6-41 657-3 Construction Methods
Install the sealant so that it forms a complete watertight bond with a high degree of elasticity, with maximum flexibility and longevity under extreme temperature ranges. Clean cracks and joints using a hot compressed air lance to blast out any vegetation, dirt, dampness and loose materials from the cracks and joints. Equip the air compressor with suitable traps and filters to remove moisture and oil from the compressed air. Use the hot air lance to d ry and warm the adjacent pavement immediately before sealing. Direct flame dryers are not allowed. Heat and apply the sealant material according to the manufacturer’s recommendations. Use a portable melting kettle for heating the material that is equippe d with indirect heating (air-jacketed flow) and is capable of constant ly agitating the joint sealer to maintain a uniform temp erature. Equip the kettle with either mechanically operated paddles and/or a continuous circulating pump to maintain agitation. Use heating equipment capable of controlling the sealant material temperature within the manufacturer’s recommended temperature range and that is thermostatically -control calibrated between 200°F to 600° F. Locate a thermometer on the kettle so the Engine er can safely check the temperature of the sealant material. Overheating of the sealant material will not be permitted. Apply sealant in the prepared cracks and joints within the manufacturer’s recommended temperature range, using a pressure screed shoe t o completely fill the crack or joint, leaving a sealed 2 inch overband. Excessive overbanding or waste of sealant materials will not be tolerated. Immediately squeegee the crack seal material to minim ize the height of the overband. All sealed cracks and j oints shall have a minimum of 1/8 inch depth of sealant installed. Do not apply the hot applied joint sealer when the surface temperature of the pavement is below 32°F. Follow m anufacturer’s recommendations. After the crack or joint has been sealed, promptly remove any surplus sealer on the pavement. Do not permit traffic over the sealed cracks and joints without approval by the Engineer. When approved by the Engineer, place sand or ot her approved material over the crack or joint to prevent tracking.
657-4 Measurement and Payment
Sealing Existing Pavement Cracks and Joints will be measured and paid as the actual number of pounds of material that has satisfactorily been used to seal pavement cracks and joints in the designated highway. Any material spilled, used in excessive overbanding, wasted, misapplied or unsatisfactorily used in any way will be deducted in determining quantities for payment. The Engineer will determine the quantity, if any, to be deducted. The Engineer's decision on the quantity to be deduc ted will be final and binding. Payment will be made under: Pay Item Pay Unit Sealing E xisting Pavement Cracks and Joints Pound
660-1 Description
Perform the work covered by this section including , but not limited to , furnishing, hauling, spreading and rolling the emulsion and aggregate consisting of one or more applications of liquid asphalt material and one or more applications of aggregate cover coat material on a prepared surface; and maintaini ng and repairing the asphalt surface treatment (AST).
6-42 660-2 Materials
Refer to Division 10. Item Section Aggregate s for Asphalt Surface Treatment 1012 -2 Emulsified Asphalt, Grade CRS -2L 1020 -3 Emulsified Asphalt, Grade CRS -2P 1020 -3 Fine Aggregate 1014 -1 Mineral Filler 1012 -1(D) Water 1024 -4 Before any asphalt surface treatment is placed, obtain from the asphalt supplier and furnish to the Engineer a C ertification of C ompatibility of the emulsion with the aggregate proposed for use.
660-3 Weather and Seasonal Limitations
Do not place any asphalt surface treatment between October 15 and April 1 , except for asphalt surface treatment that is to be overlaid immediately with asphalt plant mix. Apply AST only when the sur face to be treated is dry and when the air or surface temperatures, measured at the location of the AST operation away from artificial heat, is 55°F and rising. Do not place AST when air temperature is 98°F and rising. When placing AST that is to be immediately overlaid with asphalt plant mix, the seasonal and temperature limitations of Article 610- 4 shall apply. Do not apply asphalt material when the weather is foggy or rainy.
660-4 Surface Preparation
Clean the surface to be treated of dust, dirt, clay, grass, and any other deleterious matter before application of the AST . Properly dispose of these materials as directed by the Engineer.
660-5 Acceptance of Asphalt Materials
The acceptance of asphalt materials will be in accordance with Article 1020 -1.
660-6 Applica Tion Equipment
Use asphalt application equipment that meets Article 600 -5. Apply aggregate by the use of a self -propelled, pneumatic -tire aggregate spreader capable of maintaining a specified rate with a uniform application for the width of asphalt materia l being covered. T ailgate spreaders will not be permitted. Areas that are inaccessible to the aggregate spreader shall be covered by hand spreading or other acceptable methods.
660-7 Aggregate Type and Application Rates
Contractor shall provide aggregate types and rates as specified in the contract.
660-8 Construction Methods
For any type of AST work, demonstrate that all equipment has been calibrated in the presence of the Engineer . Once calibrated, pave a minim um 500 foot test section. If approved by the Engineer, test section may be incorporated into the production section. If the test section is not feasible, submit a calibration plan to the Engineer with detailed information on equipment and a designated area for calibration. Perform calibration and construction of test strip at the beginning of the first day of production and then as directed by the Engineer.
6-43 (A) Asphalt Seal Coat
Use the type of seal coat as required by the contract. Seal coat aggregates shall be drained of free moisture and have an amount passing the #200 sieve no greater than 1.5% in accordance with Table 1005- 1 before use. Place the seal coat in full -lane widths. Place b lotting sand in accordance with Section 818 when traffic is permitted on sections of the work in which the emulsion has not finished breaking . Aggregate is not an acceptable cover material on an AST Seal Coat. Perform rolling of each layer immediately after the aggregate has been uniformly spread. Rolling will consist of at least three complete coverages with one pneumatic -tire roller followed by at least one complete coverage with a 5 to 8 ton steel -wheel roller. All roller coverages shall be completed within 5 minutes of the asphalt emulsion being placed. Do not allow crushing of the aggregate or picking up of the material by the rollers. Wa ter spray bars on the rollers may be required by the Engineer if aggregate is being picked up from the finished surface. The use of a combination steel -wheel and pneumatic -tire roller will be permitted instead of the 5 to 8 ton steel -wheel roller. Pneumat ic tires on the combination roller or pneumatic tire roller must be smooth tread. Tractor, turf, or any aggressive tread pattern will not be allowed. After the aggregate is thoroughly seated, broom all excess aggregate off of the surface of the seal coat after 3 calendar days but no more than 7 calendar days. If necessary, use a vacuum truck as directed by the Engineer. Traffic may be permitted on the seal coat immediately after the rolling is complete. Clean driveways, ditches, turn lanes, and areas adjacent to the AST construction of excess aggregate, excess emulsion run off, over spray or debris from construction. Blotting sand may be required as directed by the Engineer and shall be applied in accordance with Section 818. Contractor is required to supply at no cost to the Department a suitable material if bleeding occurs on a completed section. Emulsion and/or aggregate applications greater than 6 inches onto the shoulder will not be allowed. Contractor will be required to remove this material and repl ace vegetation if required at no cost to the Department. The construction of the various types of seal coats will be in accordance with the following additional requirements:
1.Single Seal Apply emulsion to the existing surface followed immediately by an application of aggregate as specified in the contract . Uniformly spread the full required amount of aggregate in one application and correct all non- uniform areas before rolling. Immediately after the aggregate has been uniformly spread, perform rolling as previously described.
2.Double Seal Apply emulsion to the existing surface followed immediately by an application of aggregate as specified in the contract ensuring each is uniformly placed over the existing surface and rolled as previous ly described. Immediately after the first application of seal aggregate has been made uniform and rolled , apply the second application of the required amount of emulsion and seal coat aggregate and roll as previously described.
6-44 (3) Triple Seal
Follow the procedure outlined in Subarticle 660 -8(A)(2) and a pply emulsion and aggregate as a third layer and roll as previously described.
4.Sand Seal Place the fully required amount of asphalt material in one application and immediately cover with the seal coat aggregate. Uniformly spread the fully required amount of aggregate in one application and correct all non- uniform areas before rolling. Immediately after the aggregate has been uniformly spread, perform rolling. Broom excess aggregate material from the surfa ce of the seal coat.
B.Asphalt Mat and Seal Construct the mat coat in accordance with Subarticle 660 -8(C) using the size aggregate required by the contract. Construct the seal coat in accordance with Subarticle 660 -8(A) using the type seal required by the contract.
C.Asphalt Mat Coat for Soil Subgrade The surface on which the mat coat is to be applied shall be approved by the Engineer before the mat coat emulsion is applied. Place a string line guide for application equipment. Place the mat c oat in full- lane widths. Existing surface shall be damp prior to placement of the mat coat. Immediately follow the application of emulsion with the spreading of the aggregate. No more than 5 minutes can elapse from the time the emulsion is applied and the rolling is completed when using CRS -2L or CRS -2P. Mat coat aggregate shall be drained of free moisture and have an amount passing the #200 sieve no greater than 1.5% in accordance with Table 1005- 1 before use. Spread the aggregate uniformly at the requir ed rate and correct all non -uniform areas before rolling. Roll immediately after the aggregate is uniformly spread. Rolling consists of at least three complete coverages with two 5 to 10 ton steel -wheel rollers. Continue rolling until the aggregate is tho roughly keyed into the emulsion. Do not allow crushing of the aggregate or picking up of the material by the rollers. A combination steel- wheel and pneumatic -tire roller will not be permitted. Use two individual steel- wheel rollers. The three coverages shall be completed within 5 minutes of the spraying of the emulsion. At the discretion of the Engineer, at the beginning of each emulsion application, spread a paper over the end of the previously completed mat coat and begin the asphalt application on th e paper. After application, remove and dispose of the paper. After the aggregate is thoroughly seated, traffic may be permitted on the mat coat during construction of the adjacent lane at slow speeds under control of a pilot vehicle . Once the mat coat is applied to the second lane, the smaller aggregate shall be applied, properly rolled and set ( broke ) before turning traffic on the roadway. No brooming shall be performed on the mat coat or traffic allowed on the mat coat until a second layer of emulsion and aggregate is applied. Correct defects or damage to the mat coat before the application of seal coat or plant mix overlay.
6-45 (D) Asphalt Mat Coat for Pavement Surfaces
For mat coats with an asphalt overlay, construct the mat coat in accordance with Subarticle 660- 8(C). The same grade of emulsion used for the mat coat may be used for the tack coat of the asphalt overlay. For mat coats constructed o n existing pavement surfaces, construct the mat coat in accordance with Subarticle 660 -8(C) using the size aggregate required by the contract and the application rates specified in the contract . Application of the plant mix material should be placed after mat is seated or by the end of the day. No brooming shall be performed on the mat. No traffic shall be allowed on the mat until a second smaller emulsion and aggregate layer is applied or the plant mix material is applied. Plant mix thickness on overlays shall be at least 1 .5 inches.
E.Fog Seal Apply an emulsified asphalt and water mixture to prevent aggregate loss or as a surface seal. Fog Seal shall be delivered pre- mixed with water at a 1:1 ratio. Apply Fog Seal at a temperature of 130°F to 160°F. Complying with Weather and Seasonal Temperature Limits in Article 660 -3, with the exception that Fog Seal should be applied at 60°F and rising to ensure bond to underlying surface . Use asphalt application equipment compliant with Article 600 -5. Apply Fog Seal at the rate shown in the plans or as directed by the Engineer . Remove loose material or debris from roadway prior to application. The pavement surface must be dry before applying the fog seal. Open to traffic only after application has dried or as directed by Engineer .
660-9 Temporary Traffic Co Ntrol (Ttc)
All AST operations shall be conducted in daylight hours. Provide temporary traffic control for the asphalt surface treatment operations in accordance with the contract and in accordance with the provision RWZ -1 TEMPORARY TRAFFIC CONTROL (TTC) found elsewhere in the proposal except the following sections do not apply: TRAFFIC OPERATIONS, Drop -Off Requirements and Time Limitations TRAFFIC OPERATIONS, Project Requirements Install advance/general warning work zone signs according to the Detail Dra wing titled Signing for Asphalt Surface Treatment shown in the plans.
660-10 Warranty
The AST shall be warranted by the project payment and performance bonds for a period of 12 months.
A.Warranty Period The Department will conduct an inspection of the work and provide written acceptance in accordance with Article 105 -17. Written acceptance of the work will constitute the start date for the 12 month AST warranty period.
B.Situations Affecting the Warranty During the warranty period, the Contractor will not be held responsible for distresses that are caused by factors not related to materials and workmanship. These include, but are not limited to, chemical and fuel spills, vehicle fires, base failures, and snow
6-46 plows. Other factors considered to be beyond the control of the Contractor, which
may contribute to pavement distress, will be considered by the Engineer on a case by case basis upon receipt of a written request from the Contractor. Maintaining traf fic on the pavement surface prior to the Engineer’s acceptance will not be a condition for voiding the warranty.
C.Emergency Repairs If, in the opinion of the Department, a pavement condition covered by the warranty requires immediate attention for the safety of the traveling public, the Contractor will be notified immediately. If the Contractor cannot perform the work in a timely manner, the Department may directly perform or have the corrective work performed by another entity at the Contractor’s expense. Any emergency work performed will not alter the requirements, responsibilities, or obligations of the warranty.
D.Warranty Performance Criteria TABLE 660-1 PERFORMANCE CRITERIA Surface Defects Severity Extent (Per Lot) Surface Patterns Alternate lean and heavy lines streaking over the entire pavement surface. Greater than 20% of a lot affected; distress spotted evenly over the lot or over localized areas within the lot. Bleeding/ Flushing Distinctive appearance (with excess asphalt binder already free). Greater than 20% of the wheel tracks within a lot affected. Loss of Cover Aggregate Large patches of cover aggregate lost from the pavement surface. Greater than 20% of a lot affected; distress spotted evenly over the lot or over localized areas within the lot. Lot – A 1,000 foot section of pavement or portion thereof, a lane width wide, on which AST is constructed on a single map. The beginning point of the first lot will be the beginning point of each day’s operation or the beginning of a map, whichever is applicable. The Department will review the AST and advise the Contractor of any required corrective work in writing prior to expiration of the warranty period. The Department w ill approve all materials and methods used in warranty work. The Department will determine if warranty work performed by the Contractor meets the contract and provide written acceptance of the warranty work when complete. The Chief Engineer will review any disputes for corrective work covered under the warranty.
660-11 Maintenance
Maintain the asphalt surface treatment in an acceptable condition until final acceptance of the project.
6-47 660-12 Measurement and Payment
Asphalt Surface Treatment : Single Seal, Double Seal, Triple Seal, Mat and Single Seal, Mat and Double Seal, Sand Seal, and Mat Coat, No.___Stone. All AST will be measured and paid at the contract unit price per square yard. Payment at the above prices will be made for replacing any satisfactorily completed AST when such replacement has been made necessary by defects in subgrade or base constructe d by others. Asphalt Surface Treatment, Fog Seal will be measured and paid at the contract unit price per square yard. Price adjustments for emulsion will not be made for Asphalt Surface Treatment, Fog Seal . Emulsion for Asphalt Surface Treatment will be measured by the actual surface area of application and the specified application rate (gallon/sy) and paid at the contract unit price per gallon, which price will be full compensation for all materials including modifiers and additives, tack coat, labor, tools, equipment, and all other incidentals necessary to complete the work. Vacuum truck will be m easured and paid on a weekly basis for each week or any portion thereof that the Engineer directs the use of a vacuum truck. Price adjustments herein shall apply concurrently; however, price adjustment will not apply in the event the material is rejected by the Engineer . Furnishing and applying prime will be paid as provided in Article 600- 9 for Prime Coat . If included in the contract, furnishing and applying blotting sand will be paid as provided in
Article 818 — 4 for Blotting Sand .
Adjustment for Emulsio n for AST will be paid per the following formula: A = B + ((D – C) / 235) 0.65 Where: A = Adjusted Contract Unit Price of Emulsion for AST per gallon B = Contract Unit Price of Emulsion for AST per gallon C = Base Price Index of PG 64 -22 per ton D = M onthly Average Terminal F.O.B. Selling Price for PG 64- 22 per ton See Price Adjustment – Asphalt Binder Special Provision found elsewhere in this proposal for the base price index of PG 64 -22 per ton. Payment will be made under: Pay Item Pay Unit Asphalt Surface Treatment, Single Seal Square Yard Asphalt Surface Trea tment, Double Seal Square Yard Asphalt Surface Treatment, Triple Seal Square Yard Asphalt Surface Treatment, Mat and Single Seal Square Yard Asphalt Surface Treatment, Mat and Double Seal Square Yard Asphalt Surface Treatment, Sand Seal Square Yard Asphalt Surface Treatment, Mat Coat, No. __Stone Square Yard Asphalt Surface Treatment, Fog Seal Square Yard Emulsion for Asphalt Surface Treatment Gallon Vacuum Truck Per Week
Source: North Carolina Standard Specifications for Roads and Structures, 2024 Edition. Pages 297–303 of 857.