138 ALASKA 2020 SECTION 402
402-1.01 DESCRIPTION . Apply an asphalt tack coat on an approved surface.
402-2.01 MATERIALS. Use mater ials that conform to the following:
Asphalt Section 702 (STE -1) CONSTRUCTION REQUIREMENTS
402-3.01 WEATHER LIM ITATIONS. Do not apply tack coat to a wet surface or when the
roadway surface temperature is below 40 °F.
402-3.02 EQUIPMENT. Furnish, maintain, and operate asphalt distributor to apply asphalt
material uniformly at even heat on variable widths of surface up to 15 feet at readily determined and controlled rates from 0.01 to 0.11 gallon per square yard, with uniform pressure, and with an allowable va riation from any specified application rate not to exceed 0.02 gallon per square yard. Equip with a heater, tachometer, pressure gauges, calibrated tank, thermometer for measuring temperatures of tank contents, power unit for the pump and full circulation spray bars adjustable laterally and vertically.
402-3.03 PREPARATION OF SURFACE TO BE TR EATED. Clean and patch the existing
surface to receive the treatment. Remove irregularities to provide a reasonably smooth and uniform surface. Remove and replace unstable corrugated areas with suitable patching materials. Clean the edges of existing pavements, which are to be adjacent to new pavement, to permit the adhesion of asphalt materials.
402-3.04 APPLICATION OF ASPHALT MATERIAL . Apply tack coat uniformly with a pressure
distributor at a rate of 0.04 to 0.10 gallon per square yard, as directed. Apply the tack coat in such a manner as to offer the least inconvenience to traffic and to permit one-way traffic without pickup or tracking of the asphalt material. Limit application of tack coat so it will be covered by paving within one day.
402-4.01 METHOD OF M EASUREMENT. See Section 109.
402-5.01 BASIS OF PA YMENT. Payment for patching existing surfaces will be made at the
contract unit price for the various items used unless a reconditioning item is included in the Contract. Payment will be made under: PAY ITEM Item Number Item Description Unit 402.0001. ____ STE-1 Asphalt for Tack Coat TON 402.0002. ____ STE-1 Asphalt for Tack Coat LS 139 ALASKA 2020 SECTION 403 PRIME COAT
403-1.01 DESCRIPTION. Construct an asphalt prime coat on an approved surface. Apply blotter
material, if required.
403-2.01 MATERIALS. Use materials that conform to the following:
Asphalt Section 702 (MC -30, CSS -1) Blotter Material Suitable clean sand CONSTRUCTI ON REQUIREMENTS
403-3.01 WEATHER LIM ITATIONS. Do not apply asphalt material to a wet surface, or when the
surface temperature is below 45 °F, or when weather conditions would prevent the proper penetration of the prime coat.
403-3.02 EQUIPMENT. A distribut or meeting Subsection 402- 3.02. An approved self -propelled
aggregate spreader and rotary paver broom.
403-3.03 PREPARATION OF SURFACE. Ensure that surface to be primed is shaped to the
required grade and section, free of ruts, corrugations, segregated mat erial or other irregularities, and uniformly compacted.
403-3.04 APPLICATION OF ASPHALT MATERIAL . Before prime coat application, obtain
approval of rate of application, temperature, and areas to be treated, from the Engineer. When CSS -1 Emulsified Asphalt is specified, dilute with an equal amount of potable water at a temperature between 50 and 120 ° F and mix for a minimum of 15 minutes before using. Apply asphalt material to the width of the section to be primed by means of a pressure distributor in a uni form, continuous spread. Do not exceed maximum application rate at overlaps. Squeegee excess asphalt material from the surface. Correct any skipped areas or deficiencies. Place building paper over the end of the previous applications and start the joining application on the building paper. Remove and dispose of used building paper. When road is open to traffic, treat not more than 1/2 of the width of the section in one application. Maintain traffic on the untreated portion of the roadbed. As soon as the asphalt material has been absorbed by the surface and will not pick up, traffic may be transferred to the treated portion and the remaining width of the section primed. Maintain the surface until the next course has been placed. Protect the surface against damage.
403-3.05 APPLICATION OF BLOTTER MATERIAL . If, after the application of the prime coat, the
asphalt material fails to penetrate and dry, and traffic must be routed over the primed surface, or rain is imminent, apply blotter material as directed. Do not apply blotter material sooner than 4 hours after application of the asphalt material.
403-4.01 METHOD OF M EASUREMENT. See Section 109. By calculated residual weight for
emulsified asphalt.