4−26 402.03.4 Time Limitation. Friction course shall only be placed between the period of June 1st to August 31st. 402.04 METHOD OF MEASUREMENT.
402.04.1 Dense Friction Course. "Dense Friction Course" will be measured by the number of
tons actually placed in accordance with the Plans and/or as directed by the Engineer. 402.04.2 Ramp Friction Course. "Ramp Friction Course" will be measured by the number of tons actually placed in accordance with the Plans and/or as directed by the Engineer. 402.04.3 Ten Percent Limitation. Pavement thickness will be considered acceptable when placed within the tolerances specified. The total tonnage delivered and placed shall not exceed the tonnage calculated from the approved areas measured fr om the final surface course width, by the project length, and the pavement thickness in the Contract, by more than 10 percent. A thicker pavement may be acceptable; how ever, no payment shall be made for any quantity of asphalt concrete delivered which exceeds 110 percent of the final measured length, times measured width, times specified thickness, times unit weight. 402.05 BASIS OF PAYMENT. The accepted quantities of "Dense Friction Course" and "Ramp Friction Course" will be paid for at their respective contract unit prices per ton as listed in the Proposal. The prices so-stated constitute full and complete compensation for all labor, materials and equipment and all incidentals required to finish the work, complete and accepted by the Engineer. SECTION 403 ASPHALT EMULSION TACK COAT
403.01 DESCRIPTION . This work consists of furnishing, delivering, and placing a liquid asphalt
tack coat on bituminous concrete or Portland cement concrete, prior to the placement of a bituminous concrete overlay, all in accordance with these Specifications.
403.02 MATERIALS. The asphalt emulsion shall be RS-1.
403.03 Construction Methods.
403.03.1 Equipment. Application of the asphalt emulsion tack coat shall be by means of a pressure
distributor capable of producing a uniform continuous fine spray, through multiple nozzles, resulting in a uniform continuous coat of asphalt emulsion over the entire section to be treated. Any puddles of tack coat shall be squeegeed or broomed out or corrected by whatever means chosen by the Contractor which will achieve the required surface treatment. Any areas not receiving the specified coverage of tack coat shall be corrected and brought into compliance. 4−27
403.03.2 Application of Bituminous Material.
a.Application Rates. The asphalt emulsion shall be uniformly applied at the following rates over the entire existing surface to be overlaid:
1.Old Pavement. The application rate shall be 0.08 gallons per square yard, plus-or-minus 0.02 gallons per square yard.
2.New Pavement .
a.For new pavements at least thirty days old or have been opened to traffic: The application rate shall be 0.06 gallons per square yard, plus-or-minus 0.02 gallons per square yard.
b.For new pavements less than thirty days old and which have not been opened to traffic: A tack coat is not required.
b.Nozzle Settings . Tack coat shall be applied using the proper nozzle settings and the “double coverage” or “triple coverage” techniques as outlined in Chapter 5 of Asphalt Institute Publication MS-22, “Construction of Hot Mix Asphalt Pavements.”
c.Additional Requirements. The newly placed tack coat shall be allowed to break and set prior to paving. This process is defined as the separation of the asphalt from the water from within the emulsion which is signified by a change in color of the material from brown to black, the evaporation or removal of the resultant surface water and the adherence of the tack material to the underlying pavement. NOTE: The Contractor will be required to wait for this process to complete for up to one hour. At the end of this specified period, if the tack coat has not fully tr ansformed as defined herein (break and set), the Contractor may by his choice proceed to pave over the tacked area. Nevertheless, in any case the Contractor shall ensure that should any material be picked up by his equipment, that it be removed by whatever means, prior to its falling onto or affecting the newly placed pavement layer in any way. Special care shall be taken to eliminate or minimize equipment passage over tacked surfaces so as not to hinder or negate the tack’s effectiveness in the pavement bonding process . Furthermore, attention shall be given to gore areas to ensure that asphalt emulsion is not sprayed or tracked onto precast gore markers. This shall be accomplished by placing a covering, to be anchored in place, to prevent any movement, over the gore markers. Additionally, the Contractor shall not proceed to pave over any tacked surface until approval from the Engineer is given. Sections not approved by the Engineer shall be corrected and subsequently receive the Engineer’s approval prior to paving. Should there be multiple rejections of tack coat, the Engineer reserves the right to suspend paving and require the Contractor to submit a detailed action plan outlining those steps to be taken to ensure proper application of tack coat prior to the commencement of further paving operations.
403.04 METHOD OF MEASUREMENT. "Asphalt Emulsion Tack Coat" will be measured by the
number of square yards actually spread in the designated area(s) and at the specified rate, all in accordance with the Plans and/or as directed by the Engineer.
403.05 BASIS OF PAYMENT. The accepted quantity of "Asphalt Emulsion Tack Coat" will be paid
for at the contract unit price per square yard as listed in the Proposal. The price so-stated constitutes full and complete compensation for all labor, materials, and equipment, and all
Source: Rhode Island Standard Specifications (Bluebook), 2024 Edition. Pages 204–205 of 826.