413
4-56SECTION 413 – HOT IN -PLACE RECYCLING
413.01DESCRIPTION . This work shall consist of hot in -place recycling (HIR) of the existing pavement
surface, including heating the pavement surface using specialized equipment causing the asphalt to soften, scarifying the softened pavement surface in a continuous process to the depth specified in the Plans, mixing the scarified asphalt pavement with a recycling agent that rejuvenates the asphalt, and placing and compacting the mix back onto the roadway. Excess recycled material not used in the HIR process will become the property and responsibility of the Contractor.
413.02MATERIALS . Materials shall meet the requirements of the following subsections:
Hot Recycling Agents ................................ ................................ ................................ 702.05 The HIR mixture shall be free of any materials not generally considered to be asphalt pavement.
413.03EQUIPMENT
sizing the resulting RAP, and mixing th e RAP with the recycling agent and any additives stipulated in the mix design. The equipment used shall be capable of placing the recycled pavement mixture to the requirements provided herein and to the lines and grades shown on the Plans. Any additional equipment used by the Contract or beyond th at specified below shall be approved by the E ngineer based on its suitability to produce results meeting the specification requirements.
depth required. Care shall be taken not to overheat the existing pavement thereby softening the underlying asphalt pavement not to be scarified. The burner assembly shall be adjustable to heat between 8 feet and 14 feet i n width. The entire heating unit shall be enclosed and vented to contain the heat and prevent damage to adjacent properties and landscape. In cooler temperatures, an additional heating unit may be required.
only the upper layers of the existing pavement. The heater scarification train shall be self -propelled and capable of operating at speeds of 16 feet to 50 feet per minute while uniformly heating and scarifying the existing pavement to a minimum depth of one inch. Listed below are the various units that are part of the heater scarification train.
413 4-57 (1) Scarifying Unit . The scarifying unit shall contain at least two rows of spring -loaded tines that are a djustable in one inch increments to scarify a width of 14 feet. This unit shall also be able to conform to the pavement contours to ensure a uniform penetration from the tines and prevent damage to utility structures.
The size of the nozzles located on the spray bar and pump shall be selected based upon the rate of application rate and the forward speed of the heater scarification unit. The spray unit shall be equi pped with an electronic digital measuring system, which shall be capable of maintaining the required application rate of the recycling agent with a tolerance of ± 5% for the mix design. The electronic digital measuring system shall continuously verify and display the application rate of recycling agent and cumulative total with respect to the volume of scarified material for the road surface. The Contractor shall calibrate the electronic digital measuring system in the presence of th e Engineer. Approved calibrations shall be done for each project. Work shall not progress until the calibration has been completed and verified.
shall thoroug hly mix the agent with the scarified material to the required depth. This process may be completed with the use of a dual drum enclosed auger or mill head in a manner to perform proper and continuous blending. The remixer unit shall be an integral part of the scarifying machine and shall be located between the spray unit, which applies the recycling agent, and the screed. This unit shall be operated hydraulically, able to work at variable speeds from 0 rpm to 120 rpm, and shall be adjustable from 8 feet to 14 feet wide. In addition, this unit shall be able to break in the center to allow for quarter point and crown control.
and transverse section by the use of an attached heated, augured vibratory screed. T he temperature of the hot scarified material shall be maintained between a minimum of 275°F and a maximum of 330°F. The screed shall be equipped with an adjustable crown control and each end of the screed shall have hand wheel adjusting screws for providing the desired longitudinal grade and transverse slope.
413 4-58 (f) Rollers . Rollers shall be in good mechanical condition, capable of reversing without backlash, and operated at speeds slow enough to avoid d isplacement of the bituminous mixture. The weight of the rollers shall be sufficient to compact the mixture to the required density without crushing the aggregate. Rollers shall be equipped with tanks and spray bars for wetting the rolls or tires. Pneumat ic-tired rollers shall be equipped with appropriate skirts at all times and be preheated prior to use in order to avoid picking. The Contractor shall remove all picked material from the surface. Vibratory rollers shall have separate controls for energy an d propulsion. They shall be equipped with automatic cutoffs that stop the vibration prior to the roller stopping or reversing its direction of travel.
413.04CONSTRUCTION REQUIREMENTS
the project site at no additional compensation due the Contractor to allow for any and all sampling required to assess compliance with the provisions of this specification. The Contractor shall afford the Agency all traffic cont rol operations and provide means to extract samples as requested to achieve this effort. The recycling agent content used in production may vary throughout the project and be adjusted by the Contractor based on the results of QC testing or other variables with the approval of the Engineer, to maintain an optimized finished product.
30% over the original penetration, while not exceeding 100 microns, when te sted in accordance with AASHTO T 49 .
agent. To obtain material to conduct mix designing, the Contractor shall sample exi sting pavement to represent the recycled aggregates. A minimum of six core samples representative of the project shall be taken . The Contractor shall develop and submit a material sampling plan for review and approval by the Agency a minimum of 5 working da ys prior to obtaining HIR mix design samples. At a minimum, the sampling plan shall include the number of samples, location of samples, and the method of sampling and backfilling. The mix design process shall include recovery of the asphalt binder from the RAP for penetration testing, dosing with recycling agent, and testing to determine the percent improvement of penetration. The mix design shall provide the type and recommended d osage rate of the recycling agent.
413 4-59 (d) Cleaning . The existing pavement and shoulder to be recycled shall be cleaned by using mechanical sweepers, hand brooms, or other effective means until the surface is free of all material which might interfere with the scarification process.
adjacent property and vegetation. All heat -damaged areas shall be repaired immediately to the satisfaction of the Engineer and at no additional cost to the Agency. The speed of the equipment shall be controlled to ensure that the recycled pavement is properly mixed, and uniformly distributed to the proper thickness, slope, and crown shown in the Plans. Extra care shall be taken i n controlling heater scarification equipment to prevent segregation of the recycled mix at the start and end of paving production as well as at any locations where the heater scarification train needs to stop and restart. The hot in -place pavement shall b e constructed to conform to the depth requirements and tolerances shown in the Plans. The width of each pass shall be controlled to provide proper placement of longitudinal joints, including a 3 inch overlap onto adjacent lane passes. Recycling agent shal l be added uniformly to the scarified pavement at the predetermined application rate to produce a homogenous recycled mix. The temperature of the scarified mixture shall be maintained between 275°F and 330°F prior to initial compaction. In areas having c atch basins or manholes that are not accessible to scarifying equipment, the Engineer will determine if they require repair. Pavement surfaces that are in good condition and are less than one square yard in size do not require repair. Areas that are greate r than one square yard in size or with cracks or spalls shall be repaired with bituminous concrete pavement, as approved by the Engineer.
If two out of three co nsecutive density test results are outside of the allowable range, the Contractor will be required to construct a new test section to establish an updated TMD. If the Engineer determines that the TMD is apparently incorrect, as evidenced by being achieved with little or minimal compactive effort, then the Engineer will require a new test section to establish a new TMD.
413 4-60 (g) Surface Tolerance . The surface will be tested by the Engineer using a straightedge at least 12 feet in length at selected locati ons parallel with the centerline. Any variations exceeding 1/8 inch between any two contact points shall be eliminated. A straightedge at least 10 feet in length may be used on a vertical curve. The straightedges shall be provided by the Contractor in acco rdance with Subsection 631.0 4.
the material is determined to be stable by the Engineer. The required density shall be achieved and maintained until a wearing course pavement has been placed. Any additional compaction effort or repair of imperfections in the HIR material shall be performed as directed by the Engineer at no additional cost to t he Agency.
dates of May 16th and October 15th, inclusive. In addition, hot in-place activities shall only occur when the following conditions are met:
the shade at the recycling location, is at least 50°F and rising.
413.05QUALITY CONTROL
quality control sampling and testing and operate in accordance with an approved QC plan. Prior to performing any HIR production, the Engineer or the Contractor may request a pre -recycle conference to discuss the recycling schedule.
The Contractor shall sample, test, and evaluate the HIR process in accordance with the procedures
and minimum frequencies specified in Table 413.05A.
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TABLE 413.05A – MINIMUM QUALITY CONTROL FREQUENCIES
Test or Action Frequency Test Method
Density 1 per 1,000 feet per lane AASHTO T 355 or
AASHTO T 343
Air temperature 4 per day at even intervals Verified thermometer
Surface temperature At beginning and end of
each day’s operation Verified thermometer
Yield of recycling agent 2 per day at even intervals Tank check
Penetration of recovered
binder of mix 1 per mile per lane AASHTO T 49
Density testing shall be the average of three points across the lane (transverse) for each testing
location.
Quality control records shall include all sampling events, testing events, and process changes with
accurate time and location data. The Contractor shall submit QC records and summaries to the
Engineer by 1:00 p.m. on the next working day. The Contractor shall make all test results,
including randomly sampled densities, available to the Engineer onsite and on request.
The Contractor shall cease recycling operations whenever one of the following occurs:
values in the mix design.
checked behind the screed prior to compaction.
Recycling operations shall not resume until the Contactor and the Agency agree on the corrective
action to be taken.
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a minimum of 14 calendar days prior to initiating HIR operations and shall not commence HIR
operations until the QC plan is accepted by the Engineer.
The QC plan shall address any items that affect the quality of the recycling process including, but
not limited to, the following:
shall list their past experience on HIR projects. They shall:
involved with the acceptance activities of the project.
construction operations.
the QC Plan.
conducting quality control and inspection activities to implement the QC plan. There may
be more than one QCT on a project. They shall:
minimum of two years of experience in quality control activities in field
construction operations.
Transportation Training and Certification Program (NETTCP) for Soils and
Aggregate Inspector, or an equivalent regional program.
the QC Plan.
controlling the recycling process, quality control and inspection activities to implement the
QC plan. They shall:
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minimum of two years of experience in quality control activities in field
construction operations.
the QC plan.
equivalency.
configuration.
landscape.
contact pressure for pneumatic tired rollers.
required treatment depth is obtained and that segregation is minimized.
necessary corrective action or repair.
other applicable procedures.
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HIR, and through the project as needed.
The Contractor shall construct a control section to assure the Engineer that the Contractor’s
equipment and procedures are suitable for the work specified and establish the target maximum
density. The rolling pattern shall be determined from buildup, when the density readings show an
increase in dry density of less than 1 pcf for the final four roller passes of each roller.
The average of a minimum of 10 tests taken throughout the control section after the buildup is
complete shall be used to determine the TMD. If Agency personnel are available, their values shall
be included in the average, or used to establish the density gauge offsets, as directed by the
Engineer.
The control section shall be full lane width and a minimum of 500 feet long, or as approved by the
Engineer. No further recycling shall be performed until all aspects of the control section and the
TMD are approved by the Engineer. The Contractor shall use the same equipment for building
both the accepted test sections and performing the HIR work on the project unless equipment
substitution is approved by the Engineer.
The Engineer may require an additional test section and additional process control sampling to
investigate the suitability of substituted or changed equipment.
If the control section does not meet the requirements of this specification, or the target density is
not determined from buildup testing, then the Contractor shall modify the procedure and either
construct another test section or reconstruct the original test section until suitable results are
obtained.
The Contractor shall provide the Engineer with written copies of all process control and quality
control results from the control section by 1:00 p.m. on the next working day, including test
locations. The Contractor shall make all test results available to the Engineer onsite and on request.
413.06METHOD OF MEASUREMENT. The quantity of Hot In-Place Recycling to be measured for
payment will be the number of square yards of existing pavement which has been recycled in an acceptable
manner as determined by actual surface measurements of the lengths and widths of the recycled area as
shown on the Plans or as directed by the Engineer. No additional compensation will be made for
overlapping areas.
Areas where the scarifying equipment cannot be used and that are repaired with bituminous concrete
pavement, such as catch basins or manholes, will be measured for payment as square yards of Hot In-
Place Recycling.
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413.07BASIS OF PAYMENT. The accepted quantity of Hot In-Place Recycling will be paid for at the
Contract unit price per square yard. Payment will be full compensation for cleaning debris from the
existing pavement; providing the recycling agent; heating and scarifying, mixing, paving, compacting,
coring, and testing the recycled materials; and for furnishing all labor, tools, equipment, and incidentals
necessary to complete the work.
Furnishing and incorporating the recycling agent will not be paid for separately but will be included in the
unit price bid for Hot-In-Place Recycling.
Payment will be made under:
Pay Item Pay Unit
00 Hot In-Place Recycling .............................................................................Square Yard
414
4-66SECTION 414 – COLD IN -PLACE RECYCLING
414.01DESCRIPTION . This work shall consist of cold in -place recycling (CIR) of the existing pavement
surface, including milling bituminous pavement from the existing roadway, crushing or screening the existing bituminous pavement if needed, the addition of asphalt emulsion or foamed asphalt binder, Portland cement, and virgin aggregate, and mixing and repaving of the material to the depths, lines, and grades shown on the Plans. Excess recycled material not used in the CIR process will become the property and responsibility of the Contractor.
414.02MATERIALS . Materials shall meet the requirements of the following subsections:
Portland Cement ................................ ................................ ................................ ......... 701.02 Performance -Graded Asphalt Binder ................................ ................................ ......... 702.01 Anionic Emulsified Asphalt ................................ ................................ ....................... 702.02(a) Cationic Emulsified Asphalt ................................ ................................ ...................... 702.02(b) Aggregate f or Bituminous Concrete Mixtures ................................ ........................... 704.10 Recycled Asphalt Pavement ................................ ................................ ...................... 704.22(a) Water ................................ ................................ ................................ .......................... 745.01
Emulsified asphalt for CIR, when used, shall be type HFMS -2, HFMS -2h, HFMS -2s, CSS -1, CSS -1h, MS-2h, or as recommended by the Contractor as a result of the design criteria of this specification and approved by the Engineer. Foamed asphalt binder for CIR, w hen used, shall be unmodified and grade 58S -28, unless otherwise specified in the Contract. The CIR shall meet the gradation requirements of Table 414.02A for extracted aggregate ( AASHTO T 30 , dry) taken from the pulverized material. TABLE 414.02A – EXTRAC TED AGGREGATE GRADATION Sieve Designation Percentage by Mass (Weight) Passing Square Mesh Sieves 1-1/2 inch (37.5 mm) 100 1 inch (25.0 mm) 90 – 100 No. 4 (4.75 mm) 30 – 70 No. 200 ( 0.075 mm) 0 – 12
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