for Highway Construction Page 205 of 71 5 SECTION 404 – SURFACE TREATMENT
404.01 Description.
Construct a single or multiple course surface treatment that may consist of the application of 1 or more chip seal coats or may consist of a prime coat followed by 1 or more chip seal coats as follows:
1.Type A: Apply a chip seal coat .
2.Type B: Apply a prime coat followed by the application of a chip seal coat .
3.Type C: Apply 2 chip seal coat s.
4.Type D: Apply a prime coat followed by the application of 2 chip seal coats. A fog coat may be constructed on any of the types of surface treatments, as specified.
404.02 Materials.
Provide materials as specified in: Asphalt .................................................................................................................................... 702.01 Emulsified Asphalt .................................................................................................................. 702.03 Anti-Stripping Additive ............................................................................................................. 702.04 Aggregate for Cover Coat Material .......................................................................................... 703.06 Aggregate for Blotter and Aggregate for Choke Sand ............................................................. 703.07 Provide asphalt of the type a nd grade specified. Provide asphalt and anti -stripping additive, if required, as specified in 702 . The Engineer will accept the asphalt at the point of delivery. The emulsified asphalt is subject to viscosity and sieve testing by the Department, in the field or at a location other than the project site. Schedule the delivery time to allow testing before usage. Expect delays up to 1 hour for this testing. Provide cover coat m aterial , blotter, and choke sand as specified in 703. The Engineer will accept the cover coat material, blotter, and choke sand at the point of loading for delivery to the roadway. Submit a chip seal coat design for each stockpile using the McLeod method at least 2 weeks before construction. Field- verify the chi p seal coat design for spread rate of asphalt and aggregate.
404.03 Construction Requirements.
A.Chip Seal Coat . Do not apply asphalt if the roadway surface or weather conditions can prevent satisfactory construction. Do not start chip sealing unless the pavement surface temperatures are 80°F and rising, and do not chip seal when pavement surface temperature exceeds 140°F, unless authorized i n writing . If bleeding becomes apparent on the completed chip seal, start immediate maintenance and traffic control, and do not continue chip sealing until corrective action has been started. Do not apply chip seals when the wind velocity exceeds 15 mph without written approval . Do not apply chip seals before June 15 or after September 1. for Highway Construction Page 206 of 71 5 The following equipment or its equivalent is required by the Department:
1.Asphalt application equipment for applying asphalt. An asphalt distributor and equipment for heating the asphalt. Ensure the distributor is designed, equipped, maintained, and operated so asphalt can be applied uniformly on variable widths of surface at readily determined and controlled rates with uniform pressure. Provide distributor equipment that includes a tachometer, pressure gauges, accurate volume measuring devices or a calibrated tank, and a thermometer for measuring temperatures of tank contents. Equip distributors with a power unit for the pump and full-circulation, vertically adjustable spray bars.
2.Brooms. Use a mechanical rotary type broom. Use a mechanical pickup or vacuum broom for the following conditions:
a.In curb/gutter and on sidewalk sections .
b.In all guardrail areas.
c.On bridge deck s.
d.Within 100 feet of bridges that span water channels (wet or dry ).
e.Within 100 feet of adjacent wetlands and surface waters that reside within the right of way.
f.Maintained shoulder -foreslope areas where the adjacent property owner cares for and maintains turf or landscaping.
3.Pneumatic -tire Rollers. Do not operate the rollers at a speed in excess of 8 mph. Include enough pneumatic -tired rollers to cover a full spread width with 1 pass. Use compaction equipment and/or rolling methods to produce the required compaction without damaging the work.
4.Self-propelled aggregate spreader supported by at least 4 wheels equipped with pneumatic tires on 2 axles, of Engineer approved design. Equip the aggregate spreader with positive controls so t hat the required amount of material will be deposited uniformly over the full width required. Seal approaches before sealing the adjacent roadway. Do not chip seal bridge decks and approach slabs. Protect drains and bridge expansion joints from the chip seal application, then remove and properly dispose of material used for this protection after completion of the chip seal. After chip seal completion, remove asphalt and aggregat e that may have spilled into drains and deck expansion joint s. Do not spread asphalt until the surface has been cleaned as required and the section has been approved. Apply asphalt with a pressure distributor in a uniform, continuous spread over the section to be treated and within the temperature range specified. Design and field- verify the quantity of asphalt to be used per square yard. A preliminary asphalt application of from 0.05 to 0.10 gallon per square yard of surface may be r equired by the Engineer if the texture of the surface allows asphalt to penetrate too rapidly. Use a strip of building paper at least 3 feet wide and as long as the spray bar of the distributor plus 1 foot at the beginning of each spread. Paper may be required at the end of each spread if the cutoff is not clean. Remove and dispose of the paper in a satisfactory manner. Ensure the distributor is moving forward at the proper application speed when the spray bar is opened. Correct skipped areas or deficiencies. Carefully mark junctions of spreads to ensure a smooth riding surface. Do not expose asphalt for more than 1 minute before applying cover coat material. Limit the asphalt spread to the area that the trucks loaded with cover coat material can immediately cover. for Highway Construction Page 207 of 71 5 The Department will allow meet -lines within 1 foot of lane lines or within 1 foot of center of lanes only. Meet lines are not allowed within a wheel path. Ensure transverse longitudinal joint s are smooth and match the adjacent surfaces. Do not spread asphalt more than 6 inches wider than the width covered by the cover coat material from the spreading device. Do not allow the asphalt to chill, set up, dry, or otherwise impair retention of the cover coat material. When not spreading, park the distributor so that the spray bar or mechanism will not drip on the roadway surface when not spreading. Spread cover coat material at the designed and field- verified rate immediately following the application of asphalt . Do not allow the tires of the trucks or aggregate spreader to contact the uncovered asphalt. Do not allow pilot car traffic control operations to cross the fresh asphalt meet -line onto newly applied cover coat material. Moisten aggregate stockpiles with water 12 to 24 hours before placement to eliminate or reduce the dust coating of the aggregate. Cover deficient areas with additional approved material immediately after the cover coat material is spread. Begin rolling immediately behind the spreading operation and continue until 3 complete coverages are obtained. Complete rolling within 5 minutes of spreading cover coat material and before allowing traffic to use the new surface. If choke sand is specified, the following applies:
1.Immediately after the third roller pass, apply choke sand to the entire roadway surface at a rate of 4 pounds per square yard or as directed.
2.Do not “tailgate” or use a spinner when applying choke sand. Do not operate equipment at a speed that turns or displaces the cover coat material. The Engineer may require applying approved reject material over the surface to absorb any free asphalt before brooming. Sweep excess material from the entire roadway surface with rotary brooms. Complete the initial brooming by the morning following the previous day’s chip seal application unless otherwise directed. Do not to displace embedded material when brooming. Pickup excess material in curb and gutter sections and dispose of as directed. Perform second brooming approximately 24 hours after the first brooming and after traffic has been routed on the chip sealed roadway, when required. Provide brooms that are in good condition and capable of sweeping a path at least 70 inches wide without loosening or displacing embedded materials. 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 one-half mile. Lightly spray the surface of the roadway with enough water to prevent dust from becoming airborne when brooming operations could create dust to the extent that it would violate air pollution regulations or create a safety hazard. Keep the highway open to traffic. The Contractor may route controlled traffic on the surface treatment as soon as the asphalt is covered. Maintain the first chip seal and allow it to cure for 5 calendar days if successive chip seals are to be applied. for Highway Construction Page 208 of 71 5 B. Prime Coat . Apply the prime coat as specified in 402, when required The Engineer may require a curing period of 5 calendar days between the application of the prime coat and the next application of asphalt . Keep the primed surface in repair during the period between the application of the prime coat and the chip seal coat. Patch and repair holes, ravels, and areas deficient in the primed surface with aggregate- asphalt mixtures using penetration methods or other approved procedures. Broom off loose material before subsequent applications of asphalt.
C.Chip seal. Apply each chip seal as specified 403. Maintain the first chip seal and allow it to cure for 5 calendar days if successive chip seals are to be applied.
D.Fog Coat . Apply fog coat as specified in 408, when re quired.
404.04 Method of Measurement.
The Engineer will use plan quantity of acceptably completed work by the square yard. Chip Seal Coat will be measured by the square yard.
404.05 Basis of Payment .
The Department will pay for accepted quantities at the contract unit prices as follows: Pay Item Pay Unit Surface Treatment .................................................................................. SY Fog coat will be paid for as specified in 408. All w ork associated with chip sealing is incidental and included in the chip seal coat contract pay item, including the following:
1.Cleaning the pavement surface before chip sealing.
2.Protecting existing manholes, valve casings, street monuments, and RWIS sensors. Material used for protection is to be removed and properly disposed of after the chip sealing is completed.
3.Restoring items that were not properly pr otected.
4.Providing and applying materials, including asphalt , cover coat aggregates, and blotter , if necessary.
5.Water applications.
6.Brooming.
7.Removing and disposing of excess material.
8.All other work necessary to chip sealing. for Highway Construction Page 209 of 71 5 SECTION 405 – SU PERPAVE® HOT MIX ASPHALT
405.01 Description.
Construct 1 or more courses of Superpave hot mix asphalt (HMA) plant mix, including leveling courses if applicable, on a prepared surface. References in this section also apply to warm mix asphalt (WMA).
405.02 Materials.
Provide materials as specified in: Aggregate ..................................................................................................................................... 703 Asphalt ......................................................................................................................................... 702 Anti-Stripping Additive .................................................................................................................. 702 Hydrated Lime .......................................................................................................................... 720.06 Recycled Asphalt Pavement (RAP) ......................................................................................... 720.07 Test materials in accordance with the following applicable standard methods: Particle Size Distribution of Aggregate ............................................................ FOP for AASHTO T 27 With Materials Finer than 75um (No. 200) Sieve in Mineral Aggregate by Washing ........................................................................ FOP for AASHTO T 11 Method A or B Mechanical Analysis of Extracted Aggregate ................................................... FOP for AASHTO T 30 Preparing and Determining the Density of Hot Mix Asphalt (HMA) Specimens by Means of the Superpave Gyratory Compactor. ...................... FOP for AASHTO T 312 Superpave Volumetric Design for Hot Mix Asphalt (HMA) ............................................ AASHTO R 35 Determining the Percentage of Fracture in Coarse Aggregate ................................................................... FOP for AASHTO T 335 Method 1 Percent Air Voids in Compacted Dense and Open Bituminous Paving Mixtures ................................................................. AASHTO T 269 Theoretical Ma ximum Specific Gravity and Density of Bituminous Paving Mixtures .................................... FOP for AASHTO T 209 Bowl Method Bulk Specific Gravity of Compacted Bituminous Mixtures Using Saturated Surface Dry Specimens ........................ FOP for AASHTO T 166 Method A Pavement Straightedge Procedures .................................................................................. I daho IR 87 In-Place Density of Asphalt Mixtures by Nuclear Methods ............................ FOP for AASHTO T 355 Backscatter mode Sampling Asphalt Mixtures after Compaction (Obtaining Cores) ......................................................... FOP for AASHTO R 67 Determin ing Volume of Liquids in Horizontal or Vertical Storage Tanks ........................... Idaho IT 120
Source: Idaho Standard Specifications for Highway Construction, 2023 Edition. Pages 241–244 of 768.