613 – ULTRATHIN BONDED ASPHALT SURFACE
600-73 Consider adjusting the EBL spray rate based on th e condition of the existing surface as listed in the
TABLE 613-4 . Consult the supplier of the EBL to obtain the recommended adjustment to the spray rate. TABLE 613-4: EBL ADJUSTM ENT CONSIDERATIONS Existing Pavement Type Condition Adjustment Rate (gal/sy) PCCP Smooth 0.00 Textured +0.02 to +0.04 HMA Flushed -0.02 to -0.04 New 0.00 Matte and OGFC +0.02 Dry +0.03 Milled +0.02 to +0.04 Surface Recycle & Cold Recycle Flushed -0.02 to -0.04 Black +0.02 Dry +0.03 Chip Seal Flushed -0.02 to -0.04 Black +0.02 Dry +0.03 613.4 CONSTRUCTION REQUIREMENTS
a.Plant Operation. Adjust all plant operations to operate continuously.
1.Preparation of the Asphalt Bi nder. Heat the asphalt binder to within a range as specified in SECTION 601. When heating the asphalt binder to the specified temperat ure, avoid local overheating. At all times, provide a continuous supply of the as phalt binder to the mixer at a uniform temp erature. Asphalt binder received from the refinery at temperatures less than 37 5°F may be used as received, if the requirements regardin g the reheating of asphalt binder in SECTION 601 are met.
a.Commingling of Asphalt Binders. Do not a dd or commingle asphalt binders from 2 or more sources into a storage tank. If this occurs, th e contents of the storage tank are considered contaminated. Do not use the contents of the st orage tank on the project, except as follows: It is permissible, at the Contractor’s option, to thoroughly mix the contents of the tank and request sampling of the mixture. Submit the sample to the MRC for testing. Do not use the asphalt binder until approved, and when needed, a new mix design evaluation is completed.
b.Asphalt Binder Sources. Before changing as phalt binder sources on a project, obtain approval from the DME. A new JMF may be required. (c) Anti-Strip Additives. If liquid anti-strip additives are added at the Contractor’s plant, install a “totalizer” to monitor the quantity of anti-strip additive being added. The Engineer may approve alternative methods for including anti- strip additives in a batch plant. If added at the plant, the anti- strip will be added in line with the asphalt binder as it is being transferred from the transit unit to the asphalt binder storage tank. Provide a method for the Engineer to monitor the percent of additive being added.
2.Preparation of Mineral Aggregate. When the mineral aggregate is composed of 2 or more ingredients, combine as shown in the approved JMF. Temperature Requirements. Dry the aggregate for th e mixture and heat to a temperature to obtain an asphalt-aggregate mixture temperature immediately after mixing within the 75 to 150 second Saybolt viscosity range of the asphalt binder used. Obtain the temperature for this viscosity range from the MRC or the Asphalt Binder Producer. No mixing or compaction temperatures are to exceed 340ºF without approval from the Field Materials Engineer. The minimum temperature may be revised by the DME provided it is demonstrated that satisfactory results may be obtained at a lower temperature. In such event, de liver the HMA to the paver at a temperature sufficient to allow the material to be satisfactorily placed and compacted to the speci fied density and surface tolerance requirements.
3.Preparation of HMA. Introduce asphalt binder into the prepared aggregate in the proportionate amount determined by the P br in the JMF. 613 – ULTRATHIN BONDED ASPHALT SURFACE
600-74 (a) Basis of Rejection. HMA will be rejected if th e aggregate, as it is discharged from the drum or
the pugmill, contains sufficient moisture to cause foaming of the mixture, or if the temperature of the aggregate is such that the as phalt-aggregate mixture temperatur e is outside the range specified in SECTION 601 .
b.Mixing Time. Operate drum mixers at a rate to provide uniform aggregate coating in a continuous operation. For batch and continuous ty pe plants, the minimum wet mixing time is 40 seconds. In all cases, mix a sufficient time to produce a uniform mixture in which all the aggregate particles are thoroughly coated. On batch plants, begin the timing at the start of the asphalt binder introduction into the pugmill, and end upon the opening of the discharge gate. For continuous flow plants, mixing time in seconds shall equal: [pugmill dead capacity in pounds] divide d by [pugmill output in pounds per second].
c.Manufacturer’s Specifications. Operate all drying, pumping and mixing equipment within the limits specified by the manufacturer, unless it can be demonstrated to the satisfaction of the Engineer that such limits may be exceeded without detriment to the HMA.
d.Batcher Operation. Coordinate HMA batchers (Gob Hoppers) with the plant production rate at all times so the hopper is more than ¾ full before the gates open, and the gates close before material can drop through the gob hopper directly into the surge bin, weigh hopper or truck.
e.Wasted Material. Wasted mate rial is not measured for pay. If after an interruption of production, the drum-mixer contains cold, uncoated or otherwise unsuitable material, waste material through a diversion chute. In a continuous or batch plant drier, waste unsuitable material through the pugmill. At the end of a production run, waste any segregated material in the cone of the storage bin.
4.End of Day Quantities. At the end of each day of production, provide the Engineer with a document signed by the Plant Foreman or the Project Manager listing th e dry weight of each aggregate and mineral filler; the tons of asphalt binder, and the tons of anti-strip agent used for the project during the day. The dry weight is the tons of the material less the water content.
b.Road Surface Preparation.
1.Preparation of an Existing Asphalt Pavement. Cl ean the surface to remove all foreign material and broom to remove dust. Excavate areas shown in the Contract Documents to be patched to a depth directed by the Engineer. Fill with HMA and compact.
2.Preparation of an Existing Concrete or Brick Pavement. Clean all foreign material and broom to remove dust. Clean and fill cracks and joints, and construct surface leveling as shown in the Contract Documents.
c.Weighing Operations. See subsection 109.1 for details regarding weighing operations.
d.Hauling Operations . Schedule operations to minimize hauling over a surface course. Deliver HMA to the paver at a temper ature sufficient to allow the material to be placed and compacted to the specified density and surface tolerance.
e.Paving Operations.
1.Equipment Use a transfer device between the haul units and the paver to assist in maintaining continuous placement. Use equipment such as a shuttle buggy , material transfer vehicle or mobile conveyor. (The material will not be deposited on the roadway and a pick-up device used to transfer the material to the paver.) Use a self-priming paver, designed and built for applying the UBAS and approved by the Engineer. Use a paver with the following requirements: with a receiving hopper, feed conveyor, asphalt em ulsion storage tank, a sy stem for measuring the EBL volume applied, a spray bar, and a heated, variable width, vibratory screed; capable of spraying the EBL, applyi ng the hot mix surface course and le veling the surface of the mat in one pass; capable of placing the hot mix surface course within 5 seconds after the application of the EBL; capable of paving at a controlled speed from 30-100 feet/minute; equipped so no wheel or other part of the paving machine is in contact with the EBL before the hot mix surface course is applied; and 613 – ULTRATHIN BONDED ASPHALT SURFACE
600-75 equip the screed with the ability to crown the pave ment at the center and have vertically adjusted
extensions to accommodate the desired pavement profile. The Engineer will check the pavement for longitudinal st reaks and other irregularities. Make every effort to prevent or correct any irregularities in the pavement, su ch as changing pavers or using different and additional equipment. Do not raise (dump) the wings of the paver receiving hopper at any time during the pa ving operation.
2.Application: Spray the EBL by a metered mechanical pressure spray bar at the temperature specified in TABLE 601-1 , or as recommended by the EBL supplier. Use a sprayer that accurately and continuously monitors the rate of spray and provides a unifor m application across the entire width to be overlaid. The Engineer may make adjustments to the spray rate based upon the existing pavement surface cond itions and the recommendations of the EBL supplier. Apply the UBAS at a temperature of 290-330ºF and spread over the EBL immediately after the application of the EBL. Place the UBAS over the full width of the EBL with a heated vibratory screed. Adjust the screed and its extensions to eliminate variances in surface texture caused by density segregation. Operate the paver as continuous as possible to reduce the possibility of screed indentations in the finished mat. The target application rate of the UBAS will be stated in the Contract Documents. Use a field application rate as 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. The finished asphalt surface shall be free of oversized material. The Engineer w ill determine the extent of the oversized material in the UBAS. Take immediate corrective action to elim inate the source. If the source of the oversized material is determined to be a stockpile or a process of plant operations , cease production until corrective actions are complete. Spread the UBAS without tearing the surface. Strike a finish that is smooth, free of segregation, true to cross section, uniform in density and texture and free from surface irregularities. If the pavement does not comply with all of these requirements, plant production and paving will be suspended until the deficiency is corrected.
3.Compaction: Roll the UBAS with a minimum of 1 pass and a maximum of 3 passes with 2-axle tandem steel rollers having a minimum weight of 10 tons, before the material temperature has fallen below 195ºF. The Engineer will determine the number of passes necessary base d on appearance of the rolled material. Do not allow the roller or rollers to remain stationary on the fresh ly placed UBAS. Perform ro lling immediately following the placement of the UBAS with approved asphalt rollers. Supply adequate roller units so the rolling will be accomplished promptly following the place ment of the material. A release agent (added to the water system) may be required to prevent adhesion of the fresh mix to the roller drum and wheels. Normally, perform rolling in the static mode. Do not excessively roll the driving lanes, to the extent of aggregate degradation. The Engineer will determine the acceptable extent of fract uring at the edge of the pavement from the rolling operation. Do not open the new pavement to traffic or allow any roller to sit id le on the pavement until the rolling operation is complete and the material has cooled below 160°F. Damaged Areas: Replace any defective areas, as dete rmined by the Engineer, at no additional cost to KDOT.
4.Construction Joints. Transverse Construction Joints. Use a method of ma king transverse construction joints which provide a thorough and continuous bond and pr ovide an acceptable surface texture. Do not vary the surface elevation more than 3/16 inch in 10 feet, when tested longitudinally across the joint. When required, repair the joints or paving operations will be suspended. Longitudinal Joints. Construct well bonded and sealed longitudinal joints to obtain maximum compaction at the joint.
5.Adjustment of Manholes (Set Price). When required, this work will be performed and paid for under SECTION 816 .
f.Maintenance of Traffic . Maintain traffic according to DIVISION 800 and the following: Maintain one-way traffic, and restrict traffic speeds to 20 miles per hour in the vicinity of workers, unless otherwise designated. Use pilot cars to lead traffic through the area of pavi ng and rolling operations , and if directed, through a curing area. The use of flaggers is allowed th rough patching operations, unless the patching area or distance between flaggers exceeds ½ mile, in which case the use of a pilot car shall be required. On overlay projects with 2 lanes or more in each direction for traffic use, the Engineer may waive th e pilot car requirements. 613 – ULTRATHIN BONDED ASPHALT SURFACE
600-76 Station one flagger ahead of the application of the tack coat and one flagger ahead of the area being protected
from traffic. Take adequate protection for tr affic on side roads approaching the tack area.
g.Treatment of Adjacent Areas. Pave sideroads, entrances and turnouts for mailboxes as shown in the Contract Documents. Overlay all widening areas designated in the Contract Documents or ordered by the Engineer.
h.Pavement Smoothness. Evaluate pavement smoothness according to SECTION 603 . 613.5 PROCESS CONTROL
a.General. Establish gradation limits and proportions for each individual aggregate and mineral filler. Specify the limits and proportions such that the material produced complies with the applicable requirements of the designated mix type. The Contractor is responsible for all process control operations including testing. At no time will KDOT’s representative issue instructions to the Contractor or producer as to setting of dials, gauges, scales and meters. KDOT will collect and test verification samples an d assurance samples and inspect the Contractor’s quality control operations.
b.JMF Adjustments. Produce a mixture of uniform composition closely complying with approved design JMF to obtain the specified properties when compacted. If, during production, results from quality control tests demonstrate a need to make adjustments to the mix design, then make adjustments to the design JMF single point gradation and binder content to achiev e the specified properties. The JMF adjustments shall produce a mix that complies with TABLE 613-1 for the specified mix designation. When necessary, adjust on a sublot basis. Report the new JMF to KDOT’s field representative and the DME before making such changes, and submit a new mix design for review and approval if required by the DME.
c.Specification Working Ranges. Establish acceptable limits for fiel d test results by applying the tolerances shown in TABLE 613-5 to the JMF or adjusted JM F for binder content. Es tablish acceptable limits for the other listed mix characteristics by applying the tolerances shown in TABLE 613-5 to the requirements of TABLE 613-1 . TABLE 613-5: SPECIFICATIO N WORKING RANGES (QC/QA) Mix Characteristic Tolerance from JMF and Specification Limits Single Test Value Plot 3 Point Moving Average Value Binder Content (Maximum deviation from JMF) ±0.3% * ±0.3% Film Thickness n/a * zero tolerance Gradation** n/a * zero tolerance Course Aggregate Angularity (CAA) zero tolerance n/a Fine Aggregate Uncompacted Vo ids (FAA) zero tolerance n/a Sand Equivalent zero tolerance n/a *Values to plot. In addition, plot the Gmm values. For gradations, as a minimum, plot the No. 4, 8, 30 and 200 sieves. **The maximum deviation for UBAS from the JMF for the sieves with a ± tolerance shall be as listed in TABLE
613-6 Only the No. 16, 30, 50 and 100 si eves may exceed th e limits listed in TABLE 613-1 provided the
minimum retained percentage shown in TABLE 613-6 is met. TABLE 613-6: SPECIFICATION WORKING RANGES FROM THE JMF Mix Designation Percent Retained – Square Mesh Sieves ¾" ½" ⅜" No. 4 No. 8 No. 16 No. 30 No. 50 No. 100 No. 200 Type A ±5 68 - 78 75 min 82 min. 87 min. 90 min. 94.0 – 96.0 Type B ±5 ±4 73 - 83 77 min. 82 min 87 min. 90 min. 94.0 – 96.0 Type C ±5 ±5 ±4 73 - 83 77 min. 82 min 87 min. 90 min. 94.0 – 96.0
Source: Kansas Standard Specifications for State Road and Bridge Construction, 2015 Edition. Pages 310–313 of 978.