Rehabilitation of Kiribathgoda – Sapugaskanda road
Section of Road (From 2+500 km to 5+000 km)
CONTRACT NO. RDA/DW/WP/GOSL/443
Contractor: Hovael Construction (Private) Limited Revision:
Document No:QA/MS-06/PT
Date of Issue:
METHOD STATEMENT FOR PRIME COAT & TACK COAT
1.0 SCOPE
Prime Coat
Prime coat would act as a protective measure for the Aggregate Base, prior to laying surface
courses.
Tack Coat
Tack Coat would be applied over existing pavement so that to provide bond between two
layers.
2.0 ABBREVIATIONS
SEO -Safety & Environmental
PPE -Officer
Personal Protective Equipment
MDD -Maximum Dry Density
OMC -Optimum Moisture Content
QAE -Quality Assurance Engineer.
SE -Site Engineer
TO -Technical Officer.
QAS -Quality Assurance System.
ME -Materials Engineer.
TS -Technical Specification
QCI -Quality Control Inspector.
SSCM -Standard Specification for
Construction & Maintenance of
Roads and Bridges (Volume IV)
3.0 RESOURCES
Man power Equipment
PM Water Bowser
SE Brooms/ Brushes
ME Air Compressor
SEO Distributor
QAE Level Instruments
Lab Technicians & Helpers Safety Inventory
Surveyor 1. Barrels
Survey Helpers 2. Signal torches
Supervisor/Foreman 3. Traffic Jackets with Retro
Operator (Water Bowser) reflective patches/stripes
Operator (Sprayer Bowser) 4. Sufficient barricade tapes.
Operator (Broomer) 5. Barricade boards with Retro
Operator (Air Compressor) reflective stripes
Skilled & Unskilled laborers 6. Stop and Go signs
7. Road works ahead boards
8. Traffic cones
9. End signs ( road works end)
10. Road Narrow Signs
11. Arrow Signs
3.1 Material
Prime Coat
1. The prime coat shall consist of medium curing cutback bitumen (25 – 45 percent)
MC30,MC 70 or MC 250 complying with section 1702.2 of SSCM
2. The Blotting material shall be crushed rock or river sand having grading limit of
Table 1701-9 of SSCM.
Tack Coat
3. The Tack coat shall consist of medium curing cutback bitumen (10- 20 present) or
CRS 1.
4.0 METHODOLOGY
4.1 Prime Coat
4.1.1 General
1. The prime coat would be applied over the prepared approved aggregate base course
which is laid in accordance to the designed cross sections levels, given in the
drawings.
2. Dense graded aggregate base should be done on a prepared and accepted sub-base
course or other roadbed in accordance with the specification and specific
requirements of the contract in conformity with the required lines, levels, grades,
dimensions and cross sections.
3. Quality of the work would be secured through the careful control of the materials as
well as workmanship.
4. Adequate safety control measures would be provided to prevent from any damage or
danger to the public and the personnel involved in the work.
4.1.2 Weather Limitations
The Prime Coat would be applied in dry weather condition and when ambient
temperature is not in very low. If rain is very imminent the prime coat application would
not be done.
4.1.3 Surface Applications
1. The application rate of bitumen and percentage of cutback to be used shall be
instructed by the Engineer on site.
2. The rate of spread of bituminous material for the prime coat shall be 1.0 liter per
square meter with tolerance of 0.1 liter per square meter, as per the Technical
Specification.
3. Prime coats would be applied only when the existing surface is dry or sufficiently low
in moisture and assure uniform distribution of the bituminous material, when the
atmospheric temperature is above 15ºC, and when the weather is not foggy or rainy in
the opinion of the Engineer.
4.1.4 Preparation of Surface
1. The layer to be primed would be cleaned of all loose and deleterious material with air
compressor without damaging to the pavement surface.
2. Scale, clay and other foreign material would be removed by hand where instructed.
3. Prime coat would be applied when the moisture content is satisfactory for full
penetration as instructed by the Engineer.
4. In this manner, the surface would be prepared to expose a hard tight mosaic of large
aggregate in the base course.
5. Before prime material is sprayed the layer to be primed would be checked for
compliance with the surface and other requirements specified.
6. Sections not complying with the specification would be corrected and remedial
measures would be taken to the satisfaction of the Engineer before priming.
4.1.5 Application of Prime Coat
1. Prime coat would be applied by means of a bitumen distributor for large areas and by
lance and nozzles for small and inaccessible areas so as to achieve an even
distribution of the prime coat over the surface.
2. At the start and end of each run approved material would be spread over the surface
to ensure a clean joint between adjacent runs and to protect adjacent surfaces and also
to permit the distributor to build up sufficient speed so that at the start of each run the
distributor shall be traveling at the correct speed for the instructed application rate.
3. The distributor shall be functioning properly in accordance with the manufacture’s
instructions with all spray nozzles functioning and delivering prime coat at the same
evenly distributed rate.
4. The prime coat application rate would be achieved by two or more repeated
applications when necessary to avoid flow of prime coat on steep cross falls or
gradients.
5. Any areas deemed by the Engineer to be deficient in prime coat after passage of the
distributor shall be made good by spraying with a hand lance.
6. Road furniture such as kerbs, post boxes, sidewalks, utility poles, manhole covers etc
would be protected from prime coat spray with adhesive paper.
7. The spraying temperatures for prime coat would be as table 501.2 of the specification.
8. The rate of application shall be checked by tray test.
4.1.6 After Care
1. Following the prime coat application, the primed surface would be allowed to cure
for a minimum of 24 hrs without being disturbed so as to allow the prime coat to
penetrate the surface fully unless full penetration and curing has taken place in a
shorter period.
2. As soon as the primed surface has cured sufficiently, the road where practicable, be
opened to public traffic for a period of 14 days or less if agreed by the Engineer.
3. During this period the primed area under traffic would be maintained and all damaged
caused by traffic would be repaired as instructed by the Engineer.
4.2 Tack Coat
4.2.1 General
This work would consist of an application of a tack coat to an existing pavement prior
to construction of a surfacing so as to provide a bond between the two layers.
4.2.2 Weather Limitations
The tack Coat would be applied in dry weather condition and when ambient
temperature is not in very low. If rain is very imminent the tack coat application
would be not done.
4.2.3 Preparation of Surface
1. Prior to application of the tack coat, the surface would be dried thoroughly swept and
rendered clean of clay, dust and any other extraneous material.
2. The tack coat would be applied when the surface is dry.
4.2.4 Application
1. This would be applied at ambient temperatures and it would be warmed to facilitate
uniform application. Where necessary mechanical sprayer, hand sprayer or by any
other means would be used for the application of the tack coat.
2. The rate of spread of bituminous material for the prime coat shall be 0.4 liter per
square meter with tolerance of 0.1 liter per square meter, as per the Technical
Specification.
3. In areas being treated, precautions would be taken to prevent the surfaces of
structures and trees being spattered, and the binder getting into channels, catch pits
and drains.
4. Tacked surfaces would be allowed to dry until the proper condition of tackiness is
achieved to receive the surface course.
5. Until the surface course is placed, the tack coat would be protected from damage.
6. Tack coats would not be left applied for more than about 6 hrs without the placement
of the surface course.
5.0 SAFETY PLAN
5.1 Site Staff and Labor
Personal Protective Equipment (PPE) such as safety boots and helmets
would be provided with workers.
All tools, plant, equipment and temporary facilities and all other items
use to carry out the work should be in a safe, sound and good condition.
Signalmen would be deployed if the work spaces disturb traffic flow in
the main road. A traffic supervisor would also be deployed to take responsibility over
the traffic control.
First Aid Facilities: First aid facilities such as a first aid box would be
made available for in case of minor injury treatment.
6.0 ENVIRONMENT CONTROL
a. Strict environmental compliance would be implemented with regard to disposal of any
demolished debris. The debris in question would be transported and dump in the disposal areas
as approved by the Engineer.
b. Disposable materials would not be dumped into streams or unauthorized areas.
c. Effort would be made to clean the affected road surface, i.e., brushed off, and washed off to
prevent from dust pollution.
d. Every effort would be made not to disturb prevailing surface water run off. In case of
prevailing surface water run off could be disturbed then investigation would be conducted to
find out proper irrigation channeling system.
7.0 SOCIAL ASPECT
a. Workers involved in construction in this area would be educated with regard to HIV/AIDS
prevention. Separate HIV/AIDS prevention education program would be conducted along with
Medical Officer of Health / Public Health Inspector.
b. Relevant authorities would be educated with regard to project affected people prior to start
work in these areas. Leaflets and other sources of education material with regard to
construction shall be distributed among the project affected people.
c. Every effort would be made to minimize the disturbance from the project.
d. If not convince to an affected person with regard to disturbances every effort would be made to
direct them to Residents Engineer for amicable settlement.
8.0 ATTACHMENTS
Annex A - Checklist – Prime Coat
Annex B - Checklist – Tack Coat
Annex C - Inspection & Test Plan
9.0 REFERENCE
Standard Specification for Construction & Maintenance of Roads and Bridges (Volume IV)
