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Roads and Infrastructure Works forShiab Al Ashkar NeighbourhoodGeneral Specifications

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SECTION 4

PAVEMENT CONSTRUCTION

4.1 AGGREGATES FOR PAVING LAYERS

4.1.1 All aggregates for use in the construction of the pavement layers shall beobtained only from sources approved by the Engineer.

4.1.2 The contractor shall have determined the location, suitability and quantityof material available before tendering as well as the cost and the amountof work required to extract, crush, screen and clean the material and thelength of haul to the job site.

4.1.3 The contractor shall provide the Engineer, within thirty (30) days prior totheschedules beginning of the crushing and screening operations, with a

complete report on the origin and composition of all stone and/or gravelaggregates to be used in the work (Aggregate Resources Report). Allmaterials shall comply with the specified requirements for the variousaggregates.

4.1.4 The contractor shall provide petrographic analysis conducted by acompetent independent testing laboratory which shall include reports onthe suitability of the proposed materials for their use in concrete andasphaltic mixes.

4.1.5 The source and manufacture of the aggregates, which will meet therequirements of the Specification, is the sole responsibility of theContractor. It is also the contractor's sole responsibility to provide such

aggregates at the rates and in the quantities required to complete thework within the specified Contract Period.

4.1.6 The approval of the Contractor crushing and screening plant equipmentby the Engineer shall in no way relive the contractor of the responsibilityof producing aggregates which met the Specifications and in thequantities required for the completion of the work within the specifiedContract Period.

4.1.7 Stock piles of materials produced from each source shall be properlylabeled for clear identification of source and size.

4.1.8 Delivery of materials produced from commercial manufacturing processshall be accompanied by the manufacturer's certification and test reportsshowing that materials comply with the specification for which it issupplied.

4.1.9 No aggregate producing equipment shall be put into operation prior to theapproval of the equipment by the Engineer. If after the equipment is putinto operation it fails to perform as proposed the Contractor shall provideadditional equipment or replace the original equipment with more suitableequipment, as may be directed by the Engineer.

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4.1.18 The stockpile site shall be prepared by clearing and smoothing and mustbe approved by the Engineer. Prior to any stockpiling of aggregates,cross-sections of the stockpile site shall be taken and control pointsestablished for use in determining the quantity of subsequently stockpiledmaterial.

4.1.19 The equipment and methods used for stockpiling aggregates and forremoving aggregates from the stockpiles must be approved by theEngineer and shall be such that no segregation of the aggregates willresult and no foreign material will contaminate the aggregate. The stockpile shall be kept flat and the formation of high cone shaped piles shallnot be permitted. The height shall not exceed 5m. For asphalt works,stock piles of aggregate shall be suitably separated by bin walls and shallbe formed on bituminous or concrete floors.

4.1.20 Material shall be stored in a manner that will ensure preservation of theirspecified quality and fitness for the work. They shall be placed on hard,clean surfaces and, when required by the Engineer they shall be placed

under cover. Stored materials shall be located in such a manner tofacilitate prompt inspection and control. Private property shall not be usedfor storage purposes without written consent of the owner or lessee andpayment to him, if necessary, at the Contractor's expense.

4.1.21 The centre of the storage area shall be elevated and sloped to the sidesin order to provide proper drainage of excess moisture. The material shallbe stored in such a way to prevent segregation and to allow propercontrol of moisture. Aggregate stockpiles shall be built up in layers notexceeding one (1) meter. The height of each stockpile shall be limited toa maximum of five (5) meters.

4.1.22 Sufficient material must be stored in stockpiles to allow for testing and

approval of such materials prior to use in the works.

4.1.23 The contractor shall tidy-up the quarry areas on completion and ensurethat side slopes are not steeper than 1 to 2 and in a condition acceptableto the Employer and to the Engineer.

4.1.24 Following removal of existing asphalt / Interlocking paving blocks, theunder laying materials (sub-base/aggregate road base/wet mixmacadam) shall be retained for their re-use at such places as directed bythe engineer. Any excavated material wasted by the contractor withoutwritten permission of the engineer, shall be replaced by the contractor athis own expenses.

4.1.25 Excavated material, when required, shall be improved to meet therequirements of the specification by adding borrow material which shallbe quantified by the engineer. In such cases payment shall be made forthe quantity of the extra material borrowed.

4.2 GRANULAR SUBBASE

4.2.1 Description

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Granular sub-base shall consist of furnishing, spreading, and compacting,

sub-base in accordance with the details shown on drawings and these

specifications: Granular sub-base used under the carriageway/footpath shall

consist of hard, durable natural/screened gravel or crushed stone, having

suitable binding quality and shall be free from dirt, shale, clay balls gypsum

or other deleterious substances. The material shall lie within the grading

envelope stated below when tested in accordance with BS 812 Part 103 and

shall comply with the properties referred under Clause 4.2.5.

If more than one source is used, the Contractor shall provide a method

statement to the Engineer indicating the method of mixing, stockpiling and

delivery of the mixed material to roadbed. Each time the stockpile is made,

the Engineer shall take samples to check binding quality, homogeneity of the

mix as well as Grading, MDD, CBR and SE. Mixing of dune sand shall not be

permitted. Use of salty water for mixing in sub-base under laying bituminous

mixes shall not be permitted.

The Contractor shall carryout a site trial of at least 100m outside the

permanent work to check and confirm the blending quality and homogeneityof the mix material and also to establish the compacting effort required to

achieve the required degree of compaction.

4.2.2 Materials

a) Sub-base Type I

Granular sub-base material used under footpath shall be well graded and lie

within the grading envelope stated below when tested in accordance with BS

812 Part 103 Clause 7.3 and shall comply with the properties of type I as

referred under Clause 4.2.5.

b) Sub-base Type II

Granular sub-base type II used under the carriageway shall lie within thegrading envelope stated below when tested in accordance with BS 812 Part103 Clause 7.3 and shall comply with the properties of type II as referredunder Clause 4.2.5.

SIEVE SIZE PERCENTAGE PASSING

Type I Type II

75mm 100 100

37.5mm 85-100 85-100

19mm 62-94 62-82

9.5mm 40-90 40-70

4.75mm 25-70 25-45

0.6mm 8-35 8-22

0.075mm 0-10 0-10

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4.2.3 Equipment

Equipment shall be according to the type and number outlined in theContractor's detailed Programme of Work, as approved by the Engineer.

4.2.4 Construction

Road sub-base material shall be delivered to the roadbed as uniform mixture

and shall be spread in layers. Segregation shall be avoided and the sub-baseshall be free from pockets of coarse or fine materials.

Each road sub-base layer shall be spread by grader or other approved

mechanical methods, watered, shaped to a compacted thickness not

exceeding 150 mm and compacted to the required grade and cross section.

The compaction procedure and plant shall be to the satisfaction of the

Engineer. At the time of compaction the moisture content of the laid material

shall not vary by more than + 2% from the optimum moisture content.

The granular sub-base shall be compacted to not less than 98% of the

maximum density determined in accordance with AASHTO T 180 Method - C

with correction for oversized material Particle size analysis of solid for sieve

analysis of fine and coarse aggregate shall be carried out in accordance with

BS 812 part 103 Clause 7.3.

The surface on completion of compaction shall be well closed, free from

movement under compaction plant and free from ridges cracks or loose

material. The finished surfaces of the road sub-base shall not vary at any

point more than 10 mm above or below the grade established by the

Engineer. The road sub-base shall be maintained in a condition satisfactory

to receive any subsequent base or surfacing material. Sub-base, which doesnot conform to the above requirements, shall be reshaped or reworked

watered and thoroughly re-compacted to conform to the specified

requirements.

4.2.5 Relevant Test and Standards

The following tests should be carried out on each source and the material shall conform tothe requirements stated below:

STANDARD LIMIT

TEST Type I Type II

Sampling AASHTO T2 - -

Los Angeles Abrasion AASHTO T96 40 % max. 40 % max.

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Soundness (Magnesium

Sulphate Solution) (5 Cycles)

ASTM C88 15 % max. 12 % max.

Liquid Limit AASHTO T89 35 % max. 35 % max.

Plasticity Index AASHTO T90 6 % max. 6 % max.

Compaction Test (Modified

Proctor) with correction foroversized material

AASHTO T180 2.0 gram/ cc min. 2.0 gram/ cc

min.

C.B.R. at 98% of modified

Proctor density (96 hours

soaked)

ASTM D- 1883 45 % min. 60% min.

Field Density AASHTO T191 98% min. MDD 98% of MDD

Linear Shrinkage BS 1377 Part 2

Method 6.53% max. 3% max.

Sulphate Content (Acid

Soluble)

BS 812 Part 118 0.5% max. 0.5% max.

Chloride Content (WaterSoluble)

BS'812 Part 117 1% max. 1% max.

Sand Equivalent AASHTO T- 176 25% min. 35% min.

4.2.6 Minimum Test Requirements

One sample every l,000Cu.m shall be tested for Grading, Plasticity Index,Maximum Dry Density, CBR and Loss by Abrasion, one in-situ Density testshall be made every 500Sq.m of granular sub-base laid but a minimum oftwo tests have to be made for each section prepared.

4.3 PROTECTION OF SHOULDERS AND SLOPES

4.3.1 Cement Stabilized Aggregate Capping Layer

1) Materials Materials shall conform to Section 4.2 Granular SubbaseMaterials (Type I) of the Specifications except that CBR shall not berequired to be determined.

2) The Sulphate Resisting Cement shall conform to Section 6 of theSpecifications.

3) Water to conform to Section 6 of the Specifications.

4) The mix shall have the following properties/proportions:

i) Cement 6% by weight of the aggregates.

ii) Water to conform to the Optimum Moisture Contentcorresponding to the Maximum Dry Density determinedaccording to BS 1377 part 4.

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iii) Capping Layer shall be compacted to 95% of the MDD.

When tested in accordance with the British Department of TransportationSpecification for Highway Works, Part 3, the minimum compressive strengthat 7 days for an individual cube compacted at OMC should be not less than

4.5 N/mm

2

; and not less than 7.0 N/mm

2

for an average of 5 cubes.

4.3.2 Testing

The testing frequencies shall conform to the following:

a) One sample each for grading, P.I., Sand Equivalent and Loss due toAbrasion per 2000 cu.m of mixed aggregate before the addition ofcement.

b) MDD determination every 2000 cu.m compacted volume of completemix including cement.

c) One sample every 2000 cu.m of compacted volume for cementcontent determination according to BS 1924 Part 2 Method 5.1.

d) One In situ Density determination for every 500 sq.m of laid cappinglayer.

4.3.3 Method

1. The approved material is stockpiled next to blending plant.

2. The required quantity of cement and water shall be added before theaggregate material passed through the mixer. After mixing, thematerial is loaded on trucks ready for site use.

3. The verge and side slopes shall be prepared to the specified levelsand slopes ready to receive the capping layer material, 50cmrounding to both verge and slope shall be done.

4. The material is dumped by trucks and is spread by grader to coverthe verge and side slope up to the existing ground, the 50cmrounding is also formed.

5. The material shall be compacted to 95% of M.D.D.

a) First by steel roller, starting from the toe and moving up;

b) then tire roller, starting from the toe and moving up;

c) and a final pass with steel roller.

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6. The levels and compaction of the capping layer shall be checked.

7. Curing for three consecutive days shall be done by spraying sweetwater on the finalized surface to keep it continuously wet.

4.4 IMPROVED ROCK SUBBASE

4.4.1 Description

This work shall consist of the furnishing and placing of courses of approvedgraded coarse and fine aggregates in accordance with clause 4.4.2.1 andconforming to the specifications given below in an approved manner and inconformity with the lines, grades and thickness as shown on the typicalcross-sections or as established by the Engineer.

4.4.2 Materials

Improved rock sub-base shall be non plastic crushed rock materials freefrom dirt, organic matter, clay, shale, cemented particles and otherextraneous or deleterious matter and shall be of such a quality that will bindreadily to form a firm stable mass with a sound, smooth, well knit uppersurface free from loose materials.

At least 80 percent by weight of the materials shall have at least onefractured face materials will be accepted based on the sampling stock piles.However, acceptance of the materials does not constitute acceptance of thecourse in place.

The materials shall be laid in layers of the types and depths specified inTable 4.1 and shall be spread, rolled and compacted in such a manner that

the sizes of materials remain distinct. The surface of the Type I or II layer asappropriate shall be blinded with Type III materials to refusal and the wholere-rolled. The whole mass shall not be less than the specified thickness andthe finished surface shall be shaped and compacted to the required levelsand tolerances. Each layer shall be inspected for approval beforecommencing the next layer.

Table 4.1 - Improved Rock Sub-base layer details

Layer Type and Thickness

Bottom Top

Completed thickness ofimproved rock subbase(mm)

Type I Type II Type III

300 180 100 Nominal to complete layer200 180 - Nominal to complete layer

Where instructed by the Engineer a geo-textile membrane shall be provided,either below or above the rock layer or the whole rock layer shall be wrappedon the top and bottom by the geo-textile membrane. Depending on therequirements of the site the engineer will issue the instructions or it will beindicated on the drawing. A protection layer of Type III materials to a nominalthickness of 50mm shall be placed on top and/ or below the geo-textile

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membrane prior to placing subsequent layers. Geo-textile fabric shall meetthe requirements as described hereunder:

Grading

Gradation of the three types of layer shall be as shown in Table 4.2.Samples for checking compliance with grading requirements of Type I and IImaterials shall be taken at the Engineers instruction from completed layerafter spreading and before compaction.

Type III material may be naturally occurring in sands and gravels excludingdune sand.

Table 4.2 - Gradation of Improved Rock Sub-base

Type I (% Passing)AASHTO SIEVE

(mm) 300mm 200mm

Type II

(% Passing)Type III

(% Passing)

6" 100 100 - -

4" 25- 70 60-90 100 -

2.5" 5- 20 25- 50 25-60 -

1.5" - - 0 - 15 -

1" 0-1 0 10- 25 - -

3/4" - - 0 - 5 -

3/8" - 0 - 5 - 100

3/16" - - - 85 - 100

No.4 - - - -

No.8 - - - 60-8 0

No.40 - - 30 -5 0

No. 100 - - 8 -20

No.200 - - 0-10

Physical Requirements

Improved Rock Sub-base material shall comply with the following physicalrequirements:

Loss of Sodium Sulphate Soundness) Type I & II 20% Max.(AASHTO T104), (5 Cycles) Type III 15% Max.

Loss of magnesium Sulphate(AASHTO T104), (5 Cycles) 25% Max

Thin and elongated pieces by weight 5% Max.(Thickness less than 1/5 of length)

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Friable Particles 0.25% Max.

Dry Density of Particles 250 gm/cc Min.

Soluble Salts (Type III Material) 5% Max.

Plasticity Index (Type III Material) 6% Max.

In the case where qeotextile membrane is provided beneath the improvedrock sub-base layer, a geotextile protection layer to a nominal thickness of50mm and conforming with the requirements of Type III material shall beplaced on top of the geotextile membrane prior to placing rock sub-base toprevent the geotextile membrane from being damaged by the sub-baselayer. Geotextile shall meet the requirements of section 4.5.

4.4.3 Construction Requirements

The material shall be laid in two (2) layers of the compacted depths as givenin Table 4.1 or in one layer up to 200mm thick. The material shall be spread /laid even in such a way that there be no voids and no large lumps of materialare concentrated in small areas but shall be distributed in well packed roundwith the finer material and rolled / compacted in such manner that the sizesof material remain distinct.

The whole mass shall be to specified thickness and the finished surface shallbe shaped compacted to the required levels and tolerances, blinded withspecified blinding material and re-rolled to form a hard smooth and regularsurface.

The improved Rock Subbase shall be compacted by means of approvedcompaction equipment progressing gradually from the outside towards the

centre with each succeeding pass uniformly overlapping the previous pass.Rolling shall continue until the entire thickness of each layer is thoroughlyand uniformly compacted to the Contract requirements. The surface of thetop layer shall be finished with sufficient balding and rolling or similar in amanner approved by the Engineer to ensure a smooth surface free from rutsand ridges and having a cross section conforming to the requirements of theContract. The whole shall be carefully blinded to refusal with blindingmaterial and the surface re-rolled to be hard, smooth, free from lean patchesand be suitable for the operation of paving plant for the overlying layer. If thesurface of the rock Subbase becomes loose and dusty following compactionthen the surface layer shall be watered and compacted.

Compaction trials shall be carried out as specified in the Specification for

Aggregate Road base using the materials and equipment proposed for theWorks.

Sampling and testing shall be carried out by excavation at not less than onepit per kilometer of each carriageway to check the compaction andpenetration of the fines (blinding material). After approval the pits shall berefilled and compacted by the Contractor at his own cost and to the approvalof the Engineer.

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The compacted thickness shall be such that the finished level does not varyby more than 20mm from the required elevation. The variation between twopoints on testing with a 3m straightedge shall not exceed 20mm.

No further construction shall be laid on the Improved Rock Subbase until thelater has been approved.

4.4.4 STABILISING CRUSHED MATERIAL

4.4.4.1 In the event the foundation on which the embankment or the subgradematerials will be laid is saturated by water and unstable, the Engineer maydecide to lay crushed granular material to stabilise the foundation. Stabilisingcrushed material shall not be laid directly on ground soil but it shall always belaid on geotextile fabric covering the area to be stabilised as shown on thedrawings or directed by the Engineer.

4.4.4.2 Such stabilising crushed material when tested in accordance with BS1377:P2 Cl:9.3, 1990 in accordance with Clause 1/12.8 shall have thefollowing gradation:-

ASTM SIEVE % PASSING2" 1001" 80 - 1001/2" 60 - 85No.4 40 - 70No.10 20 - 50No.20 5 - 25No.40 0 - 10No.80 0 - 2

4.4.4.3 The stabilising crushed material shall have the following characteristics:-

Los Angeles Abrasion - Not more than 30% loss(ASTM C-131 or(ASTM C-535)

BulkSpecific Gravity - Not less than 2.65(ASTM C-127 and C-128)

Absorbtion - Not more than 2.0%(ASTM C-127 and C-128)

4.4.4.4 The stabilising crushed material will be laid in layers of 15 cm andcompacted until the foundation is fully stabilised such that the total thickness

of the stabilising layer shall not be less than 30 cm. Only after inspection andapproval by the Engineer the Contractor may be allowed to continue theconstruction of the embankment with other layers of embankment materialand/or subgrade material. The Engineer may decide, after having taken thelevels of the existing water table in the area, and keeping in considerationthe finished road levels, to excavate portions of the foundation saturated bywater, disposing of the excavated material, and replacing it with stabilisingcrushed material.

4.4.4.5 Before starting any stabilising of the foundation the Engineer will instruct the

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Contractor specifying the areas to be stabilised and the final levels to bereached with the stabilising crushed material.

4.5 GEOTEXTILE FABRIC

4.5.1 Description

The Contractor shall furnish and install geotextile fabric at locations and to the

lines and grades shown on the Drawings or as directed by the Engineer.

Geotextile fabric shall be supplied, tested or suitably certified, and placed on the

prepared roadway subgrade and at other locations prepared for its use to restrain

soil movement, to provide for drainage, and/or to prevent soil erosion.

4.5.2 Material.

Geotextile fabric shall be supplied, tested or suitably certified, and placed on

the prepared base at the locations shown on the drawings or as directed by theEngineer.

The geotextile fabric shall be a non-woven type produced from long chain

polymeric filaments or yarns such as polypropylene, polyethylene, polyester,

polyamide, or polyvinyl-chloride and formed into a stable network such that the

filaments or yarns retain their relative position to each other when subjected to the

proposed use within the limits of the physical characteristics required and

specified herein. In addition, the fabric shall be inert to commonly

encountered chemicals and shall conform to the requirements of AASHTO

Designation: M288, Standard Specifications for Geotextiles used for

Subsurface Drainage Purposes, except as amended and supplemented herein.

The physical characteristics of the geotextile fabric shall comply with the

requirements of Table 4.3 when subjected to the tests indicated therein. Prior to

shipping of any geotextile fabric to the Site, the Contractor shall provide the

Engineer with certification by the manufacturer of the date and location of its

manufacture, and a statement that the material has been manufactured and

tested and found to comply with the requirements of these specifications. A

copy of such certification, a listing of test results obtained, and date of such

testings shall be physically attached to each roll by the manufacturer prior to

shipment. In addition each roll of fabric shall show the date that it has been

supplied from the manufacturer's plant. At the discretion of the Engineer,

random samples of fabric from any or all rolls of fabric delivered to the job site

shall be tested prior to use. Such samples of material shall be tested at a

laboratory approved by the Engineer for the purpose of verifying the certification

provided. Any sample of material that fails to pass the specified requirements or

material that does not fully comply with these specifications shall subject the

entire roll of fabric to rejection by the Engineer, and such rolls of fabric shall be

removed from the job site within three (3) calendar days after the date of such

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notification by the Engineer. To insure proper control of fabric delivered to the

job site, each roll shall be marked and identified by date of delivery and an alpha-

numeric designation approved by the Engineer.

The fabric shall be supplied in rolls wound on a suitable disposable paper

tube or other non-abrading resilient tube that has an outside diameter of not

less than 10 cm. The width of fabric supplied on each roll shall be such as to

minimize the development of longitudinal and transverse overlaps. Where

longitudinal overlaps are required the width of fabric used shall be not less

than 4.5 m. A narrower width may be used if the number of longitudinal

overlaps is the same as would be developed using the minimum fabric width of

4.5 m. Where transverse overlaps are required, the minimum length of fabric on

a roll shall be 90m. Shorter lengths of fabric may be employed provided that the

number of overlaps resulting there from is the same as that developed using the

specified 90m minimum length rolls.

Table 4.3 - Physical

Requirements

Test Minimum Physical Characteristicsof Fabrics

Description Method ApplicableUnits

ProtectedType 1

UnprotectedType 2

Fabric Weight ASTM D19IO GM/m2

100 135

Tensile Strength ASTMD1682 N 560 900

Elongation ASTM D 1682 % 20 20

PunctureStrength

ASTMD751 N 200 600

Mullen BurstStrength

ASTM D3786 kPa 860 2,200

Tear Strength ASTM Dl 117 N 80 225

Permeability AASHTO M288* cm/sec 0.01 (Note 1) 0.01 (Note 1)

E.O.S CW-022 15-77 U.S. STD (Note 2) (Note 2)

Sieve

StrengthRetention

ASTM D 1682 N 560 900

After AATCC-

30-74

Flow Rate AASHTO M288 l/s/m2

25 25

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Appendix

Note 1: Permeability shall not be less than 10 times the permeability of thesoil being drained where the fabric is used to permit drainage of water from the

soil. A constant head (10 cm) permeability test may be utilized when approved by

the Engineer.

Note 2: The E.O.S. value shall be based upon retention of 95% of the size of

beads used in the test. For soil having less than 50% of its sand fraction

(minus No. 4 sieve) passing a No. 200 sieve, the fabric shall have a maximum

E.O.S. of No. 70. Where soil has more than 50% of its sand fraction passing

a No. 200 sieve, the fabric shall have a maximum E.O.S. of 100.

4.6 POLYETHYLENE SHEETS

Where described in the Contact or directed by the Engineer, a protective

membrane to asphalt pavements shall be alkathene grade min 1500 or

similar approved and shall comply with the following requirements: -

a) Tensile Strength - 16.7 MN/Sq.m

b) Strain at break - 800%

c) Tear Strength - 125gm/0.001 inch

d) Bursting Strength - 0.7 MN/Sq.m

e) Impact Strength - 800gm

The protective membrane layer shall be laid over the ground at a minimum

depth of 150 mm below finished subgrade level with a minimum overlap at

joints of 300 mm. It shall be retained in a manner approved by the Engineer

until covered by suitable material.

Before laying the membrane all necessary measures shall be taken to

ensure all the voids in the ground are filled, the surface of the area is graded

to a smooth profile and cleared of all debris and material liable to penetrate

or damage the membrane. Any damage to the membrane shall be rectified

by overlaying a new layer of protective membrane with a minimum overlap of

600mm beyond the damaged area.

The overlaying subgrade material shall be free of large or sharp stones orother injurious materials and shall be of size not greater than 25mmdiameter. It shall be deposited by end tipping and spread evenly over themembrane by tracked plant approved by the Engineer. The tracked plantshall not run on the surface of the membrane. Compaction of the subgradeand formation shall be undertaken in accordance with the requirements ofSection 3 unless otherwise directed by the Engineer.

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A test area of not less than 300 square metres will be carried out prior toapproval being given by the Engineer. Should approval not be given by theEngineer the test will be repeated until such time as the Engineer is satisfiedwith the Contractor's method of working.

At overlaps of the polythene membrane, the splice shall be effected by

means of an approved adhesive tape of adequate width.

4.7 AGGREGATE ROAD BASE

4.7.1 Description

This work shall consist of furnishing and placing one or more courses of

aggregate including binder soil if required, on a prepared subgrade or sub-

base in accordance with the Specifications, in conformity with the lines,

grades, thickness and typical cross-sections shown on the drawings or

established by the Engineer.

4.7.2 Material

4.7.2.1 Material used for aggregate road base shall be free from dirt, shale, gypsumor other deleterious matter and shall be of such quality that it will bind readily

to form a stable aggregate road base. If more than one source is used thecontractor shall provide a method statement to the Engineer indicating the

method of mixing, stockpiling and delivery of the mixed material to roadbed.Each time the stockpile is made, the Engineer shall take samples to check

binding quality, homogeneity of the mix as well as grading, MDD, CBR and

SE. Mixing of the dune sand shall not be permitted to improve the SE. Use ofsalty water for mixing in sub-base/aggregate road base underlying

bituminous mixes shall not be permitted. The contractor shall carry out a site

trial of at least 30 m outside the permanent work to check and confirm thebinding quality and homogeneity of the mixed material and also to establish

the compacting effort required to achieve the required degree of compaction.The tests shall be carried out on each source of materials and shall confirm

to the requirements as stated in clause 4.7.2.2.

4.7.2.2 The following tests shall be carried out on each source of material and shall

comply with the requirement stated against each test:-

Liquid Limit (AASHTO T89)

25% max

Plasticity Index (AASHTO 90) 6% max

Sand Equivalent (AASHTO T176) 40% min

Loss by Abrasion (AASHTO T96) 35% max

Flakiness Index (85812 Part 105.1) (Coarse Aggregate) 35% max

Elongation Index (85812 Part 105.2) (Coarse Aggregate) 35% max.

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Soundness (ASTM C88) (Magnesium Sulphate) (5 Cycles) 12% max.

Organic Impurities (BS 1377 Part 3 Method 3) 0.15%

max.

Acid Soluble Chlorides (BS 812 Part 117) 1% max

(Combined Aggregate)

Dry Density (AASHTO T180 Method C

(with correction for oversized material) 2.0% gr/ccmin.

CBR on Remolded Samples after 4 days soaking at 98% of 80% minimumMDD (ASTM D1883)

4.7.2.3 The gradation limits when tested in accordance with BS 812 Part 103 Clause

7.3 shall be as follows:

SIEVE SIZE (BS) PERCENT PASSING

50mm 100

37.5mm 70-100

28mm 55-85

20mm 50-80

100mm 40-70

5mm 30-60

2.36mm 20-50

0.425mm 10-30

0.075mm 5-15

4.7.2.4 Aggregate road base shall consist of uniform mixtures of gravel and/or

crushed gravel with sand, silt and clay, conforming to the specified gradationlimits.

4.7.3 Spreading / Laying

4.7.3.1 Aggregate road base shall only be machine laid with approved paver and laid

on subgrade or subbase, which has been approved by the Engineer.

Aggregate road base, which has been placed on a subgrade or subbase notapproved by the Engineer, shall be removed at the Contractor's expense.

4.7.3.2 Aggregate road base shall be laid on the approved subgrade in layers not

exceeding fifteen (15) centimeters in compacted depth.

4.7.3.3 The material shall be handled in a manner, which avoids segregation.

Segregated materials shall be remixed until uniform. Suitable precautionsshall be taken to prevent rutting of the subgrade or sub-base during the

laying of aggregate road base materials. No hauling or placement of material

will be permitted when, in the judgment of the Engineer, the weather or roadconditions are such that the hauling operations will cause cutting or putting of

the subgrade or cause contamination of aggregate road base material.

4.7.4 Compaction

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4.7.4.1 The moisture content of the aggregate road base material shall be adjustedprior to compaction, by watering with approved sprinkler trucks or by dryingout as directed by the Engineer, to that required to obtain the specifieddensity for aggregate road base. Aggregate road base shall be compacted toninety eight (98) percent of the maximum dry density determined accordingto AASHTO T- 180 Method C with correction for oversized material.

Variation of moisture content shall be between +2% of the OMC. The fielddensity and actual moisture content shall be determined according toAASHTO T 191-86.

4.7.4.2 The aggregate road base shall be compacted by means of approvedcompaction equipment progressing gradually from the outside of the roadtowards the centre with each succeeding pass uniformly overlapping theprevious pass. Rolling shall continue until the entire thickness of each layeris thoroughly and uniformly compacted to the specified density. Rolling shallbe accompanied by sufficient blading in a manner approved by the Engineer,to ensure a smooth surface free from ruts ridges and having the propersection and crown.

4.7.4.3 The surface of the course shall, on completion of compaction, be wellclosed, free from movement under the compaction plant and free fromridges, cracks, or loose material.

4.7.4.4 Any areas inaccessible to normal compaction equipment shall be compactedby means of mechanical tampers until satisfactory compaction is obtained.

4.7.4.5 The Contractor shall program his operations to avoid the drying out of thesubbase during construction. If any layer of aggregate road base material orpart thereof, is permitted to dry out after compaction or does not conform tothe required density or finish, the contractor shall, at his own expense,rework, water and recompact the material, as directed by the Engineer, to

the density specified, before the next layer of aggregate road base orsubsequent pavement layers is placed.

4.7.5 Compaction trials

4.7.5.1 If directed by the Engineer, prior to the commencement of the aggregateroad base operations, the Contractor shall construct trial lengths not less

than 100 metres. The materials used in the trials shall be those approved for

use as aggregate road base, and the equipment used shall be that accordingto the contractor's approved detailed program of work.

4.7.5.2 Trial lengths may not form part of the permanent works but may be permitted

in the construction of temporary detours of sufficient length.

4.7.5.3 The object of these trials is to determine the adequacy of the Contractor's

equipment, the loose depth measurements necessary to result in thespecified compact layers depths, the field moisture content, and the

relationship between the number of compaction passes and the resultingdensity of the material.

4.7.5.4 The Contractor may proceed with the aggregate road base work, only afterthe methods and procedures, established in the compaction trials have been

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approved by the Engineer.

4.7.6 Finishing

4.7.6.1 Immediately prior to the placing of the first layer of the next pavement courseonto the aggregate road base the final layer of aggregate road bases shall

be at the specified density and to the required grade and section. In order tomaintain these requirements while placing the next course it may benecessary to water and reshape the surface of the aggregate road base.This work shall be at the contractor's expense.

4.7.6.2 The surface of the finished aggregate road base will be tested with a three(3) metre straightedge by the Engineer at selected locations. The variationsof the surface from the testing edge of the straightedge between any two (2)Contacts with the surface shall at no point exceed nine (9) millimeters whenplaced on or parallel to the centerline or nine (9) millimeters when placedperpendicular to the centerline of the roadway. The aggregate cross-sectionas shown on the drawings shall not vary by more than nine (9) millimetersfrom the required elevation. All humps and depressions and thickness

deficiencies exceeding the specified tolerance shall be corrected by removingthe defective work or by adding new material as directed by the Engineer.

4.7.7 Minimum Test Requirement

4.7.7.1 One sample every l,000 Cu.m shall be tested for grading, plasticity Index,Sand Equivalent, Maximum Dry Density, C.B.R and loss by abrasion. One in

situ Density test shall be made every 300Sq.m of aggregate road base laid.

4.8 Wet Mix Macadam Road Base

4.8.1 Description

This work shall consist of furnishing and placing one or more courses of high

quality crushed aggregate, bound by means of carefully controlled moisture

content, on the approved subgrade or sub-base in conformity to the line,

level and thickness shown on the drawings or as directed by the Engineer.

4.8.2 Material

4.8.3 The coarse aggregate shall consist of crushed rock (each particle shall have

a minimum of one crushed face) and the fine aggregate also shall be

crushed rock. The aggregate shall conform to the following gradation.

BS SIEVESIZE

PERCENTPASSING

50 mm 100

37.5 mm 95-100

20 mm 60-80

10 mm 40-60

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5 mm 25-40

2.36 mm 15-30

0.6 mm 8-22

0.075 mm 2-8

The particle size shall be determined in accordance with the requirements ofBS 1377 Part 2 (Method 9.2 and 9.3).

The gradation shall be adjusted as required or as directed by the Engineer

within the above limits to ensure the mix has adequate binding properties.

Wet-mix road-base material shall have physical properties, which do not

exceed the following values:

Liquid Limit (AASHTO T 89) 25%

Linear Shrinkage (BS 1377 Part 2 Method 6.5) 3%

Plasticity Index (AASHTO T90) 6%

Aggregate Crushing Value (BS 812 Part 110) 25%

Water Absorption (ASTM C 128/C127) 2%

Flakiness Index (BS 812 Part 105.1)30%

Elongation Index (BS 812 Part 105.2) 30%

Los Angeles Abrasion Loss (AASHTO T 96) 30%

(*) Soundness Loss (ASTM C 88) (5 cycles) (Magnesium) 12%Organic Impurities (BS 1377 Part 3 Method 3) 0.1%

Chloride Content (Acid Soluble) BS 12 Part 117 1% max

Sulphate Content (Acid Soluble) BS 12 Part 118 0.5% max

Sand equivalent (AASHTO T 176) 45%

(*) Soundness requirements shall apply to both course and fine aggregates.

The moisture content of the wet-mix macadam at the time of laying shall be

the optimum + 1%. Water required to achieve this moisture content shall be

added at the mixing plant only.

The mix shall be produced from mechanical mixing plant.

4.8.3.1 Transport and Spreading

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Transport vehicles carrying the plant mixed material shall have a capacitysuited to the output of the mixing plant and the site conditions and becapable of discharging cleanly. Material when mixed shall be removed atonce from the mixer and transported directly to the point where it is to be laidand protected from the weather both during transit from the mixer to thelaying site and whilst awaiting tipping. No. water shall be added on site.

The material shall be placed and spread evenly. The material shall be spreadusing a paving machine or spreader box operated with a mechanism whilelevels of the material at an even depth and without delay. Except whereotherwise specified, the material shall be laid and compacted in layers ofmaximum thickness of 150mm.

4.8.3.2 Compaction Trials

If directed by the Engineer, prior to the commencement of the Wet -mix

Macadam Road base operations, the contractor shall construct trial lengths

not less than 100 metres. The materials used in the trials shall be those

approved for use as Wet mix Macadam Road base and the equipment used

shall be that according to the Contractor's method statement.

Trial lengths may not form part of the permanent works but may be permitted

in the construction of temporary detours of sufficient length.

The objective of these trials is to determine the adequacy of the contractor's

equipment, the loose depth measurements necessary to result in the

specified compacted layer depths, the field moisture content, and the

relationship between the number of compaction passes and the resulting

density of the material.

The contractor may proceed with the Wet-mix Macadam Rod base work only

after the methods and procedures established in the compaction trials havebeen approved by the Engineer.

4.8.3.3 Compaction

The Material shall be compacted to a field density equal to or greater than

98% of the maximum dry density value obtained when tested in accordance

with (AASHTO T-180) method C with correction for oversized material andshall have a minimum CBR of 80% at 98% compaction after 96 hours

soaking (Test 16, BS 1377). Field Density tests shall be carried out inaccordance with Clause 4.4.2.7.

Compaction shall be completed as soon as possible after the material has

been spread.

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Special care shall be taken to obtain full compaction in the vicinity of bothlongitudinal and transverse joints.

The surface of any layer of material shall on completion of compaction be

well closed, free from movement under compaction plant and free fromcompaction planes, ridges, cracks or loose material. All loose, segregated or

otherwise defective areas shall be made good to the full thickness of layerand re-compacted.

Where directed by the Engineer a sieve analysis shall be carried out on the

material recovered from 5 consecutive field density tests. Where this sieve

analysis shows oversize material content of 10% or greater the area ofconstruction will be removed and the source of the material rejected until

further tests are carried out to ensure compliance with the specificationrequirements. Where considered necessary other areas of work which were

carried on using material from the same source shall be tested in a similarmanner.

4.8.3.4 Finishing

Immediately prior to the placing of the first layer of the next pavement course

on to the Wet-mix Macadam Road base the final layer of Wet-mix Macadam

Road base shall be at the specified density and to the required grade and

section. In order to maintain these requirements while placing the next

course it may be necessary to water and reshape the surface of the Wet-mix

Macadam Road base. This work shall be at the contractor's expense.

The surface of the finished Wet -mix Macadam Road base will be tested with

a three (3) metre straight edge by the Engineer at selected locations. The

variations of the surface from the testing edge between any two (2) contacts

with the surface shall at no point exceed ten (10) millimeters when placed onor parallel to the centerline, or ten (10) millimeters when placed perpendicular

to the centerline of the roadway. The Wet-mix Macadam Road base shall be

compacted to the thickness and cross sections as shown on the drawings

and shall be compacted to the thickness and cross sections as shown on the

drawings and shall not vary by more than ten (10) millimeters from the

required elevation. All humps and depressions and thickness deficiencies

exceeding the specified tolerance shall be corrected by removing the

defective work or by adding new material as directed by the Engineer.

Before placing the next construction layer or applying prime coat, the wet-mixroad base shall be mechanically swept then cleaned with compressed air to

remove loose material. As soon as possible after cleaning of the surface the

wet-mix road base shall be sealed by the application of a prime coat as

specified. Should the surface of the material be allowed to dry out before the

seal is applied, it shall be lightly watered and re-compacted immediately prior

to spraying with prime-coat.

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In the event of a section of Wet-mix Road base failing to comply, either by

level or degree of compaction, and where the full depth of the layer has been

allowed to dry out, it shall be removed and replaced at the contractor's

expense, with fresh material. Watering and re-mixing in place will not be

permitted.

4.8.3.5 Minimum Test Requirements

One sample every l, 000 Cu.m shall be tested for Grading, Plasticity Index,

Sand Equivalent Value, Maximum Dry Density, C.B.R and loss by Abrasion.

For compaction and moisture content; one test per 250 sq.m of each layer of

carriageway and one test per 100 linear metre of shoulder.

Special care shall be taken to obtain full compaction in the vicinity of both

longitudinal and transverse joints.

4.9 BITUMINOUS PAVING COURSES

4.9.1 Description

This work shall consist of the construction of the following hot-mix bituminous

courses which shall be either Asphaltic Concrete or Dense Bitumen Macadam

as shown on the drawings.

Bituminous Base Course.

Bituminous Binder Course

Bituminous Wearing Course

Bituminous paving courses shall consist of coarse aggregates, fine

aggregates, filler material, and bitumen binder. Mixture of two different types of

rocks e.g. igneous and sedimentary having different specific gravities in a

single fraction shall not be permitted.

4.9.2 Coarse Aggregates

4.9.2.1 Coarse aggregates, which is the material retained on a 4.75mm sieve, shall

consist of crushed rock or crushed gravel. It shall be clean, hard, tough,

durable and sound, and shall be of uniform quality and free from decomposed

stone, shale, clay, lumps and other deleterious substances. Organic matter

shall not exceed0.05% (BS 1377 Test 3 Method 3) mixing of two different

types of rocks e.g. igneous and sedimentary having different specific gravities

in a single proctor shall not be permitted.

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4.9.2.2 Crushed gravel for use as coarse aggregate shall consist of the product

obtained by crushing material that has first been screened in such a manner

4.9.2.3 that not less than ninety (90) percent of the material to be crushed is retained

on an AASHTO 3/8 inch sieve.

4.9.2.4 The coarse aggregate shall have an affinity for bitumen such that when coated

with bitumen it shall pass a stripping test prepared in accordance with

AASHTO T-182.

Each particle will have a minimum of one crushed face. In addition each

stockpile aggregate shall have all faces crushed as indicated below: -

11/2" - 40% Min.

1" - 50% Min.

3/4" - 55% Min.

3/8" - 65% Min.

Water absorption of the coarse aggregate as determined by BS 812 shall not

exceed 2% by weight.

4.9.2.5 Coarse aggregate shall have properties, which comply with the following

values:

Los Angeles Abrasion Loss (AASHTO T96)

Base Course and Binder Course 30% max

Wearing Course 25% max;

Aggregate Crushing Valve (BS 812 part 110)

Base Course and Binder Course 25%max

Wearing Course 20% max

Soundness Loss (ASTM C88) (5 cycles)

Magnesium Sulphate 10% max

Flakiness Index (BS 812 part 105.1)


Wearing course 25% max

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Elongation Index (BS 812 part 105.2)


Wearing course 25% max

4.10 FINE AGGREGATE

4.10.1 Fine Aggregate shall consist of the material passing a 4.75mm sieve.

4.10.2 Fine aggregate including filler shall be obtained from 100% crushed gravel orcrushed rock pre-screened to exclude natural uncrushed fine material orweathered unsound fines. The use of dune sand shall not be permitted.

4.10.3 Fine aggregates shall have properties, which comply with the followingvalues:

Soundness Loss (ASTM C88) (5 cycles)

Magnesium Sulphate 10 % max

Plasticity Index (AASHTO T 90) Non Plastic

Acid Soluble Chlorides

(BS 812 Part 117) 0.1% max

Acid Soluble Sulphate 0.5% max

Water Absorption (BS 812) 2% max.

4.11 MINERAL FILLER

4.11.1 When the combined grading of the coarse and fine aggregates is deficient inmaterial passing the AASHTO No. 200 sieve, mineral filler shall be added as

approved by the Engineer at the Contractor's expense.

4.11.2 Mineral filler shall consist of finely ground particles of limestone or cement in

accordance with AASHTO M 17. It shall be thoroughly dry and free from

organic substances and clay and meet the following grading requirements:

MINERAL FILLER

BS SIEVEASTM

SIEVE SIZEPRECENTAGE BYMASS PASSING

600 micron No. 30 100

300 Micron No. 50 95-100

150 Micron No. 100 90-100

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70 Micron No. 200 70-100

4.12 COMBINED AGGREGATE

4.12.1 The combined mineral aggregate shall meet the following physicalrequirements:

Sand Equivalent (AASHTO T 176)Determined after all processing

Except for addition of asphalt binder 65% Minimum

Plasticity Index (AASHTO T 90) Non Plastic

4.12.2 When tested according to AASHTO T 11 and AASHTO T 27, the combined

mineral aggregate shall conform to Table 4.4 for Asphaltic Concrete.

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TABLE 4.4 AGGRERATE GRADING FOR ASPHALTIC CONCRETE

SIEVE SIZE (SQUARE OPENINGS) PERCENT PASSING (BY WEIGHT)

Base Binder Wearing

ASTM Course Course Course37.5mm 100 _ _

25mm 80-100 100 100

19mm 62-92 80-100 86-100

12.5mm - 63-85 69-87

9.5mm45-75 57-77 58-78

4.75mm 30-55 40-60 40-60

2.36mm 20-40 25-45 25-45

0.85mm 15-30 15-30 15-30

0.425mm 10-22 10-22 10-22

0.18mm 6-15 6-15 6-15

0.075mm 2-8 2-8 2-8

4.12.2.1 The coarse aggregate shall show no detrimental amount of stripping when

tested in accordance with AASHTO T 182. The minimum value of non strippedarea shall be 95%. If stripping occurs, the aggregate shall be rejected and anapproved method of treatment specified to change the material from ahydrophilic to a hydrophobic state as directed by the Engineer, or an approvedadditive shall be used with the bituminous binder

4.12.2.2 When necessary to improve the coating of aggregate by bitumen, additives ofapproved type will be added to the bituminous material in such percentage asrequired to obtain satisfactory results in the affinity, with bitumen testperformed in accordance with ASTM D 1664. The approved additive will beused in accordance with Technical Specifications issued by the manufacturerand approved by the Engineer after appropriate testing,

4.12.2.3 No extra payment will be made for required anti stripping additives.

4.13 BITUMEN BINDER

4.13.1 Bitumen Binder for the Bituminous paving Courses shall be Bitumen Binder

penetration grade 60-70 unless otherwise specified as 40-50. Generally,

penetration grade 40-50 will be used for Type "H" mixes.

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TABLE 4.6 - BITUMEN CONTENT FOR ASPHALTIC CONCRETE

PAVEMENT

COURSE

BITUMEN PERCENTAGE BY WEIGHT OF MIX

INCLUSIVE OF TOLERANCES

Base 3.2 to 4.4

Binder 3.4 to 4.4

Wearing 3.4 to 4.4

4.13.7 Each consignment of bituminous material delivered to asphalt plant site shallbe accompanied by a delivery note and test certificates indicating name of therefinery, country of origin and results in support of the material's compliancewith the specification. Samples for compliance test shall be taken by the

Engineer as and when deemed necessary.

4.14 JOB MIX

4.14.1 The mix approved for use in the works shall be designed by Marshall method

as per MS-2 and field trials with the following recommendations taken into

account.

a) For base course the aggregates for Marshall specimen shall be

modified by substituting all aggregate size over 25 mm with an equal

weight of aggregate sizes in the next lower grading size.

b) The combined aggregate gradation should be adjusted within the

allowable limits to achieve maximum stability whilst not going below the

minimum requirement for void content.

c) The minimum bitumen binder content according to the results of the

Marshall Method of Mix Design as recommended by MS-2 should be

used provided that it will still satisfy the durability, the stability and the

void content requirements.

d) Prior to final approval, the proposed job mix, but with a bituminous

content at the upper percentage limits shall be compacted to refusal,

(400, 500 and 600 blows) and the resulting voids in the mix shall not be

less than 2% for asphaltic concrete.

e) The final job mix must display the marshal characteristics specified in

Table 4.8 for Asphaltic Concrete.

f) Height of the Marshall specimens outside the limit specified in AASHTO

T-245 shall be discarded but a minimum of 3 specimens shall be

averaged.

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4.14.2 The mix formula must take into consideration the absorption of bitumen in to

the aggregates. Thus, for calculations for air voids in the mix (VIM) the

maximum theoretical specific gravity as prescribed by ASTM D 2041 (Rice

Method) shall be used. For calculation of voids in the mineral aggregate (VMA)

the equations as mentioned in Asphalt Institute Manual MS-2 shall be used.

VFB shall be calculated using the following equation:-

VFB = {VMA VIM} X 100VMA

4.14.3 The Contractor shall be responsible for the design and performance of all

bituminous mixes. The Contractor shall submit, for the Engineer's approval, a

proposed "Laboratory Design Mixture" together with all applicable design data

atleast 30 days prior to commencement of the relevant asphalt works. The

Engineer will take samples of materials proposed for use in the mix in order to

check their quality and to cross check the proposed mix design for which the

Contractor shall repeat the laboratory design exercise in the site laboratory

under the supervision of Engineer to confirm the Marshall properties submittedby the Contractor.

After receiving the approval of aggregate and bitumen from the Engineer, theContractor shall make a written request for the approval of the job mix formulaprepared by the Contractor under the supervision of the Engineer in thelaboratory.

The approved Laboratory Design Mixture shall be used for agreeing theapproved Job Standard Mixture.

4.14.4 The laboratory job mix formula shall fix a single definite percentage of

aggregate

passing each required sieve size, a single definite percentage of bitumenbinder to be added to the aggregate, a single definite temperature at which the

mix is to be emptied from the mixer, and a single definite temperature at which

the mix is to be delivered to the works site.

4.14.5 The laboratory job mix formula shall be used for the basis of approval of the

Job standard mixture.

4.14.6 Trial areas having lengths of at least 100m and to the specified layer thickness

shall be laid outside the area of the permanent work by the Contractor. At least

two samples of non compacted material from the trial area shall be taken in

accordance with AASHTO T 168, and shall be analyzed in the presence of the

Engineer to determine the aggregate grading, binder content, stability, flow,Marshall density and voids. The results shall be submitted to the Engineer and

shall be approved by him before further mixing or laying is carried out.

4.14.7 Trial areas may from part of a temporary traffic detour subject to the approval

of the Engineer. The compaction trials should be performed on the trial mixes.

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If the trial areas form a part of the temporary traffic detour they shall not be

paid for under the relevant bill item.

4.14.8 Should the laboratory job mix formula after passing the mixing plant and laid

and compacted with approved plant fail to produce a satisfactory trial area, the

mix proportions may be modified by agreement with the Engineer, as

necessary and within the requirements of Tables 4.7 and 4.8 as applicable to

produce a mix of satisfactory workability and acceptable surface finish. After

approval of the trial area by the Engineer this mix shall be designated the job

standard Mix and shall there after be the approved mix. A copy of the

approved job Standard Mixture signed by the Contractor and Consultant have

to be submitted to the road section, Al Ain Municipality.

4.14.9 All mixes produced shall conform to the job Standard Mix approved by the

Engineer, within the ranges of tolerance specified in Table 4.7, (within) the

limits of Tables 4.4, 4.6 and 4.8 for asphaltic concrete. Each day the Engineer

shall take as many samples of the materials and mix as he considers

necessary and minimum of one sample for every 200 tons laid or part thereof

for checking their required characteristics. When unsatisfactory results or

changed conditions make it necessary, the Engineer shall instruct the

Contractor to establish a new job standard.

4.14.10 Should a change in a material be encountered or should a change in a source

of material be made a new job-Standard Mix shall be submitted by the

Contractor and approved by the Engineer before the mix containing the new

material is delivered. Job materials will be rejected if they are found not to

have the characteristics required by the approved job Standard Mix.

TABLE 4.7 - JOB MIX TOLERANCE

TABLE 4.8 - PROPERTIES OF MIX FOR ASPHALTIC CONCRETE

Aggregate retained on 4.75mm sieve or large 5%

Aggregate passing 4.75mm sieve and retained on0.85mm sieve

4%

Aggregate passing 0.85mm sieve and retained on0.075mm sieve

2%

Aggregate passing 0.075mm sieve 1%

Bitumen Binder 0.2%

Temperature of mixing and placing 10 C

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PROPERTIES BITUMINOUSBASECOURSE

BITUMIOUSBINDERCOURSE

BITUMINOUSWEARINGCOURSE

Number of Compactionblow at each end ofspecimen

75 75 75

Stability ( Marshall )Minimum Kg. F

1200 1400 1500

Flow (Marshal) mm 2 - 4 2 - 4 2 - 4

Stiffness minimum Kg.F/mm

500 500 550

Percent air voids (VIM) 4 - 8 4 - 8 4-8

Percent voids in

Mineral Aggregate (VMA)

1 3 1 4 15

Percent voids filledwith Bitumen (VFB)

50 -6 5 50 -7 0 50-75

Loss of Marshall stabilityby submerging specimensin water at 60deg. C fortwenty four (24) hourscompared to stabilitymeasured aftersubmersion in water at 60deg. C for thirty (30)

minutes

Max. 25% Max. 25% Max. 25%

Filler / Bitumen Ratio 0 . 6 - 1 . 5 0 . 6 - 1 . 5 0 . 6 - 1

4.14.11 Samples of the mixed materials shall be taken from the first two hundred tones

and from every two hundred tones thereafter to determine aggregate grading

and binder content. Samples of loose asphaltic concrete mix shall be taken

behind the paver before compaction and shall be obtained in accordance with,

ASTM D 979.Samples of compacted asphaltic concrete shall be obtained by

coring in accordance with Method B of AASHTO T-230.

Determination of bitumen content and extraction gradation may be performedon either loose or compacted samples in accordance with AASHTO T-164 and

AASHTO T-30 except that the mass of mineral matter in the total volume of

the extract shall be determined by using a bitumen meter or other equipment

and procedures which give equally satisfactory results. The specific gravity of

compacted asphalt course shall be measured in accordance with AASHTO T -

230. Gmm as per ASTM D2041shall be checked on daily bases and used for

calculating air voids.

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If any of these tests show results which are not in accordance with approved

job standard mix within permissible variations the material shall be rejected

and suitable adjustments shall immediately be made to ensure compliance

therewith. Samples of the mixed material shall be taken at least twice a day or

as determined by the Engineer for making Marshall specimens to determine

stability, flow and unit weight. For the taking of daily Marshall specimens themixing pug mill temperature shall be set to the mixing temperature as specified

in AASHTO T-245 and the compaction temperature of the moulds shall also

be in accordance with AASHTO T-245. Should for practical reasons the pug

mill temperature be different from that used in AASHTO T-245 then the

Engineer shall set the compaction temperatures for the moulds to so

compensate. All approved sampling and testing required under the sub-clause

of this clause shall be undertaken by the Engineer. Sampling and testing by

the Engineer in no way relives the Contractor of his responsibility for regular

quality control testing in order to ensure compliance with the Specifications.

4.14.12 The density of the compacted mixes shall be related to the daily Marshall

Density, which shall be determined by making four standard Marshallspecimens from samples of the mix taken from the mixing plant or paver. The

density of each sample shall be determined and compared with the mean

value. Any individual result which varies from the mean by more than 0.015

gm /cc shall be rejected. Marshall tests shall be repeated on a daily basis to

establish the daily Marshal Density for that particular day's production. The

daily Marshall Density shall not vary from the job mix Design Density by more

than + 0.75%. If it does, the Job Standard Density shall be applied to satisfy

the requirements of in-situ compaction.

4.14.13 The Job Standard Mixture Reference Density shall be obtained by making six

standard Marshall Specimens from samples of the approved Job Standard

Mixture determining the relative density or each and comparing them with themean values of the six. Any individual result which differs from the mean by

more than 0.015 gm/cc shall be rejected and provided not more than two

results are so rejected the mean of the remaining results shall be designated

the Job Standard Mixture Reference Density.

4.14.14 The assistance of the Engineer in the preparation of the job standard mix in no

way relieves the Contractor of the responsibility of producing a bituminous mix

meeting the requirements of the Specifications.

4.15 EQUIPMENT FOR BITUMENS PAVING OPERATIONS

The Method statement and equipment list shall be according to the type and numberoutlined in the Contractor's detailed programme of work, as approved by theEngineer.

In addition to the above requirements, trucks used for hauling bituminous mixshall have tight, clean, smooth metal beds which have been thinly coated witha minimal amount of paraffin oil, lime solution, or other approved material toprevent the mix from adhering to the beds. When required by the Engineer,

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each vehicle shall be equipped with a canvas cover or other suitable materialof such size as to protect the mix from the weather.

Rolling equipment shall be self-propelled. The wheels on the rollers shall beequipped with adjustable scrapers and the rollers shall have water tanks andsprinkling apparatus, which shall be used to keep the wheel wet and prevent

the surface material from sticking.

4.16 PREPARATION OF BITUMEN BINDER

The heating of the bitumen binder for mixing and compacting shall be in

accordance with AASHTO T-245.

4.17 PREPARATION OF MINERAL AGGREGATE FOR BITUMINOUS MIX

4.17.1 Coarse and fine aggregate shall be stored at the asphalt plant in such a

manner that the separate stockpiles will not become intermixed. The

stockpiles shall be of sufficient size to provide a minimum quantity of one week

continuous production of asphalt mix. Aggregates brought to the asphalt plant

to supplement stocks should be tested and approved prior to placing in the

existing approved stockpiles.

The cold bins shall be calibrated with the materials to be used and the settings

shall be such as to produce a combined gradation in accordance with the job

mix. The proportioning shall be such that surpluses and shortages in the hot

bins will not cause breaks in the continuous operation. All the above shall be

as approved by the Engineer.

The materials shall be thoroughly dried and heated so that their temperature

is within 8 deg. C of the temperature needed to satisfy the viscosity

requirements of the asphalt cement. The moisture content of the heated and

dried materials shall not exceed 0.5 per cent. The quantity of materials fed

through the drier shall in all cases be held to an amount, which can be

thoroughly dried and heated within the limits specified.

4.17.2 Immediately after heating, the aggregate or aggregates shall be screened into

at least five (5) sizes and conveyed in to separate bins ready for batching and

mixing with bituminous material. When the aggregates supplied are of such

size and grading that separating into five (5) bins is impractical, the number of

required separations may be reduced to four (4) or to three (3) with the

approval of the Engineer. The efficiency of the screening operations shall be

sufficient to produce, at plant operating capacity, gradations in each of the

sizes of heated and dried aggregates which are reasonably uniform and result

in the production of a mix complying with the limits specified for the aggregate

gradation.

4.18 REPARATION OF BITUMINOUS MIX

4.18.1 Dried aggregate as specified and prepared as prescribed above shall be

combined in the plant conforming to ASTM D 995 in the approved

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proportions. The bitumen binder shall be introduced into the mix in the

proportion specified by the job-mix formula.

4.18.2 The initial mixing time will be designated by the Engineer. Mixing time may be

increased by the Engineer if additional time is necessary to obtain a

homogeneous mix and satisfactory coating.

4.18.3 The batch plants timing shall begin at the start of the introduction of the

bitumen

into the pug mill.

4.18.4 The length of mixing time for continuous plants will be determined by the

following formula or other approved methods: -

Mixing time in seconds = Pug mill dead load capacity in kgPug mill output in kg / second

4.18.5 The temperature of the aggregate immediately prior to mixing shall be within +

10 deg. C of the temperature of the asphalt cement and the temperature of theaggregate and asphalt prior to mixing shall be approximately that of the

completed mix as defined in the job mix formula approved by the Engineer.

The mix temperature shall be within the limits set out in the job mix formula

when emptied from the mixer.

4.19 SURFACE PREPARATION

4.19.1 When the Bituminous mix is placed on a prepared road base and whether or

not a prime coat is designated on the Drawings, the Granular Road base shall

be even and firm and within the construction tolerances specified for the road

base to the satisfaction of the Engineer.

4.19.2 When the paving layer is constructed on an existing bituminous surface, the

surface shall be cleaned of all foreign material and broomed free of dust, In

addition any loose, broken or shattered bituminous material along the edge of

the existing surface shall be removed, and the exposed subgrade and

sufficient width of the shoulder adjacent to the edge of the existing surface to

receive the new bituminous mix shall be shaped, bladed, compacted and

broomed and primed to provide a uniform firm sub grade of the new surface

course.

4.19.3 The existing bituminous surface, base, or sub grade shall be removed if

broken, shattered, or unstable. The areas shall be excavated to a depth as

directed by the Engineer, and refilled with the bituminous mix according to thespecifications.

4.19.4 Prior to the placing of the mix, when designated on the Drawings or as directed

by the Engineer, a prime coat or tack coat shall be applied to the road base or

surface in accordance with the specification for prime coat or Tack coat.

4.20 PLACING OF THE MIX

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4.20.1 All bituminous mixes shall be introduced to the paver at a temperature not less

than 135 deg. C and not more than 163 deg. C. Mixes outside this temperature

range shall be discarded. Temperature along the edge of the longitudinal joint,

prior to rolling, shall not fall below 120 deg. C.

4.20.2 The bituminous mix shall be spread and finished to crown and grade by

automatically controlled bituminous paver. Bituminous mix may be spread and

finished by hand methods only where machine methods are impractical as

determined by the Engineer.

4.20.3 The automatically controlled paver shall lay the bituminous mix without tearing

the surface and shall strike a finish that is smooth, true to cross-section,

uniform in density and texture, free from hollows, transverse corrugations and

other irregularities.

All paving machines, prior to using on site shall be checked to ensure proper

functioning and expected surface finish. Texture of the paved asphalt behind

the paver shall be smooth, uniform close textured, free from segregation drag

or other unacceptable surface finish. Extension of the paver with extra screeds

shall be subject to extension of the auger as well as proper functioning of the

inbuilt tamping mechanism of the screeds and the paved surface being similar

to the remaining section without any sign of drag or any other surface defects.

Defective pavers shall not be used on site unless they are rectified to the

satisfaction of the Engineer.

4.20.4 The paver shall be operated at a speed which will give the best results for the

type of paver being used and which co-ordinates satisfactorily with the rate of

delivery of the mix to the paver, to provide a uniform rate of placement without

intermittent operations of the paver.

4.20.5 The mix shall be delivered to the paver in time to permit completion of

spreading, finishing and compaction of the mix during daylight hours.

4.20.6 The longitudinal joints in successive layers shall be offset not less than fifteen

(15) centimeter. The width of surface or top course placements shall conform

to trafficlane edges as shown on the Drawings.

4.20.7 The leading half of half road way paving shall not get ahead of the trailing half

of the pavement by more than one (1) average full-day of paving and, in no

case, shall the leading half be more than one half (1/2) kilometers ahead of the

trailing half without the written permission of the Engineer. If the Contractor

fails to comply with this requirement, the Engineer may suspend paving on the

leading half until such time, as the Contractor shall pave the trailing half to a

point approximately even with the leading half.

4.20.8 Unless otherwise directed by the Engineer, where successive layers are to be

placed, the surface of the existing layer shall be swept clean with a power

broom, or by other means as approved by the Engineer, and tack coat applied.

Tack coat may not be required where the delay between courses laying is less

than 48 hours and when the surface is fresh and clean and at the discretion of

the Engineers

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4.20.9 After the approval of the "job standard mixture" (JSM) the trial area as

specified in Clause 4.14.6 of the specifications shall be used to establish the

rolling/compaction method required to produce the specified relative density.

Three pairs of course shall be taken from the compacted trial area and the

mean density of each pair shall be not less than 98% of the "Job Standard

Mixture density (JSMD). If the required field density is not obtained the rolling

procedure shall be adjusted and further trial areas shall be laid and tested until

satisfactory results are obtained. These procedures shall be reported to the

Engineer and the rolling method agreed before mixing or laying of the

pavement works is commenced. Agreed procedures shall not subsequently be

varied without the Engineer's written approval.

4.21 RELIMINARY SURVEY AND REFERENCE STRING LINE

4.21.1 The contractor shall make the necessary survey required for the referencegrade. When the survey is approved by the Engineer the Contractor shall erect

and maintain an approved reference string line and operate the paver to

conform to the reference string line for the initial layer and /or any other layersas directed. Elevation control point stakes for the first layer of bituminous

paving course shall be set at a maximum spacing of twenty (20) metres. Forsubsequent layers, control points shall be set at ten (10) metres maximum

spacing. The contractor shall furnish and maintain an approved mobile string

line for all layers not laid with the erected string line. The string line shall be

erected parallel to the reference grade, and the bituminous mix shall be spreadat a constant elevation above, below or at the string line elevations as directed.

4.21.2 The use of the automatically controlled bituminous paver, to provide bothlongitudinal and traverse control, shall include the furnishing and maintaining of

a string line, fixed or mobile, by the Contractor. The longitudinal and traversecontrols shall operate independently of each other to the extent that the

surface of the bituminous mix will conform to the string line and will be uniformin cross -section and crown.

4.21.3 The Contractor shall establish the centre -line points and shall maintain the

location of the points until the completion of the surfacing or as directed. When

directed by the Engineer, the contractor shall erect a string line, to be used asa guide for the furnishing machine, in order to maintain a uniform edge

alignment. If any other method is proposed by the Contractor it shall first beapproved by the Engineer.

4.22 BITUMINOUS LEVELING AND WIDENING OF EXISTING PAVEMENT

4.22.1 A levelling course, consisting of a layer of bituminous material of variablethickness may be used to eliminate irregularities in existing surfaces or bases

and to vary existing cross -section elements of roadways.

4.22.2 In areas where levelling courses are required as shown in the drawings

determined by the Engineer, the Contractor shall make a survey of the existing

surface or base. When the survey is approved, the Engineer will determine

and inform the Contractor of the precise locations and thickness of leveling

course to obtain the smoothest possible riding surface. Upon receipt of the

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location and thickness from the Engineer, the Contractor shall proceed with

the placement of the levelling course.

4.22.3 Where the existing carriageway is to be widened, the sides shall be trimmed in

accordance with the drawings or as required by the Engineer. The bituminous

courses shall be cut back to a clean vertical face which shall be completely

coated with a grade of hot bitumen suitable for the purpose immediately

before laying new bituminous material adjacent to it.

4.22.4 The material for regulating shall be as shown on the drawings and shall be

made and laid in accordance with the appropriate clauses of the Specification.

4.22.5 Unless stated to the contrary, any thickness of material described means the

finished or fully compacted thickness.

4.22.6 Where the existing carriageway requires regulating to accommodate the new

pavement overlay the following methods may be adopted.

a) Cold Planning

Cold planning is the recommended method for removing large quantities of

bituminous material. Trial sections are to be carried out, under the supervision

and direction of the Engineer to establish the degree of cold planning required

along each individual section as indicated on the drawings or instructed by the

Engineer.

b) Heating and Planning

Heating and planning may only be used as an alternative to cold planning with

the Engineer's permission. Should this method be adopted there shall be a

minimum period two weeks before the pavement overlay is applied. Trial

sections shall be carried out under the Engineer's supervision and direction to

determine the degree of planning required along each individual section as

indicated on the drawings. A tack coat shall be applied to the planed surface in

accordance with Section 4.36 at the discretion of the Engineer.

4.22.7 The material removed from the existing carriageway shall be disposed off as

instructed by the Engineer.

4.22.8 Scarifying of the existing pavement shall be used to prepare the surface of the

existing pavement to provide a key for the subsequent layers of asphalt. The

scarification shall comprise forming a grooved surface to the existing asphalt

with an average depth of groove being 5mm from the existing surface with an

average spacing between grooves of 50mm or as otherwise approved by the

Engineer.

4.23 THICKNESS CORES

4.23.1 The depth of each bituminous paving course shall be measured by cores

samples.

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The Contractor shall furnish and operate an approved core drill for cutting

samples from the compacted mix on the road. The equipment shall be capable

of cutting the mix without shattering the edges of the specimen or otherwise

disturbing the density of the specimen. Cored samples shall be ten (10)

centimeters in diameter for binder course and wearing course and fifteen (15)

centimeters in diameter for base course and road base.

Cores extracted for thickness measurement may be used for density

determination and density samples may be used for thickness measurements.

4.24 COMPACTION OF BITUMINOUS LAYERS

4.24.1 After spreading and strike off, and as soon as the mix conditions permit the

rolling to be performed without excessive shoving or tearing, the mixture shall

be thoroughly and uniformly compacted. Rolling will not be prolonged to an

extent that cracks appear.

4.24.2 Rollers shall be of the steel-wheel and pneumatic tyre type and shall be in

good condition, capable of reversing without backlash, and shall be operated at

speeds slow enough to avoid displacement of the bituminous mix. The number

and weight of rollers shall be sufficient to compact the mix to the required

density while it is still in a workable condition. The use of equipment which

results in excessive crushing of the aggregate will not be permitted. A

minimum of three (3) rollers, one (1) steel-wheel and two (2) pneumatic -tyre

type, shall be used with each spreading operation for each lane.

4.24.3 The Contractor shall provide adequate back-up equipment for use in the event

of mechanical failure, all to the satisfaction of the Engineer.

4.24.4 Initial or breakdown rolling shall be done by means of either a tandem power

steel roller or three-wheel roller followed by a pneumatic-tyre roller or as

agreed by the Engineer. Rolling shall be longitudinal, beginning at the low side

of the spread of material and proceeding toward the high side, overlapping on

successive passes by at least one half (1/2) the width of the near wheels,

alternate passes of the roller shall be of slightly different lengths.

4.24.5 The motion of the roller shall at all times be slow enough to avoid displacement

of the mix. To prevent adhesion of the mix to the rollers,

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