614 – HMA BASE (REFLECTIVE CRACK INTERLAYER (RCI)
600-83 Failure Point – Failure is defined at the maximum or peak Normalized Modulus when Normalized Modulus x
Cycles is plotted versus Load Cycles. Section 9.1.10: Delete Section 10.4, Table 2: Change the last two headings to “Normalized Modulus” and “Nor malized Modulus x Cycles”, respectively Section 10.7: Delete Section 10.8: Replace with the following: Prepare a plot of Normalized Modulus x Cycles versus load cycles TABLE 614-6: MIX DESIGN TEST DATA SUBMITTALS Submittal Information Minimum of 1 Mix Design As a minimum, 1 mix design at the P br Gmm Determined at each binder content. Individual and Bulk Specific Gravity Tests Provide results for a minimum of 2 specimens at each binder content. Percent Air Voids Provide % Va in the mixture for each binder content when compacted to N des gyratory revolutions along with copies of the Gyratory graphs. Percent VMA Provide %VMA at each binder content. 614.4 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.
2.Preparation of Mineral Aggregate. When the mineral aggregate is composed of 2 or more ingredients, combine as shown in the approved JMF.
a.Temperature Requirements. Dry the aggregate fo r the 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 aspha lt 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 Mate rials 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, deliver the HMA to the paver at a temperature sufficient to allow the material to be satisfactorily placed and comp acted to the specified 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.
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 614 – HMA BASE (REFLECTIVE CRACK INTERLAYER (RCI)
600-84 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 the dry weight of each aggregate, mineral filler and the tons of asphalt binder. The dry weight is the tons of the material less the water content.
b.Road Surface Preparation. Clean all foreign material and broom to remove dust from existing concrete pavement. Clean and fill cracks and joints, and construc t surface leveling as shown in the Contract Documents. Prior to placing the HMA, apply a t ack coat to the existing surface, as shown in the Contract Documents. When warranted by weather conditions, the Engineer may author ize a change in the asphalt for tack coat. When such changes are made, the price per ton of material being used will be the unit price bid for the material designated in the contract plus or minus the difference in the invoice price per ton of the 2 materials at the refinery as determined at the time of application.
c.Weighing Operations. See SECTION 109 for details regarding weighing operations.
d.Hauling Operations . Schedule operations to minimize haulin g over a surface course for the RCI. 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. The Engineer will check the pavement for longitudinal streaks and other irregularities. Make every effort to pr event or correct any irregularities in the pavement, such 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 paving operation. The Engineer may waive this requirement if it is determined that raising (dumping) the wings will not produce detrimental segregation. If segregation or irregularities in the pavement surface or de nsity are noted, review the plant, hauling and paving operations and take correct ive action. The recommendations made in KDOT’s "Segregation Check Points" sh ould reduce the segregation and irregular ities to an acceptable level. Copies of KDOT’s "Segregation Check Points" may be obtained from the KDOT District Of fice or Field Engineer. Spread the HMA and finish to the specified crown and grade using an automatically controlled HMA paver. Operate the paver at a speed to provide a uniform rate of placement without undue interruption. At all times, keep the paver hopper sufficiently full to prevent non-uniform flow of the HMA to the augers and screed. If the automatic grade control devices break down, the E ngineer may allow the paver to operate to the close of the working day, provided the surface is satisfactory. (1) Surface Quality. Spread the HM A 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. The Engineer may verify segregation and uniformity of density requirements in TABLE 602-7 are met by using methods outlined in Section 5.8.3 – Segregation Check Using the Nuclear Density Gauge, Part V.
2.Grade Control. Achieve grade control by use of 1 or more of the following grade reference devices. Approval of any of these devices will be based upon satisfactory performance.
a.Traveling Stringline. Attach a traveling stringline or ski type attachment, a minimum length of 30 feet, to the paver and operate parallel with its line of travel. 614 – HMA BASE (REFLECTIVE CRACK INTERLAYER (RCI)
600-85 (b) Reference Shoe. Attach a short reference shoe or joint matching de vice to the paver for control in
matching surface grades along longitudinal joints.
c.Erect Stringline. Use an erected stringline cons isting of a tightly stretched wire or string offset from and parallel to the pavement edge on 1 or both sides. Erect the stringline parallel to the established pavement surface grade and support at in tervals as necessary to maintain the established grade and alignment.
d.Stringless Paving. Control line, grade and pavement cross-section as shown in the Contract Documents. Use electronic guidance systems that meet the requirements and tolerances listed in SECTION 802 . Horizontal control is guided by GPS. Vertical control is guided by Total Stations. GPS will not be allowed for Vertical control.
3.Compaction of Mixtures. Uniformly compact th e HMA as soon after spreading and strike-off as possible without shoving or tearing. Use self-propelled rollers operated at speeds slow enough to avoid displacement of the HMA. Equipment and rolling procedures whic h result in excessive crushing of the aggregate are prohibited. Use a sufficient number and weight of rollers to compact the HMA to the required density. Perform final rolling with a steel roller unless otherwise specified. On the final pass, operate finishing, vibratory rollers in the static mode. Coordinate the frequency, amplitude and forward speed of the vibratory roller to achieve satisfactory compaction without objectionable undulations. For HMA lifts wi th a compacted thickness less than 1¼ inch, operate vibratory rollers in the static mode. Keep rollers in operation as necessary so all parts of the pavement receive substantially equal compaction at the proper time. The Engineer will suspend HMA delivery to the project at any time proper compaction is not being performed. Remove, replace with suitable material and finish acco rding to these specifications any mixture that becomes loose, broken, mixed with foreign material or which does not comply in all respects with the specifications.
4.Density Requirements. RCI mixes will not have a density pay adjustment. Control density using an approved rolling procedure with random nuclear gauge de nsity determinations. Incl ude a method for controlling density in the QCP. Designate a "Compaction Foreman". This person sh all control compaction procedures, review nuclear gauge results as they are obtained, ad just compaction procedures as needed to optimize compaction and report any changes in the compaction process and results of nuclear gauge testing to the Engineer. The compaction foreman may also be the nuclear gauge operator. The nuclear gauge operator shall continuously monitor compaction procedures. As a minimum, take 10 random nuclear gauge density determinations per day and report results to the Engineer. Throughout the day, nuclear gauge results shall be available fo r review by the Engineer. The compaction foreman shall document at a minimum of once every 2 hours that the approved rolling sequence is being followed. Documentation shall include roller passes, the mat temperature at each pass, amplitude setting of rollers and roller speed. Provide the documentation to the Engineer. Determine and periodically update an approved rolling procedure as outlined in this section. As a minimum, evaluate the initial rolling procedure using 3 rollers. If the hot mix plant is operating at over 275 tons per hour, use a minimum of 4 rollers in the initial evaluation. The number of rollers may be reduced to 2 (or 3 if the plant is operating at over 275 tons per hour) provided cores (minimum of 3 sets of 3) are taken from both a segment (single truck load) using 3 rollers and a segment (single truck load) using 2 rollers (4 and 3 rollers, respectively if plant is running over 275 tons per hour). Determine the G mb of the cores using KT-15. If the G mb of the segment with less rollers is equal to or greater than the G mb of the segment with more rollers, then the minimum number of rollers may be reduced by 1. Operate vibratory rollers in the static mode only. Evaluate RCI paver screed operation with the nuclear gauge at various vibration settings. For screed evaluation, take the nuclear gauge readings directly behind the screed and before rolling. The Compaction Foreman and Engineer will evaluate the densities obtained with the various roller combinations and screed settin gs to determine the initial approved rolling procedure. Together, the Compaction Foreman and Engineer will de termine when new rolling procedures are required. RCI production may be stopped by the Compaction Foreman or Engineer when ever rolling is not being performed according to the approv ed rolling procedure. For all lots, achieve the maximum density before the temperature of the HMA falls below 175 F. Do not crush the aggregate. When the mat temperature falls below 175 F, roller marks may be removed from the mat with a self-propelled static steel roller.
5.Contact Surfaces. Coat contact su rfaces of curbing, gutters, manholes a nd similar structures with a thin uniform coating of asphalt material. Pl ace the HMA uniformly high n ear the contact surfaces so that after compaction it shall be approximately ¼ inch above the edge of such structures. 614 – HMA BASE (REFLECTIVE CRACK INTERLAYER (RCI)
600-86 (6) Adjustment of Manholes (Set Price). When required, this work will be performed and paid for under
SECTION 816 .
7.Construction Joints.
a.Transverse Construction Joints. Use a met hod of making transverse construction joints to provide a thorough and c ontinuous bond, provide an acceptable surface texture and meet density requirements. 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.
b.Longitudinal Joints. Construct well bonded a nd sealed longitudinal joints to obtain maximum compaction at the joint. If deemed necessary by the Engineer to properly seal the joint, apply a light coat of asphalt emulsion or asphalt binder to the exposed edge before the joint is made. Before placing the fresh HMA against a cut joint or against old pavement, spray or paint the contact surface with a thin uniform coat of asphalt emulsion or asphalt binder. Where a finishing machine is used, make the longitudinal joint by depositing a sufficient amount of HMA to form a smooth and tight joint. Offset the longitudinal joint in successive courses by 6 to 12 inches. Comply with traffic lane edges for the width of the surf ace of top course placement.
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. 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.Special RCI Requirements. Technical Support: Personnel familiar with the process will provide technical support for production and placement of the RCI. Tack Coat: Place a tack coat pr ior to the placement of the RCI. Thickness: Compact the RCI, as a minimum, to the depth shown in the Contract Documents. Thicknesses less than the plan thickness are not acceptable and may resu lt in removal and replacement at no additional cost to KDOT. Longitudinal Joint: Overlap the PCCP or HMA longitudinal joint with the RCI by at least 6 inches. Compaction and Density: Control the in-place density of all lots of the RCI using an approved rolling procedure as outlined in subsection 614.4e . If cores are taken use extreme care when handling the cores. Use a solid flat and un-textured surface to transp ort and store the cores prior to testing. Release to Traffic and Overlay Placement: Cover the RCI with a hot mixture over lay within 10 days after placement. The RCI may be opened to traffic or covered w ith the hot mix overlay after cooling to less than 140°F or as determined by the Engineer. Unacceptable work: Remove and replace areas dete rmined unacceptable by the Engineer, in accordance with this specification, at no additional cost to KDOT. Damaged Areas: Replace any traffic-damaged or marred areas at no additional cost to KDOT. Blisters: Perforate blisters that are a minimum of 8” in diameter or a minimum of 1” high that have not disappeared by the time of the overlay using a method approved by the Engineer.
i.Pavement Smoothness. Evaluate pavement smoothness according to SECTION 603 . 614.5 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
Source: Kansas Standard Specifications for State Road and Bridge Construction, 2015 Edition. Pages 320–323 of 978.