06 2 iok a1 THRUWAY

Place the embankment material on the site Use dump truck and bulldozer place the embankment in horizontal layerhorizontal layers suitable thick prior to compaction base on type of layer

METHOD STATEMENT FOR ROAD WORKS

V CONSTRUCTION SUB - BASE AND BASE COURSE

VI CONSTRUCTION ASPHALT CONCRETE PAVEMENT, ASPHALT TREATED BASE COURSE

VII CEMENT TREATED BASE COURSE

VIII PORTLAND CEMENT CONCRETE PAVEMENT

IX BITUMINOUS SURFACE TREATMENT

CHAPTER I: METHOD STATEMENT FOR ROAD

I Site Clearing, grubbing, excavation top soil

1 Site clearing, grubbing, excavation top soil

Site clearance and grubbing: This work shall include the removal from groundsurface and grubbing of root and miscellaneous foundation of all densevegetation, bushes, trees, hedges, debris, rubbish, fence, obstructions and thelike together with the removal and disposal off the Site, of all materials and wastearising therefore, all as indicated on the drawings or as instructed by theEngineer and as specified

The waste material and disposal and unsuitable materials shall be disposed bydump trucks to dispose site

The suitable material to be reused under Engineer’s instruction shall be storedand protected separately by Bidder

The quantity of clearing and grubbing for payment shall be the actualcompleted area approved by the Engineer upon completion

The construction sequence is as follows:

+Step 1: Site is cleared be bulldozer and labor

+Step 2: The top soil is excavated and removed by excavator

+Step 3: The excavated top soil shall be removed and dumped in dumps andleveled by bulldozer

+Step 4: The waste and unsuitable materials shall be loaded on the dump truckand then transported to the disposal site

2 Demolition and removing existing structures

Demolition and Removal of Existing Structures consist of the removal, wholly

or in part, and satisfactory disposal of blocks of masonry of an individual sizegreater than 1 cubic meter, of all buildings, hedges, fences, structures,pavements regardless of its nature (asphalt, concrete, etc.), curbs, and any otherobstructions which are not designated or permitted to remain Demolitionincludes the salvaging of designated materials and proper backfilling (inaccordance with specification requirements) of any and all trenches, holes andpits resulting from demolition and removal work

Right of way acquisition may not be completed in all areas at the start-up ofthe construction period and the Bidder shall schedule the work associated withSpecification

II Excavation

1 General

This section bidder presents method statement for excavation, this workinclude supports to the sides or additional excavation to form sloped sides,

working space, keeping the excavations free of all water (including surface waterand ground water), segregation of material suitable for backfilling orembankments, all necessary handling, stockpiling, disposal, shaping andtrimming completed excavations in accordance with the locations, lines, levels,grades and dimensions shown on the Drawings and as specified herein This workalso includes general over site excavation to reduce levels, excavation in and thenecessary diversion of or containment of canals and water courses; including allnecessary pumping, draining, sheeting, bracing and the construction,maintenance and subsequent removal of cribs and cofferdams

2 Method statement

2.1 Preparation

2.1.1 Machine and labor

Machine and personnel construction are fully prepared by Bidders to ensurequality and quantity Prior to construction, the Bidder will trial operation ofmachinery and equipment to ensure all the equipment stable operation duringconstruction

2.1.2 Preparation construction site

Prior to the construction of the excavation bidder conducting the cleanup,grass, tree, stripping of top soil and cleaning obstacles within the constructionsite

Ensure drainage construction sites

2.1.3 Disposal

Prior to construction, the Bidder will test expected disposal field position toensure that the disposal work is not cause negative impact to environment, localplanning as well as the effects the stability of the roadbed itself

2.2 Detail method statement

Road excavation shall not start until topsoil has been removed from the workarea

Based on the plans and drawings the Bidder shall proceed the survey andsetting out for the construction limits, submit the daily requests for inspection ofwork to the Engineer

Based on the topographic conditions of the package, type of cross-sectionexcavation, the length and direction of excavated transport , the roadway shall

be excavated by Bulldozer, excavator in combination with manual and transport

by dump truck in accordance with the level, line, dimensions, cross section shown

on the Drawing /or as required by the Engineer In the case the thickness ofground to be excavated and removed is bigger than design thickness, our Biddershall stop the work and make and submit report to Employer and Engineer fortheir instruction

Road excavation is constructed from top layer to bottom layer over the entirecross section.

Excavation shall be performed carefully to avoid over break or unnecessarydisturbance of adjacent surfaces Any over break or disturbance caused byexcavation operations shall be backfilled, compacted and restored by the Bidderand as directed by the Engineer

Slopes in excavations shall be formed and maintained to prevent the formation

of standing water, The Bidder will inspect geometrical factor, flatness of the slopeaccording to technical standards Every 20m length to check quality completeexcavation slope in a cross-sectional All excavations shall be finished toreasonably smooth and uniform surfaces

In the case the excavated material is suitable for slop protection or for plantingtrees or grass, or for backfill to structure, embankment which shall made free ofsand, stone, rubbish and other foreign matters and complies with thespecification will be transported to shoulder of embankment for re-used , ifapproved by Engineer

The excavated shall be stockpiled on the both sides of the road, a part ofwhich will be used to make temporary water-retaining dyke; the remaining will betransported to the disposal area as regulated

Excess material shall be placed in the right places The Bidder spray andcompaction to make 2% slope on surface of excess material stockpiled, excessmaterial stockpiled no higher than 3m

Temporary Ditch shall be set along Excavated Area for gathering surfacewater Make soakage pit at suitable location Temporary drainage ditches shall becleaned and trimmed from time to time so that there may be a free flow of waterthroughout the whole Construction Period

After excavation to design level, the Bidder take soil samples within the workarea to laboratory about natural moisture, liquid limit, plasticity index, densitystandards, criteria and the load capacity swelling from CBR laboratory todetermine whether to change the material within the area

3 Quality control of excavation construction

Check

The inspection of excavation construction includes

Check the material classification and criteria of natural moisture, liquid limit,plasticity index, density standards criteria and the load capacity swelling fromCBR laboratory

The classification of excavated material into soil or rock shall be madeaccording to the following test using a bulldozer with a hydraulic ripper The testshall be performed by the Bidder under the direction of the Engineer

Standard Test Method for Classification of Soil and Rock

Test Items Requirements

Standard Specification of Test

Machine

Bulldozer (110CV) with one tyne hydraulic ripper

construction site

Hauling distance: 20 - 30m Slope of test area : 0 - 5 %

bulldozerQR=Net excavation volume (m3) / Time (hr)Criteria for judge of the

classification

Rock : Qr /Q < 0.4Q= Standard excavation capacity (21 m3/hr)Check the quality of the construction of geometrical factor, flatness slope.Check the disposal

Tolerances

After excavation the dimensional tolerance for; finished lines, grades andformations of designated areas instructed by the Engineer shall be ±2cm ofdimensions shown on the Drawings

All exposed finished excavated surfaces shall be; properly graded, uniform andshall have sufficient slope to ensure that they are free draining and free fromponding during rainfall

III Rock blasting

1 General description

In this part, the Bidder describes method statement for the construction rockexcavation by blast fracturing and the constructing of stable final rock cut facesusing controlled blasting and production blasting techniques Controlled blastinguses explosives to form a shear plane in the rock along a specified back slope.Controlled blasting includes presplitting and cushion blasting Production blastinguses explosives to fracture rock in accordance with Specification and inconformity with the lines, grades and typical cross sections shown on theDrawings

2 Method statement

2.1 Preparation

2.1.1 Machine and labor

Machine personnel construction are fully prepared by Bidders to ensure qualityand quantity Prior to construction, the Bidder trial operation of machinery andequipment to ensure all the equipment stable operation during construction.

2.1.2 Preparation construction site

Prior to the construction of the embankment, the Bidder conducting thecleanup, grass, tree, stripping of top soil and cleaning obstacles within theconstruction site, prepare the under layer in accordance with Specification

Ensure drainage construction sites

2.1.3 Site Specific Blasting Plan

The Bidder will submit site specific blasting plan for acceptance before drillingoperations begin included:

 Bidder’s drawings showing a scaled map of the blast area and crosssectional views which indicate beginning and ending stations, free facelocation, hole spacing, hole diameter, hole depth, burden, hole inclination,and sub-drill depth The drawings shall show any significant joints orbedding planes within the blast zone and these geological features shall beincorporated into the blast design

 Where blasting may affect nearby structures or utilities, the Bidder shallprovide the method of monitoring and controlling blast vibrations

 A loading pattern diagram showing the location and amount of each type ofexplosive to be used in the holes including primer and initiators and thelocation, type, and depth of stemming, column heights, and overall powderfactor for each type of loading

 A delay and initiation diagram showing the delay pattern, sequence, anddelay times

2.2 Rock excavation by blasting sequence

Rock excavation by blasting sequence:

 Specify location of drilling and depth of drilling

 Drill holes with drill D42mm (or D76mm)

 Blow, cleaning drilling holes, acceptance drilling holes

 Install explosive

 Blasting, test explosion sites

 Excavation rock to dump truck

2.3 Method statement detail

2.3.1 General

Drill and blast shall be made in accordance with the approved blasting plan.Before drilling remove overburden soil and loose rock along the top of the

excavation for at least 10 meters beyond the hole drilling limits or to the end ofthe cut;

 Cap all holes to prevent unwanted backfill; place a stake next to each holewith hole number and total depth drilled;

 Use the types of explosives and blasting accessories necessary to obtain therequired results (a bottom charge may be larger than the line charges if noover break results);

 Free blast holes of obstructions for their entire depth; place charges withoutcaving the blast hole walls; stem the upper portion of all blast holes with drysand or other granular material passing the 9.5-millimeter sieve; not stemthe hole with drill cuttings;

 Following a blast, stop work in the entire blast area and check for misfiresbefore allowing workers to return to excavate the rock;

 Remove or stabilize all cut face rock that is loose, hanging, or potentiallydangerous; scale by hand or machine methods as approved by theEngineer; leave minor irregularities or surface variations in place if they donot create a hazard; drill the next lift only after the cleanup work andstabilization work are completed;

2.3.2 Drill holes

Drill holes with drill D42mm (or D76mm)

The Bidder shall submit drill logs including the following:

 Blast plan map showing designated hole numbers; and

 Individual hole logs completed and signed by the driller showing; total depthdrilled, depths and descriptions of significant conditions encountered duringdrilling that may affect loading such as water or voids and date drilled

Controlled blast holes shall be drilled not greater than 100 millimeters indiameter along the final rock face line Controlled blast holes shall be drilled

within 75 millimeters of the proposed surface location and shall be at least 10meters beyond the production holes to be detonated or to the end of the cut.Drilling equipment with mechanical or electromechanical devices thataccurately control the angle the drill enters the rock shall be used A lift heightshall be selected and drilling operations shall be conducted in such a way thatthe blast hole spacing and down hole alignment does not vary more than 225millimeters from the proposed spacing and alignment When more than 5 percent

of the holes exceed the variance the lift height shall be reduced and the drillingoperations shall be modified until the blast holes are within the allowablevariance Maximum lift height is 15 meters

A 600 millimeter offset is allowed for a working bench at the bottom of each liftfor drilling the next lower controlled blasting hole pattern The drill inclinationangle or the initial drill collar location shall be so adjusted that the required ditchcross section is obtained when the bench is used Drilling 500 millimetres belowthe ditch bottom is allowed for removing the toe Bulk ammonium nitrate and fueloil shall not be used for controlled blasting

In presplitting, the nearest production blast row shall be delayed by at least 25milliseconds after the presplit line blasting Presplitting shall be done at aminimum of 10 meters ahead of the production blasting zone

In cushion (trim) blasting, the cushion blast row shall be delayed by 25 to 75milliseconds after blasting the nearest production row

Requirement for Compaction

2.1.2 Machine and labor

Machine personnel construction are fully prepared by Bidders to ensure qualityand quantity Prior to construction Bidders trial operation of machinery andequipment to ensure all the equipment stable operation during construction

2.1.3 Preparation construction site

Prior to the construction of the embankment, the Bidder conducting thecleanup, grass, tree, stripping of top soil and cleaning obstacles within theconstruction site, prepare the under layer in accordance with Specification

As with the natural substrate, the hollows, to clear the bottom and use thematerial in accordance with the technical standards for filling

Ensure drainage construction sites

2.1.4 Trial section construction

The Bidder will carry out in accordance with our method statement for thecompaction of each type of fill material to be used in the Works to determine therelation between; the types of compaction equipment, the number of passesrequired and such methods as may be necessary for adjusting moisture content

in order to construct Embankments in accordance with this Specification SectionTrials areas will be 10 m wide and 50 m long and subject to the approval of theEngineer

2.2 Construction sequence

Embankment construction sequence:

truck

 Place the embankment material on the site.

 Compact embankment material using roller to density requirement

 Check the level and carry out the test compliance with the specified qualityrequirements

 Construct another layer with the same above procedure until the designlevel

2.3 Method statement detail

2.3.1 Transport material to the site

The material used for embankment material will meet requirements ofembankment material and approved by Engineer before transported to the site.Because stockpiling of Embankment material is generally not be permitted,especially during the wet season so Embankment material generally will betransferred directly from the excavation or borrow areas to the prepared surfaceand spread during dry weather be dump truck

The embankment material will be placed on the site in pits with properdistances so that it will be leveled in the layer of specified thickness

2.3.2 Place the embankment material on the site

Use dump truck and bulldozer place the embankment in horizontal layerhorizontal layers suitable thick prior to compaction (base on type of layer) orsuch other thickness as may be confirmed by the Bidder’s trial sections and overeach edge of embankment about 20cm in order that the embankment is enoughfor compaction of shoulders The surplus material shall be trimmed and removed.Each layer shall be compacted as specified, tested for density and accepted bythe Engineer, before the next layer is placed Each layer shall be placed in amanner that ensures a uniform density

Water shall be added or removed as necessary in order to obtain the requireddensity Removal of water shall be accomplished through aeration by ploughing,blading, disking, or other methods subject to the approval of the Engineer

Lower Embankment layers shall be compacted and shaped with a 4% cross fallfrom the centre of the Embankment to allow drainage of rainwater duringconstruction The cross fall shall be gradually reduced in the upper layers suchthat the required design cross fall is achieved below the pavement structure.Dumping and spreading and compaction areas shall be kept separate and nowork shall be permitted on completed layers until such time as compactioncomplies with the requirements of this Specification Section and the layer hasbeen approved by the Engineer

2.3.3 Compact embankment material.

The compaction will be undertaken by several rollers and water shall be added orremoved

For subgrade layer and general embankment layer

 All layers will be compacted to a uniform moisture content of -3% to +1% ofthe optimum moisture content for the particular material being laid

 For subgrade layer 30cm in thick will be divided to 02 layers thickness of 15

cm for each layer

For embankment layers below the subgrade layer

 For embankment layers below the subgrade layer 50cm in thick will bedivided to 02 layers thickness of 25 cm for each layer

The following sequence will be used for undertaking embankment compaction:

 First stage using steel wheel roller: 8t-10t

 Second stage using vibration roller 14-25t

(The rolling number and time shall be determined after obtaining result of trial

compaction).

The rolling is undertaken along the embankment, its procedure is from lowpoint forward high point, the next rolling trip shall overrun at least 1/3 previousrolling trip

For straight section, rolling shall be undertaken from both edges ofembankment forward the centerline For the super-elevation section, the rollingshall be undertaken from the small curve to large curve

The water may be sprinkled by water truck, if necessary to proper moisturefor ensuring compaction of embankment to specified density

In addition, for sections (due to located at narrow positions or within theretaining wall, embankment over the culvert etc.), the rolling of which shall beundertaken by small roller or other suitable compactor

Upon completion of first embankment layer, this shall be inspected andapproved by the Engineer The next embankment layers shall be constructedsimilar to construction of first embankment until to design level

The next embankment layer shall be undertaken only when the previousembankment has been completed in accordance with the Technical Specificationand approved by Engineer

3 Quality control of embankment

 Check the material exploitation, material transport to the site andconformity of construction material

 Check the surface of under layer

 Check the place the embankment quality and compaction quality

During progress of the Works the Bidder will carry out density tests oncompacted material in accordance with Vietnamese Standard 22TCN346-06

At least one group of three in-situ density tests shall be carried out for every1,500 m2 of material placed for each layer of compacted fill subject to theapproval of the Engineer

Irrespective of the tolerances given below, all exposed finished fill surfacesshall be sufficiently smooth and uniform, and shall have sufficient slope to ensurethat they are free draining and that no ponding occurs

[Table 0] Tolerances after Compaction

Embankment

Smaller value of either every 20m shown on the approved Bidder’s

Drawing or 1000m3

Slope

every 20m shown on the approved Bidder’s

Drawing or 500m2

Surface irregularity from the

Longitudinal grade over 25 m

2.1.1 Material

Construction material will be prepared by Bidder in conformance with thequantity, quality shown on the project specification, please reference item …

2.1.2 Machine and labor

Machine personnel construction are fully prepared by Bidders to ensure qualityand quantity Prior to construction Bidders trial operation of machinery andequipment to ensure all the equipment stable operation during construction

2.1.3 Preparation construction site

Prior construction of base, subbase aggregate course, the surface of subgradeshall be cleaned free dirty, deleterious material by brooms and spraying water toOMC for creating good contact with sub base, base course and avoidingsegregation

2.1.4 Trial work

The trial work shall be undertaken in section of 100m length and 05 m widthunder the Engineer instruction for determining the material thickness to bespreader, rolling coefficient, OMC for rolling and other technical parameter to beapplied etc

2.2 Detail construction method

The construction sequence of aggregate layer is as follows:

Use spreader spread aggregate

The sub-base aggregate 35cm layer divided to 02 layer 18cm and 17cm ofthickness for each layer

The sub-base aggregate 18cm layer divided to 01 layer 18cm of thicknessfor each layer

For the base layer with the thickness of 30 cm shall be divided into 02layers of 15 cm of thickness for each layer

For the base layer with the thickness of 20 cm shall be divided into 02layers of 10 cm of thickness for each layer

The thickness of sub base or base aggregate layer shall be controlled byautomatic sensor bar and steel wire 1mm is tied with standard remark oflevel of sub base or base course

During leveling and rolling, if segregation is happened, so that aggregateshall be removed and replaced by other proper aggregate

Prior spreading of aggregate of next layer, the moisture of first layer shall

be checked and adjusted for creating the good contact of two layerswithout segregation

o The uneven places, where is lack of aggregate shall be added withaggregate by common

Density rolling:

o Rolling by Vib roller 25T Rolling Capacity is 85-90% of required capacity,rolling speed is < 2km/h for first 12-20 rolling times and 3km/h from fifthrolling time and avoiding broken aggregate Water content to be sprayed

of this rolling stage is 3-4 litter/m2

o The finishing of density rolling stage on time is very important, because iffinished sooner, so density of aggregate course may be not enough, iffinished late, so aggregate may be broken The density rolling may befinished when roller overrun on the sub base or base course surface and itwheels are not tripped on that surface

o The water will be lightly sprayed of aggregate course during rolling forkeeping moisture proper for rolling to density

o Rolling shall be undertaken from edge of road forward centerline for theroad section with cross fall and from down side to up side of road for theroad section with talus in one side The next rolling trip overrun previousrolling trip at least 25-30cm

o The density of aggregate course shall be 98MDD upon completion ofrolling The density of aggregate course shall be checked regularly bysand cone method during rolling

Finish rolling:

o Rolling by steel roller 8T-10T

CHAPTER I

3 Quality control measures for aggregate layer construction

The aggregate layer construction shall conform to the constructionspecification and accept the aggregate layer in the pavement structure TCVN8859-2011 and the specifications in the bidding document

 Checking construction stages :

o The Bidder’s quality control supervisor shall regularly check the level andgeometrical dimensions, density of granular sub base course and granularbase course in compliance with the drawings during construction byelevator and steel tape, sand cone.

o Sprinkling water for maintaining moisture and avoiding loosing finefractions

o The traffic is not open over the completed sub - base and base courses

 Checking during construction:

o Checking quality of crushed stone aggregate prior undertaking trial work:Checking the aggregate properties, flat fractions ratio, plasticity index orequivalent sand (ES) for once every 200m3 or for each working shipment,the testing samples shall be taken at the dump truck, when it arrives tothe site When the source of crushed aggregate is change, so testing forchecking quality of that source shall be repeated from beginning

o Checking moisture of crushed stone aggregate for once every 200m3 ofworking shipment prior spreading

o Checking density of crushed stone aggregate for once every 800m2byCBR test

 Checking for approval

o Checking density for once every 7000m2 by taking incidentally threesample by sand cone method The testing result should be greater thandesign density

o Checking cross section for measuring geometrical and thickness for onceevery 40-50m section for straight alignment and for once every 20-25msection of curve alignment shall be undertaken as follows :

 Checking thickness: The thickness shall be determined by the datameasured at levels before and after completion of granular sub-base orbase layer at the same cross section, if necessary excavating hole forchecking thickness of sub-base or base course may be applied Theallowable tolerance is + 5% but not >+10mm for sub base course andnot >+5mm

 Checking width by steel rule with allowable tolerance is -5cm for base and base courses

sub- Allowable tolerance of cross fall is +5% for sub-base course and +3%for base course

 Checking evenness measuring for once every 100m by steel rule Thegap between rule and surface is not than 10mm for sub-base courseand not than 5mm for base course

[Table 0 ]: Tolerances for aggregate sub base and base

No Characteristic

Permitted Variation from Drawings Frequency of Checking Subbase Base

section, 20-25m in curvesection per one cross

2.1.2 Machine and labor

Machine personnel construction are fully prepared by Bidders to ensure qualityand quantity as specified in item… Prior to construction Bidders trial operation

of machinery and equipment to ensure all the equipment stable operation duringconstruction

The entire machinery, construction manpower for construction this items prior

to the use, the Bidder will submit Engineer to approval, in order to meet thetechnical standards of the project as follows:

2.1.2.1 Equipment for construction prime and tack coats

The equipment to be used by the Bidder include; a power broom a pressurizedbitumen distributor and equipment for heating bitumen and distributor

The distributor will have a minimum capacity of 1,000 liters

The distributor will be so designed, equipped, maintained and operated thatbitumen at an even heat can be applied uniformly on variable widths of surface,

at a controlled rate of transverse and longitudinal spread within ±10 percent ofthe required rate of application

The distributor equipment will include a tachometer, pressure gauges, acalibrated tank dipstick, a thermometer for measuring the temperature of thetank contents and an instrument for measuring the speed of travel at low speed.All measuring equipment on the distributor shall have been recently calibratedand an accurate and satisfactory record of such calibration will be supplied to theEngineer

2.1.2.2 Mixing plant

The mixing plant will be of weigh-batching type and will have a capacitysufficient to ensure the finisher(s) can without interruption when spreading theasphalt mix at a normal speed and the required thickness The plant will becapable of producing a mixture within the job mix tolerances

The plant shall be provided with Automatic or Computer Controlled batchingsystems able to print records for each batch The plant must comply withapplicable environmental standards of Vietnam and the requirements for theBidder’s Environmental Management Plan

The Bidder ensure that at all times the process of mixing asphalt material iscarried out in a safe manner The Bidder shall provide and maintain adequate fireprevention and control measures and first aid supplies and facilities at the site ofthe mixing plant

The Bidder provide safe and secure access to all inspection, sampling andmeasuring points on the mixing plant and for the sampling and checking ofmaterials contained in the delivery trucks

2.1.2.2.1 Plant Scales

The mixing plant will be of weigh-batching type and will have a capacitysufficient to ensure the finisher(s) can without interruption when spreading theasphalt mix at a normal speed and the required thickness The plant will becapable of producing a mixture within the job mix tolerances

The plant will be provided with Automatic or Computer Controlled batchingsystems able to print records for each batch The plant must comply withapplicable environmental standards of Vietnam and the requirements for theBidder’s Environmental Management Plan

The Bidder ensure that at all times the process of mixing asphalt material iscarried out in a safe manner The Bidder will provide and maintain adequate fireprevention and control measures and first aid supplies and facilities at the site ofthe mixing plant

The Bidder will provide safe and secure access to all inspection, sampling andmeasuring points on the mixing plant and for the sampling and checking ofmaterials contained in the delivery trucks

2.1.2.2.2 Plant Scales

Scales for all weigh boxes or hoppers will be of the spring-less dial type, loadcell, or equivalent subject to the approval of the Engineer, will be of standardmake, will have an accuracy of within 0.5%of the maximum expected load andwill be located so that they are in plain view of the operator at all times Thevalue of the minimum graduation will not be greater than one kilogram

Pointers on dial scales will be set close to the face of the dial to avoidexcessive parallax

Dial scales will be provided with adjustable pointers for marking the weight ofeach material included in the batch

Scales for weighing the Bitumen will conform to the specifications for scales foraggregate

The calibration of all scales will be checked in accordance with themanufacturer’s recommendations or, subject to the approval of the Engineer,when it is apparent that the scales are in error The Bidder will keep on site suchequipment as may be necessary for calibrating the scales

2.1.2.2.3 Equipment for Storage of Bitumen

Tanks for storage of Bitumen will be equipped with heaters with effective andpositive control capable of keeping the bitumen within the temperature rangespecified at all times

The circulating system for the Bitumen will be capable of ensuring proper andcontinuous circulation during the entire operating period Suitable means will beprovided, either by steam jackets or other insulation, for maintaining thespecified temperature of the Bitumen in the pipe lines, meters, weight buckets,spray bars, and other containers in the flow lines Subject to the approval of theEngineer, Bitumen may be partially heated in the tanks and brought to thespecified temperature by means of booster heating equipment between thetanks and the mixer

The total storage of the tanks will be sufficient to provide 10 hours of fulloperation of the asphalt mixing plant If more than one storage tank is used, theywill be so connected to the circulatory system that each tank can be isolatedwithout interference to the circulation of bitumen to the mixer

2.1.2.2.4 Bins

The plant shall include storage bins of sufficient capacity to supply the mixerwhen it is operating at full capacity

Bins shall be divided into at least four compartments and shall be arranged toensure separate and adequate storage of appropriate fractions of the aggregate,not including mineral filler.

Each compartment shall be provided with an overflow pipe that shall be ofsuch size and at such location as to prevent any backing up of material into otherbins

Bins shall be so constructed that the gates do not leak and samples can bereadily obtained

2.1.2.2.5 Feeder for Drier

A separate feeder shall be provided for each aggregate to be used in the mix.Other types may be used, with the Engineer’s approval, only if they are able todeliver wet materials at a constant rate without clogging

The walls to the cold feed bins shall be of sufficient height and width toprevent intermingling of materials from adjacent bins

All feeders shall be calibrated and the gate opening and speed settings foreach approved job mix clearly indicated on the gates and on the plant controlpanel Once established, the feeder settings shall not be altered without theapproval of the Engineer

A system of “No Flow” switches shall be installed on each aggregate feeder tostop the plant if no material is flowing from the feed bin after 30 seconds

Screens shall ensure that the aggregate deposited in any bin shall not containmore than 1.0 percent of oversized or undersized materials

2.1.2.2.8 Weigh Box or Hopper

The equipment shall include a means to accurately weigh each aggregate sizeand be large enough to hold a full batch without hand raking or running over There shall be sufficient clearance between hoppers and their supports toprevent accumulations of foreign materials

The discharge gate of the weigh box shall be so hung that the aggregate willnot be segregated when dumped into the mixer and shall close tightly when thehopper is empty so that no material is allowed to leak into the batch being mixedduring the process of weighing aggregate for the next batch

2.1.2.2.9 Mixer

The batch mixer shall be of a twin pug-mill type capable of producing auniform mixture within the job-mix tolerances

The mixer capacity shall be not less than a one-ton batch and shall be soconstructed as to prevent leakage of contents If not enclosed, the mixer boxshall be equipped with a dust hood to prevent loss of dust by dispersion

The design shall permit visual inspection of the mix

It shall be heat-jacketed with steam, hot oil, or other means subject to theapproval of the Engineer

The mixer shall have an accurate time clock to control the operation of acomplete mixing cycle and shall be capable of locking the weigh box gatebetween the charging of the mixer and the closing of the mixer gate at thecompletion of the cycle

Timing control shall be flexible and capable of being set at intervals of notmore than 5 seconds throughout cycles of up to 3 minutes A mechanical batchcounter shall be installed as a part of the timing device and shall be so designed

as to register only completely mixed batches

The clearance of blades from all fixed and moving parts shall not exceed 2 cmexcept in the case of aggregates having a nominal maximum size of over 2.5 cm,

in which case the clearance shall be so adjusted as to prevent undue breakage ofthe coarse aggregate during the mixing operation

2.1.2.2.10 Bituminous Control Unit

The metering device shall be designed and constructed to automaticallymeasure the required amount of liquid asphalt into each batch within a tolerance

2.1.2.2.11 Thermometric Equipment

An armored thermometer reading from 100°C to 200°C shall be fixed in thebituminous feed line at a suitable location near the discharge valve into themixer unit

A thermocouple or resistance bulb shall be mounted near the bottom of thefine aggregates bin to measure the temperature of the material before it entersthe mixer

The thermocouple used for discharge and for the fine aggregate bin shall bewired to a temperature recording apparatus Charts showing time andtemperature from the temperature recording device shall be provided to theEngineer daily

The plant shall be further equipped with either an approved dial scale mercurythermometer or an electric pyrometer or other approved thermometricinstrument at the discharge chute of the drier to automatically register orindicate the temperature of the heated aggregates

The burner to the drier for aggregates shall be equipped with automatictemperature controls

2.1.2.2.12 Dust Collector

The plant shall be equipped with a dust collector capable of storing dust to bedisposed of as waste or returning dust uniformly to the elevator, as directed bythe Engineer

2.1.2.2.13 Control of Mixing Time

The plant shall be equipped with a positive means to control and consistentlymaintain the mixing time unless a change to the timing has been approved bythe Engineer

2.1.2.2.14 Electronic Weight System with Automatic Ticket Print Out General

The asphalt plant shall be equipped with electronic weight systems capable ofautomatically printing a delivery ticket The ticket shall contain the informationbelow as a minimum, subject to the approval of the Engineer, and a copy of eachticket shall be provided to the Engineer

 Sequential load number,

 Date and time,

 Name or location of plant,

 Type of mix,

 Truck number,

 Gross, tare, net weight or batch weight (as applicable),

 Accumulated total of mix (for that day, the year to date or total for jobsubject to the approval of the Engineer),

 Temperature of mix at the plant and site (may be hand recorded),

 Pavement layer,

 Location (chainage or station) of placing mix,

 Signatures subject to the approval of the Engineer

The ticket shall be printed with original and at least 2 copies, one of whichshall be submit to the Engineer

Automatic Printer System for Batch Plant

The batch plant’s automatic printer system shall print the individual weight ofaggregate and Bitumen delivered to the pug-mill and the total weight of batchescontained in a truckload

The automatic printer system shall be used only in conjunction with automaticbatching and mixing control systems which have been approved by the Engineer

In the event of a printer or other equipment failure, the approval of theEngineer will be required for the delivery hot mix to site In no case shall thiscontinue for more than 12 hours

Truck Scales Weight House

The weight house shall be of sufficient size, shall be completely enclosed andweatherproof and shall be equipped with air a conditioner/heater There shall besufficient window opening as directed by the Engineer

The Bidder shall provide all necessary facilities to enable the safe collectionand lifting of samples and the safe collection of other data as necessary from allsampling, measuring and inspection points on the mixing plant

Ample and unobstructed space shall be maintained at all times in and aroundthe truck loading space and this space shall be kept free from materials spillsand other waste materials

2.1.2.3 Hauling Equipment

Trucks for hauling bituminous mixtures to site shall have tight, clean andsmooth metal beds that have been sprayed with a minimum amount of soapywater, vegetable oil, or lime solution to prevent the mixture from adhering to thebeds Fuel or oil shall not be used for this purpose

Any truck which due to its condition causes excessive segregation of material,spills materials or has leaks of oil or other fluids detrimental to the work not beused for the hauling bituminous mixtures until such conditions have beencorrected

All loads shall be covered with a canvas or other suitable material sufficient toentirely cover the mixture and protect it from the weather The cover shall besecurely fixed to the truck body during hauling

2.1.2.4 Spreading & Finishing Equipment

Paving equipment for the spreading and finishing of asphalt layers shall beapproved mechanical, self-powered pavers, capable of spreading and finishing

the mixture true to the lines, grades, levels and cross sections given on theDrawings or as subject to approval by the Engineer.

The pavers shall be equipped with screed controls which can be adjusted formanual, semi-automatic and fully automatic operation, to ensure that a smoothasphalt surface can be placed within the required tolerances regardless ofirregularities in the surface being paved The screed controls shall be capable ofdetecting the required grades and levels from either a taut piano wire guideline

or a sliding ski of a sufficient length subject to the approval of the Engineer

Pavers shall be equipped with activated screeds of either the tamping orvibrating type, and devices for heating the screeds to the temperature requiredfor the laying of the mixture without pulling or marring

The pavers shall be equipped with hoppers and distributing screws of thereversing type to place the mixture evenly in front of adjustable screeds Theyshall be equipped with quick and efficient steering devices and shall have reverse

as well as forward traveling speeds

The pavers shall also be equipped with mechanical devices such as equalizingrunners, straightedge runners, evener arms, or other compensating devices, tomaintain the trueness of grade and to form the edges of the pavement to truelines without the use of stationary side forms

If, during construction, it is found that the spreading and finishing equipment

in operation leaves surface tracks in the pavement or indented areas or otherobjectionable irregularities that are not satisfactorily corrected by scheduledoperations, the use of such equipment shall be discontinued and othersatisfactory spreading and finishing equipment shall be provided by the Bidder

2.1.2.5 Compacting Equipment

All rollers shall be equipped with a watering system to prevent sticking of theasphalt mixture to the pneumatic or steel wheels

All rollers must be self-propelled

The Bidder may use less compaction equipment or other equipment typessubject to their use in satisfactory trial sections completed to the approval of theEngineer

2.1.3 Preparation surface

Prior to construction of asphalt surface, the Bidder will inspect the base layer

to ensure base layer has been completed and accepted in accordance with thetechnical design documents and project standards Repair, replacement andimprovement of the damaged location

Prior to the construction of the bitumen, loose dirty and other objectionablematerials shall be removed from the surface by means of power broom of blower

If this does not provide a uniformly clean surface, additional sweeping shall bedone by hand using stiff brooms Sweeping shall extend at least 20 centimetersbeyond each edge of the area to be sprayed

The surfaces of structures or trees of property adjacent to the areas shall beprotected against marring and spattering.

Adherent patches of objectionable materials shall be removed from the surface

by steel scraped method and where the Engineer so directs, the scraped areashall be washed down with water and hand brooms

The Bidder will provide and maintain at the heating site, adequate firepreventing and also first aid supplies and facilities

2.1.4 Asphalt mixture design

Asphalt mixture will be designed by Marshall Method

Asphalt mixture design sequence:

 Cold mix design

 Hot mix design

 Job mix formula

Requirement for mix properties of asphalt surface

Aggregate voids (corresponding to

Properties of Bituminous Mixture (Table 6 of Vietnamese Standard 06)

22TCN345-No Properties Anti-skid A/C

Surface layer Testing method

AASHTO T245-97 (2001)

4

Residual stability (having soaked at

600C for 24 hour) comparing with

initial stability, %

Min 75

2.1.5 Trial section

Based on the design line technology, the Bidder will carry out in accordancewith our method statement for the trial section for each pavement layer 100m inlength and of at least 02 strips of spreader in width in witnessed by relatedparties

Based on the results of the trial section construction, the Bidder will collect thefollowing data as a basis for editing (if any) and approval for popularconstruction

 The manufacture formula of asphalt concrete mixtures

Alternative construction and construction technology: material type of primeand tack coat, ratio of prime and tack coat; allow time for spread asphalt afterconstruction prime or tack coat; thickness of asphalt layer (beforecompaction), laying temperature, compaction temperature (start and finish),compacting diagram of different types of rollers, number of turns rollerrequired over a point, compacted density, flatness, roughness of the surfaceafter construction

2.2 Construction sequence

 Spraying prime and tack coat

 Asphalt concrete mixture hauling

 Paving asphalt concrete mixture

 Rolling Asphalt concrete mixture

2.3 Construction detail

2.3.1 Spraying prime and tack coat

Prime coat and Tack coat will be application by the distributor having rubberwheels and has a minimum capacity of 1,000 liters The areas, prime coat andtack coat of which cannot be sprayed by Distributor shall be applied by sprinklingcan

The construction of prime coat shall not be permitted to under while theoutside temperature under + 150C

Spraying temperatures shall comply with the following Table:

Spraying temperature (prime coat)

Type of Material Spraying temperature range

Cutback, 50pph kerosene (MC-70 grade

Spraying temperatures (tack coat)

Type of Material Spraying Temperature

The Bidder shall maintain the coated surface to the specified standard until it

is overlaid by the subsequent course

2.3.2 Asphalt concrete mixture hauling

The Asphalt concrete mixture will be delivered from AC mixing Plant to the site

by dump truck

The truck with the tank using for hauling Asphalt concrete mixture will beclean and covered with the canvas during transportation Before loading Asphaltconcrete mixture from the AC Plant, the tank containing Asphalt concrete mixturewill be coated lightly with soap liquid or anti-cohesive oil, but the petroleum oilwill be used for coating inside of tank

Each truck hauling Asphalt concrete mixture will be recorded all necessarilydata as required before leaving AC Mixing Plant.

Bidder will calculate and mobilize enough number of dump trucks for haulingAsphalt concrete mixture proper capacity of AC Mixing Plant; Paver and Rollers.The Bidder will prepare sufficient manpower and machinery and specifichauling plans to ensure that the temperature of the mixture was required as thetable below

Before dump mixture to hopper spreader, inspecting mixture temperature bythermometer If the temperature of the mixture does not guarantee the followingtable will be removed

Specified Limits for Bitumen Asphalt Mix Temperatures

to 70 Pen)

2.3.3 Paving asphalt concrete mixture

The paving Asphalt concrete mixture will be undertaken the paver and in thetemperature of outside condition not less than 50C and in dry

The temperature of Asphalt concrete mixture prior loading into hope of paverwill be > 1200C

At the narrow places, where paving Asphalt concrete mixture cannotundertake by paver, so that will be executed by workers and meet followingrequirements:

 Using shovel for placing Asphalt concrete mixture in near interval

 The placed Asphalt concrete mixture is leveled in even layer in1.35 – 1.45 of design thickness and required gradient by raker

 The narrow placed paved with Asphalt concrete mixture by workers

in adjacent with the area to be paved by Paver in order that allplaced Asphalt concrete mixture will be rolled to specified density

in even layer without joint

Prior staring paving work, the pave will operate without load about 10- 15minutes for checking its operation conditions such as spiral axis, conveyor,heating plates

Two dices or two wood bars in the 1.2 – 1.3 height of design of AC thickness to

be fitted under heating plate The designed AC thickness was determinedthrough trial work and approved by the Engineer before undertaking AC paving atthe site

The formwork to be placed at both edges of road surface will be heated

The paving speed will be adjusted so that the paving surface will be withoutbreak, crash or uneven

After finishing paving the paver will run from paving trip about 5-7m and stop.The end of paving trip will be trimmed in right manner by hot raker

One part of Asphalt concrete mixture of end of paving trip will be removed forcreating the straight joint, this work will be done upon completion of rolling whenthe temperature of Asphalt concrete mixture is still hot but not than 700C

Prior paving next trip, the cross and longitudinal joint will be trimmed in rightmanner and coated with liquid bitumen or emulsion bitumen or heating formaking good contact of existing paving trip and new once

The longitudinal joint of above and under layer will be unequal at least 20cm.The cross joint of existing paving trip and new once is at least 1m

2.3.4 Rolling Asphalt concrete mixture

The rolling paved Asphalt concrete mixture will be undertaken almost afterpaving The effective rolling is that rolling hot laid Asphalt concrete mixture isundertaken in 1300C – 1400C The rolling will be completed before thetemperature of Asphalt concrete mixture down to > 700C

The steel wheels of roller will be sprinkled with water during rolling foravoiding Asphalt concrete mixture sticking and spilling The tires of roller will becoated with oil for avoiding Asphalt concrete mixture stick The water orpetroleum oil will be not used for coating tires of roller

The places where is lacked or spilled of Asphalt concrete mixture, that will beadded with Asphalt concrete mixture and compacted in as required by worker

Rolling Sequence:

The paved Asphalt concrete mixture rolling is undertaken in sunny conditions and high temperature of Asphalt concrete mixture

 Preliminary Rolling by steel wheel roller 8T : 04 times/point, theworkers will arranged with the roller for adding Asphalt concretemixture of uneven places and lacked of Asphalt concrete mixture.

 Density Rolling by tire roller 10-12T : 12 times/point for bindercourse and 10 times/point for surface course in 2km/h speed forfirst 6-8 times and then 3-5km/h speed for next times

 Finishing Rolling by steel wheel roller 10T

The paved Asphalt concrete mixture rolling is undertaken in winter conditions and minimum temperature of Asphalt concrete mixture

 Firstly rolling by tire roller: 10-14 times/point

 Next rolling by steel wheel roller 10T : 04 times/point

 The speed of rollers is as similar to above

 The rolling Asphalt concrete mixture will be completed when thetemperature of Asphalt concrete mixture is not less than 700C.Time after laying

 Preliminary rolling 0 - 10 min

 Final or finish rolling 20 - 45 min

The paving Asphalt concrete mixture will be undertaken so that thelongitudinal joint of AC surface course will be coincided with the vehicle separatorline for avoiding coinciding the longitudinal joints of binder course and surfacecourse, therefore the width of Asphalt concrete mixture paving trips will bearranged as follows:

 The AC binder course will be paved in each once trip of 3.5m width(from middle separator forward the road edge)

 The AC surface coarse will be paved in each one trip of 3.5m width(form this edge to other edge of road)

 The cross joints will be arranged unequally at least 25cm formaking the smooth and even surface

Note: Anti skid Asphalt Concrete Surface Course: Material workmanship and testing for the layer shall comply with requirements in Vietnamese Standard 22TCN319-04 “Polymer Asphalt - Technical Requirement and Testing Method.” Additional particular requirements for the roughness layer are given below.

The optimal number of passes for compaction shall be determined from the results of compaction of the trial sections However it is expected that compaction will be by at least two roller passes using only tandem steel wheel rollers.

Crushing or breaking of aggregate particles during compaction shall not be

Cooling with water will not be permitted;

Additional equipment and tools for keeping the steel wheel rollers permanently clean shall be provided until completion of compaction work After compaction has been completed all traffic or load application on the paved surface will not be permitted at least during 24 hours.

3 Quality control

3.1 Test construction site before construction

 Asphalt paving preparation surface status, cross slope, longitudinal slope,height, width

 Prime coat, tack coat status

 Standard landmark system

 Equipment spreading, compacting, communications equipment, constructionforces, traffic safety and work safety

3.2 Material control

Bitumen: Check the quality criteria for bituminous materials for each material intake

Bitumen Properties Requirement (referred table 1 of 22TCN279-01)

60/70

Testing method

Reference standard

22TCN279-01

ASTM D5 AASHTO T49

22TCN279-01

ASTM D113 AASHTO T151

3 Softening point (ring and

01

22TCN279-AASHTO T53- 96

22TCN279-01

ASTM D92 AASHTO T48

01

22TCN279-ASTM D6 AASHTO T47