CHAPTER - 9 HIGHWAY II R = 4.pptx

HIGHWAY
MAINTENANCE AND
REHABILITATION
HIGHWAY II - Highway Maintenance &
Rehabilitation
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Highway maintenance and rehabilitation
HIGHWAY II - Highway Maintenance & Rehabilitation
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 Pavement maintenance is work performed from
time to time to keep a pavement, under normal
conditions of traffic and forces of nature, as nearly
as possible in its as-constructed condition.
 Distinctions are usually made between forms of
maintenance, based on their required frequency.
 The International Road Maintenance Handbook uses
the grouping of “routine” and “periodic”
maintenance.

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 Routine Maintenance
 Routine maintenance is carried out on routine wise basis &
regularly inorder to preserve and keep the original pavement
shape by crack sealing, small patching, repair of some rutting,
& depression.
 A well equipped, an efficient and committed maintenance
crew is essential.
 The crew should be able to carry out small maintenance works
with a little, or even without interrupting the vehicular
movement.
 Extensive practice has proved that if the maintenance work is
carried out on routine basis, the expenses of maintenance
work of a road could be minimize.
 The maintenance crew will always make a frequent site visit,
and will detect and identify the distress arose along the
roadway due to different reasons.

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 Periodic Maintenance
 This is a major maintenance work, which includes all the
maintenance works as mentioned earlier and in addition
to that the overlay of the existing bituminous surfacing
up to a thickness of 50 mm.
 Some agencies consider this overlay layer as a part of
rehabilitation.
 But this over lay is needed when the riding quality of the
surface becomes uneven due to continuous routine
maintenance works.
 This could happen even before completion of the design
period of the existing pavement.

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 While other sources (e.g. TRRL) use “routine”,
“recurrent”, “periodic” and “urgent”. The following
excerpt from Reference 8 illustrates these categories:
“… There are four categories:
 routine maintenance, required continually on every road,
whatever its engineering characteristics or traffic volume
 recurrent maintenance, required at intervals during the year
with a frequency that depends on the volume of traffic using
the road
 periodic maintenance, required only at intervals of several
years
 urgent maintenance, needed to deal with emergencies and
problems calling for immediate action when a road is blocked.

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 Examples of activities within these categories are as
follows:
 routine:
 grass cutting; drain clearing; recutting ditches; culvert maintenance;
road signs maintenance
 recurrent on paved roads:
 repairing pot-holes; patching; repairing edges; sealing cracks
 periodic on paved roads:
 resealing (surface dressing, slurry sealing, fog spray, etc.);
regravelling shoulders; road surface marking
 urgent:
 removal of debris and other obstacles; placement of warning signs
and diversion works.”

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 Maintenance procedures
 Maintenance procedures for correcting distress in asphalt
pavements include patching, sealing of cracks and in some
cases resurfacing.
 Crack sealing is accomplished using emulsified or cutback
asphalts, special asphalt compounds, special crack or joint
sealers or possibly sealing the entire surface area.
 Surface treatment and thin overlays can also be part of the
maintenance procedure
 After identifying the defects on the pavement surfaces, the
defects should be marked with chalk and the marking should
be either in the shape of a square or rectangular.
 After completion of the marking the measurement should be
taken to assess the volume of work and resources required to
complete the maintenance work.

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 Repair Techniques
 Patching is probably the most widespread method of repair
in highway and street maintenance.
 All pavements require patching at one time or another.
 If holes do not occur from natural causes, manmade service
cuts and trenches produce them.
 Defects vary from cracked areas and shallow abrasion to
deep holes.
 Prompt repair of small breaks will help keep down
expenditures because once an area is broken and water
enters the sub-grade, a large failure will result.

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 Surface Patches
 If the area to be repaired consists of small hair-cracks,
minor surface distortion or ravelling, a surface or skin
patch may be the most cost effective technique to
employ.
 The construction of a surface patch normally does not
require removal of the existing pavement.
 Typically, only a layer of hot-mix asphalt or a chip seal
cover to the distressed area is required.
 The reason for this is that surface patches are “feather-
edged” to a zero thickness and the maximum thickness of
a surface patch usually does not exceed 10 to 20 mm.
 Thus the use of mixes containing coarse aggregate should
be avoided in this application.

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 Surface Patches
 The area to be patched should first be cleaned by brooming with
pressure air.
 A tack coat should then be applied over the entire area to be
patched.
 The hot mix is then spread rapidly over the tack coat and
immediately compacted with a roller or flat-plate vibratory
compactor.
 The edges should be finished to a neat, clean line.
 An alternative procedure for patching with hot mix is to apply a
sprayed membrane of emulsified asphalt to the distressed area
followed by application of “chips” or aggregate.
 The aggregate of a uniform size is immediately spread over the
emulsion coating.
 The aggregate should then be embedded with an appropriate
compaction device.

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 Repairs of cracks
 Cracks are sealed for two major reasons:
 To prevent the intrusion of clayey materials, and
 To prevent the intrusion of water into the underlying pavement layers.
 Many types of satisfactory crack sealing materials are
available. However, there are certain general properties that
should apply to any material used for this purpose.
 These properties include:
 Good bonding/ adhesion
 Flexibility and Extendibility
 Ease of application
 Resistance to softening
 Resistance to tracking
 Resistance to weathering.
 Compatibility to asphalt
 Crack sealing might be broken into two general classifications.

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 Temporary crack sealing:
 The work is done with materials other than modified asphalt
or specially prepared crack or joint sealers.
 These crack sealers (mostly emulsified and cutback asphalts)
maintain a tightly sealed crack usually only as long as the
pavement remains quite stationary, both longitudinally &
vertically.
 Once expansion and contraction or excessive vertical
movement occurs the effectiveness of the seal can be lost and
the cracks must be resealed.
 In climates with severe temperature changes, the resealing
may be necessary every year. In moderate climates this will be
necessary less often, and in mild climates even less frequently.
 Although the cost per unit crack sealing is relatively low, the
frequency with which it must be done might dictate a more
lasting solution.

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 Pavement rehabilitation
 Pavement rehabilitation is defined as taking constructive
measures to restore the structural and functional condition
of roads where distress has caused unacceptable pavement
serviceability.
 Structural strength of the existing pavement is utilized to
some extent in the design of the rehabilitated pavement.
 Other factors such as agency policy, practical construction
aspects, availability of skills, materials, environmental
mitigation and maintenance aspects shall be considered in
selection of the rehabilitation option.
 Rehabilitation options are classified into:
 overlays
 partial reconstruction
 full reconstruction

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 Overlays are One or more courses of asphalt
construction on existing pavement.
 The overlay often includes a leveling course, to correct
the contour of the old pavement, followed by a uniform
course or courses to provide needed thickness.
 Rehabilitation methods other than overlays include:
 Reconstruction: in this category, little or no contribution is expected
from the existing pavement materials and the materials needed for
rehabilitation will be mostly new materials.
 Recycling: the rehabilitation takes advantage of the existing
pavement materials, which are re-used in part or as a whole, in the
construction of the rehabilitated pavement.

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 These techniques, however, in order to truly qualify as
rehabilitation techniques, must satisfy several criteria:
 They must be applied only to pavements which are structurally adequate
to support future traffic loadings over the design period without
structural improvement from an overlay. Only structurally adequate
pavements, or pavements restored to a structurally adequate state, are
candidates for rehabilitation without overlay.
 They must address the cause(s) of the pavement distress and be effective
in both repairing existing deterioration and preventing its recurrence.
For this, a combination of techniques may be required (one repair
method and one preventive technique).
 If each of the repair and preventive methods meet the
pavement’s needs and satisfy the imposed constraints (such as
available funding and minimum life extension), then they
qualify as feasible rehabilitation alternatives.
 If the alternative considered fails to satisfy the above criteria,
it will be better classified under the term of maintenance.

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 Examples of major rehabilitation methods that may be
employed as non-overlay techniques include:
 Full-Depth Repair
 Partial Depth Patching
 Joint-Crack Sealing
 Subsealing-Undersealing
 Grinding and Milling
 Subdrainage
 Pressure Relief Joints
 Load Transfer Restoration
 Surface Treatments
 Finally, non-overlay rehabilitation methods also include,
as required when these elements have become deficient,
geometric improvements and/or drainage improvements
or restoration.

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 Evaluation and Testing
 The purpose of pavement evaluation is primarily to
determine why the present pavement condition prevails
so that appropriate rehabilitation measures can be
identified.
 Pavement evaluation involves detailing appropriate
methods for pavement investigations, relating the
symptoms of distress to their causes and explaining the
reason for distress.
 The outcome of the study forms the basis to carry out a
rehabilitation design using appropriate design methods
(MoW, 1999).

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 The extent of the pavement investigation depends on
prevailing conditions on site and shall be carried out
in the following sequence:
 desk study (shall always be carried out)
 initial assessment (shall always be carried out)
 detailed condition surveys (if required)
 structural surveys (if required)

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 A desk study shall always be carried out to gather
available information about the road section, which
may include:
 as-built data including construction records and information
about geometry and drainage
 maintenance records
 data from previous traffic counts and axle load surveys
 data from previous investigations such as measurements of
deflection, DCP, rutting, roughness, surface defects, sampling,
rutting, roughness, cracks, and others
 data on climate, geology and topography

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 Initial assessment includes visual inspection and
examination of data obtained in the desk study. The initial
assessment shall establish the length of sections with
 no significant problems
 localised distress clearly related to specific problems such as
poor drainage, expansive subgrade soils, or others
 distress obviously related to the surfacing only
 possibilities of inadequate structural strength
 Initial assessment shall give recommendations on:
 remedial action for the localised distress
 remedial action for the surface distress
 a further field test programme for sections with possibilities of
inadequate structural strength or with distress where the
existing pavement may be salvaged

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 Detailed condition surveys shall be carried out where the
existing pavement may be salvaged and distress is not
obviously related to either surfacing only or localized
problems.
 Detailed condition surveys include measurements of the
following parameters
 rutting
 surface defects
 potholes
 cracks, all cracks and wide cracks> 3 mm
 loss of stones (ravelling)
 patches
 roughness
 shoulder conditions
 drainage conditions

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 Structural surveys shall include collection of one or
more of the following data:
 Dynamic Cone Penetrometer (DCP)
 Maximum surface deflection with Benkelman beam (8160 kg
axle)
 Pit logs and laboratory tests of samples such as moisture
content, grading, Atterberg limits, CBR, or others as required

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 Which method is the appropriate for a road section
depends on the following:
 condition of the existing pavement
 strength requirements for the new pavement
 types of material in the existing pavement
 available materials for construction of the new pavement
 required surface levels of the new road
 construction practicalities

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 The following options are available for pavement
rehabilitation:
 overlays with a new surfacing
 overlays with a new surfacing and base course
 partial reconstruction by reworking the existing pavement and
adding new pavement layers as required
 full reconstruction by downgrading of the existing pavement to
sub grade for the new pavement

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 Overlays
 Overlays are used for the following purposes:
 to add sufficient structural strength so the pavement can carry the
future traffic in the design period
 to restore the riding quality of the pavement
 Overlays shall not be used under the following
conditions:
 on severely cracked pavements where there is a risk of early crack
reflection through the new layers.
 on pavements with deformation (shoving) in bituminous layers
unless repair or removal of the deformed material is carried out
 where there is uncertainty about the performance of the overlay due
to defects in the existing base course or in patches in the existing
pavement

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 Special materials and methods may be used for the purpose of
minimising reflection of cracks from the underlying surface
below asphalt concrete overlays.
 Special binders are also available for use in surface treatments
for maintenance reseals.
 Special methods or materials shall only be considered in the
cases when alternative conventional rehabilitation options
incur considerable additional cost or are unlikely to be
successful.
 Conventional options to minimise crack reflection through
overlays shall always be considered and include the following:
 partly or full removal (milling) of the cracked layer is often a
preferred option where the cracks do not extend deep into the
pavement overlays using penetration macadam prevents crack
reflection
 removal of the cracked layer in individual locations -and patching -
before overlay is cost effective where the total cracked area is small

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 Partial reconstruction
 Partial reconstruction is reprocessing or removal of
material from the existing pavement to let the
existing pavement form either base course or
subbase in the new pavement.
 Whether the existing pavement forms a new base
course or a new subbase depends on:
 the material properties of the existing pavement layers
 the condition of the existing pavement
 the strength requirements for the new pavement
 any required adjustments of road levels

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 Full reconstruction
 Full reconstruction is when the existing pavement is
reprocessed to improved subgrade in the new
pavement, whether or not reworking is carried out.
 The pavement design charts shall be used for
selection of surfacing, base course and subbase.
 The subgrade, consisting of the old pavement
layer(s) and/or subgrade shall meet the requirement
for subgrade.

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 DESIGN OFASPHALTOVERLAYS
 Asphalt Overlays of Flexible Pavements
 Asphalt overlays may be used to correct both surface
deficiencies (raveling, roughness, slipperiness) and
structural deficiencies.
 Surface deficiencies in asphalt pavements usually are
corrected by thin resurfacings (functional overlays),
but structural deficiencies require overlays designed
on factors such as pavement properties and traffic
loadings (structural overlays).

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 There are many instances when a surface treatment will not
accomplish what is needed. Examples are depressions or
severe raveling. In such cases, a thin overlay should be used
over any required leveling course.
 Thin overlays usually range from 2.5 cm to 5 cm thick using a
fine-grained top size dense mix. These are considered
maintenance.
 The overlay design procedures provide an overlay thickness to
correct a structural deficiency.
 If no structural deficiency exists, a thin overlay may still be
required to correct a functional deficiency.
 It is assumed that this option is feasible, i.e. that the condition
of the existing pavement is not such that it dictates substantial
removal and replacement of the existing pavement.

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 Such conditions would include:
 A large amount of very severe alligator cracking
 Excessive rutting which can be attributed to unstable existing
materials
 Seriously deteriorated stabilized roadbase requiring an
excessive amount of repairs prior to overlay operations
 Contaminated granular roadbase
 Excessive stripping of the existing AC surface
 Two methods of overlay design are recommended,
namely a deflection procedure and an effective
thickness (or component analysis) procedure.
 Here effective thickness procedure will be discussed.

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 EFFECTIVE THICKNESS PROCEDURE
 The required thickness of AC overlay is computed as:
where
T0 = required overlay thickness in centimeters
SNnew = structural number of a new pavement(cm)
SNeff = effective structural number of the existing pavement(cm)
a0 = structural coefficient of the AC overlay
 It may be noted that the structural numbers have the same
dimension as a thickness.

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 SNnew is required in the component analysis procedure to
determine a required asphalt overlay thickness.
 SNnew is computed in three steps as follows:
 Step 1:
 Select an appropriate required structure of a new pavement for
the specific subgrade strength and traffic applicable to the
project, in accordance with the procedure detailed in ERA’s
Pavement Design Manual-2002. The structure selected is
characterized by the thicknesses Ti of its component layers, i.e.
T1, T2, T3= thicknesses of required pavement surfacing,
roadbase and subbase layers respectively.
 Step 2:
 To each of the layers determined in Step 1, assign an
appropriate structural layer coefficient ai.

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 The following structural layer coefficients are
recommended:
 Bituminous surface: a1 = 0.44
 Bituminous roadbase: a1 = 0.30 (note: use 0.25 for in-place
recycled materials)
 Cement or lime stabilized roadbase: a2 = 0.15 to 0.20
 Granular roadbase: a2 = 0.14
 Cement or lime stabilized subbase: a3 = 0.12
 Granular subbase: a3 = 0.11
 Granular capping layer: a3 = 0.09
 Step 3: compute SNnew as:
SNnew = a1T1 + a2T2 + a3T3

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 Example: subgrade strength class S4, anticipated future traffic
class T6.
 Step 1: An adequate new pavement structure (ERA Pavement
Design Manual Volume I - 2002) consists of:
 10 cm AC surfacing
 20 cm granular roadbase
 17.5 cm subbase
 Step 2: Structural layer coefficients are assigned as follows:
 a1 = 0.44; a2 = 0.14; a3 = 0.11
 Step 3:
SNnew = a1T1 + a2T2 + a3T3
= 0.44x10 + 0.14x20 +0.11x17.5 = 9.13

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 SNeff requires knowing the existing pavement structure
and using the equation:
SNeff = a1T1 + a2T2m2 + a3T3m3
 Where
 T1, T2, T3 = thicknesses (in centimeters) of existing pavement surface,
roadbase, and subbase layers
 a1, a2, a3 = corresponding structural layer coefficients
 m2, m3 = drainage coefficients for granular roadbase and subbase
 The thicknesses Ti are determined from the previously collected data
and field work.
 The coefficients ai may be determined from Table 9.1,
which lists suggested layer coefficients for commonly
used materials. Other suggested coefficients, for
stabilized roadbase materials, are given in Table 9.2.

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 Table 9.1 Suggested Layer Coeff. for Existing AC Pavement Layer Materials

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 Table 9.2 Additional Suggested Layer Coeff. for Stabilized Roadbase Materials

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 The drainage coefficients m2 and m3 may be determined on the
basis of Table 9.3 and 9.4.
 Table 9.3: Quality of Drainage
 Table 9.4 Recommended mi Values for Modifying Structural Layer Coefficients of
Untreated Roadbase and Subbase Materials

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 Example
 An existing pavement is made up of the following layers:
 5 cm AC surfacing (T1)
 15 cm granular roadbase (T2)
 15 cm subbase (T3)
 The AC surface shows less than 10 percent of low-severity
cracking, very little medium and high-severity transverse
cracking, and can be assigned (Table 9.1) a structural layer
coefficient a1 of 0.30.
 Roadbase and subbase courses show no evidence of
degradation or contamination.
 The coefficients a2 and a3 may both be taken as 0.12.
 The quality of drainage is considered fair and the pavement
structure is exposed to levels near saturation on the order of
5%. Both coefficients m2 and m3 can be taken as 1.00.

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 SNeff is calculated as:
SNeff = 0.30x5 + 0.12x1.00x (15 + 15) = 5.1
 It is contemplated to overlay the pavement for an expected
traffic class T6.
 The subgrade strength class is S4.
 The structural number of an adequate pavement structure for
these conditions is SNnew = 9.13 (From the above Example).
 The required overlay thickness is:
T0 = (9.13 – 5.1)/0.44 = 9.15 cm
 (which may be rounded up to 10 cm).
 The above method is based on the determination of Sneff from
an assessment of the quality of the pavement layers from
visual, field (e.g., DCP) and/or laboratory testing.

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 SURFACE PREPARATION FOR OVERLAY
 In the design of overlays and the adoption of the overlay as
a rehabilitation solution, the construction feasibility should
be verified first (besides the economic constraints) with
reference to factors such as:
 Traffic control, traffic disruption
 Materials and equipment availability
 Construction problems such as utilities, bridge clearances, side
slope extension

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 SURFACE PREPARATION FOR OVERLAY
 Having determined the feasibility, careful and correct
preparation of the existing pavement, prior to
construction of overlays, is essential to good construction
and to maximum overlay performance.
 The overlay thickness is designed to correct a below
average pavement condition, but not to provide the extra
structural strength needed for localized weak areas.
 If the overlay thickness is based on the weakest condition
in the section, it would be over-designed for the rest of
the section and thus be needlessly costly.
 Therefore, the weaker areas must be corrected to provide
a uniform foundation for the overlay.

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 Some of the factors which need consideration in
preparation of the existing pavement are as follows:
• Pre-Overlay Pavement Repairs
 If distress in the existing pavement is likely to affect the performance
of the overlay, it should be repaired prior to the placement of the
overlay.
 Much of the deterioration that occurs in overlays results from
deterioration that was not repaired in the existing pavements.
 The cost tradeoffs of pre-overlay repair and overlay type should also
be considered.
 Severe alligator cracking and linear cracks, rutting and surface
irregularities should be repaired prior to overlay of AC pavements.
 The pre-overlay repairs generally fall in the maintenance categories.
One particular preoverlay operation to consider is an effective
reflection crack control.

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 Reflection Crack Control
 Reflection cracks are a frequent cause of overlay
deterioration.
 The thickness design procedures described in the
preceding sections do not consider reflection cracking.
 Preoverlay repairs (patching and crack filling) may help
delay the occurrence and deterioration of reflection
cracks.
 Additional reflection crack control measures include:
 Pavement fabrics
 Crack relief layers. These are composed of open-graded coarse
aggregate and a small percentage of asphalt cement.
 Increased overlay thickness

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 Subdrainage
 The existing subdrainage condition of the pavement should be evaluated.
 Removal of excess water from the pavement cross-section will increase
the strength of the pavement and subgrade, and reduce deflections.
 Surface Recycling
 This process may be considered as analogous to pre-overlay
surface preparation or an in place variant of cold milling and
recycling.
 The asphalt pavement surface is heated in place, scarified,
remixed, relaid, and rolled.
 Asphalts, recycling agents, new asphalt hotmix, aggregates, or
a combination of these may be added to obtain a desirable
mixture.
 When new asphalt hot-mix is added, the finished product may
be used as the final surface; otherwise, an asphalt surface
course should be used.

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 Shoulders
 Overlaying traffic lanes generally requires that the shoulders
be overlaid to match the grade line of the traffic lanes.
 In selecting an overlay material and thickness for the
shoulder, the extent to which the existing shoulder is
deteriorated and the amount of traffic should be considered.
 If trucks tend to park on the shoulder at certain locations, this
should be considered in the shoulder overlay design.
 If an existing shoulder is in good condition, any deteriorated
areas should be patched.
 An overlay may then be placed to match the shoulder grade to
that of the traffic lanes.
 If an existing shoulder is in such poor condition that it cannot
be patched economically, it should be removed and replaced.

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 Asphalt Overlays of Rigid Pavements
 EFFECTIVE THICKNESS PROCEDURE
 If the overlay is being placed for some functional purpose
such as roughness or friction, a minimum thickness overlay
that solves the functional problem should be placed.
 If the overlay is being placed for the purpose of structural
improvement, the required thickness of the overlay is a
function of the structural capacity required to meet future
traffic demands and the structural capacity of the existing
pavement.

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 Asphalt Overlays of Rigid Pavements
 The required overlay thickness to increase structural
capacity to carry future traffic is determined by the
following equation:
Dol = A(Df – Deff)
 where
 Dol = Required thickness of AC overlay, cm
 A = Factor to convert PCC thickness deficiency to AC overlay
thickness
 Df = Slab thickness to carry future traffic, cm
 Deff = Effective thickness of existing slab, cm
 The A factor, which is a function of the PCC thickness
deficiency, is given by the following equation:
A = 2.2233 + 0.0015(Df – Deff) 2 – 0.0604(Df – Deff)

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 AC overlays of conventional JPCP, JRCP, and CRCP have
been constructed as thin as 5 cm and as thick as 25 cm.
 The most typical thicknesses that have been constructed
for highways are 7.5 to 15 cm.
 Deff is computed from the following equation:
Deff = Fjc x Fdur x Ffat x D
 where
 D= Existing PCC slab thickness, cm
 Fjc = Joints and cracks adjustment factor
 Fdur = durability adjustment factor
 Ffat = fatigue damage adjustment factor
 The factors Fjc, Fdur, Ffat, are dependent on the existing
condition of the pavement and can be evaluated based on
the condition survey.

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 Fjc depends on the total number of unrepaired deteriorated
joints, cracks, punch outs and other discontinuities per km in
the design lane and is determined using Figure 9.1.
 Fdur depends on the existing durability problems, such as
aggregate distress.
 Using the condition survey, Fdur is determined as follows:
 1.00: No sign of PCC durability problems
 0.96-0.99: Durability cracking exists, but no spalling
 0.88-0.95: Substantial cracking and some spalling exists
 0.80-0.88: Extensive cracking and severe spalling exists
 The Ffat factor adjusts for past fatigue damage that may exist
in the slab. It is determined by observing the extent of
transverse cracking (JPCP, JRCP) or punchouts (CRCP) that
may be caused primarily by repeated loading.

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 The following guidelines can be used to estimate the Ffat factor
in the design lane:
 0.97-1.00: Few transverse cracks/punchouts exist (none caused by
 “D” cracking or reactive aggregate distress)
 JPCP: <5 percent slabs are cracked
 JRCP: <25 working cracks per mile (about 16 per km)
 CRCP: <4 punchouts per mile (2 or 3 per km)
 0.94-0.96: A significant number of transverse cracks/punchouts exist
(none caused by “D” cracking or reactive aggregate distress)
 JPCP: 5-15 percent slabs are cracked
 JRCP: 25-75 working cracks per mile (16-47 per km)
 CRCP: 4-12 punchouts per mile (3 to 8 per km)
 0.90-0.93: A large number of transverse cracks/punchouts exist (none
caused by “D” cracking or reactive aggregate distress)
 JPCP: >15 percent slabs are cracked
 JRCP: >75 working cracks per mile (>47 per km)
 CRCP: >12 punchouts per mile (>8 per km)

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 Figure 9.1 Fjc Adjustment Factor

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 SURFACE PREPARATION FOR OVERLAYS
 The following types of distress in JPCP, JRCP and CRCP
should be repaired prior to placement of an AC overlay.
 Full depth repairs and slab replacements in JPCP and JRCP
should be PCC, dowelled or tied to provide load transfer
across repair joints.

55
 Full depth repairs in CRCP should be PCC and should be
continuously reinforced with steel which is tied or
welded to reinforcing steel in the existing slab to provide
load transfer across joints and slab continuity.
 Installation of edge drains, maintenance of existing edge
drains, or other subdrainage improvement should be
done prior to placement of the overlay if a sub-drainage
evaluation indicates a need for such an improvement.
 Pressure relief joints should be placed only at fixed
structures, and not at regular intervals along the
pavement. The only exception to this is where reactive
aggregate has caused expansion of the slab.
 The basic mechanism of reflection cracking is strain
concentration in the overlay due to movement in the
vicinity of joints and cracks in the existing pavement.

56
 The following treatments may be employed in an effort to
control reflection cracking in an AC overlay of JPCP or
JRCP:
 Sawing and sealing joints in the AC overlay at locations coinciding
with joints in the underlying JPCP or JRCP.
 Increasing AC overlay thickness. Reflection cracks will take more
time to propagate through a thicker overlay and deteriorate slowly.
 Placing a bituminous-stabilized granular interlayer (large-sized
crushed stone crack relief layer), prior to or in combination with
placement of the AC overlay has been effective. See Figure 9.5.
 Cracking and seating JPCP or breaking and seating JRCP prior to
placement of the AC overlay. It reduces the size of PCC pieces and
seats them in the underlying base, which reduces movements at
cracks.

57
 Reflection cracking can have a considerable influence on
the life of an AC overlay of JPCP or JRCP.
 Deteriorated reflection cracks detract from a pavement’s
serviceability and also require frequent maintenance, such
as sealing, milling, and patching.
 Figure 9.2 Crack-Relief Layer in an Overlay System, Cross-Section

58
 When the pavement has been rendered as uniformly
stable as possible, it must be cleaned thoroughly and
tack-coated with asphalt before the overlay is placed.
 When overlaying a PCC pavement that has been grooved,
special treatment is necessary to prevent moisture
intrusion.
 Here, a heavy asphalt tack coat, an asphalt slurry seal, or
a sand (fine-graded) asphalt leveling course is used to fill
the grooves.
 Polished surfaces can be re-textured to improve their
bonding with overlays.
 However, in most cases, the proper use of a tack coat,
selection of the proper mix type and overlay thickness,
coupled with correct construction procedures, will prove
more economical in ensuring a good bond.

Highway Contractual Document and Consultancy Services
59
 Consultancy service for highway includes:
 Detailed Engineering Design of Roads & Drainage
structures and
 Tender Document Preparation
 Construction Supervision and
 Contract Administration

60
Methodology of the consultant for complete design
of highways may include the following activities:
1. Mobilization
2. Collection And Study/Review Of Data
3. Traffic Study
4. Selecting And Establishing Design Standard
5. Detailed Engineering Design Stage
i. Topographic Survey
ii. Engineering Investigation
 Bridge Foundation Investigation
 Soil and Material Investigation
 Sub-grade Material (Soil) Investigation (DCP test, Test
pitting, sampling)
 Construction materials investigation and testing
 Laboratory Investigations

61
iii. Preliminary Design
iv. Estimating Construction And Maintenance Costs
v. Final Engineering Design
 Final Detailed Geometric Design
 Pavement Design
 Hydraulic Recommendation and Structures Detailed Design
 Road Marking and Road Furniture
 Final Quantity Estimation /Bill of Quantities/
vi. Unit Rates and Engineering Cost Estimate
vii. Preparation of Specification
viii. Environmental Impact Assessment

62
6. Preparation Of Tender Documents
7. Preparation And Submission Of Reports
 Inception Report
 Progress Report
 Soil And Material Report
 Hydrological/Hydraulic And Structural Report
 Engineering Report
 Drawings
 Engineering Cost Estimate
 Tender Documents
 Final Consultancy Completion Report

63
 Generally, the tender document for the road shall include:
 Volume I
 Invitation to Tender
 conditions of Tender and Instruction to Tenders,
 appendix to Tender
 Tender and Agreement Forms, Schedules,
 General Conditions of Contract
 Conditions of Particular Application
 Standard Technical Specifications
 Special Provisions
 Bills of Quantities with preamble to BOQ
 Schedule of Basic Rates,
 Pre/post qualification questionnaire If required
 Volume II: - Complete Set of Drawings including:
 Cross sections
 Plans and profiles
 Detail Drawings for Bridges and Drainage Structures

THANK YOU
HIGHWAY II - Highway Maintenance &
Rehabilitation
64

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