Presentation

STABILISATION IN
ROAD WORKS
COMPACTO International is anAustralian
organization whose mission is to contribute
to the development of improved practices for
road construction.
INTRODUCTION
A stabilisation process is aimed at bringing together materials of one or more
criteria that will effect each other simultaneously to improve otherwise
substandard materials to ensure performance throughout the life of the pavement,
particularly under wet conditions.
Stabilisation with the product COMPACTO is a preventative measure or
insurance against the adverse water conditions developed during construction or
while the pavement is in service.
Seasonal changes in moisture can cause considerable damage to a pavement
structure. COMPACTO product is used to ensure a satisfactory performance by
minimizing the moisture movement, making the soil less sensitive to the effects of
water.
COMPACTO TM INTERNATIONAL Email: COMPACTO2@bigpond.com
COMPACTO TM
INTERNATIONAL
Rev 9 October, 2012

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TABLE OF CONTENTS
CHAPTER 1 TYPES OF STABILISATION AND THEIR APPLICATION
1.1 CLASSIFICATION OF STABILISATION..........................................................1
CATEGORIES OF MATERIALS...............................................................................1
1.3 APPLICATION OF STABILISERS......................................................................2
1.4CATEGORIES OF STABILISATION AGENTS...................................................2
1.5 SELECTION OF THE CORRECT STABILISING AGENT..............................5
1.6 FINAL SELECTION OF STABILISATION TYPE.............................................5
2.1 WATER IN COMPACTION.................................................................................6
2.2 SHRINKAGE OF MATERIALS...........................................................................6
2.3 CRACKING MECHANISMS.................................................................................7
2.4COMPACTO SOIL MODIFICATION...................................................................8
3.1 UNCONFINED COMPRESSIVE STRENGTH..................................................11
3.2 FLEXURAL STRENGTH....................................................................................11
3.3 MODULUS............................................................................................................11
3.4 FATIGUE LIFE.....................................................................................................12
3.5 DURABILITY OR ERODABILITY....................................................................12
4.1 OVERVIEW..........................................................................................................13
4.2 FACTORS INFLUENCING MAINTENANCE REQUIREMENTS..................14
4.3 DEFECTS – CAUSE AND CURES......................................................................15
4.3.1 SURFACE DEFECTS........................................................................................16
4.3.2 FOUNDATION DEFECTS ............................................................................21
4.3.3 ROAD CLOSURES ...........................................................................................22
4.4 SHAPING THE FORMATION...........................................................................22
4.5 DRAINAGE..........................................................................................................24
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.........4.6 GRADING FREQUENCY .................................................................................25
4.7 GRAVEL RESURFACING..................................................................................27
4.8 DUST CONTROL.................................................................................................27
PRESENTATION BY:
Roger Golding for and on behalf of
COMPACTO International Pty Ltd
500Avro Road
Bankstown Areodrome NSW 2200
Technical Services
Facsimile: 61 2 46473455
Email: COMPACTO2@bigpond.com
www. compacto.org
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COMPACTO TM INTERNATIONAL
Types of Stabilisation and their Application
1.1 Classification of Stabilisation
No longer can road construction groups classify stabilisation as a
binding action.
Several pavement design procedures are now available to enable the
performance of stabilised layers within the pavement structure to be
evaluated.
Close evaluation of the pavement layer will determine the type of
stabilisation required which is now classified in terms of their structural
performance based on the Categories of Materials.
Additionally the climatic conditions and the properties of the non-
standard material will determine the choice of stabilisation method.
Categories of Materials
There are three main categories of materials in terms of their
performance characteristics:
UNBOUND Materials. Natural gravel and rocks
MODIFIED Materials Unbound material where small
amounts of stabiliser are added to
correct deficiency or reduce moisture
problems. The resulting materials may
be characterized as an unbound
granular material for pavements
BOUND Materials Produced by adding cementitious
stabilising agents to granular material.
Where stiffness and tensile strength of
the materials are sufficiently enhanced
to have a practical application in
stiffening of the pavement.
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1.3 Application of Stabilisers
Stabilisation is used to enhance or improve material properties for pavement
design purposes.
Stabilisation is used to overcome deficiencies in available materials
Naturally occurring materials can be improved by the addition of chemical
stabilising agents or by blending and mixing to improve their performance
as pavement materials.
The availability of suitable local materials for pavements is becoming
increasingly difficult as conventional road construction materials are
becoming depleted in many areas. This lack of available material is
compounded by the cost of hauling them from further distances.
The possible solution to this problem which is becoming more time and
cost effective is the utilization of various stabilisers and stabilisation
techniques to improve the quality of local materials which do not conform
with the existing specifications and requirements for roads.
Stabilisation materials themselves fall into a number of categories
1.4 Categories of Stabilisation Agents
CEMENT
LIME
BITUMEN
PLASTIC FINES
GRANULAR MATERIAL
CHEMICAL COMPACTO
CEMENT
• Cement is the most common form of binder and it has two effects on
the subgrade material:
1 It improves a bond between granular materials in order to achieve
tensile strength
COMPACTO TM INTERNATIONAL Email: COMPACTO2@bigpond.com2

2 Reduces the susceptibility of moisture movement in materials
• Material cannot be re-worked after a short time span has elapsed
• Low working times typically less than 2 hours
• BOUND Materials Category of stabilising agents
• Involves mixing of a small percentage of cement in a variety of soil
materials ranging from non-cohesive sands and gravels, to plastic
clays and silts, to reduce moisture susceptibility and to increase
strength.
• Cement is used in sub-base levels under granular, asphalt or concrete
base layers
• Cement is used in base layers in lightly trafficked roads and rural
highways in thickness’ ranging from 25cm to 35cm.
• Too high strength will result in extensive shrinkage cracking with
resulting declines in durability
LIME
Lime refers to either quicklime (calcium oxide) or hydrated lime (calcium
hydroxide) and is typically used as a binder for clayey soils.
• Lime improves both workability and strength of the subgrade material.
• Lime is not effective for granular materials and should preferably have
a Plasticity Index of >10 per cent, and should contain clay minerals
rather than sands or silts
• Lime has a lower rate of strength gain than cement
• High lime content is unlikely to increase high-early strength as the non-
reacted lime in the stabilised soil causes a slowing of the strength gain.
• Care should be taken to avoid the use of lime in high silica content
materials which can result in an extreme form of alkali-silica reaction
• Proper safety precautions are needed because of lime dust and the
corrosive action of lime.

BITUMEN
• Often involves specialised equipment
• Additives such as cement, lime or COMPACTO are typically used in
combinations with bitumen emulsion
• Effective on granular materials and sandy soils
• Bitumen , cutback bitumen, bitumen emulsion and foamed bitumen are
used in bitumen stabilisation
• Foamed bitumen as bitumen emulsion is a suspension of bitumen
particles in water and improves cohesion and waterproofing of
granular, low cohesive, low plasticity (<6 per cent) materials.
• Acts as a cohesion agent in granular soils
• Waterproofing agent in clay soils
• Thin films of bitumen produce a stronger material
• Thick films create a weaker although less permeable material
PLASTIC FINES
• Usually introduction of clay to increase the plasticity of highly granular
material.
• MODIFIED Materials Category of stabilising agents
GRANULAR MATERIAL
• The mixing of two or more complying materials to achieve stabilisation
rather than by chemical or bitumen stabilisation.
• Usually done to improve both grading and plasticity
• Dense well-graded mass offers the maximum resistance to lateral
displacement under load.

CHEMICAL COMPACTO
• For the most effective COMPACTO stabilisation the soil should have a
Plastic Index of >10 percent, and should contain clay materials rather
than sands or silts
• Plastic soils and gravels stabilised with COMPACTO have improved
strength and permeability
• Soils to achieve pozzolanic reactions by maintaining a high pH
environment to liberate the soluble Silicon and Aluminum and to form
the pozzolanic reactions to form calcium aluminates or silicates. This
action along with the agglomeration of the fine clay particles into
coarse, friable particles through an ion exchange results in a treated
clay with reduced plasticity and lower affinity for water
1.5 Selection of the Correct Stabilising Agent
NO ONE soil condition is alike, and so no one Stabilising Agent does all
applications.
The need for a combination of Stabilising Agents is also a possible
application.
To gain a preliminary assessment of the type of stabilisation required for a
particular pavement material, particle size distribution and Atterberg limits
are commonly used.
A Stabilising Agent should be chosen for both its cost and applicability to
the soil.
Poor performance of stabilised pavement materials due to the incorrect
selection of a stabiliser is not a saving for the road network.
1.6 Final Selection of Stabilisation Type
After analysis of all available data, there may be a number of possible
stabilisation methods. In selecting a stabiliser, it is an essential issue to
establish if the material needs to be modified or bound.

The decision to choose is generally a financial one
Life cycle costs of all feasible alternatives are compared considering
skills, resources and availability of materials
Consideration needs to be given to COMPACTO for minimization
of water problems
The Value of Water in Compaction and
Water Damage after Construction
2.1 Water in Compaction
Water is necessary to gain maximum compaction during the
construction process. The quantity of water to be used can be
determined through testing.
At the Optimum Moisture Content (OMC), the material will attain its
maximum density for a given compactive effort. Strength loss, as well
as a reduced density, will result from too high moisture content in the
soil during compaction.
Curing with water prevents rapid evaporation of moisture from the
treated surface and allows the stabiliser to achieve full strength.
Seasonal changes in moisture causes clay soils to swell and shrink,
thereby causing considerable damage to the pavement structure. The
COMPACTO product is one product used to minimise these changes
by controlling moisture movement or making the soil less sensitive to
the effects of water. The product COMPACTO reduces the soil’s
tendency to shrink and swell.
2.2 Shrinkage of materials
Some road designers are reluctant to specify stabilised pavements due
to shrinkage cracking. Up until recently the lack of research into what
Chapter
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6

causes shrinkage cracking has lead to misunderstanding of how to
provide sufficient design details in the pavement.
Studies of dry shrinkage measurements in the laboratory and in the
field indicate that the shrinkage measurements in the field are about
half that predicted in the laboratory. The amount of shrinkage in the
field will depend on the rate of removal of water from the pavement
material.
Slowing the rate of removal of water on soils of low plasticity by sealing
the pavement will somewhat reverse the shrinkage and to some extent
will reverse the cycles of wetting and drying effects of pavement soils.
Early sealing of highly plastic soils will retain water that will eventually
lead to unsatisfactory heave and swell, causing damage.
A crack in a stabilised layer will result in a stress distribution that can
affect the behaviour of the overlaying layer. This layer above the
stabilised material may in turn crack and “reflect” through the surfacing,
in particular bituminous surfacings.
The crack in the stabilised layer may have resulted from two distinct
mechanisms, namely fatigue cracking and shrinkage cracking.
2.3 Cracking mechanisms
The two cracking mechanisms of fatigue cracking and shrinkage
cracking have two design approaches that can be adopted:
Avoidance of Surface Cracks
Acceptance of cracking with, in wet climatic zones, adequate
maintenance (crack sealing). Alternatively, apply a special surfacing,
for example a ‘geoseal’.
Bound stabilised materials will shrink due to a combination of excess
moisture drying out of the layer and secondly that the hydration
process of the binder reacting with the water causes heat and that the
material will shrink on cooling. When the stabilised layer is restrained
by friction, by the under-laying layer, the layer cracks as the layer is
subject to stresses trying to move it but it is prevented from doing so
and its tensile strength is insufficient for the stresses developed.
Where the base layers are insitu stabilised with COMPACTO product
the design can decided to limit the tensile strength of the pavement
layer forming only fine cracks which do not reflect through bituminous
surfacings, rather than a few wide cracks which can show through the
thickness of overlaying material.

Shrinkage cracking of a stabilised pavement is also a function of the
characteristics of the parent material. A material with a high shrinkage
characteristic will also show similar characteristics when stabilised.
This is COMPACTO product can be used to change the liquid limit
characteristics of the soil and reduce the effect of changing water
conditions.
Proportion of Clay
The proportion of clay minerals is an important factor influencing the
development of shrinkage cracks.
Where there may be too much clay fines in the existing subgrade the
addition of milled aggregate to the surface and mixed has been found
to improve the performance of the stabilised layer.
Bitumen Overlay
The addition of a thick asphalt layer of a bound stabilised pavement
layer has been an interesting debate and their appears to be no
research or rational design approach for the optimal thickness of
asphalt over a stabilised base to take advantage of the structural
stiffness of the bound base whilst not compromising the need to
prevent reflective cracking. However, based on experience in Australia,
the Roads Transport authority specifies in New South Wales a
minimum of 15-cm in thickness and in Victoria 17.5-cm.
2.4 COMPACTO soil modification
To consider COMPACTO soil stabilisation only in the terms of remedial
treatment for particular or obvious deficiencies in a material is an
under-estimate of the products potential.
Stabilisation is also a means by which the road builder can be in better
command of a situation by altering the properties of materials to
optimize benefits.
Using COMPACTO should be considered for its present value benefits,
being more cost effective over traditional methods of stabilisation or the
“do nothing” alternative. Maintenance costs over the life cycle of the
pavement are also a factor to be considered in the economic analysis,
and being analytical, are based on values adopted for particular
parameters.
UNDER SUITABLE CONDITIONS COMPACTO ALTERS COLLOIDS
AND ORGANIC MATTER IN SOILS, REDUCING THE TENDENCY
FOR SWELL AND SHRINK THAT OCCURE WITH CHANGES IN

MOISTURE CONTENT, AND INCREASING BEARING CAPACITY
AND SHEAR STRENGTH.
COMPACTO is cost effective and easy to use. It needs no special
equipment for application, mixes readily with water, and is both non-
toxic and environmental safe in its diluted state.
Costs of road construction and maintenance are becoming increasingly
more and more expensive, as labour and basic material costs continue
to escalate. Pressures from the community and management are
placing increased demands on the road building and maintenance
bodies to provide and maintain roads to the necessary standards
expected.
COMPACTO offers many benefits to Engineers, Contractors and road
builders as an aid to reduce permeability and improve compaction,
especially where constant heavy usage, traffic wear and weather
conditions cause severe repetitive problems.
COMPACTO product :-
INCREASES DECREASES
- strength - moisture
- density - shrinkage
- compaction - swell and heaving
- bearing ratio - dust generation
- pavement life - maintenance costs

Characteristics of Stabilised Pavement
Stabilisation is directed at on or more of the following criteria:
Strength
Permeability
Stability
Durability
The type of stabilisation will effect one or all of the criteria to different degrees.
The strength of the soil can be improved by using stabilisation to bind the material
to improve its cohesive strength and make it stable under adverse moisture
conditions.
Stabilisation brings the pavement materials together in a form that ensures
performance throughout the life of the pavement.
COMPACTO aids this process particularly under wet conditions. Soil when in a
wet state possesses a low shear strength.
Stabilisation work including COMPACTO product provides a strong base for
pavement reconstruction. Unstabilised or poorly stabilised materials will break
down under repeated traffic loads and will have little value for repair, eventually
requiring reconstruction.
Several tests or the required results need to be considered by the designer of the
pavement. Generally, the established tests still have restrictions on the type of
materials that can be tested
Chapter
3apter
10

3.1 Unconfined compressive strength
With the increase of the use of slow setting binders, the unconfined compressive
strength (UCS) form of testing is coming under increased scrutiny. There still
remains a strong reason to continue this form of testing for both the evaluation of
binders and for the quality control purpose.
The alternative 7-day accelerated (at 65 deg.C) test is known to suffer from poor
repeatability and reproducibility and hence, some experts argue that the test
shows variable response with different materials and binders due to inconsistent
response under pretreatment.
3.2 Flexural strength
The third point loading of flexure beam typically measures flexural strength
testing, and the ultimate load of the beam is considered the flexural material
strength.
The flexural strength is not used in the mechanistic design analysis and is only
carried out for the determination for the flexural modulus of the stabilised material.
The material to be tested is the cemented or bound pavement material at various
thicknesses.
3.3 Modulus
The preferred method of testing for determining the design modulus is by third
point loading of flexure beam specimens.
Using this approach, the modulus is calculated by using the straight line portion of
the load-deflection plot using beam loading theory. This is a reasonable method of
testing for materials where the modulus is high (concrete), that is over 2,500 MPa
and the loading is probably less than half the ultimate stress.
Unfortunately, there is no standardized procedure for determination of flexural
modulus of field placed binders, nor laboratory prepared beam samples taken
from the field. Further research is required in this area of testing.

3.4 Fatigue life
Fatigue cracking of materials is characterised by the initiation and propagation of
cracks under repetitive loading typically traffic loading rather than environmental
loading. Cracks that develop from fatigue form a continuous fracture surface and
the overall material becomes weakened.
Tests can be performed both in the field and in the laboratory, however the
performance is typically calculated applying a constant load to failure and applied
to a modulus values at the stress ratio. In other words, mathematical calculations
are applied to produce results that can be understood.
Fatigue resistance decreases with increased strength. Generally, a decrease in
material density will result in a decrease in the fatigue life of stabilised materials.
Thermal and shrinkage stresses resulting in cracks reduces the effective working
modulus of the pavement layer. Cracking where the pavement base has good
interlock are structurally insignificant except where these cracks are as a result of
cracks formed in the base.
3.5 Durability or erodability
Erosion of a pavement layer occurs when repeated loading in the presence of
water abrades an interface of a pavement layer. Normally there are three
conditions required for erosion to occur:
• Repeated traffic loading that will cause pavement material to deflect
• Sufficient water within the pavement material from water penetration of
surface cracks or voids
• Materials that are susceptible to pumping or erosion
There are several laboratory assessment that can be done to assess the erosion
potential, however the complexity of the tests and the cost of performing these
tests is a major limitation.
Generally, field monitoring or field observations of the exposed pavement over
time of the vehicle wheel tracking is the preferred method of assessing material
performance and considering the preferred design for the traffic in the area.

Maintenance Practices
4.1 Overview
Effective maintenance practices rely on sound technical knowledge and good
management practices.
Unsealed roads are susceptible to rapid deterioration because of loss of wearing
course material and damage from water.
The main objectives of maintaining gravel or earth surfaces are to:
• Provide a good riding surface
• Minimise safety hazards to vehicular traffic
• Provide a free draining surface to the formation.
To achieve these objectives, maintenance must be adapted to the physical
condition of the pavement, traffic volume, predominate vehicle type and climate.
Each road, no matter how carefully designed and constructed, will deteriorate as
a result of traffic movements, climatic conditions and the properties of pavement
materials. Regular maintenance is therefore essential to provide the desired level
of service for each road in the network.
Chapter
4apter
13

There are a number of reasons for the rapid deterioration of pavements, including:
• Varying climatic conditions
• Construction standards
• Availability of suitable pavement materials
• Drainage provisions
The severity and frequency of defects such as corrugations, potholes, rutting and
loss of crossfall, coupled with service levels commensurate with available
resources, should set the maintenance requirements for the road network.
Maintenance can vary from on-demand corrective maintenance, when a defect
arises, to preventive maintenance which attempts to predict defects in advance of
their occurring and taking action such as the application of COMPACTO product
to eliminate or reduce the occurrence or frequency of the defect.
The approach adopted will depend on the importance of the road link in the
network, available resources and knowledge of the performance of each road link.
• On-demand corrective maintenance reduces the overall efficiency of
maintenance resources, can result in higher vehicle operating costs for road
users and can contribute to more severe pavement deterioration if defects are
allowed to remain uncorrected for any length of time.
• Preventative maintenance on the other hand can have higher initial costs.
Balanced against this is the potential longer service life of a pavement,
reduced vehicle operating costs, and increased safety for road users and
more efficient use of maintenance resources.
On-demand maintenance will be necessary when unforeseen events such as
floods occur.
4.2 Factors influencing maintenance requirements
Maintenance normally consists of reshaping pavement cross-sections, replacing
lost material, adding material where weaknesses show up, cleaning and
extending roadside drainage, removal of surface defects.
Preventative maintenance may be categorized as:
• Routine or patrol maintenance comprising light grading to smooth road
surface restoring crossfall, clearing blocked drains and culverts, and the
restoration of signs.

• Periodic maintenance comprising regrading of pavements, recompacting
pavement, reshaping of cross-sections and restoring drainage systems.
When undertaking regravelling of pavements, to achieve proper
compaction of the freshly placed aggregate, it is important that the depth of
aggregate when compacted is approximately twice as thick as the largest
particle size.
It is also important that compaction takes place using the correct plant and
equipment. Traffic compaction of fresh aggregate or reshaped pavements can
cause excessive pavement material loss when compared to using the correct
plant.
Using COMPACTO product and materials that meet the desirable pavement
design specifications can significantly reduce maintenance compared with
pavements constructed from materials outside of the specification limits.
Modification of poorer quality in situ materials by stabilisation can be an effective
means of containing maintenance requirements and costs where suitable
materials cannot be found locally.
The use of self-cementing materials or material with large stones is unsuitable for
pavements requiring routine maintenance grading, as this could result in torn out
material and greater damage to the pavement. Also, pavements low in fines
content allow water to penetrate and this can cause both surface and foundation
defects to develop.
4.3 Defects – Cause and Cures
Defects are usually the result of interactions between pavement materials, traffic,
climate conditions, and construction methods. When assessing defects and the
necessary action to repair the road, it is the level or qualities of service that is
critical in determining the maintenance effort required. The quality of service
affects the speed at which vehicles can travel safely over the road without loss of
control or suffering damage to tyres, suspension or underbody.
Classification of defects into ‘surface’ and ‘structural’ provides a base upon which
to analyse the causes and cures, and to distinguish between superficial and deep
seated problems. Structural defects are caused through over-stressing the
pavement and/or subgrade causing failure of the pavement. On the other hand,
surface defects relate to the safety and comfort of road users.
Generally surface defects, which are confined to the upper pavement layers, can
be attributed to a variety of factors including climatic conditions, inappropriate
maintenance, poor availability of suitable material, inappropriate grading, poor
compaction or any combination of the foregoing. Surface defects can be removed
by grading or planing the surface. Structural defects on the other hand require

investigation into the causes. Causes can be a lack of drainage, poor compaction
and the use of inappropriate or insufficient material to carry the axle loads.
4.3.1 Surface Defects
Corrugations
Corrugations are formed through material displacement because of tyre
action coupled with the mass and speed of the vehicle. The surface material
arranges itself into parallel ridges that lie at right angles to the direction of the
traffic. Spacing (wavelength) can vary from 50-cm to 1 metre and depths can
range up to 15-cm.
Granular materials with particle sizes greater than 0.5-cm, low plasticity
and limited fines, or which have lost fines due to traffic action, are susceptible to
corrugations. In wet climates, corrective action must be performed during the dry
season by respreading the materials and cutting to the depth of the corrugation.
However; in the wet season, surface deformation maybe transmitted to the
subgrade and lower pavement layers by water penetrating the surface, causing
structural defects. Deformations in subgrade and lower pavement layers may
therefore, be in or out of phase with the corrugations. Where the deformation and
corrugation are out of phase, weak spots may appear as potholes at the trough of
the corrugation.
The absence of a tight surface, combined with coarse sandy material, if
present in high proportions, can lead to the formation of corrugations.
High speed grader operations can be another source of corrugations
developing. The combined horizontal speed and vertical movement can initiate a
wave formation in the formation in the surface that can develop into corrugations
by passage of vehicles over the surface.
Short-term relief of corrugations centers on cutting just below the trough of
the corrugation. The use of ‘lightweight drags’ towed behind a vehicle can be an
effective treatment for corrugations formed in sandy material and in their initial
stages of development. Towing speeds of up to 15km/h can be achieved while
still eliminating the corrugation. At these speeds, considerable lengths of unsealed
roads can be treated in their initial stages of corrugation formation, effectively
reducing the cost of maintenance operations. However, like grading and cutting
corrugations below the trough, the use of drags is a short-term solution only.
Longer term solutions may be found in the careful addition and blending of
COMPACTO product for the appropriate soils along with the importation, when
available, of a higher quality crushed aggregate or clay for isolated trouble spots.
Short sections of seal may also provide the solution in critical locations,

particularly on bridge approaches or steep grades and low-radius horizontal
curves.
If corrugations are a problem, check for:
• Particle size distribution
• Compaction of material at optimum moisture content
• Grader operating speeds
• Correct depth of cut, to remove corrugations with grader blade.
If after checking the above and taking appropriate corrective action, the
corrugations persist, sealing may be the last resort.
Potholes
Areas particularly susceptible to potholing are those with flatter grades and
crossfalls – particularly at bridge approaches, alignment changes from ‘left to
right’, superelevation at ‘S’ bends, and intersections where water can lie on the
surface, particularly in wheelpaths. On gravel roads with correct crossfall and
super-elevation pothole occurrence is rare. Stripping of the surface material and
the infiltration of water trigger the development of potholes. Solids in suspension
are carried away by wheel action on the surface and, as water penetrates the
pavement further, the action continues, forming a hole in the pavement.
The remedy is to restore the surface shape and crossfall to prevent water
retention in flat spots. Although success has been reported by some road
authorities in using stabilised material to fill potholes, it is recommended that
material with the same properties as the pavement material be used.
Patching alone will not solve the problem if the road lacks crossfall. Where
potholing is severe, the surface will require scarifying and reshaping. New
material will need to be added and mixed with the existing material to replace
material displaced by traffic.
At bridge approaches and locations where crossfalls are reduced below
that required for shedding of water, consideration should be given to either
stabilising the pavement or providing short lengths of seal over the affected areas.
Isolated potholes can, however, be repaired manually. All contaminated material
should be removed and new sound material compacted at optimum moisture
content used in its place.
If potholes occur, check for:
• correct crossfall on pavement;
• compaction of pavement material; and
• shading on pavement preventing drying of the pavement material.
Where shade retains moisture in the pavement, the use of a moisture-
resistant paving material or alternatively stabilising of the pavement may be
desirable.

Where manual patching of isolated potholes or groups of potholes is
carried out, the procedures listed below should be considered:
• Remove loose material or shading water from the area to be patched.
• Large or deep potholes should have their sides cut back to be vertical with
square corners and to reach sound material.
• If the material is dry, the area to be patched should be moistened and moisture
added to the patching material.
• The moisture content of the material to be used to backfill the hole can be
checked by squeezing in the hand. If the material is at the correct moisture
content, it will stick together. If moisture runs out of the material, it is too wet.
• Fill the hole in multiples of 100mm thickness and compact with a roller or
vibrating plate. Rolling with truck wheels is inadequate and will not provide
correct compaction.
• The hole is filled and compacted to give a finished surface that is marginally
above the surrounding pavement surface.
Rutting
Ruts are longitudinal deformations in wheelpaths, caused by the passage
of vehicles. Dry season rutting is found in non-cohesive materials such as sands
or gravels that have a low fines content.
In contrast, wet season rutting is found in materials sensitive to water.
Water enters the pavement either from the surface or though capillary action and
consequently deformations are formed. Rutting can be caused through failure of
the subgrade, basecourse or surface material because of excessive quantities of
water entering the pavement and/or subgrade.
Surface ruts form for a number of seasons including:
• poor grading of material;
• poor compacting;
• inadequate pavement depth;
• poor surface drainage; and
• excessive fines in pavement materials.
Providing correct crossfall may reduce surface rutting. Stabilisation
can also help solve this problem.

As with corrugations and potholes, ruts can be removed by cutting to the bottom
of the rut, blending material and compacting at optimum moisture content.
If the material contains too many fines, then it will be necessary to improve
the grading of the material. On the other hand, the addition of fines may be
necessary if loose aggregate exists on the surface. In both cases visual
inspection followed by sieve analysis will be necessary to determine the amount
of material to be added to correct the grading deficiency. Refer to Section 3 for
guidelines on correct grading of material.
If rutting occurs it is advisable to check:
• grading of material;
• crossfall on pavement;
• compacting; and
• aggregate breakdown.
Slippery Surface
Clayey materials, clay/gravel mixes, or even clay deficient materials fouled
by mud or other foreign material can exhibit slippery properties. Slippery surfaces
can be dangerous irrespective of the cause, and require consideration on how to
correct the problem once the matter has been brought to the attention of the road
authority. The extent to which remedial action can be taken will depend on the
authority’s available resources.
Once a surface becomes slippery, the surface will require restoration,
subject to the available resources. This can range from the use of clean gravel or
crushed aggregate placed over the surface, grading and reshaping the surface, to
the removal and replacement of the affected areas with clean well-graded
material meeting the design criteria.
Surface Scour
Pavements with high content of fines and small aggregate are more
inclined to scour than those with a well – graded mixture containing crushed stone
of 19mm or larger size. Up to 40mm stone size can be appropriate in high rainfall
environments.
Scouring is caused through lack of compaction, excessive grades, lack of
shoulder crossfall, and the build-up of debris on shoulders preventing surface
water from flowing off the pavement.
Scouring includes both transverse and longitudinal scours. Transverse
scours commence at the edge of the shoulder or on less compacted areas and
work towards the road pavement. Alternatively, lack of slope on the shoulders
may lead to water standing on the road and eventually finding an escape route.

Plant growth on shoulders and the consequent entrapment of debris and earth,
preventing water draining from the pavement, particularly in areas where
longitudinal grades encourages water to flow along the pavement in preference to
the direction of the crossfall, gives rise to longitudinal scours. The scouring of the
surface not only creates adverse driving conditions but it also leads further
deterioration of the pavement through exposure to the environment. Scouring can
be pronounced when combined with material susceptible to rutting.
When scouring is a problem, the use of high quality aggregate that relies
on mechanical interlock is most suitable to minimise the problem. Stabilisation
can also assist particularly where longitudinal scouring occurs. On longitudinal
grades of 4% and above, crossfall may have to be increased to 5 to 6%
depending on alignment and other factors to ensure that the water finds the
shortest possible route off the pavement.
The most cost-effective precaution against scouring is to pay
attention to drainage and material grading.
Soft Surfaces
The section of suitable material for the pavement is essential if soft
surfaces are to be avoided. Material containing a high percentage of fines may
show signs of movement under the passage of vehicles. Lack of compaction or
water being allowed to enter the pavement also contributes to soft surfaces.
To obtain maximum compaction the material needs to be at optimum
moisture content. The quality of binder in the material is crucial to the optimum
performance. A simple field test can be applied to determine the optimum
moisture content of the material. If the material is at the optimum moisture
content, it will stick together when squeezed in the hand. If moisture runs of the
material, it is too wet. If too dry, it will lack cohesion.
Materials with too much binder, even of good quality, should be avoided,
as these will tend to become slippery, potholed and soft when wet. On the other
hand, too little binder will cause both wet and dry weather problems. In wet
weather, absorption or penetration of moisture will be excessive and in dry
weather, the surface will ravel. Stabilisation can be used to overcome soft
surfaces.
Loose Material
Loose material on the surface is caused through the lack of binder to hold
the surface aggregate in place. Surfaces with loose material can have a major
effect on vehicles operating costs and safety.

During wet periods, water-bound pavements hold together. However,
when allowed to dry out, the pavements start to break-up with dust emissions and
raveling of the surface material leading to excessive quantities of loose aggregate.
Replenishing with a well-graded material mixed with the existing surface material
can restore the surface. The new surface needs to be watered and compacted to
form a crust after blending of the new and existing materials.
Loss of Surface Material
The passage of vehicles, combined with lack of strength and cohesion in
pavement materials, leads to a loss of pavement materials.
As aggregate replacement can be as high as 60% of the total maintenance
costs, losses caused through dust emissions, breakdown of aggregate, scouring
and erosion, poor maintenance practices and poor selection of pavement
materials need to be addressed if maximum benefit is to be obtained from
available resources such as finance, plant and labour.
Compaction, combined with selection of surface material with suitable
grading, is also important in reducing losses.
4.3.2 Foundation Defects
The recognition and identification of pavement foundation defects is a pre-
requisite to economic solutions to road defects. Foundation defects, in contrast to
surface defects, are generally characterised by large area settlements and
heaving. Understanding the material characteristics making up the foundation is
important in resolving the problem.
Heaving of the pavement is caused through movement of material under load and
results from a weak spot further softened by water and/or low quality material. To
resolve the problem, removal of existing material to a depth of sound, relatively
firm material is required, along with subsurface drains (if necessary) and
replacement with suitably compacted material.
Settlement in embankments is a slow process and may require attention over a
number of years. Consolidation is the cause of settlement and is the result of
moisture being forced out of the underlying material in embankments and bridge
approaches. The only solution is to periodically build up the surface to match the
design profile and longitudinal grade. Care should be exercised in not allowing the
deformation to reach excessive levels before remedial action is taken. Differential
settlement can lead to pavements holding water and contributing to surface
defects.

Intrusion of subgrade into the pavement is another foundation defect aggravated
by lack of drainage. Overloading the subgrade is a cause of subgrade and
pavement materials mixing. In some circumstances, the use of geotextiles is an
appropriate solution to segregate material. Placing additional pavement material
over the subgrade will only serve as a short-term solution without appropriate
measures to separate the basecourse and improve drainage.
Defects in the drainage system should be corrected before, or in conjunction with,
correction of pavement and foundation defects. The filling of drains by siltation
over time can be attributed to insufficient gradients, poor filter design or lack of
routine maintenance. Where it is not possible to increase the gradients, then
additional turnouts may help to reduce siltation.
4.3.3 Road Closures
Unsealed roads may have weight limits placed on them or may need to be
temporarily closed to traffic when they are unsafe for use due to excessive rainfall
or extensive damage by the passage of vehicles. When closure of the road is the
only option available, all legal requirements, as applicable in each State, must be
observed. In most cases where the action of a driver in illegally entering a closed
section of road results in damage to the road, the cost of repairing the damage
may be recovered from the owner of the vehicle or alternatively the driver.
Obtaining evidence to prosecute offenders successfully can, however, be difficult
unless witnesses to the breach of a legal road closure are available.
If it is proposed to close a road for any purpose then appropriate advance warning
signs, are necessary to warn motorists well in advance of the closure, to enable
alternative routes to be taken. Similarly, at the section of the road to be closed,
appropriate signs and barriers are necessary to prevent the passage of vehicles.
The use of media facilities such as radio and telephone, road condition
information services are important to the travelling public when flooding or
excessive rainfall results in road closures.
4.4 Shaping the Formation

Lack of adequate crossfall is one of the principal problems
associated with unsealed roads because of drainage problems.
Crossfall should not normally be less than 1:24 (4%) and may be as steep as 1:17
(6%). The importance of maintaining the correct crossfall cannot be over
emphasized. While this practice is most desirable, it is recognised that in some
cases, due to lack of resources, this may not always be possible. When crossfall
requires attention, this is best achieved by scarifying the surface, adding material,
mixing and shaping the surface to form a crown and finally compacting at the
optimum moisture content for the material.
Loss of shape is often caused by improper grading practices, loss of material,
settlement, poor construction, or inadequate drainage. Light grading will provide a
smooth surface; however, heavy grading is necessary to reshape and restore the
surface to its correct profile. The frequency with which either light or heavy
grading is found necessary will depend on the traffic, materials, the skill of the
operator, and the available resources of the road authority.
Grading should commence from the edge of the road and work towards the
centre, making sure to maintain the correct crossfall with each successive pass
and to remove all surface defects. The depth of irregulation and width of formation
will govern the number of passes. The windrowed material is deposited beyond
the centerline and spread back across the surface, depositing the material on the
cut surface to give correct crossfall. The material is compacted and the procedure
repeated for the opposite and the procedure repeating for the opposite side of the
formation.
In these operations, the grader blade should not pass the centerline and checks
should be made, using a camber board, at 100m intervals to ensure the desired
crossfall is being achieved, particularly when reshaping and resurfacing a
pavement.
It is important that the grader does not make a final pass down the
centre of the road with the blade horizontal as this will remove the
crown and accelerate deterioration.
Retaining superelevation on curves is as important as retaining the crown on
straight road sections as it allows surface water to drain from the pavement.
Particular care is required in shaping and maintaining the transition in cross-
slopes between tangents and curves. Nevertheless, superelevation should be
developed as quickly as possible, commensurate with design speed and ride
quality requirements, to limit the length of pavement with less than desirable
minimum crossfall for purposes.

4.5 Drainage
One of the most important aspects of a road design is the provision made for
protecting made for the road pavement from surface and ground water. Water
penetrating the pavement weakens the structure, making the pavement more
susceptible to damage by traffic. The objective of the drainage system is to
prevent the pavement from becoming saturated in the zone between the surface
and a level approximately one metre below the surface. This zone should not be
allowed to dry out excessively as most unsealed roads depend on pore suction to
bond the material together, i.e. water is lost by evaporation from the running
surface and replaced by water from lower levels in the pavement structure.
To reduce the adverse impact of water, the road must be
constructed with a crossfall that effectively sheds surface water with
the sub-base treated with COMPACTO product.
The road must also be raised above the level of the local water table
to prevent soaking by groundwater.
Good maintenance practice ensures that the features of the original
geometric design are properly maintained.
Table drain inverts should be maintained at a level of between 500mm and 1m
below the level of the shoulders where practicable and, depending on topography,
to reduce the influence of the water table on the strength of the subgrade.
Regular grading to maintain crossfall, eliminate surface defects, and
restore drainage profiles should reduce the effects of the surface
water.

Sub-surface water effects can be overcome by improving the drainage through
installation of sub-surface drains, and clearing table drains of debris. The design
profile of the drain will determine the method of cleaning.
Drains formed in the shape of a ‘V’ or wide flat-bottomed drains can be
mechanically cleared and maintained with a grader, or slashed if surface with
grass. Other profiles such as the semi-circular profile can be formed and
maintained using a hydraulically operated and driven circular cutting edge
attachment mounted on maintenance or construction equipment. Drains
inaccessible to mechanical equipment require manual maintenance with hand
tools and approved non-sterilant herbicides.
Maintenance of floodways and fords may be divided into three types as
follows:
• During Dry Weather. The pavement, batters and supplementary culverts
require routine maintenance similar to that of a normal road. Warning signs and
depth indicators need special attention, the former because they warn of a dip in
the pavement during dry weather as well as indicating the possible presence of
water over the pavement in wet weather, and the latter because they must be
easily read at a distance when there is water over the floodway.
• During Flooding. Regular inspection is necessary to ensure that the floodway
is safe for traffic, having regard to fact that deep holes and washed out batters
may not be apparent to all drivers. Debris that may collect on the floodway should
be removed and holes under the water filled with rock pending permanent repair
when water has receded.
• After Flooding. High priority must be given to the repair of physical damage
so that floodway is safe for traffic and is not further damaged by subsequent
floods. Debris should be cleared from the upstream channels leading to the
floodway and culvert. Markers and signs should receive attention to ensure they
are sound. It is also important to ensure the designed crossfall on the pavement
through the floodway is reinstated.
Many dry watercourses contain loose sand and gravel which may be deposited
on the floodway in sufficient thickness to prevent the passage of vehicles or at
least create hazardous conditions from them. The removal of this loose material is
generally the most urgent restoration work after floods. In some cases it may also
be desirable to raise the pavement level of the floodway to inhibit the further
deposition of sand when the water course next carries water, provided this did not
cause damage upstream by afflux or lead to scour due to increased velocity.
4.6 Grading Frequency

The frequency of either light of heavy maintenance grading on any particular road
will be determined by the maintenance authority’s policy on the quality of ride,
available funds and ad hoc repairs doe to unforeseen circumstances. This will be
influenced by the importance of the local economy, number of properties
serviced, type and function of traffic, and the total resources available to maintain
the unsealed road network. The effect of more frequent grading is to improve the
condition of the road surface and thereby lower vehicle operating costs.
Moisture conditions greatly influence the effectiveness of grading operations with
best results obtained when the surface is reasonably firm and when there is
enough moisture retained to facilitate cutting, moving and compacting materials.
Maintenance grading should, when carried out on a dry pavement, have water
added to it. It is recognised that this may not always be possible.
The optimum grading frequency from an economic stand-point is defined as the
breakeven point where incremental reduction in vehicle operating costs due to an
additional grading is equal to the incremental cost of one grading. Nevertheless,
optimum grading frequency resulting from economic analysis should be used only
as a guide in the design of maintenance programs. Actual operating conditions
and financial constraints should be reflected in modifications to the economic
analysis.
The principal performance indicator, which affects vehicle operating costs, is road
roughness. The relationship between roughness and vehicle operating costs
emphasizes the likely additional costs to road users if roads are allowed to
deteriorate.
Used as a management tool, roughness will allow predictions on the frequency of
grading to be made more readily.
Studies under taken over a number of years show an optimal grading
frequency in the range 4,000 to 8,000 vehicle passes. This is
consistent with a grading frequency of approximately once every
three months for roads with 50 to 100veh/day.
There are no clear guidelines that are universally applicable for every road. The
grading frequency will be dictated by a number of issues ranging from political,
through to economic and technical priorities, all of which carry appropriate
weighting that varies with the local circumstances. Grading, irrespective of the
task being undertaken, is the single most important function in maintaining an
unsealed road network. It achieves the standard set by the maintenance policy.
Grading frequency prediction requires constant monitoring of the road surfaces
within the network with actual operating conditions taking precedence over
theoretical analysis. Nevertheless, the relationship between roughness and
vehicle operating costs places a great deal more emphasis on maintenance
standards and efficient use of resources in reducing road user costs.

4.7 Gravel Resurfacing
Resurfacing is necessary due to loss of pavement material resulting
from:
• degradation of stone;
• climate conditions, i.e. wind and rain;
• scouring and erosion;
• traffic abrasion;
• maintenance practices; and
• pavement material selection.
The rate of gravel loss is not constant over life of the pavement. The rates of
gravel loss are approximately constant for the first two to three years only
following resurfacing and vary with vehicle speed, residual pavement thickness
and climatic conditions. As the wearing course is reduced in thickness, other
developments such as the formation of ruts will effect the loss of pavement
material. Although gravel loss can be seen as a loss of the upper surfacing layer,
any inherent weaknesses or strengths due to varying depth of wearing course will
influence the resistance of the road to deformation.
Using a gravel loss prediction model may assist planned resurfacing schedules.
When resurfacing pavements, it is essential that the existing surface is scarified
with all new material added to pavement being blended with existing material.
If the loss of material is excessive, then an analysis of the material used for the
pavement should be undertaken.
However, if the loss of material is principally caused by excessive dust emission
and if modification by stabilisation cannot be achieved, then use of dust palliatives
may be economically feasible.
Loss of surface material aggregated replacement can be as high as 60% of the
total maintenance costs and, if maximum benefit is to be obtained from available
resources, then pavement material selection and placement is critical to efficient
maintenance of unsealed roads.
4.8 Dust Control

The economic and environmental implications of road dust on adjacent land use
can be significant, let alone the problems resulting in the loss of material from the
road surface.
Dust also has safety consequences that require addressing. The adoption of a
road dust control program for a specific road depends upon an evaluation taking
into consideration:
• degree of social and environmental impact;
• average daily traffic; and
• road safety.
Dust is caused both by the loss of fine particles from road surfaces arising from
loosening of pavement materials, and disturbance of the wearing course caused
by the action of traffic and climatic conditions.
The effect of the loss of fines is to increase the permeability of the surface,
resulting in early pavement deterioration and accelerating the need of resurfacing.
Loss of fines also exposes a coarser textured surface, creating higher levels of
irregularities, which, in turn, increase vehicle operating costs. Loss of fines incurs
replacement costs of pavement material, and social and economic costs. As the
proportion of fines increases in the pavement so does the potential loss.
Maintenance plays a major role in controlling fines loss by dust and
erosion.
Short-term or seasonal dust suppression can be effected by the application of
dust palliatives to the road surface. Longer-term solutions involve either sealing of
the pavement or using materials with optimum plasticity limits, to achieve
cohesion in the wearing course material without affecting its strength and
resistance to skidding.
The remedies for dust emission problems can be expensive; nevertheless, dust
palliatives provide an alternative short-term solution to sealing the road. Where
dust is the Principal cause of accidents or degradation of primary produce, the
use of dust palliatives may be justified in terms of the benefits occurring from the
reduction in accidents and loss in value of primary produce. Any long-term
improvement to the dust problem however, is likely to come from either sealing of
the pavement or, alternatively, upgrading the gravel surfacing materials to the
specifications discussed.

Quality Management
Preplanning works will effect the final finished quality of the works.
There needs to be adequate survey, design and laboratory work completed
before any insitu stabilisation work commencing.
Results are attributable not only to planning, but also to the ongoing
implementation and improvement of Quality Systems and Quality Assurance
procedures.
TRAINING
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Highly skilled and motivated grader operators who are trained and form part of the
project team before work commencement.
A commitment from the entire work team to quality and pride in the finished work
PRE-PLANNING REQUIRED
Development of Local Quality Plans and consider the requirements of the road
• Know the volume and type of traffic
• Prepare processes for the control of speed
• Decide minimum requirements when located close the housing (e.g.
dust minimisation, speed reduction, sound)
• Is there enough Hazard warning signage for bends, crests, danger or
villages and schools
Road design
• Investigate the road and report problem and probable causes.
• Review the road report using the Local Quality Plan and initiate a list of
required corrections to the road.
• Produce a set of new pavement levels which allow for shape correction
of the road and drainage
• Design work before the job commencing with the aim of correcting any
noted areas where there are hollows in the pavement.
Pavement design
It is essential that the correct stabiliser for the material is selected, the
correct application rate of stabiliser is used and the construction plant and
technique employed are suitable. Reworking of a completed pavement is
expensive, and not all stabilisation is easily reworked.
Source of Water supply
• During the operation, several water tanker loads may be required each
day.
• It is necessary to determine the location and quality of the water source for
each job to be undertaken
Plan the activity for the days so as to work all men and equipment efficiently.
Ensure that there is a source of ready fuel available to avoid delays.
PREPARE WORK METHOD STATEMENTS
Ensure that all activities have been outlined and discussed with the crew each
day so that every one knows what is expected of them for the successful result.
Attention to shape correction work to ensure that the correction works is in
accordance with the design

Stringing of works to verify that the finished surface levels is as designed.
Prevention of Over Compaction
• Apply only the recommended number of passes with the roller to achieve
maximum density specific to the actual moisture content of the material to
be compacted.
• Roller moving at speeds less than 4kph will achieve most successful
compaction.
• The roller speed and the number of passes are dependent variables and
experience has shown that it is more efficient to use fewer passes at lower
speeds.
• The operator of the roller is to be trained to be aware that maximum
density has been achieved when the roller drum begins to “bounce”. This
is because the depth of the compaction is directly proportional to the
centrifugal force of the roller
CHECKING
• As part of the Quality Assurance procedures, the finished levels are to be
checked every 20 metres
• Surface quality is checked by carrying out ten 3 metro straight edge readings
for every 200 metre lane lengths
Construction Process
The first step in the stabilisation process is to perform simple laboratory
tests on the material to be stabilised. From these tests we are to
determine the soils suitability for stabilisation and the content of
stabiliser or stabilisers to be used to achieve the desired engineering
properties, and the amount of water that must be added during the
construction to gain the maximum compaction.
A mix-insitu process allows the use of the insitu materials or borrows
materials to be blended with the stabiliser and water during the
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construction. Saving on the costs of preparing a pug mill and cartage
both to the pug mill as well as to the site.
The basic aspects for the construction process for a mix-insitu method
are as follows:
PREPARATION
• Levels should be adjusted before the stabilisation process.
Bring the area to be worked to the required profile and grade
the underlying sub-base ready then adequately compacted to
assist full compaction of the stabilised area.
• Remove excess material where levels are required to be
reduced prior to stabilising
• Pre-tyning to the depth of stabilisation before the application of
the stabiliser and/or COMPACTO product.
The use of the product COMPACTO is recommended in the sub-
base for the long-term moisture control.
MIXING
• Scarification of the area to be worked with a grader is needed to
improve the degree of pulverizing and mixing.
• Where a binder has been selected, the binder in addition to the
COMPACTO are combined with water, incorporated into the
material, and mixed thoroughly through the layer depth.
• The required quantity of water enhances the mixed material by
providing uniformity of mixing of the materials.
During this process, the mixing requires the material to be
pulverized to its natural grading.
COMPACTION
• The strength of the pavement depends on the extent of the
compaction achieved. Care must be taken as over compaction
occurs once maximum density is achieved
Over compaction can lead to failure in the soil layer due to:

 Crushing
 Lateral movement of soil causing cracking
 Forcing underlying water up to flood the layer.
• The use of COMPACTO product facilitates a greater
compaction or density by its action to reduce final moisture
levels.
• One of the major advances in the last ten years has been in
construction equipment used for road stabilisation.
Equipment used for pulverizing to natural grading
Vibratory Sheepsfoot and Padfoot rollers
Rollers – 10 to 28 tonne according to stabilised depth
Reclaimer – pulverizing and mixer combination
• Equipment used to achieve best compaction results
Cohesive soils – multi-tyred pneumatic rollers
Granular Soils – smooth wheel rollers or vibratory
rollers
• Compaction of the stabilised pavement is carried out following
the full depth mixing of the treated base or pavement. After
about 4 to six passes, the grader shapes the stabilised material
prior to the compactor and the padfoot completing the
compaction process by “walking out” of the layer.
• Final rolling is completed by a combination of vibrating smooth
drum and/or medium/large pneumatic tyred rollers. This is
carried out after grading to eliminate padfoot marks.
GRADING
• As soon as the work is sufficiently compacted, grading must
commence and be carried out in conjunction with compaction
until a smoothly graded finish is obtained
• The use of slow setting additives allows final trimming to start
after compaction
• The grader cuts the pavement only with all material being cut to
waste to prevent laminations occurring in the pavement.

• This final trim work still leaves pavement in a range o to 5cm
high as per the specification.
CURING
• The final step in the construction process is curing.
Curing prevents rapid evaporation of moisture from the surface
and allows the stabiliser to achieve full strength.
Final Surface:
• A light coat of bituminous material is commonly used as a first line of
defence against water penetration the COMPACTO works as the
secondary line of defence.
• Additionally the bituminous material will serve as a dust control.

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