376 P= Percent of contract unit price allowed (Table 1005- 1) CP= Current Price for asphalt cement (bituminous material), as determined by the Department, for the month in which a deficiency was noted. This value will be posted on the ADOT Contracts and Specifications Group website, on or shortly after the last Wednesday of each month. MEMBRANE : 410- 1 Description: The work under this section shall consist of furnishing all mater ials including asphalt -rubber, tack coat , and cover material , and applying the materials in accordance with the details shown on the project plans and the requirements of the specifications. 410- 2 Materials: 410- 2.01 Tack Coat: Prior to the application of the asphalt rubber stress- absorbing membrane, the existing pavement surface shall be cleaned of all objectionable material and tacked with a light coat of bituminous material in accordance with the requirements of Section 404 of the specifications. The cleaning of the surface, the tacking of the surface, and the type of bituminous material used shall be acceptable to the Engineer. The amount of bituminous material used shall be as directed by the Engineer; however, the application rate shal l not exceed 0.06 gallons per square yard. 410- 2.02 Asphalt -Rubber: Asphalt -Rubber shall conform to the requirements of Section 1009 of the specifications. The type of asphalt -rubber shall be as shown in the Special Provisions. The crumb rubber gradation shall be Type A conforming to the requirements of Section 1009 of the specifications . 410- 2.03 Cover Material: Cover material shall conform to the requirements of Subsection 404- 2.02(C) of the specifications. The class of cover material shall be as show n in the Special Provisions. Prior to placing, the cover material shall be precoated with any grade of PG asphalt cement which meets the requirements of Section 1005 of the TABLE OF CONTENTS INDEX 377 specifications. The precoating shall be accomplished by mixing at a central plant until the aggregate is thoroughly coated. The cover material shall have a minimum t emperature of 250 degrees F at the time of precoating with asphalt cement. The cover material shall be precoated with approximately 0.40 percent to 0.60 percent asphalt cement, by weight of the aggregate. The final percentage of asphalt cement used for precoating will be as directed by the Engineer. The end result shall be a dust free material. 410- 3 Construction Requirements: 410- 3.01 General: All equipment used to mix and apply asphalt -rubber material shall meet the requirements specified under Subsection 404- 3.02(A) of the specifications. The equipment shall also be capable of maintaining a uniform, homogeneous mixture throughout the operation. 410- 3.02 Application of the Asphalt -Rubber Stress -Absorbing Membrane: Asphalt -rubber stress- absorbing membranes shall be placed between the dates below for the average elevation of the project. Average Elevation of Project, Feet Beginning and Ending Dates 0 – 3499 0 – 3499 3500 – 4999 5000 and over March 15 – May 31 September 1 – October 31 April 15 – October 15 June 1 – September 15 The existing pavement shall be cleaned in accordance with the requirements of Subsection 404- 3.04 of the specifications. After cleaning and prior to the application of the membrane, the existing pavement surface shall be treated with a tack coat as hereinbefore specified. Placement of the asphalt -rubber membrane shall be made only when all of the following conditions are met:
distributor, aggregate spreader, haul trucks with cover TABLE OF CONTENTS INDEX 378 material, and rollers are in position and ready to commence placement operations. The distributor shall be capable of spreading the asphalt -rubber mixture in accordance with the tolerances specified in Subsection 404- 3.02(A) of the specifications except that the maximum deviation from the specified rate shall not exceed 0.05 gallons per square yard. The hot asphalt -rubber mixture shall be applied at the rate of approximately 0.55 ± 0.05 gallons per square yard (based on a unit weight of 7.75 pounds per gallon of hot asphalt -rubber); however, the Engineer will specify the exact rate based on existing surface conditions. All transverse joints shall be made by placing building paper over the end of the previous application, and the joining application shall start on the building paper. Once the application process has progressed beyond the paper, the paper shall be disposed of as directed by the Engineer. All longitudinal joints shall be lapped appr oximately 4 inches. Traffic shall not be permitted on the asphalt -rubber membrane prior to the application of cover material. 410- 3.03 Application of Cover Material: Cover material shall be applied in accordance with the requirements of Subsection 404-3.06 of the specifications. Cover material shall be immediately and uniformly spread over the freshly applied asphalt -rubber at the rate of approximately 0.014 cubic yards per square yard; however, the actual rate of application will be determined by the Engineer. 410- 3.04 Rolling: At least three pneumatic -tired rollers shall be provided to accomplish the required rolling. The rollers shall conform to the requirements of Subsection 416-7.05(A) (2) of the specifications , except that the minimum air pressure in each tire shall be 100 pounds per square inch, and steel wheel rollers shall not be used. A sufficient number of rollers shall be furnished to cover the width of the spread on the first pass and complete the required number of passes within the time specified hereinafter. The first pass shall be made immediately behind the spreader and if the spreading is stopped for any reason, the spreader shall be moved ahead so that all cover material may be immediately rolled. The rolling shall continue until a minimum of four complete coverages have been made. Final rolling shall be completed in accordance with the following: TABLE OF CONTENTS INDEX 379 Existing Pavement Temperature Complete Rolling Within 100° F and above 20 Minutes Below 100° F 10 Minutes
410- 3.05 Traffic: Traffic of all types shall be kept off the stress- absorbing membrane until it has had time to set properly. The minimum traffic free period shall be three hours. However, when it is absolutely necessary that hauling equipment or piloted traffic travel on the newly applied membrane and the use is approved in advance by the Engineer, the speed shall not exceed 15 miles per hour. Stress- absorbing membrane operations shall be scheduled so that the normal flow of traffic will be resumed before sunset. 410- 3.06 Removing Loose Cover Material: Loose cover material shall be removed in accordance with the requirements of Subsection 404- 7.06 of the specifications. Sweeping shall be completed and all excess cover material removed prior to the placement of any subsequent layers of asphaltic concrete. 410- 3.07 Placement of Asphaltic Concrete: If the asphalt -rubber membrane has been subjected to traffic, a tack coat, as hereinbefore specified, shall be applied at the rate of approximately 0.06 gallons per square yard prior to placement of the asphaltic concrete. When asphaltic concrete is to be placed over the asphalt -rubber membrane, it shall be placed as soon as practicable; however, in no instance shall it be placed later than seven days after membrane placement. 410- 4 Method of Measurement: Asphalt -rubber material will be measured by the ton. Conversion from volume to weight will be calculated on the basis of 7.75 pounds per gallon of hot asphalt -rubber material. Cover material will be measured by the cubic yard. Cover material will be weighed before precoating, and the amount in tons of dry material will be converted to cubic yards. The weight of all moisture contained in the cover material will be deducted prior to the conversion of the weight in tons to the volume in cubic yards. The dry weight per cubic foot will be determined in accordance with the requirements of AASHTO T 19 (Shoveling Procedure) . The quantities of bituminous tack coat and time to apply tack coat will be measured in accordance with the requirements of Section 404 of the specifications. TABLE OF CONTENTS INDEX