurs.
Causes:
 Lack of lateral support from shoulder.
 Poor drainage and frost heavy condition.
 Settlement or yielding of the underlying materials.
 Non provision of extra width of pavement on curve.
Treatment:
 Improve the shoulder condition and give lateral support to pavement.
 Seal the cracks with either of these depending on severity level and width of
cracks as follows:
1.Low viscosity binder.
2.A slurry seal.
4. Edge Cracking.

16. General Description:-
 The cracking pattern appears all along the center line of pavement.
Causes:
 Improper or weak joint between adjoining, spreads all along the center line
of the pavement.
 Different moisture conditions on both sides of the pavement.
 Improper design of pavement with reference to camber.
Treatment:
 It is better to take full precautions while constructing a pavement.
 This can be rectified by sealing the cracks with slurry seal and or fog seal
depending on width of the cracks.
5. Center Cracking.

17. a.Rutting:
Rutting is a longitudinal surface depression or groove in the wheel path
Causes:
 Weak pavement and heavy channelized traffic.
 Improper mix design and lack of stability.
 Inadequate compaction of underlying layers during construction.
Treatment:
 Fill with premix open/dense graded material and compact to the desired
levels after applying a tack coat.
 rutting is due to subgrade failure then excavation and rectification of
subgrade is done
B. Rutting and shoving

18. b.Shoving:
It is a form of plastic movement resulting into localized bulging of surface.
Causes:
 Lack of stability in mix (excessive binder, high proportion of fines, too
soft binder) of surface or base course.
 Pushing action by wheels of heavy traffic at time of acceleration and de-
acceleration
Treatment:
 Filling the depression with premix materials after applying suitable tack
coat.
 Remove the material in the affected area down to a firm base and laying
a suitable premix patch.

19. These are bowl shaped holes of various sizes in the surface layer or
extending into the base course.
Causes:
 Localized disintegration of materials.
 Ingress of water in the pavement through cracks in surface course.
 Poor bond between surface and base course layers.
 Less bitumen content in localized areas or too thin bituminous surface
Treatment:
 Treatment is done by patch work or patch repairs.
 To fill pot holes (after cleaning) with the premix open/dense graded
patching or even penetration patching and followed by compaction
C.Pot Holes:

20. 1. Shrinkage crack
2. Scaling of cement concrete.
3. Mud pumping
4. Warping of cracks.
Shrinkage crack:
 These are longitudinal and transverse
crack developed due to heat of
hydration and less curing.
Types of Failure in Rigid Pavement:

21. Scaling of cement concrete:
Scaling is nothing but formation of layer of cement slurry on
surface
Of road.
It is caused due to
1. Deficiency in mix
2. Presence of chemical impurities.
3. Excessive vibration

22. Mud pumpimng:
 When soil slurry comes out through the joints and cracks of
rigid pavement due to heavy wheel load then it is called mud
pumping.
 Following are the various factors which responsible for mud
pumping:
1.Amount of free water.
2. Slab Deflection.
3.Subgrade Soil Type.
4.Lack of support from subgrade which develops cracks in
pavements.

23. Warping Cracks:
 Improper design of joints makes warping of slab at
edge.
 Due to this there is development of excess stresses
producing cracks at edges.
 Warping cracks are prevented by providing Hing joints

24. 1. Patching pot holes
2. Patching ruts.
3. Patching corrugation.
4. Base repairs.
5. Surface treatment.
6. Re-surfacing.
1.Patching pot holes:
 Pot holes are caused due to heavy load, variation in climatic condition
and improper quality material.
 In this process pot holes are first cut square or rectangular in shape up
to required depth
 Then holes are cleaned and suitable bitumen coat is applied.
 Then placing of premixed patching mix in hole and compact it well.
 In cold weather, cutback or bitumen emulsion is used as refilling
material under traffic.
Maintenance of Flexible Pavement:

25. 2.Patching Ruts:
 Ruts are the formation of depression along the length of road below the wheel
path .
 In the process of patching ruts,continous trenches are duged along the ruts.
 Then trenches are cleaned .
 Then Application of bitumen coat for bonding with old surface.
 Placing of premixed bitumen mix in duged trenches and compaction is carried
out.
3.Patching Shoving (Corrugatuon):
 Corrugation are nothing but bulging or formation of undulating surface
 It caused due to increase in temperature.
 This can be prepared by cutting the crest or high ridge of corrugation.
up to small depth .
 These cutting portion is then filled with premixed bitumen and compacted .

26. 4.Base Patching:
 this defect observed due to insufficient thickness of base
course.
 It is repaired by providing additional thickness in base course.
 The old loose material of base course is removed and then new
base course is prepared by using good material.
 New layer of base course should not be more than 75 mm.
5.Surface treatment:
 Surface treatment is carried out in two stages-
1.correcting bleeding
2.Applying renewal coat or seal coat.
 It is carried out when cracks are formed on road surface.

27. 6.Re-Surfacing:
 It is the process of renewal or surface dressing of the pavement
which damaged after its useful life known as re-surfacing.
 When existing road pavement is completely out of use due to wear
and tear then re-surfacing is carried out.
 In this process existing surface is repaired by patching and
suitable tack coat is applied over surface .
 After that surface dressing is done.

28. Thank You