326 Page 195326 ASPHALT CONCRETE – CLASS HR
326.1DESCRIPTION
This work consists of constructing one or more courses of asphalt concrete with RAP on a prepared surface.
326.2MATERIALS
The materials for asphalt concrete Class HR and their use will conform to Section 320.2 except as modified by the following: Asphalt concrete aggregates will consist of RAP and virgin aggregate. The proportions of materials in the mixture will be determined by the job mix formula. The virgin mineral aggregate for asphalt concrete Class HR will conform to Section 321 - Class E, Type 1. The virgin aggregates will meet the specifications of the class and type specified. The combined virgin aggregate and RAP will not be further tested for gradation or quality control purposes.
326.3CONSTRUCTION REQUIREMENTS
The construction requirements will be as prescribed in Section 320.3 with the following modifications: A.The compacted thickness of each lift will not exceed 3 inches. B.The minimum density requirement will be 92% of the maximum specific gravity of the test specimens prepared in the field in accordance with SD 312. The compacted density of asphalt concrete will be determined according to SD 311. C.The RAP, virgin aggregate materials, and asphalt cement will be mixed by a conventional hot mix batch plant or a drum mix type hot plant.
326.4METHOD OF MEASUREMENT
Measurement as provided in Section 320.4 .
326.5BASIS OF PAYMENT
Payment as provided in Section 320.5 . 330 Page 196330 PRIME, TACK, FOG SEAL, AND FLUSH SEAL
330.1DESCRIPTION
This work consists of preparing and treating a prepared surface with asphalt material and sand as required.
330.2MATERIALS
Materials will conform to the following Sections: A.Asphalt: Section 890. B.Blotting Sand for Prime: Section 879. C.Sand for Flush Seal: Section 879. D.Sand for Fog Seal: Section 879.
330.3CONSTRUCTION REQUIREMENTS
A.Weather and Seasonal Requirements: Application will be made only during daylight hours, when the wind does not adversely affect the spraying operation and when the following conditions are met: 1.Asphalt for Prime: The application of asphalt for prime will be permitted only: a.When the ambient air and surface temperatures on the project are both at least 60F in the shade. b.When conditions are dry. When plans call for prime on interim surfacing, the prime application will closely follow the base finishing operation and at no time will the prime operation be more than 3 miles from the base finishing operation. The cure time for the processed base, prime, and blotting sand application will be determined by the Engineer. Surfaces primed with cutback asphalt will be allowed to cure for a minimum of 72 hours prior to being overlaid with asphalt concrete. 2.Asphalt for Tack: The application of asphalt for tack will be permitted only: a.When the ambient air and surface temperature on the project are both at least 35F in the shade. b.When conditions are dry, except emulsified asphalt may be applied when the surface is slightly damp.