asphalt base course - rev1

JV GARBOLI CONICOS SpA / TIRRENA SCAVI SpACLUJ –NAPOCA, Xenopol street, no. 1

CONTRACTS 4.R.16 & 4.R.17MEHADIA SITE

Method statement

BITUMINOUSE LAYERS: BASE COURSE TYPE AB 2

APRIL 2007

JV GARBOLI CONICOS/TIRRENA

SCAVI MEHADIA SITE

METHOD STATEMENT Code: ITE 13Edition: 1Revision: 1Page: 1 / 9

BITUMINOUS LAYERS BASE COURSE TIPE AB 2

1.Purpose The Method Statement purpose is specification of actions, technological stages, of

machinery and materials used to the laying of the hot composition of mixtures for base course.

2.FieldThe procedure is to be used for the bituminous mixture type AB 2 prepared with hot

bitumen laid as base course as by SR 7970 - 2001, and SR 174/1-2002; 174/2-1997.

3.DefinitionsTechnical terms, notations according to STAS 4032/1 - 90, SR 7970/2001, SR 174/1-2002,

174/2-1997.

4.Reference docs (standards, technical norms)4.1 Execution design with afferent execution details4.2 Work tasks book4.3 Mentioned standards: SR 174/1-02; SR 174/2-97, STAS 7970 - 01, STAS 4032/1 - 90

5.Responsibilities

1.6.1. Work head is responsible to correct application of procedure and of technical execution documentation, of job attributions afferent quality records and its evidence.

1.6.2. Quality control responsible (CQ) on work, follows the correct application of this procedure, of execution design, correct elaboration of quality records and its evidence.

1.6.3. Machinery mechanics and formation electricians are responsible for assurance and working of machinery (mechanical broom, compressor for air, vibrating pavers, smooth compactor and rubber - Tyrell roller) mixture laying afferent and executed surfaces finished.

1.6.4. Formation laboratory are responsible for tests taking out samples and verifications, correct elaboration of quality records in standardized docs of laboratory, of imposed by tasks book records, before and during of work execution, and their in time and operative presentation to implicated parts.

6.Procedure

6.1. Preliminary conditions

Assurance at the laying spot, of the execution details and present procedure. Existence of Engineer’s approval for all contents materials (bitumen, aggregates, filler,

additives) and for bituminous emulsion. Existing of the mix design approved by Engineer. Assuring RFI sending for support layer and for starting preparatory works and laying

bituminous layer type AB2. The work spot personal are trained to know the execution projects, task book, and standard

machinery using way specific for this type of works and of present technical execution procedure stipulation.

1


SCAVI MEHADIA SITE



Assurance on site the materials, machinery tools and necessary instruments of road surface laying and finishing.

Existing of quality records forms stipulated in task book. Existing of orders forms, materials transport respectively (order tickets, transport tickets),

mixture transport including. Existing of quality records for base course, official report of quality reception respectively,

(verification on stratum compaction and level heights) for the laying sections.

6.2. Preventive actions

The training and observing that the execution personnel uses protection equipment, utilizing will be followed, overall, protective helmet, wood sole sandals according to work security technique in force.

The knowledges by the executing personnel of protection work will be verified also of PSI norms and especially of under traffic execution work norms, particularly when the laying is executed on the half of carriageway.

Before of laying starting will be verified the suitability of site signing for public traffic.

6.3. Execution

6.3.1. Preparatory worksThe bituminous mixture laying on the designed lane will be allowed only after the following

operations are effectuated: Reception of support stratum according to tasks book stipulations. Surveying checking of final heights, of support stratum surface slope and elaboration of

quality records by official quality reception report by works stages confirmed. Support stratum preparation . Verifying and adjustment for work to the designed parameters of laying and compaction

machinery.

6.3.2. Laying of bituminous mixture on a trial section.Testing will be made on the experimentally road section of at least 250 to of mixture

according to Technical Specifications clause 213 C4.4. To be followed: 6.3.2.1. The adjustment of technical work parameters of the laying and compacting workshop;6.3.2.2. The established of under sections (number and each length) for the determination of

compacting characteristics (numbers of passes, compacting degree) conform technical specification.

6.3.2.3. If the stipulated compaction degree is not realized, a new test will be done, changing the work conditions by thickness laying modifications, of laying temperature or of the laying workshop used.

6.3.2.4. The part of the experimental road section executed, with the best results, especially regarding the compaction degree, will take in account as a reference section for the other part of work.

6.3.3. Preparing the layer support stratum

The following stipulations as a general prescription of execution will be considered to the bituminous mixture laying:

2


SCAVI MEHADIA SITE



6.3.3.1. Before laying, the support stratum will be verified to the designed heights adjusted like in the execution project

6.3.3.2. All deficiencies are rectified, then the support stratum surface is cleaned obligatory and the work joint are primed.

6.3.3.3. The support stratum priming must be uniform sprayed with special device on which the binder quality per m² can be adjusted according to the support stratum nature.

6.3.3.4. In case that the support system presents degradations (cracks) the totally cover of its surface with geo synthetic reinforced is necessary.

6.3.3.5. The support stratum surface to which the bituminous pavement are laying has to be dry and clean.

6.4. Tack coatIt is compulsory on the whole surface before laying bituminous pavements. According to

the support stratum nature the 0,3 - 0,5 kg/ mp residual bitumen will be used for primingAfter priming, the necessary time(20 min. to 45 min., according to environment’s

temperature) for solvent volatilization (emulsion breaking) must pass.In case of open bituminous surface the priming must be done to the internal faces of kerb

and work joints too.

6.5. Laying6.5.1. At laying, the minimum temperature is necessary to be achieved according to the

specifications.6.5.2. In accordance to SR 174/1&2 stipulations, the mixture laying must be done by mechanical

means, with a finisher that has a good pre compaction, and that can follow the designed levels and cross fall. Only in the exceptional cases, the manual laying is permitted (narrow spaces). In this case, the unloading of mixture is to be done in successive piles, the mixture laying in this case is to be by the slave transport and from slave with shovel (not by throw) levelling will be mode with rake and the transverse profile achievement with pattern, which, for verification, move in the road length supported by the height moulds adequate height, before compaction, the mixture thickness is to be 20% higher the prescribed thickness for the compacted stratum.

6.5.3. Checking with a 3 meter straight edge are to be effectuated after the first passing of the roller, than the surface corrections are effectuate, to achieve adequate uniting of new laying mixture with before laying mixture, rolling being continuity after that.

6.5.4. In case of mechanical means, the uniform laying of mixture is followed to have by pre compaction a levelled surface, which needs the minimum corrections. In this sense the pedestrian and vehicle traffic are forbidden on laid but no compacted mixture.

6.5.5. For the plants of 30 - 40 t/hour capacity, using a mechanic finisher is compulsory to achieve the spreading, levelling, heating, vibration works so achieving a pre compaction.

6.5.6. Using pavers with vibratory beam is compulsory because without vibration, levelling is only apparent, at the surface, but inside the mixture is non uniform, during the rolling unevenness can appear and corrections are necessary, the quality of road surface is reduced regarding smoothness.

6.5.7. The laying rate must be in such a way dimensioned, in corroboration with mixture plant rhythm, so that laying could be achieved without stopping. The pavers must establish laying levels by electronic devices with sensors or with stretched thread, or skate and it can work on variable width 2,5 - 12,5 cm.

3


SCAVI MEHADIA SITE



6.5.8. After pavers adjustment checking regarding laying thickness, the height and slope of project profile which has to be achieved, any modifications during the work is not permitted, only in case these have to be adapted to project or tasks book. The modifications have to be adapted to task book and project. Modification has to be made gentle graduated without shocks, in accordance with pavers speed, avoiding the Passover of limit positions of stipulated by project beam, to avoid the return.

6.5.9. The laying on the whole road width is preferable, with a single paver, or by two pavers, in parallel. In this case or when the mixture is transported in reverse direction of laying, the average distance between them have to be about 5 m but not more then 30m. When the mixture is transported on the road executed in laying direction, the distance between pavers, have to permit passing of transport means over compacted mixture. When these are not possible the work will be executed on traffic lane with suitable width, the narrowest lane being executed the first.

6.5.10. On the level stretch sections or with small declivity, where transverse profile in unique slope, in rainy period, the upper lane will be first executed to avoid the rains water accumulation which could appear in case of executed the lower lane at first.

6.5.11. On declivities, the mixture is laid in climb sense.6.5.12. Longitudinal joints between lanes will be placed staggered comparative with the support

stratum joint, at least 10 - 20 cm, and cross joint with min. 2m.. When three lanes covers the total width, it will have to be avoided that the median lane be last executed.

6.5.13. In outstanding cases, in cold weather period, asphalt can be laid on short length and for compaction machinery width, and only approved by the Engineer, according to Technical Specifications clause 213 C4.4.

6.5.14. When work is resumed on adjoining lane, the edge of previous executed lane is primed with bituminous emulsion. Using the bituminous fluxed with solvent is admitted only when emulsion isn’t disposable, and in small quantities.

6.5.15. When the work is resumed on the same lane, to cut on the whole thickness the cross joint.6.5.16. Successive stratum will not be stopped in the same transverse profile but with at least 15 -

20 cm. staged.

6.6. Compaction

6.6.1. General remarks 6.6.1.1. To the bituminous mixture laying compaction the temperatures by the table below”

Bitumen The mixture temperature (C)Maximum temperature during

compaction (C)At the plant At laying At the beginning At the end

D 60 / 80 165…175 min. 155 min. 150 min. 110D 80 / 100 160…170 min. 150 min. 145 min. 105

6.6.1.2. The compaction is very important because this operation influences directly the stratum service life. When the compaction is performed at 125 - 130 0C, good compaction results are obtained with small compaction energy.

6.6.1.3. The compaction is indispensable in the laying mixture to obtain the optimum physical - mechanical characteristics values and of deformability (apparent specific weight, voids percent, compression resistance, high temperature stabilizing, deformation and elasticity modulus) and a good road surface, assuring the quality and durability for the road system.

4


SCAVI MEHADIA SITE



6.6.1.4. The following factors influences the compaction quality: o mixture layingo laying method (mechanical, manual)o compaction machinery features (weight, speed, station, vibratory,

metallic smooth rollers, rubber - tyre roller)o the compaction plant structureo working temperatures (laying and compaction, mixture type)

6.6.1.5. During the mixture laying, the scope is to achieve a homogeneous compaction, no surface will be less rolled than other, in order to avoid cooling.

6.6.1.6. Basically the compaction is to be effectuated of straight line, the changing of rollers direction must be done on compacted mixture where the roller leaves no traces.

6.6.1.7. In all cases, the rolling is to be executed in the single round to obtain the prescribed compaction in the shortest time, on the hot mixture respectively. The mixture temperature will be frequently verified to obtain a good leading of compaction system.

6.6.2. Establishing the rollers passing number of for each work point.At the site opening, an experimental road section will be executed with fresh mixture which

will be laid and compacted, in the presence and with approval of the Engineer, with existent rollers, to verify the necessary number of passing for obtaining prescribed compaction, because these are direct influenced by the nature and composition of mixture.

From executed road section, after mixture cooling (usually min. 24 h after compaction) the intact cores will be took over, on which the compaction degree will be determined in laboratory. The diagram compaction degree - number of passing in accordance to prescribed compaction degree will be elaborated. This number of passing will be observed to execution..

6.6.3. Compaction workshop

The compaction workshop is composed from a rubber-tyre compactor type Bitteli RG 248 by weight = 20 to and a metallic smooth roller type Bitteli Grifone DTV 100 by weight = 10 to. The number of passes was established in the follow of executing of trial sector (located on km 1+260 – 1+701, RHS, By-Pass Mehadia) in the presence and having the accord of the Engineer: 10 passes with rubber-tyre compactor and 4 passes with metallic smoother compactor.

6.6.4. Compaction technology

6.6.4.1. The mixture has to be compacted in the shortest time after laying to benefit of advantages gave by rolling to high temperature.

6.6.4.2. The compaction will be effectuated in road length from the edge to axis. Each roller run will be superposed lateral with at least 10 cm above precedent run.

6.6.4.3. In case of work on half of lane width, when the work on the second half is beginning, the finished edge of mixture will be primed and the compaction will be started from longitudinal joint . In the same way will restart the work after interruption.

6.6.4.4. The work joints of the superposed stratum will be staggered at least 10 cm face to face. 6.6.4.5. The roller will execute long passing. First passing will be done with law speed 2 – 4 Km/h

and follow passing with higher speed 4 – 6 Km/h. The 6 Km speed will not be surpassed.6.6.4.6. Running inversion and direction changing will be progressive effectuated with out

shocks, for avoiding the waving in face of rollers. Stopping in the road lengths will be staged between them.

5


SCAVI MEHADIA SITE



6.6.4.7. Unevenness which appear in face on surface will be corrected by mixture addition, levelling with rake and verified by template after first pass of the roller.

6.6.4.8. Avoiding of hot mixture adhesion to metallic smooth rollers will be assured by their wetting them.

6.6.5. Compaction degree

6.6.5.1. Compaction degree is a relative dimension which defines compaction efficiency and is obtained by the report of apparent density of compacted mixture determined according STAS 1338/2 - 87 by taking out samples by stratum, to apparent density determined in standard conditions by Marshall laboratory sample cylindrical, from the same mixture.

6.6.5.2. It will be followed to obtain the characteristics, according to Technical Specifications, SR 7970 and mix design approved by the Engineer:

Mix AB2 - A01Bitumen 80 - 100

Bitumen 60 - 80

Bitumen (%) 4.3 3.4 … 5.0 3.4 … 5.0

Tests on cylinders

Stability (60 0C) (KN) 9.7 min. 5 min. 5.5Creeping (mm) 3.3 1.5 … 4.0 1.5 … 3.5Density (kg/m3) 2300 min. 2200 min. 2200Water absorption (%) 4.8 2 … 8 2 … 8Holes volume (%) 6.5 2 … 8 2 … 8Stiffness (KN/mm) 2.9

Tests on cubes

Density (kg/m3) 2263 min. 2150 min. 2150Water absorption (%) 5.1 2 … 10 2 … 10Resistence at 22 0C (N/mm2) 2.7 min. 2.5 min. 2.5Resistance diminution at 28 days

(%) 26.9 max 30 max 30

Tests on core samples

Density (kg/m3) … min. 2150 min. 2150Water absorption (%) … 2 … 10 2 … 10Compaction degree (%) … 96 96

6.6.5.3. After finishing the compaction, the bituminous mixture stratum has to have an compaction degree at least

6

LayerMinimum compaction

degree (%)Base 96


SCAVI MEHADIA SITE



6.6.6. Compaction control on site6.6.6.1. Operative the control is effectuated by monitoring of prescribed passing

number for rollers.6.6.6.2. For laboratory testing, periodically will be token core sample, for

determining the achieved compaction degree according with par.6.6.5.2. The cores will be sampled 24 hours after compaction.

6.6.6.3. Fast determination can be done with modern devices (i.e. gamma densimeter).The compaction degree has to correspond to mentioned values in the above table.

6.7. Checking of the asfhaltic mixture

6.7.1. Testing the laid bituminous mixture’s temperature.In accordance to SR 174/1-01; 167/2-97, the bituminous mixture must have at laying and

compaction the temperatures showed in table 1, according to binder type. Temperatures are verified with different type of thermometers with maximum200 C (with mercury of thermocouple)

6.7.2. Verifying of road surface uniformity After bituminous pavement execution, the uniformity of road surface is made:- longitudinal profile- transversal profileMeasurement of in a transversal and longitudinal profile is done using a 3 meter straight

edge. The straight edge is moved in the length of road upon two generators situated at 1 m and 2m to carriage way edge.

The unevenness in mm by gradation key introducing it between straight edge and pavement surface are noticed in a table.

The road surface is suitable if the number of profiles in which the measured unevenness over running maximal allowed unevenness (see the table below) is under 5% from the number of measured profiles, and these unevenness are not continuous.

6.7.3. Measuring longitudinal profile using topographic apparatus.The topographic apparatus using (level or theodolite) permit o very exact certification of

road longitudinal profile. The measuring of longitudinal profile heights are achieved on a long axis for roads and on the axis and channel for street. The measuring done after works determination represent the longitudinal profile of road. Usually precision of measuring is 1mm

7. Records Request for inspection

7


SCAVI MEHADIA SITE



Produced mixture registry. Daily command.

Temperature registry at plant.Temperature registry in situ.Transport tickets.Testing reports for physical-mechanical characteristics Marshal.Testing reports on aggregates, bitumen, filler.Testing reports for compaction degree on cores sample.Testing reports for priming specific density.Quality certificate registry for bitumen, filler emulsion, additives.Quality Report for the prepare support stratum reception.Quality Report for base stratum reception.Quality Report for course reception.Survey tables with performed levels.Form F for acceptance of works for payment.

Nonconformity.

8. RISK ASSESSMENT

LEGISLATION: - The Law no.90/1996 – The Law of the protection of the work; - Norms methodological by the applications of the law of the protection of

the works; - General norms by the protection of the works;

- Specifies norms by safety of the works for works by the exploitation and the care of the roads and bridges.

The workers involved in the activity describe is obligate to acquire the legislation and to wear the equipment by protection.

The foreman has obligation to check the physical state of the workers and operators by machines from the point by work, at beginning of the work and on the during day by work. At beginning of the day-work make the daily instruction by protection.

The chief by motorcade is obligate to check the physical state of the drivers and to make the daily instruction by protection of the work at beginning of the day-work.

The responsible with the safety make the periodic instruction (monthly) of the all staff.Respect of the Plan of the Traffic Management, chapter 2.4 whereby mention : - the staff which in zone of the carriage-way is obligated to keep reverberating vests; - the signalizing of the work point shall be made as per schedule by signalizing approved by

N.A.R. and I.G.P. Bucuresti; - on all sectors of road with reduced visibility is obligatory putting the pilots for street-traffic

control with reverberating vests, shunting signals and if is case emission receive stations; - is interdicted the staying of the staff on the carriage-way without the work areas; the circulation

of the workers on public roads making on the left side, on shoulder, and when this miss, nearly by the edge of carriage-way.

8. List of machines and gears:- lorries Astra and Iveco (capacity by transport = 20 and22to) = 6 pieces.- spreader Marini with vibrant beam.

8


SCAVI MEHADIA SITE



- rubber – Tyrell type Bittelli RG248, weight = 20 to.- metallic smooth roller type Bitelli Grifone DTV100, weight = 10to.- machine for spreading bituminous emulsion type Gutherm SPE 50, quantity by emulsion

spread = 0,5 – 3 kg/mp, in function of sped of the vehicle .

Responsible technical with execution Quality Manager,Dondas Mihai Dutescu Daniel

9

asphalt base course - rev1

Documents