for Highway Construction Page 197 of 71 5 SECTION 401 – TACK COAT
401.01 Description.
Prepare and treat an existing surface with asphalt .
401.02 Materials.
Provide asphalt of the type and grade specified. Provide asphalt as specified in 702 . The Engineer will accept the asphalt at point of delivery.
401.03 Construction Requirements.
Provide distributor equipment as specified in 406.03. Patch and clean the existing surface and ensure it is without irregularities to provide a reasonably smooth and uniform surface to receive the treatment. Remove and replace unstable corrugated areas with suitable patching materials. Clean the edges of existing pavement that are to be adjacent to new pavement to allow adhesion. Broom before applying tack coat . Provide brooms that are in good condition and capable of sweeping a path at least 70 inches wide without loosening or displacing embedded m aterials. Sweep the surface as directed. Accompany each broom by a shadow vehicle if working on highways open to traff ic. Equip the shadow vehicle with at least 1 roof -mounted high intensity rotating or strobe- type amber flasher that is readily visible from front and rear for 0.5 mile. Lightly spray the surface of the roadway to be swept with enough water to prevent broom ing operations from creating dust to the extent that it would violate air pollution regulations or create a safety hazard. Do not broom from the surface onto maintained shoulder -foreslope areas where the adjacent property owner cares for the area and maintains turf or landscape. Apply asphalt tack so the application is uniform, the limits of placement are appropriate, there is the least amount of inconvenience to traffic, and traffic will not cause pickup or tracking. Mix approximately equal volumes of emulsified asphalt and water before application. Do not apply asphalt if surface or weather conditions can prevent proper construction.
401.04 Method of Measurement.
The Engineer will measure acceptably completed work for the tack coat as diluted emulsified asphalt by the gallon with no correction for temperature.
401.05 Basis of Payment .
The Department will pay for accepted quantities at the contract unit prices as follows: Pay Item Pay Unit ____ Diluted Emulsified Asphalt for Tack Coat ....................................... gal The Department will not pay for reapplication of the asphalt tack required due to time lag between the initial application and the paving oper ation. for Highway Construction Page 198 of 715 Brooming and patching is incidental and included in other contract pay items . for Highway Construction Page 199 of 715 SECTION 402 – PRIME COAT
402.01 Description.
Prepare and treat an existing surface with asphalt and blotter as specified.
402.02 Materials.
Provide asphalt of the type and grade specified in 702 . The Engineer will accept the asphalt at the point of delivery. Provide blotter as specified in 703 . The Engineer will accept material at the point of delivery from the Contractor -provided s ources or from designated sources.
402.03 Construction Requirements.
Do not apply asphalt if surface or weather conditions can prevent proper construction. Provide distributor equipment as specified in 406.03. Shape the surface to be primed to the required grade and section. Ensure it is uniformly compact and without ruts, c orrugations, segregated material, or other irregularities. Obtain approval of quantities , rates of application, temperatures, and areas to be treated before prime coat application. Apply asphalt to the width of the section to be primed with a pressure distributor in a uniform, continuous spread. Do not exceed the specified asphalt application rate at the spread overlap junction. Correct skipped areas or deficiencies. Provide for 1- way traffic on the untreated portion of the surface when traffic is maintained. Transfer traffic to the treated portion as soon as the asphalt has been absor bed by the surface and will not pick up, and then prime the remaining width of the section. If a roadw ay must be used by traffic but the asphalt does not penetrate after application of the prime coat , spread blotter with a self -propelled aggregate spreader supported by at least 4 wheels equipped with pneumatic tires on 2 axles, as approved. Equip the aggregate spreader with positive controls so the required amount of material will be depos ited uniformly over the full width required to absorb the ex cess asphalt.
402.04 Method of Measurement.
The Engineer will measure acceptably completed work as follows:
1.Asphalt will be by the ton.
2.Blotter will be by th e ton or cubic yard.
402.05 Basis of Payment .
The Department will pay for accepted quantities at the contract unit prices as follows: Pay Item Pay Unit ____ Emulsified Asphalt for Prime Coat ................................................. Ton Blotter ..................................................................................................... Ton or CY
Source: Idaho Standard Specifications for Highway Construction, 2023 Edition. Pages 233–234 of 768.