STATE OF OHIO DEPARTMENT OF TRANSPORTATION SUPPLEMENTAL SPECIFICATION 874 ULTRATHINBONDED ASPHALT CONCRETE. April 20, 2007

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1 STATE OF OHIO DEPARTMENT OF TRANSPORTATION SUPPLEMENTAL SPECIFICATION 874 ULTRATHINBONDED ASPHALT CONCRETE April 20, Description Materials Composition Equipment Weather Limitations Construction Quality Control Acceptance Method of Measurement Basis of Payment Description. This work consists of constructing an ultrathin bonded asphalt concrete wearing surface. The ultrathin bonded asphalt concrete consists of application of a warm polymer modified asphalt emulsion followed immediately with a 5/8 inch (16mm) minimum hot asphalt concrete overlay Materials. Conform to the following requirements: A. Polymer Modified Emulsion. Conform to , Type B. B. PG Binder. Use a PG 70-22M asphalt binder. C. Coarse Aggregate. Use approved coarse aggregates. Ensure coarse aggregates meet and the following: Tests Description Specification AASHTO T Loss, sodium sulfate soundness test, % max 10 max ASTM D 4791 Flat & Elongated Ratio at 3:1, % 25 max ASTM D 5821 % Crushed, one / two faces 95 / 85 min AASHTO TP58-99 Micro-Deval, % loss 18 max D. Fine Aggregate. Use approved fine aggregate. Ensure fine aggregate meets , except for gradation, and the following:

2 Tests Description Specification AASHTO T Sand Equivalent 45 min AASHTO TP Methylene Blue, materials passing No. 200 (75 µm) 10 max AASHTO T Uncompacted Void Content 40 min E. Mineral Filler. Conform to Composition. Do not use reclaimed materials. Conform to except as follows: replace Table with: Sieve 1/2 inch (12.5 mm) 100 3/8 inch (9.5 mm) No. 4 (4.75 mm) No. 8 (2.36 mm) No. 16 (1.18 mm) No. 30 (600 um) No. 50 (300 um) 8 14 No. 100 (150 um) 6 10 Total Percent Passing No. 200 (75 um) 4-6 Binder Content, % (a) (a) Increase the upper limit on asphalt content by 0.5% when coarse aggregate water absorption values per Supplement 1031 are greater than 2%. Select the JMF optimum PG binder content to meet the following criteria: Perform tests A, B, and C of and, if necessary, modify the mix per Use 50 blow Marshall compaction. The TSR will be 0.80 minimum. Perform draindown testing per AASHTO T 305. Use a test temperature of mixing temperature plus 27 F (15 C) but do not exceed 350 F (180 C). Draindown will be 0.10% maximum. Calculate film thickness using effective PG binder content as follows. Film thickness will be inch (9 micron) minimum. TF = V asp / SA x W Where, TF = Average film thickness, (in) V asp = Effective volume of asphalt cement (in 3 ) SA = Surface area of the aggregate (ft 2 per lb. of aggregate) W = Weight of aggregate (lb.)

3 Sieve size Surface area factor (constant) (ft 2 /lb) Example percent passing Example surface area (ft 2 /lb) ** 1/2 inch (12.5 mm)* /8 inch (9.5 mm)* No. 4 (4.75 mm) No. 8 (2.36 mm) No. 16 (1.18 mm) No. 30 (600 :m) No. 50 (300 :m) No. 100 (150 :m) No. 200 (75 :m) Total surface area = ft 2 /lb * The surface area factor is 2 for any material above the No. 4 (4.75 mm) sieve ** Only calculate values if material is retained on the sieve Film thickness calculation example: Measured bulk specific gravity of the aggregates, G sb = Effective specific gravity from the theoretical maximum density, G se = Asphalt binder specific gravity, G b = Mixture asphalt content = 5.3% Bulk density of the mixture, G mb = 2.161, In accordance with AASHTO T 269 using 50 blow Marshall compaction. Total volume of asphalt cement = total weight x asphalt content / (asphalt specific gravity x water density) = 1 lb. of mix x 5.3% / x 8.34 lb./gallon = gallon = 1.43 in 3 total asphalt cement Asphalt absorbed by weight of aggregate = 100 x ((Gse - Gsb) / G sb G se ) x G b = 100 x (( ) / (2.574)(2.627)) x = 0.803% Weight of absorbed asphalt = percent of asphalt absorbed by weight of aggregate x weight of aggregate = 0.803% x 1 lb. of mix x 94.7% aggregate = lb. of absorbed asphalt Volume of absorbed asphalt = weight of absorbed asphalt / asphalt specific gravity x water specific gravity = lb. / x 8.34 lb./gallon = gallon = in 3 absorbed asphalt

4 Effective volume of asphalt, V asp = total asphalt volume - volume of absorbed asphalt = 1.43 in in 3 = in 3 Film thickness, TF = Vasp / SA x W TF = (1.225 in 3 / ft 2 /lb x 1 lb. x 94.7%) = in 3 / (20.78 ft 2 )(144 in 2 /ft 2 ) = in Equipment. Provide self-priming spreading equipment capable of spraying the polymer modified asphalt emulsion with a metered mechanical pressure spray bar and applying the hot asphalt concrete overlay in one pass at the rate of 30 to 90 ft/minute (10 to 30 m/minute). Place the asphalt concrete on the polymer emulsion with no vehicle contact on the emulsion prior to asphalt concrete placement. The selfpriming spreading equipment must incorporate a receiving hopper, feed conveyor, storage tank for polymer modified asphalt emulsion, polymer modified asphalt emulsion spray bar and a variable width, heated, vibratory tamper bar screed. Provide a screed with the ability to be positively crowned at the center and have vertically adjustable extensions to accommodate the desired pavement profile. Use a minimum of two steel wheel rollers with a minimum capacity of 11 tons (10 metric tons) and conforming to for compaction. Approval of the spreading equipment by the Engineer will be based on the demonstrated capability of the equipment to uniformly apply the polymer modified asphalt emulsion, place the asphalt mixture to the required cross-section, profile and alignment in an acceptable, finished condition ready for rolling. All other equipment and tools will be approved by the Engineer. Maintain all equipment and tools in satisfactory working condition at all times Weather Limitations. Place material only when the pavement surface temperature and the ambient air temperature are not less than 50 F (10 C) at the time of placement. A damp pavement surface is acceptable for placement if it is free of standing water and no rain is predicted to follow prior to placement of the asphalt mixture Construction A. Surface Preparation. Perform the following items prior to the commencement of paving operations. 1. Protect and cover manhole covers, drains, grates catch basins and other such utility structures with plastic or building felt prior to paving and clearly reference these for location and adjustment after paving. 2. Remove thermoplastic traffic markings if greater than 1/4 inch (6 mm) thickness (ride quality). 3. Fill surface irregularities greater than 1/2 inch (12 mm) deep with a material approved by the Engineer. Ensure areas to be repaired are dry. 4. Thoroughly clean the entire pavement surface to be overlaid, giving specific attention to accumulated mud and debris. Use pressurized water and/or vacuum systems to provide a suitable surface for bonding.

5 B. Polymer Modified Emulsion Application. Spray the polymer modified asphalt emulsion at a temperature F (50-80 C). The sprayer will provide a uniform application across the entire width to be overlaid. Apply emulsion at 0.17 gal/yd 2 ± 0.07 gal/yd 2 (0.8 l/m 2 ± 0.3 l/m 2 ). Make adjustments to the spray rate based upon the existing pavement surface conditions and recommendations of the polymer modified asphalt emulsion supplier. C. Asphalt Concrete Application. Apply the asphalt concrete at a temperature of F ( C) and spread over the polymer modified asphalt emulsion immediately after its application. Use an application rate necessary to minimize fracturing of the top size aggregate by the screed. The Engineer will determine the acceptable extent of fracturing at the edge of the paving for tapering purposes. Do not open the asphalt concrete to traffic until the rolling operation is complete and the material has cooled sufficiently to resist damage. E. Compaction. Compact the asphalt concrete in the static mode. Make a minimum of two passes. F. Hauling. Conform to up and back passes before the material temperature has fallen below 185/F(85/C). Do not allow the rollers to remain stationary on the freshly placed asphalt concrete Quality Control. The requirements of will apply except as noted below. Section B. Gradation: Do not apply requirements for the F-T value and F/A ratio. Section C. Air Voids and MSG: Do not apply requirements for air voids and MSG Acceptance. Accept Ultrathin Bonded Asphalt Concrete per Method of Measurement. Measure the ultrathin bonded asphalt concrete according to Basis of Payment. The Department will pay for accepted quantities, completed in place, at the contract prices, or at the contract price as modified in , as follows: Item Unit Description 874 Cubic Yards ( Cubic Meters ) Ultrathin Bonded Asphalt Concrete