SECTION 05100 - PRIME COAT

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The amount of binder used in each sprayer run shall be measured by dipping the distributor binder tank on level ground immediately before and after each run.
The average binder application rate achieved on each sprayer run, calculated as the volume of binder used divided by the product of the number of nozzles in use and the spacing between nozzles, shall lie within + 5% of the rate directed by the Engineer. The achieved application rate shall be calculated before any subsequent spray run is made and any necessary adjustments shall be made to ensure that the directed rate of application is maintained in subsequent runs.
Spraying shall cease immediately if any defect develops in the spraying equipment and shall not recommence until the fault has been rectified
Following the spraying of the binder, any areas of pooling or excessive binder shall be continually redistributed across the sprayed surface, until absorption and curing of the binder prevents further movement of the binder. A pneumatic typed roller shall be used for this purpose.
Maintenance of Prime Coat
The Contractor shall maintain the primed surface to the specified standard until it is overlaid by the subsequent course. The subsequent course shall be applied only after sufficient time has elapsed to allow the primer binder to be fully absorbed and to harden, in order to avoid flushing and softening of the subsequent course.
The delay period, which shall be as directed by the Engineer, shall be a minimum of two and generally not more than fourteen days, depending on the traffic, weather, binder and base materials.
Traffic shall not be permitted on the primed surface until the bituminous material has penetrated and dried and, in the opinion of the Engineer, will not pick up under traffic. In exceptional circumstances where it becomes necessary to permit traffic prior to that time, but in no case sooner than four hours after the application of the bituminous material, clean cover aggregate shall be applied as directed by the Engineer and traffic may be permitted to use the lanes so treated. Cover aggregate shall be spread from trucks in such a manner that no wheel will travel on uncovered wet bituminous material. When applying cover aggregate to a treated lane that adjoins a lane yet to be treated, a strip at least 20 cm wide along the adjoining edge shall be left uncovered, or if covered shall be uncovered when the second lane is being prepared for treatment, in order to permit an overlap of bituminous material as required above. The use of cover aggregate shall be the minimum extent possible.
Field Quality Control and Testing 
A bitumen sample and certificate shall be provided for each delivery of bitumen to the site of the works.
Samples of the Prime Coat shall be taken from the distributor as directed by the Engineer.
The bitumen distributor shall be inspected and tested as follows:
Prior to the commencement of spraying works on the Contract;
Every 6 months or every 150,000 liters of binder sprayed by the distributor, whichever is the more frequent;
Following any accident or modification to the distributor, or any other occurrence, which in the opinion of the Engineer warrants rechecking the distributor.
The result of the wet sieve testing of the proposed cover aggregate shall be submitted to the Engineer for approval prior to any use of that aggregate.
A detailed written record of daily surfacing operations, including the location, binder used on each sprayer run, application rates achieved, and area covered shall be made and submitted to the Engineer.
Equipment
General
The equipment used by the Contractor shall include a power broom and/or a power blower, a pressurized bitumen distributor, equipment for heating bituminous material and, for Prime Coat work, a pneumatic tired roller or other means of dispersing excess primer binder. The Engineer will not permit the use of gravity distributors.
Distributor Capacity
The distributor shall have a minimum capacity of 1,000 litters.
Distributor Application
The distributor shall be so designed, equipped, maintained and operated that bituminous material at even heat may be applied uniformly on variable widths of surface, at a controlled rate of transverse and longitudinal spread within ± 10 percent of the required rate of application.
When so directed by the Engineer, the Contractor shall make equipment and operators available for field testing and shall supply any other assistance required for this purpose.
The transverse distribution of bitumen application rates produced by the distributor shall be tested by passing the spray bar over a test area laid with 25 cm x 25 cm sheets of absorbent material with a binder-proof backing, which are weighed before and after the spray application. The difference in weight shall be used in determining the spraying rate actually applied to each sheet and the variation from the mean rate for any sheet across the full width sprayed shall not exceed 15 percent.
Distributor Spray Bars and Spreading Equipment
Spray bars shall be of the full circulating type. Spray bar extensions shall also be of the full circulating type. The spray bar shall be adjustable to maintain a constant height above the surface to be treated. The spray bar nozzles shall be slotted and shall be of such design so as to provide a uniform unbroken spread of bituminous material on the surface. Levers shall operate the valves so that one or all valves may be quickly opened or closed in one operation. The distributor and booster tanks shall be so maintained at all times as to prevent dripping of bituminous material from any part of the equipment. A device for hand spraying of the bituminous liquid shall also be included as part of the distributor.
The spreading equipment shall be provided with a separate power unit for the pump or a variable displacement pump driven by a hydrostatic transmission that results in a uniform application of bituminous material, in controlled amounts. The distributor shall have satisfactory heating equipment in order to provide the full range of application temperatures for the bituminous material being used.
Instrumentation/Calibration
Distributor equipment shall include a tachometer, pressure gauges, a calibrated tank dipstick, a thermometer for measuring the temperature of the tank contents and an instrument for measuring the speed of travel at low speed. All measuring equipment on the distributor shall have been recently calibrated and an accurate and satisfactory record of such calibration shall be supplied to the Engineer.
Spray Chart and Operations Manual
The distributor shall be equipped with a spray chart and operations manual, which shall be carried with the sprayer, in good condition, at all times.
The operations manual shall include pipe flow diagrams and full instructions for all operations of the distributor.
The spray chart shall show the relationship between speed and application rate for the bitumen distributor being used as well as the relationship between pump speed and the number of nozzles in use, based on a constant bitumen output per nozzle. The constant nozzle output (liters/min) shall be noted on the spray chart as well as the spraying pressure.
The spray chart should also show the height of the spray bar from the surface and the correct horizontal angle of the spray nozzles to ensure triple overlap of the nozzle fans (i.e. the width of road coated by each nozzle is exactly three times the spacing between nozzles).
Unacceptable Equipment
The Engineer will have the right to stop the use of any equipment or plant which he deems to be inferior to the quality required and to instruct the removal of such equipment and to have it replaced by suitable equipment or to alter the method of operation at any time.
The Contractor shall immediately comply with such instructions without being entitled to any indemnities or extensions as a result of such instructions. The Contractor shall not be allowed to use any equipment or plant before obtaining the approval of the Engineer, and the Contractor shall undertake to follow sound technical methods in operation and to engage skilled and trained operators, mechanics and labor to carry out the works. The Engineer will have the right to expel any operators, mechanics or labor and to instruct suitable replacement thereof at any time he deems such action is necessary.
Measurement and Payment
Measurement for Payment
The quantity of asphaltic material measured for payment shall be the actual number of square meter coverage accepted.
Any cover aggregate used shall be considered incidental to the work of achieving a satisfactory Prime Coat and shall not be measured or paid separately.
The work of preparing and maintaining the formation on which Prime Coat is to be placed will not be measured or paid under this Specification section.
Final cleaning and preparation of the surface and maintenance of the completed prime coated surface shall be considered incidental to the work of achieving a satisfactory Prime Coat and shall not be measured or paid separately.
Measurement of Rectified Work
Where rectification of unsatisfactory Prime Coat has been directed by the Engineer, the quantities to be measured for payment shall be those that would have been paid if the original work had been acceptable. No additional payment will be made for the extra work or quantities or testing necessitated by the rectification.
Basis of Payment
The quantities as determined above shall be paid for in accordance with applicable Unit Prices as indicated on the Bid Price Schedule. Payment shall be deemed full compensation for furnishing and placing all the material, including any cover aggregate and including all labor, equipment and tools, and any incidentals necessary to complete and maintain the work prescribed in this Specification section.
Pay Item
Description
Unit
05100-1
Prime Coat
m2