Abu Dhabi, United Arab Emirates. STANDARD CONSTRUCTION SPECIFICATIONS (PART 1 - ROADS, Second Edition 2020)

ISSA TEST NO.

DESCRIPTION

SPECIFICATION

@ 30 Minutes Minimum (Set)

12 kg-cm Minimum

@ 60 Minutes Minimum

(Traffic)

20 kg-cm or Near Spin Minimum

ISSA TB-100

Wet-Track Abrasion Loss

One-hour Soak

540 g/m

Maximum

Six-day Soak

800 g/m

Maximum

ISSA TB-147

Lateral Displacement

5% Maximum

Specify Gravity after 1,000

Cycles of 55 kg

2.10 Maximum

ISSA TB-109

Excess Asphalt by LWT Sand

Adhesion

540 g/m

Maximum

ISSA TB-144

Classification Compatibility

11 Grade Points Minimum (AAA, BBA)

*ISSA

– International Slurry Surfacing Association

3.5.2.4 Composition of Mixture

The Owner shall approve the design mix and all Micro Surfacing materials and methods prior to use
and shall designate the proportions to be used within the following limits:

•

Residual Asphalt: 5.5% to 10.5% by dry weight of aggregate

•

Mineral Filler: 0% to 3% by dry weight of aggregate

•

Polymer Based Modifier: Shall be a minimum of 3% solids content

•

Water (Potable): As required to provide proper consistency

3.5.2.5 Construction Requirements

a. Equipment

The machine shall be specifically designed and manufactured to apply Micro Surfacing. The material
shall be mixed by an automatic-sequenced, self-propelled Micro Surfacing mixing machine. It shall
be a continuous-flow mixing unit that accurately delivers and proportions the mix components
through a revolving multi-blade, double-shafted mixer. Sufficient storage capacity for all mix
components is required to maintain an adequate supply to the proportioning controls.

When specifying continuous machinery to minimize transverse joints, the specified machine must be
capable of loading materials while continuing to apply Micro Surfacing. The continuous-run machine
shall be equipped to provide the operator with full control of the forward and reverse speeds during
application. It shall be equipped with opposite-side driver stations to assist in alignment. The self-
loading device, opposite-side driver stations, and forward and reverse speed controls shall be of
original-equipment-manufacturer design.

b. Spreading Equipment

The mixture shall be agitated and spread uniformly in the surfacing box by means of twin shafted
paddles or spiral augers fixed in the spreader box. A front seal shall be provided to insure no loss of
the mixture at the road contact point. The rear seal shall act as a final strike-off and shall be
adjustable. The spreader box and rear strike-off shall be so designed and operated that a uniform
consistency is achieved and a free flow of material is provided to the rear strike-off. The spreader
box shall have suitable means provided to side shift the box to compensate for variations in the
pavement geometry.

Each mixing unit to be used in the performance of the work shall be calibrated in the presence of the
Engineer  prior  to  the  start  of  the  project.  Previous  calibration  documentation  covering  the  exact
materials  to  be  used  may  be  acceptable,  provided  that  no  more  than  60  days  have  lapsed.  The
documentation shall include an individual calibration of each material at various settings that can be
related  to  the  machine  metering  devices.  Any  component  replacement  affecting  material
proportioning requires that the machine be recalibrated. No machine will be allowed to work on the
project until the calibration has been completed and/or accepted. ISSA Inspector’s Manual describes
a method of machine calibration. ISSA contractors and/or machine manufacturers may also provide
methods of machine calibration.

d. Lines

Care shall be taken to insure straight lines along kerbs and shoulders. No runoff on these areas will
be permitted. Lines at intersections shall be kept straight to provide a good appearance.

e. Handwork

Approved hand squeegees, with burlap drags, shall be used to spread Micro Surfacing in areas not
accessible to the Micro Surfacing spreader box. Care shall be exercised in leaving no unsightly
appearance from handwork.

f. Curing

Areas receiving Micro Surfacing will be allowed to cure from one to three hours or until the treated
pavement will not be damaged by traffic. The Contractor will protect the area with suitable barricades
or markers for the full curing period. Areas which are damaged within 24 hours of application of Micro
Surfacing, or prior to moving to new work locations, shall be repaired by the Contractor at his
expense.

g. Surface Preparation

Immediately prior to applying the Micro Surfacing, the surface shall be cleared of all loose material,
oil  spots,  vegetation  and  other  objectionable  material.  Any  standard  cleaning  method  will  be
acceptable.  If  water  is  used,  cracks  shall  be  allowed  to  dry  thoroughly  before  Micro  Surfacing.
Manholes, valve boxes, drop inlets and other service entrances shall be protected from the Micro
Surfacing  by  a  suitable  method.  The  Engineer  shall  approve  the  surface  preparation  prior  to
surfacing.

h. Weather Limitations

Micro surfacing shall not be applied if either the pavement or air temperature is below 10°C and
falling, but may be applied when both pavement and air temperatures are above 7°C and rising. No
Micro Surfacing shall be applied when there is the possibility of freezing temperatures at the project
location within 24 hours after application. The Micro Surfacing shall not be applied when weather
conditions prolong opening to traffic beyond a reasonable time.

i. Notification

All homeowners and businesses affected by the paving shall be notified 24 hours in advance of the
surfacing. Suitable tow-away signs may be posted prior to the surfacing. Should work not occur on
the specified day, a new notification will be distributed. The notification shall be in a form of written
posting, stating the time and date that the surfacing will take place.

j. Traffic Control

Suitable methods shall be used by the contractor to protect the Micro Surfacing from damage from
all types of vehicular traffic. Opening to traffic does not constitute acceptance of the work. The
Engineer shall be notified of the methods to be used. In areas that are subject to an increased rate
of sharp-turning vehicles, additional time may be required for a more complete cure of the Micro

k. Clean Up

All areas, such as man-ways, gutters and intersections, shall have the Micro Surfacing removed as
specified by the Engineer. The Contractor shall remove any debris associated with the performance
of the work on a daily basis.

3.6 Miscellaneous Pavement Items

3.6.1 Coloured Bituminous Pavement

3.6.1.1 Description

This work consists of supplying and applying coloured bituminous pavement surfaces of the type
and colour as shown in the Contract plans or as included in the Particular Specifications. This
Specification provides the requirements for the following types of coloured pavement:

1. Coloured bituminous paving final top course, where the colour additives are added to the

bituminous mixture at time of mixing in the batch plant.

2. Colour additives included in the emulsified asphalt used for surface treatment.

3. Coloured surface coatings.

3.6.1.2 Materials

a. Contractor Submittals

Contractor shall prepare and submit to the Engineer for approval trial pavement samples of the type
and colours as shown on the Contract plans or as included in the Particular Specifications. Trial
sample sizes, numbers and methods shall be agreed with the Engineer prior to preparation which
may require a full size trial section for final approval by the Owner.

For coloured bituminous paving final course and surface treatments the submittal shall include the
pigment  manufacturers  name,  pigment  name  and  number  and  details  of  the  final  mix,  stipulating
where this mix deviates from the approved wearing course final layer bituminous pavement mix or
surface treatment materials.  Details shall include such items as quantity of the pigment added and
mixing  time,  any  use  of  clear  asphalt,  any  use  of  coloured  aggregate,  and  associated  details  as
needed to supply a consistent and Owner accepted coloured pavement surfacing.

The Contractor submittals for coloured surface coatings shall meet the requirements of Article 8.2.2.8
of Chapter 8, Traffic Marking and Signs, of these Standard Specifications.

b. Bituminous Mixes

Materials for coloured top course bituminous mixes shall meet the applicable requirements in Section
3.3.2 with the addition of a pigment (colorant) that is usually added at the time of the asphalt mixing
in  a  powder  or  pelletized  form.    Replacement  of  the  bitumen  binder  with  a  clear  binder  or  the
aggregate  with  coloured  aggregate  may  be  necessary  to  achieve  the  require  colour  tint.    Such
replacement shall be done with materials of similar properties as otherwise specified and approved
by the Engineer.  Application rates of the pigment and mixing requirements shall be made as per the
initial suggestions of the pigment supplier or manufacture, and then adjusted as necessary to meet
the final approved colour tint, as approved by the Engineer.

Materials  for  coloured  surface  treatments  shall  meet  the  requirements  of  Article  3.5.1.2  with  the
addition of an approved colour pigment pre-mixed with the bitumen prior to application.  Replacement
of the bitumen binder with a clear binder or the aggregate with coloured aggregate may be necessary
to achieve the require colour tint.  Such replacement shall be done with materials of similar properties

as otherwise specified and approved by the Engineer. Application rates of the pigment to the
bitumen shall be made as per the initial suggestions of the pigment supplier or manufacture, and
then adjusted as necessary to meet the final approved colour tint, as approved by the Engineer.

c. Coloured Surface Coatings

Materials for coloured surface coatings shall meet the requirements of Article 8.2 of Chapter 8, Traffic
Marking and Signs, of these Standard Specifications.

3.6.1.3 Construction Requirements

Installation  of  coloured  top  course  bituminous  pavement  shall  meet  the  requirements  of  Section
3.3.3.  Installation of coloured bituminous surface treatment shall meet the requirements of  Article
3.5.1.4.  Installation of coloured epoxy surface coatings shall meet the requirements of Section 8.2
of Chapter 8, Traffic Marking and Signs, of these Standard Specifications.

3.6.2 Speed humps

3.6.2.1 Description

Work consists of construction of speed humps, or installation of temporary speed humps, as shown
in the Contract plans, specified in the Particular Specifications, and as approved by the Engineer.

3.6.2.2 Materials

a. Asphalt Concrete

Asphalt concrete shall meet the requirements of either Sub-article a) of Article 3.3.2.5 or Paragraph
1 of Sub-article b of Article 3.3.2.5 as defined for wearing course layers for hot mix asphalt.

b. Tack Coat

Tack coat shall meet the requirements of Article 3.4.3.2.

c. Temporary Speed Humps

Temporary speed humps to be provided by the Contractor shall be new prefabricated rubber product
in accordance with traffic calming safety standards and specifications outlined by Institute of
Transportation Engineers (ITE), that are capable of being removed and reinstalled numerous times
without showing signs of excessive wear and tear. Type of temporary speed humps shall be as
shown on the Contract plans or described in the Particular Specifications, and as approved by the
Engineer.

d. Striping

Striping  for  speed  humps  shall  be  white  plastic  preformed  permanent  pavement  marking  tape
material  meeting  the  requirements  of  Article  8.2.2.11  or  a  white  Thermoplastic  marking  material
meeting  the  requirements  of  Article  8.2.2.5,  or  of  type  as  shown  on  the  Contract  plans  and  as
approved by the Engineer .

Temporary speed humps will normally be pre-striped by the manufacture, and if not, the striping
material shall meet the requirements of this Specification Section.

e. Signing

Signing for speed humps shall be the type and size shown on the Contract plans meeting the
applicable requirements of Section 9.5, of Chapter 9, Traffic Control System, of these Standard
Specifications.

3.6.2.3 Construction Requirements

a. General

Contractor shall submit a method statement to the Engineer for approval prior to the start of
construction of speed humps. Method statement shall include schedule, timing, construction
methods and details including type and number of equipment to be used, material to be used with
the necessary material approval submittals, and detailed traffic management plan.

If construction of speed humps is on existing streets where no other construction work having traffic
detours is already in place, Contractor shall apply for and provide to the Engineer proof of acceptance
that the necessary street traffic closure has been approved by the concerned authorities. Closures
shall be temporary, with work performed during the day and the street reopened to traffic by the end
of the normal work day, all as approved by the Engineer.

Speed humps shall be constructed at the locations and to the shapes and configurations shown in
the Contract plans. Speed humps are to be constructed of asphalt top (wearing) course, across and
60 cm narrower than width of existing pavement, leaving 30 cm wide open area between outer most
edge of speed hump and pavement edge for drainage purposes.

Use any method necessary to form parabolic shape and to achieve proper height of speed hump.
One such proven method for forming a parabolic shape of speed hump is to construct template from
minimum 5 m long wooden board, with centre portion of bottom of template cut into basic parabolic
shape of speed hump, leaving 60 cm flat area at each end of template. To stiffen template and to
minimize any bending of template, attach aluminium or steel channel section to top portion of
template.

After initial placement of asphalt (before compaction and while asphalt is still fresh and pliant) form
asphalt surface into basic parabolic shape using template. With flat ends of template resting on
abutting pavement surface, drag or shimmy template across asphalt surface forming basic parabolic
shape of speed hump. During compaction it may be necessary to remove excess asphalt material,
or place additional asphalt material. Repeat template operation until speed hump is fully compacted
and has achieved its proper height and shape.

Do not perform final rolling operation until required parabolic shape of each speed hump has been
approved by the Engineer

Pavement markings and striping are to be installed per the layout and configurations shown on the
Contract plans and per the requirements included in Section 8.2.3 of Chapter 8, Pavement Marking
and Signs, for the respective approved striping materials. Signing shall be installed as shown on the
Contract plans and per the appropriate signing types as included in Section 9.5.3 of Chapter 9, Traffic
Control System, of these Standard Specifications.

b. Installation of Speed Humps on Existing Pavement

Construct keyway 60 cm wide in shape of speed hump and across existing pavement where speed
hump is to be installed. Keyway is to be constructed by saw cutting existing pavement minimum of
38 mm deep along outer most edge of speed hump, then milling on bias to 0 mm at inner edge of
keyway. Thoroughly clean pavement surface, and apply tack coat making sure to completely cover
surface area. Tack coat must be applied before placement of any new asphalt material, and between
any and all subsequent asphalt courses.

c. Installation of Speed Humps as Part of New Pavement Laying or Pavement

Resurfacing Work

Finish paving street with asphalt top course up to outer most limits of speed hump before constructing
speed hump. Take extra steps to ensure that portion of asphalt top course placed within 30 cm wide
open area between outer most edges of speed hump and pavement edge is properly compacted.
Speed hump is to be constructed on top of the asphaltic base course. Thoroughly clean pavement
surface, and apply tack coat making sure to completely cover surface area. Tack coat must be

If Contractor elects to, or inadvertently, paves the entire street without making allowances for speed
hump construction, speed hump is to be constructed in accordance with Sub-article b of Article
3.6.2.3.

d. Installation of Temporary Speed Humps

Speed hump warning signs are to be installed minimum of 10 calendar days in advance of installation
of temporary speed humps.  Speed hump warning signs are to be installed on sign posts at each
temporary  speed  hump  location.    Speed  hump  warning  signs  are  to  be  covered  until  temporary
speed humps have been installed.

Temporary speed hump is to be installed across and 60  centimetre shorter than width of existing
pavement,  leaving  30  centimetre  wide  open  area  between  outer  most  edge  of  temporary  speed
hump  and  pavement  edge  for  drainage  purposes.  Prior  to  installation  of  temporary  speed  hump,
existing pavement area is to be thoroughly cleaned. Installation of temporary speed humps is to be
in  accordance  with  manufacturer’s  instructions.  Maintain  temporary  speed  humps,  making  any
adjustments  or  re-installation  necessary  to  ensure  that  temporary  speed  humps  remain  properly
situated.

If temporary speed humps do not come pre-striped, pavement markings are to be installed using
methods described in Sub-article a) of Article 3.6.2.3.

For Owner supplied speed humps, Contractor shall obtain the temporary speed humps including all
appurtenances and mounting hardware from the Owners stores and otherwise install as required in
this Specification Section. Contractor shall supply any additional mounting equipment, hardware
and bonding agent as may be needed to properly install the Owner supplied temporary speed humps
as recommended by the manufacturer.

Contractor shall remove any temporary speed humps and hardware when directed by the Engineer
within the project limits, permanently restore existing pavement, filling in all holes necessitated for
installation of temporary speed hump anchoring system.

Removed temporary speed humps will remain the property of the Contractor to be removed from the
site, except where required in the Contract Documents that they remain the property of the Owner.
Contractor shall protect, package and deliver to Owner store yards as directed by the Engineer, all
temporary speed humps and hardware that are to remain the property of the Owner. Any materials
to remain the property of the Owner, that are damaged beyond repair, are to be replaced with new
materials.

3.6.3 Sand asphalt for foot path

3.6.3.1 Introduction

When bituminous materials are being applied, the surface of all structures, foot path, wheel guards,
guard rail, kerbs and gutters, and other, roadway appurtenances shall be protected in an approved
manner to prevent them from being splattered with bituminous material. The contractor shall at his
own expense, remove all the trace of bituminous material, and repaired all the damage, and leave
the appurtenance in an approved condition.

3.6.3.2 Material and Mix Design

a. Aggregate

Aggregate should be crushed rock or gravel. Aggregate gradation for sand asphalt concrete is shown
in the following table:

Table 3-47: Sand Asphalt Gradation

Percent passing by weight

9.5

100

4.75

– 100

2.36

– 100

1.18

– 80

0.600

– 65

0.300

– 40

0.150

– 20

0.075

– 10

Asphalt Binder by weight of total mix

– 12 %

b. Bitumen grade

The binder shall be normal black bitumen (penetration grade 40

– 50)

c. Design criteria

Marshall Method of mix design (Asphalt Institute Manual series MS

– 2) will be used in designing the

asphaltic concrete mix. The contractor proposed mix design shall be cross checked prior to approval.

The mix design for the sand asphalt shall be as follows:

Table 3-48: Sand Asphalt Mix requirements

3.6.3.3 Construction Requirements

a. Laying of sand asphalt

The sand asphalt shall be laid by paving machine unless otherwise approved by the Engineer.

b. Trial area

The contractor shall prepare trial area 2 meter wide by 10 meter long as part of acceptance
procedure of the mix.

c. Weather limitation for paving operations

•

Hot bituminous mix shall be placed when weather is not dusty, fogy, or rainy and when the

existing surface is free from moisture. Bituminous mix shall not be placed during sand storms.

•

Prime and tack coat should only be applied when ambient temperature 16˚C.

•

No paving operation shall be started if rain is imminent.

Properties

Sand Asphalt Mix

Marshall Stability (kgf)

900 Min

Flow (mm)

– 5

Percentage air voids (VIM)

– 18

Design Binder Content

– 12

3.6.4.1 Scope

This specification provides the minimum requirements for the inclusion of recycled asphalt
pavement to replace a percentage of the raw materials in new hot mix asphalt.

3.6.4.2 Description

Recycled asphalt pavement (RAP) shall consist of a blend of clean, hard, durable crushed
rock, sand, filler and bitumen which is available from pavement rehabilitation or rejected and
surplus asphalt production.

It generally comprises 3 to 5% bitumen by mass with the balance generally consisting of
clean hard durable aggregate. RAP is used as aggregate and bitumen in new asphalt
pavement layers.

RAP is typically recovered by milling or excavating existing asphalt pavements or as waste
from asphalt production. RAP that is recovered by milling or as plant waste is generally clean
RAP with no contaminants. RAP that is recovered to full depth by conventional excavation
can become contaminated during the removal process and is not normally suitable for reuse
in new asphalt.

3.6.4.3 Materials

a. Stockpile Management Plan

The contractor/supplier shall prepare a Stockpile management plan for the RAP to ensure a
consistent quality product is achieved. The management plan shall be submitted to the
Engineer for acceptance, before the RAP can be used on the project

The Stockpile Management Plan shall detail the stockpiling, processing, storage and testing
requirements of each Lot and should be in place at each RAP processing / storage facility.

Each stockpile shall be defined as a Lot to ensure traceability.

b. Processing and Storage

RAP shall be maintained in a separate stockpile prior to processing for use in asphalt.
RAP shall be crushed and screened so that the maximum aggregate size is not greater
than the aggregate size of the asphalt mix being produced. The processed RAP shall
be a well-graded, free-flowing and consistent product. Where the stored RAP is not
free flowing it shall be screened and/or crushed again.

Processed RAP shall be stored in conical or longitudinal stockpiles. Processed RAP
must not be agglomerated or be allowed to congeal in large stockpiles.

c. Unacceptable Materials

The contactor shall ensure that RAP delivered to the stockpiles is devoid of
construction contaminants including amongst others, crushed gravel, timber, concrete
and other building waste.

RAP shall be free of tar and/or asbestos.

RAP shall be free from any metal contamination.

d. Sources of Materials

The contractor shall distinguish the RAP sources as either combined or single source RAP.

RAP that is won from a single source by milling shall be stockpiled individually to ensure it
remains uncontaminated. Testing shall be carried out as indicated to determine the
representative properties of the stockpile.

Combined source RAP

RAP that is combined from different projects should be blended to construct a uniform
stockpile prior to additional processing including crushing, screening or fractionating. Testing
of the blended samples is required to determine the representative properties and variability
of the RAP.

e. Moisture Management

The RAP stockpile areas shall be well drained and laid to falls to prevent build-up of
moisture. The contractor shall take adequate precautions to keep the stockpile dry to ensure
that unnecessary moisture is not incorporated into the mix.

The moisture of the hot mix asphalt produced shall not exceed 0.5% by dry mass
immediately after manufacture.

The moisture of the completed asphalt layer shall not exceed 0.30% by dry mass when cores
are extracted using dry ice coring (for bit cooling).

f. Quantity of RAP to be Included

RAP may be added to the mix so that the contribution of the RAP binder does not exceed
15% of the mix design binder content by mass.

3.6.4.4 Physical Requirements

RAP aggregate after extraction of bitumen shall conform to the physical requirements
described in the following sections of the Standard Construction Specifications:



Superpave mix design materials: Paragraph 1 of Sub-article a of Article 3.3.2.5; OR



Marshall mix design materials: Paragraph 4 of Sub-article b of Article 3.3.2.5

3.6.4.5 Minimum Testing Requirements of RAP

Characterisation testing shall be carried out on completed stockpiles to determine the
stockpile characteristics as listed in Table 5-1 below. Samples shall be taken from at least
ten random locations around the stockpile. The individual samples from different parts of the
stockpile shall not be combined, as tests need to be performed on individual samples to
assess uniformity. A minimum of ten samples is required to allow statistical analysis of the
stockpile.

For continuously replenished stockpiles the stockpile sampling regime shall be continued at a
frequency of one per 1,000 tons of RAP.

Table 3: Minimum Testing Requirements for Static Stockpiles

Test

Method

Frequency

Gradation

AASHTO T30

1 per 1000 tons (min 10)

Asphalt binder content

AASHTO T164

1 per 1000 tons (min 10)

Bulk specific gravity

AASHTO T308 then

1 per 1000 tons (min 10)

Method

Frequency

AASTHO T84 and T85

Aggregate properties1

See Standard Construction
Specifications

1 per 5000 tons (min 2)

Moisture content

AASHTO T110-03

3 per 1000 tons (min 2)

Foreign material

Table 3-14 Standard
Construction Specifications

1 per 5000 tons (min 2)

Aggregate properties evaluation testing includes:

•

Los Angeles abrasion

•

Magnesium sulfate soundness loss of coarse and fine aggregate

•

Sodium sulphate soundness

•

Fractured faces

•

Fine aggregate angularity

•

Flat and elongated particles, 3 to 1 ratio

•

Flakiness

•

Abrasion loss

•

Sand equivalent value

•

Water absorption of coarse aggregate

a. Environmental Testing

The contactor or stockpile owner shall take a representative sample of every 10,000 tons of
unprocessed RAP and conduct a Toxicity Characteristic Leaching Procedure (TCLP) test to
analyse the specific contamination concentration (SCC) and the leachable concentrations for
the following pollutants:



Polycyclic aromatic hydrocarbons(PAHs); and



Heavy Metals: Barium, Cadmium, Chromium, Lead, Nickel, Arsenic, and Mercury.

The testing will be undertaken by a laboratory approved by Abu Dhabi Quality and
Conformity Council (ADQCC) or accredited with Emirates Standardisation and Metrology
Authority (ESMA).

The results will be compared against the

Threshold Values for Specific Contaminant and

Leachable Concentrations

listed in Annex 1 of the Environment Agency Abu Dhabi (EAD)

2016,

Waste Classification Technical Guideline

(EAD-EQ-PR-TGD-01).

If contaminants of interest reported SCC and TCLP concentrations below threshold limits, the
material will be congruent with being non-hazardous waste, which once milled will become a
reusable construction product.

3.6.4.6 Acceptance of RAP

a. Statistical Evaluation

The Contractor shall summarise the results of the testing in a spreadsheet which includes the
stockpile name/description and date of sampling and submitted with the job-mix formula. The

spreadsheet shall calculate the average and standard deviation for each property. The
allowable variation for key properties is shown in Table 3.

b. Exceedance of Statistical Deviation

Where the standard deviation exceeds the maximum allowable standard deviation the
material source shall be rejected until such time as additional processing improves the
variability to within the allowable limit.

c. Acceptance Criteria for RAP

The Contractor shall ensure that the processed RAP complies with the maximum standard
deviation limits in Table 3.

Table 3: RAP Stockpile Maximum Variability

RAP Property

Maximum Standard Deviation
(%)

AASHTO Test Methods

Asphalt Binder Content

0.5

T 164

% Passing Median Sieve
(2mm)

5.0

T-30

% Passing 0.075 mm Sieve

1.5

T-30

Bulk specific gravity (Gsb)

±50 kg /m3

T 84 and T 85

3.6.4.7 Mix Design Requirements

A separate job-mix design shall be prepared for each RAP stockpile. The average asphalt
binder content, gradation and specific gravity of the nominated RAP stockpile shall be used
in the mix design.

Grading and Marshall characteristics of the mixture shall be in compliance with the Standard
Construction Specifications Part- 1- Roads.

The procedure outlined in the latest edition of Asphalt Institute MS-2 under sub title
"Recycled Asphalt Materials in the Mix Design Process" shall be used for laboratory mix
design.

a. Plant mix trials

•

Trial mixes shall be carried out by manufacturing small quantities in the plant at three

different binder contents, targeting the optimum binder content found in the laboratory mix,
as well as at bitumen contents 0.2% above and below the optimum.

•

The results of tests on these trial mixes shall be examined, to identify any shift in properties

between mixes produced in the laboratory compared to those manufactured full-scale.

•

The Contractor shall make final adjustments to the plant to ensure the job mix properties

obtained from laboratory testing are achieved.

•

The Contractor shall check the moisture content of the final product to ensure that the mix

complies with maximum moisture requirements.

a. RAP Cold Feed

The Contractor shall provide a separate cold feed bin for each RAP stockpile required by the
mix design. The cold feed bins shall be equipped with accurate mechanical means for
feeding the aggregate uniformly into the plant in the proportions required for the finished mix
to maintain uniform production and temperature. Oversized RAP shall be prevented from
being incorporated into the completed mixture by the use of a grizzly or grid over the RAP
bin; in-line roller or impact crusher; screen; or other suitable means. If oversized RAP
material appears in the completed recycled mix, the appropriate corrective action shall be
taken immediately.

During asphalt production the recycled mix shall be sampled and tested daily as summarised
in Table 3. Where testing indicates that the recycled mix fails to meet the job-mix formula
within the tolerances specified plant operations shall be stopped.

b. RAP Heating and Blending

RAP shall be heated through indirect heat only with no exposure of the RAP to naked flame.

c. Production Testing

The contractor shall carry out production testing as scheduled in the Standard Construction
Specifications and as specified in Table 3.

Table 3 Production Testing

Test

AASHTO Method

Frequency

Tolerances

Retained 4.75 mm
sieve and larger

T 30

1 per day

± 5.0 %

Passing 4.75 mm
and retained 75 mm
sieves

T 30

1 per day

± 4.0 %

Passing 75 mm sieve T 30

1 per day

± 1.5 %

Asphalt

binder

content

T 164

1 per day

± 0.2 %

Moisture content

T 110-03

2 per day

<0.15%

3.7 Bituminous Pavement Repairs

3.7.1 Description

This work consists of performing all operations and furnishing all materials, labor, tools, equipment
and appurtenances that may be required for the various pavement repair items.  This work is required
to  correct  structural  failures,  grade  elevations,  drainage  and  deterioration  and/or  to  prepare  the
existing pavement surface prior to placing asphaltic concrete overlays or seal coats  as shown on
the Contract plans, as specified herein and/or in the particular specifications and included in the bills
of quantities.

The materials required for the various pavement repair items shall be as specified and shall be in
accordance with the requirements of Sections 3.3 through 3.5.

3.7.3 Construction Requirements

3.7.3.1 Equipment

Contractor shall be responsible to supply all the equipment and labor necessary to perform the work
described for the various types of pavement repair items in accordance with these specifications and
as directed by the Engineer. Major equipment shall conform to Sub-article (a) of Article 3.2.2.3.

3.7.3.2 Pavement Repair Types

a. Repair of Potholes (isolated holes in asphaltic concrete pavements of less than

one square meter) using hot asphalt mixture

Contractor shall perform the following:

1. Saw cut the failed pavement 0.3 to 1.0 meter beyond the perimeter of the failed area as

directed by the Engineer. Make the cut square or rectangular with faces straight and vertical.
One pair of faces shall be at right angles to the direction of traffic

2. Remove and dispose the cut pavement and loose unsuitable material in compliance with the

requirements of Section 2.3.2 of Chapter 2, Earthworks, of these Standard Specifications
and as directed by the Engineer.

3. If base material is removed, fill the excavat

ion with a Gradation ‘C’ (sand-gravel), which has

been premixed to optimum moisture content. Place the material in 150 mm lifts and compact
each lift to at least 95 % modified Proctor density (AASHTO T 180) with mechanical
compactors; same treatment is to be applied to subgrade before filling the excavation with
sand-gravel

4. Wire broom clean the cut edges of the pavement and paint with bituminous emulsion

5. Prime the compacted soil or the upper surface of the sand-gravel with a light coating of MC-

70 when directed by the Engineer. Place Type II wearing course of hot asphaltic concrete
mix with minimum thickness as the existing pavement and compact in lifts not exceeding 70
mm to the same level as the adjacent surface. Vibratory compactors shall be used to compact
the hot asphalt concrete

6. Check level of the patch with a straight edge and make corrections as required

b. Repair of potholes (Isolated holes in asphaltic concrete pavement) Using Cold
Emulsion Asphalt Mixtures

Description

This work shall consist of performing all operations and furnishing all materials, labour, tools,
and equipment that may be required for the asphalt pavement repair of potholes and similar
works. This work shall be performed during any season of the year and as specified herein
or as directed by the Engineer.

2. Materials

The materials of the cold mixture are obtained by blending dense crushed fine and coarse
aggregate, bitumen emulsion with bio oil to give the mixture the required workability. The
mixture shall be a homogeneous distribution of the binder on the aggregate and provides
excellent coating properties, easy, long lasting workability, and good immediate mechanical
performance. The grading and binder content of this mixture shall be as follows:

Property

Ranges

Percent Passing 2.0mm

30 to 50

Percent Passing 0.08mm

4 to 8

Residual binder content, ppc

4-6

The mixture is manufactured in cold mix plant or by using mixers adapted to the quantities
manufactured. The mixture shall be a storable cold mix ready for use, available in bags ideal
for roadway maintenance work and shall have certification from ADQCC or Equivalent.

3. Mixture Performance

The cold mixture shall have the following properties:

Test Characteristics

Test Method

Specification

Marshall Stability

AASHTO T245

Min 500 kg f

Marshall Flow

AASHTO T245

1-3 mm

Stiffness

Stability/Flow

250kgf/mm

Loss of Marshall

stability

Submerging

specimens in water at

60 C for 24 hours as

compared to stability

measured after

submersion in water at

60 C for 30 minutes

(max. % loss)

30%

. Construction Requirements

i. Equipment

Contractor shall be responsible to supply all the equipment and labour necessary to
perform the work described for patching potholes in accordance with these specifications and
as directed by the Engineer.

ii. Repair of potholes

Contractor shall perform the following:

▪

Clean the cavity by removing any water present and all unbound items

(fines, stones, topsoil, etc.) to ensure good adhesion of the asphalt mix to the support.

▪

place cold asphalt mixture manually into the cavity by distributing evenly in layers.

Establish an additional thickness on the surface.

▪

Compact with a hand-held tamper or a vibrating plate for larger areas. A small

cylinder, used in either smooth or vibrating mode, is also suitable. This operation is
essential to accelerate the increase in cohesion and sealing of cold asphalt mixture
and to ensure waterproofing of the surface.

▪

If the level of the repaired area after compaction is lower than that of the road, scarify

the already compacted surface and add the emulsion cold mixture, and compact
again. The level of the repaired area must be the same as that of the pavement.

▪

After compaction, the cold asphalt mixture shall provide a closed surface, limiting

rainwater seepage into repaired potholes.

▪

A primer is recommended when the fill thickness is thin, or when the ambient

temperature is low

iii. Re-open the road to traffic immediately after compaction is completed

iv. During traffic, any sticking of asphalt emulsion cold mixture to vehicle tires can be
avoided by a light surface sanding

c. Repair of Failed Pavement (deep patch)

Contractor shall perform the following:

1. Saw cut the failed pavement 1 meter beyond the perimeter of the failed area as directed by

the Engineer. Make the cut square or rectangular with faces straight and each asphalt layer
stepped back from the one below it by a step width at least equal to the layer thickness. One
pair of faces shall be at right angles to the direction of traffic

2. Remove the cut pavement and excavate the underlying soil to a depth of not less than 300

mm. Engineer may, when deemed necessary, order substantially greater depths of
excavation payable at daily works schedule rates. Remove and dispose the cut pavement
and loose unsuitable material in compliance with the requirements of Section 2.3.2 of Chapter
2, Earthworks, of these Standard Specifications and as directed by the Engineer.

3. Thoroughly compact the subgrade soil with mechanical compactors to at least 95 % of

modified Proctor density

4. Place aggregate

base course meeting Gradation ‘B’, which has been premixed to optimum

moisture content to the bottom of asphalt concrete. Place the material in 150 mm lifts and
compact each lift to at least 95 % modified Proctor density (AASHTO T 180) with mechanical
compactors; same treatment is to be applied to subgrade before filling the excavation with
sand-gravel

5. Wire broom clean the cut edges of the pavement and paint with bituminous emulsion

6. Lightly prime the compacted sand-gravel with MC-70 when directed by the Engineer

7. Place and compact a Type II wearing course of asphaltic concrete in the excavation in 70

mm lifts to the same level as the adjacent surface. Thoroughly and uniformly compact the
pavement by rolling.  Lower lift shall be compacted with a vibratory compactor and the top lift
shall be compacted with a steel wheel roller by first compacting the hot asphaltic concrete
150 mm from the two traffic edges and then by rolling in the direction of traffic.  Drive wheel
of the roller shall be in a forward position.  Use of an asphaltic concrete pavement finisher
will depend on the size of the area being patched.

d. Repair of Depressed Pavement (skin patch)

In cases where the pavement has depressed but the asphaltic concrete has not fractured and the
pavement appears stable, the Contractor shall perform the following:

1. Mill the upper 50 mm of the pavement starting just in back of the depression. Dispose the

milling in accordance with the requirements of Section 2.3.2 of Chapter 2, Earthworks, of
these Standard Specifications and as directed by the Engineer.

2. Wire broom clean the surface and lightly tack the surface and paint the edges of the cut with

bituminous emulsion at the rate of 0.25 to 0.50 kg/m

of tack coat as shown on the Contract

plans or as directed by the Engineer.

3. Place wearing course hot mix asphaltic concrete and compact with a steel wheel roller by

first compacting the hot asphaltic concrete 150 mm from the two traffic edges and then by
rolling in the direction of traffic. Drive wheel of the roller shall be in the forward position.

4. Check the level of the patch with a straight edge and make corrections as required.

e. Repair of Utility Cuts (open pavement and depressed pavement)

Contractor shall perform the following:

1. In cases where the asphaltic concrete pavement is broken or cracked:

i. Saw cut the pavement 1 m beyond the perimeter of the failed area. Make the cut

rectangular with faces straight and each asphalt layer stepped back from the one below
it by step width at least equal to the layer thickness. One pair of faces shall be
approximately parallel to the utility cut.

ii. Remove the cut pavement and excavate the underlying soil to a depth of not less than

300 mm. Engineer may, when deemed necessary, order substantially greater depths
of excavation payable at daily works schedule rates. Dispose the excavated material
in accordance with the requirements of Section 2.3.2 of Chapter 2, Earthworks, of these
Standard Specifications and as directed by the Engineer.

iii. Thoroughly compact the subsoil with mechanical compactors to at least 95 % of

modified Proctor density.

iv. If base material is removed, fill the excavati

on with a Gradation ‘B’ (table 3-6 of clause

3.2.2), which has been premixed to optimum moisture content. Place the material in
150 mm lifts and compact each lift to at least 95 % modified Proctor density (AASHTO
T 180) with mechanical compactors; same treatment is to be applied to subgrade before
filling the excavation with sand-gravel.

v. Wire broom clean the cut edges of the pavement and paint with bituminous emulsion.

vi. Prime the compacted sand-gravel with a light coating of MC-70 when directed by the

Engineer.

vii. Place wearing course of asphaltic concrete in the excavation in 70 mm lifts to the same

level  as  the  adjacent  surface.  Thoroughly  and  uniformly  compact  the  pavement  by
rolling.  Lower lift shall be compacted with a vibratory compactor and the top lift shall
be compacted with a steel wheel roller by first compacting the hot asphaltic concrete
150 mm from the two traffic edges and then by rolling in the direction of traffic.  Drive
wheel of the roller shall be in a forward position.  Use of an asphaltic concrete pavement
finisher will depend on the size of the area being patched.  Use of a vibratory compactor
on the top lift shall be only with the approval of the Engineer.

viii. A vibratory plate compactor shall be used to compact the hot asphaltic concrete against

kerbing and inlets, catch basins or gullies.

Abu Dhabi, United Arab Emirates. STANDARD CONSTRUCTION SPECIFICATIONS (PART 1 - ROADS, Second Edition 2020) - page 39