07 bvt asphalt leveling course (sua l1 30 5 16)

SECURITY AND SAFENESS VRAMP – CONTRACT PACKAGE RAP/CP15 – MAINTENANCE OF NH6 FROM KM193÷KM233 IN SON LA ASPHALT LEVELLING COURSE TABLE OF CONTENTS I MATERIAL II MATERIAL FOR ASPHALT MIXTURE III CONSTR[.]

ASPHALT LEVELLING COURSE

TABLE OF CONTENTS

II MATERIAL FOR ASPHALT MIXTURE

III CONSTRUCTION METHOD

I MATERIAL

1 Reference Standards

The lastest version of the below standards shall be applied for the materials in this section:

TCVN 8818-2011 Liquid Bitumen - Technical requirements and Test methods TCVN 8819-2011 Hot asphalt concrete pavement - Requirements on

construction and acceptance TCVN 8820-2011 Hot asphalt concrete mixture — Design according to

Marshall method TCVN 8860-2011 Asphalt concrete - Test methods

TCVN 7572-2006 Aggregates for concrete and mortar - Test methods

TCVN 8864-2011 Standard Test Method for Measuring Road Pavement Surface

Roughness Using a 3.0 m Straight Edge TCVN 8865-2011 Method for measuring and assessment roughness by

International Roughness Index (IRI)

TCVN 8866-2011 Standard Test Method for Measuring Pavement Macrotexture

Depth Using a Volumetric Technique

AASHTO T176 Plastic fines in graded aggregates and soils by use of the sand

equivalent test TCVN 7493-2005 Bitumen — Technical requirements

TCVN 7494-2005 Bitumen - Method for sampling

TCVN 7504-2005 Bitumen - Test method for determination of adhesion with

paving stone

2 General Requirement for Materials

Material which will be used for the construction should be appropriate with material requirements mentioned in Section - Hot asphalt mixture under the Specification of asphalt concrete of upper and lower layers

The Contractor is not allowed to use materials before the prior approval of the Project Director The material should be stored according to requirements on material preservation under the Specification Section “Upper and lower foundation ”

2.1 Characteristics of requied mixture

The characteristics of the mixture are stipulated in Section- Hot asphalt mixture under the Specification of asphalt concrete of upper and lower layers

2.2 Submittal

The The contractor has to provide the Engineer the following documents:

- Samples of all materials which have been approved to be used The Project Director will keep these samples during the contract implementation for reference

- Documents reporting the testing result of all materials, which formula the mixture

is using and testing data of mixture density in accordance with the Technical Specification

II CONSTRUCTION METHOD

1 Trial section

- Following approval of the proposed Job Mix Formula by the Project Manager, the Conừactor shall place a trial section at a location agreed to by the Project Manager

- The test section shall be at least 100 meters of width and depth pavement agreed to

by the Project Manager

- The trial section shall be made using the approved mix design and proposed production and placing equipment and procedures

- The trial section shall meet all Field Quality Confrol and Testing requừements as well as all Material Acceptance reqmrements as detailed in Sections 13 and 14 herein

- If the trial section fails to conform to the specifications in any respect the necessary ' adjustments shall be made and the ừial repeated Permanent paving work shall not

- commence until a satisfactory trial has been placed and the Project Manager has approved a final Job Mix Formula

2 Placement of asphaltic leveling

- Asphalt Leveling Course shall be placed in locations as indicated on the drawings

or as required by the Project Manager

- Asphalt leveling courses shall be placed in compacted layers of not more than 75

mm thick In placing multiple layers, the shortest layer shall be placed first with the successive layer or layers extending over and covering the short ones

- The minimum thickness of asphalt leveling course to be laid using the “medium” mix is 3 cm If regulating thicknesses of less than 3 cm are required the Confractor shall achieve this by locally thickening the next layer immediately above and subject to the combined layer not being generally thicker than 8 cm and at maximum 10cm [albeit the Confractor will be paid for this local thickening as leveling material],

- Unless otherwise approved by the Project Manager, tack coat in accordance with Specification Section “Tack Coat” shall be placed prior to the initial application, in the areas to receive Asphalt Leveling

2.1 Preparation of surface to be covered

- Any and all distressed areas in the existing pavement shall be identified and limits for correction marked as dừected by the Project Manager, then appropriate repaừs shall be as dừected by the Project Manager, guided by the technical specifications and drawings for such repaừs When completed, these repaừs shall be approved by the Project Manager prior to any overlay or leveling activity proceeding

- Immediately before placing the bituminous mixture, the surface shall be cleaned of loose or deleterious material by sweeping with a power broom, supplemented by hand brooming if necessary

- After the surface has been appropriately cleaned, the surface will have a Tack Coat applied as per these specifications'or as dừected by the Project Manager

- If rain commences during the paving operation, the batch plant will be shut down until the rain stops at the location of paving With the Project Manager's approval, the mixture already loaded into the trucks may be placed, if the trucks have been appropriately covered to prevent any rainwater from directly contacting the hot mix, and if the mixture has remained sufficiently hot to allow proper laydown and compaction, providing freestanding water is not on the surface to be paved All freestanding water shall be broomed or blown off the paving surface using a compressor prior to placing the bituminous mixture The surface shall bere-tack coated when necessary, as directed by the Project Manager

- Where the surface to be covered does not meet the requirements of Specification

2.2 Spreading and finishing

- The mixture shall be spread and struck off to the grade, elevation, and cross section shape required

- Where the road is to be paved half width at a time The paving sequence shall be organized in such a way that the length of half width paving remaining at the end

of each days work is minimized Exposure of a longitudinal centerline joint greater than 250 mm to traffic is hazardous and should be avoided when ever possible If a longitudinal joint of greater than 250 mm must be exposed to traffic, the hazard shall be marked with appropriate warning devices as approved by the Project Manager

2.3 Compaction

- The temperature of the loose laid mix shall be monitored and rolling shall be earned out within the temperature limits given in Specification or as directed by the Project Manager

- The Project Manager may require that initial or breakdown rolling be accomplished with a pneumatic tired roller in order to assure more uniform compaction of variable depth leveling material place over irregular surfaces

- Rolling shall progress continuously as may be necessary to obtain uniform compaction while the mixture is in workable condition and until all roller marks and other irregularities are eliminated

- To prevent adhesion of the mixture to the roller, the wheels shall be kept properly moistened, but excess water will not be permitted

- Heavy equipment or rollers shall not be permitted to stand on the finished surface until it has thoroughly cooled or set

- The surface of the mixture after compaction shall be smooth and true to the longitudinal and transverse profiles desired to be achieved with this leveling process, as shown in the profile drawings and as otherwise directed by the Project Manager Any mixture that becomes loose and broken, mixed with dirt, or which is defective in any way, shall be removed and replaced with fresh hot mixture

3 Initial rolling compaction

To compact mixture of materials by vibrating sheep foot roller The roller is not 150 m further behind the milling machine The vibrating sheep foot roller compacts until there is no longer clear footprints on the material surface The rolling speed does not exceed 3 km/h The rolling shall be uniform on the entire width of each streak Number of rolling compaction is determined in the chart made in the trial process

4 Grading pavement

The motor grader is used to smooth the surface of initially compacted material layer Grader blade has to smooth the sheep footprints (or tire tracks), but create no trace deeper than the remaining footprints, and create cross slope, longitudinal slope and shape according to the pavement design

5 Final rolling compaction

The one and two-steel-wheeled vibration roller and rubber-tyred roller are used to compact the graded layers of materials Vibration is not allowed in the final turn of rolling Rolling compaction shall follow the diagram approved by the Supervision Consultant in the trial period of construction

During the process of grading and smoothing and rubber-tired roller’s working, strengthened surface must be kept moist by a water truck

6 Maintenance

Watering lightly and maintaining at least every 4-5 hours are required before traffic operation However, the heavy truck is limited and after at least 48 hours, a new layer

of pavement is overlaid In case of bad weather (little sunny and much rainy), 0.6 kg to 0.8 kg of emulsion is sprayed for every square meter and a thin layer of sand covers the surface during 2-3 days for the purpose of maintenance

After the maintenance period, the pavement layer shall be overlaid immediately If the pavement layer can not be done, the Contractor shall apply the regulating method and traffic flow distribution to prevent the vehicle from damaging the structure No longer than 10 days, the upper layer shall be done

III FIELD QUALITY CONTROL AND TESTING

1 Compaction requirements

Compaction requirements are given in Specification- section “Hot Asphalt Mixtures”

2 Mix quality control sampling

Samples of the following shall be taken for daily testing:

- All incoming aggregates to be used for the bituminous mixtures

- Bituminous mixture from haul trucks destined for the paving operations

- Core sample of in-place finished mixture, when necessary

In addition, when changing the job-mix formula, or in any event from time to time, additional samples will be taken as directed by the Project Manager to enable determination of any necessary material property

3 Mix quality control testing

The Contractor shall keep daily records of all his tests and these records shall be sent

to the Project Manager the following day The Contractor shall provide the Project Manager with the following results and records of tests carried out on each day’s

- Temperature of mix when sampled at the mixing plant and on the road (each truck load), fhl Marshall Stability and Flow as defined in this Snecification section of the three soecimens prepared for the determination of Laboratory Density for each type mix

- Asphalt content and aggregate grading of mix as determined by bitumen exfraction testing for at least two samples, one for the morning production and one for the afternoon production

- Air voids in laboratory compacted specimens as calculated based on the Maximum Specific Gravity of Bituminous Paving Mixtures performed on the same sample of mix used for the laboratory compacted specimens

- Voids in the Mineral Aggregate (VMA) calculated as per AI MS-2 6th Èd., Chapter 4

- Control charts showing a moving average of 5 sample results for extracted bitumen content, the 4.75mm, 2.36mm, 0.300mm and 0.075mm sieve sizes, as well as percent afr voids, shall be updated daily and posted at the plant site in clear view The Project Manager may request copies of these charts at any time