The Table of Contents for this section is available.
The work covered by this section consists of the production, delivery, placement, and compaction of all types of recycled asphalt plant mix bases and surface courses except Type F1, Type J1, and asphalt drainage course. Any asphalt plant mix which incorporates reclaimed asphalt pavement materials will be considered to be recycled asphalt plant mix.
The Contractor may, at his option, use a recycled asphalt plant mix in accordance with this section for any work covered by Section 610. However, all provisions of Section 610 will also apply to the work covered by this section except where in conflict therewith.
The work shall include crushing and screening of the reclaimed asphalt pavement where necessary; mixing of the reclaimed asphalt pavement with new aggregates, additional asphalt cement, and additives in an approved asphalt plant; and placing and compacting the recycled mixture in accordance with the lines, grades, and typical sections shown in the plans and with the requirements of these specifications.
(A) Reclaimed Asphalt Materials:
(1) Classifications
(a) Millings
Existing reclaimed asphalt pavement (RAP) that is removed from the original location by a milling process as specified in Section 612.
(b) Processed RAP
RAP that is processed in some form (possibly by crushing or use of a blending method) to produce a uniform gradation and AC content in the RAP prior to use in a recycled mix. The RAP shall be processed so that all materials will pass a 2 inch sieve prior to introduction into the plant mixer unit. Millings are considered processed provided it has a uniform gradation and AC content.
(c) Unprocessed RAP
RAP in the form as removed from the original location which has not been processed for gradation and AC content uniformity. Different sources of unprocessed RAP may be stockpiled together provided it is generally free of contamination and will be processed prior to use in a recycled mix. RAP contamination in the form of excessive dirt, debris, clean stone, concrete, etc. will not be allowed. Incidental amounts of dirt, concrete, and clean stone will be acceptable.
(d) New Source RAP
New source RAP will be classified into two (2) categories:
Millings and Processed RAP.
(1) Millings coming from a different source than that of the millings used for the recycled mix design process, and that are not to be further processed, will be considered a new source RAP.
(2) All processed RAP other than that included in the original stockpile sampled and approved for the recycled mix design will be considered a new source RAP.
(2) Sampling of Reclaimed Asphalt Pavement For Mix Design Purposes:
All sampling of reclaimed asphalt pavement materials for mix design purposes shall be performed by the Contractor in the presence of a representative of the Engineer. Samples shall be submitted to the Department's Materials and Tests Unit at least 3 weeks prior to production of the recycled mixture.
Samples from existing asphalt pavement may be taken, at the option of the Contractor, by either sawing, coring, or milling.
Cored or sawed samples shall consist of a minimum of ten 6-inch samples cut from areas approved by the Engineer. The sample holes shall be immediately repaired and compacted by the Contractor to conform to the surrounding area.
Milled samples shall be obtained by milling the existing pavement at three locations approved by the Engineer for a length of at least 200 feet to the depth called for by the plans for pavement removal. The milled pavement shall be immediately replaced with the type mix called for in the plans using plant mix meeting the requirements of a job mix formula issued by the Department.
When reclaimed asphalt pavement material from sources outside the project is to be used in recycled asphalt mixtures, the Contractor shall submit a sufficient number of samples of the reclaimed asphalt pavement to adequately represent each proposed stockpile to the Department's Materials and Tests Unit. Processed RAP and/or millings may be sampled and used for mix design purposes. Unprocessed RAP will not be used for mix design purposes. The Contractor shall also submit extraction test results indicating the gradation and the percentage of asphalt cement along with the samples.
(B) New Aggregate:
New aggregate materials used in the recycled plant mix shall meet the applicable requirements of Article 10121.
(C) Asphalt Materials:
New asphalt cement required in the production of recycled asphalt mixtures shall meet the requirements of Article 10201. Other grades may be permitted subject to written approval by the Engineer. The viscosity grade of the asphalt cement shall be as determined in accordance with Article 6113. (See Standard Special Provisions)
The new asphalt cement will be accepted at the source of shipment subject to the provisions of Article 10201. Silicone shall be added to the additional asphalt cement used in recycled asphalt mixtures in accordance with applicable requirements of Article 6202.
The Contractor shall submit samples of the asphalt cement from actual sources he proposes to use to the Department's Materials and Tests Unit at least 3 weeks prior to beginning production of the recycled mixture.
(D) Non-Strip Additive:
Non-strip additive shall meet the requirements of Article 10208.
611-3 COMPOSITION OF RECYCLED MIXTURES (JOB MIX FORMULA).(See Standard Special Provisions)
The recycled mixture shall be a homogeneous mixture composed of reclaimed asphalt pavement (RAP), new aggregates, asphalt cement, and additives combined in the proportions established by a job mix formula issued by the Department in accordance with Article 6103. Materials which will not produce a mixture meeting the requirements of the appropriate section of the Specifications will be rejected, unless otherwise approved by the Engineer.
At least 3 weeks prior to the beginning of production, the Contractor shall submit to the Department's Materials and Tests Unit his proposed blend of RAP/virgin materials, the proposed grade of additional asphalt cement, and representative samples of all materials to be used in the recycled mixture.
Reclaimed asphalt pavement shall constitute not more than 60 percent of the total material used in the recycled mixture. The Contractor's proposed materials blend ratio (RAP/virgin materials) and the grade (viscosity) of additional asphalt cement shall be compatible so that the combined viscosity of the old asphalt and new asphalt cement results in a target viscosity of 2,000 ± 400 poises @ 140°F. (60°C.) prior to production. The procedure for making this determination is available from the Asphalt Design Engineer located in the Department's Materials and Tests Unit. This procedure is based on information included in the Asphalt Institute publication MS-2 (Sixth Edition) "Mix Design Methods".
When the percentage of asphalt cement contributed by the RAP is not more than 15 percent of the total asphalt cement in the completed mix, or the percentage of RAP is not more than 15 percent of the total mixture, Asphalt Cement, Grade AC 20 may be used. Approval by the Engineer will not nullify the authority of the Engineer to require the Contractor to adjust the mixture as provided in the last paragraph of this article.
When directed by the Engineer, the additional asphalt cement shall contain an approved non-strip additive in accordance with the requirements of Section 622. The percentage of non-strip additive shall be 0.5 percent of the additional asphalt cement unless otherwise directed by the Engineer.
The job mix formula with the allowable tolerances shall be within the design limits specified for the particular type mixture to be produced. The job mix formula will establish the percentage of reclaimed aggregate, the percentage of each additional aggregate required, a single percentage of aggregate passing each sieve size, the total percentage of asphalt cement in the mixture, a single percentage of additional asphalt cement to be added, the percentage of non-strip additive to be added to the additional asphalt cement, a single temperature at which the mixture is to be discharged from the plant, and the required field density.
Should a change in the source of RAP be made, a new mix design and/or job mix formula may be required based on the requirements in Article 6114.
The job mix formula for the mixture shall be in effect until modified in writing by the Engineer. All mixtures furnished for the work shall conform to the job mix formula within the tolerance ranges as specified. When unsatisfactory results or other conditions warrant, the Engineer may establish a new job mix formula.
Samples of the completed recycled asphalt mixture may be taken by the Department on a random basis to determine the absolute viscosity on the recovered asphalt cement in accordance with AASHTO T 202. The absolute viscosity at 140F. shall be within a range of 3,000 to 12,000 poises. If the viscosity is determined to be out of this specified range, the Engineer may require the Contractor to adjust the additional asphalt cement formulation and/or blend of reclaimed material to bring the viscosity within the allowable range.
611-4 FIELD VERIFICATION OF NEW SOURCE RAP
After a stockpile of processed RAP or millings has been sampled and mix designs made from these samples, no new source RAP will be added to the original stockpile without prior field testing to insure gradation and AC uniformity. New source RAP must be sampled before blending with the existing stockpile.
New source RAP shall be stored in a separate stockpile until the material can be sampled and tested for comparison with the original RAP mix design data. New source RAP may also be placed against the existing stockpile in a linear manner provided it is sampled for mix design conformity prior to its use in the recycled mix.
Field approval will be based on Table 6111, a Marshall test and maximum specific gravity tests on the mix with the new source RAP included. Provided the Table 6111 tolerances are met, a Marshall and maximum specific gravity test from the new mix will then be performed. If the Marshall and maximum specific gravity tests on the new mix meet allowable tolerances, the new source RAP may continue to be used.
If the gradation, AC content, Marshall test or maximum specific gravity test on the new mix is not within the allowable tolerances, the new source RAP shall not be used unless approved by the Engineer. A decision to either not use the stockpile, adjust the JMF, or redesign the mix may be made.
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NOTE: Tolerances shall be applied to the RAP gradation shown on the mix design (M&T Form 601) currently being used. New source RAP sampled and tested within these tolerances may be used in an existing JMF subject to satisfactory Marshall and maximum specific gravity test results on the new mix.
The recycled mixture shall be produced in a batch plant or dryer-drum mixer asphalt plant which meets all applicable requirements of Article 6105 and which has been modified to accommodate the hot recycling process. The plant shall be capable of producing uniform mixtures at temperatures within the job mix formula limits. The plant shall have been certified in accordance with the requirements of Section 610.
When recycled mixture is being produced, storage tanks for the additional asphalt cement shall be provided in accordance with Subarticle 6105(B)(1). The mixing of different grades of asphalt cement will not be allowed.
When a batch plant is used to produce the recycled mixture, the reclaimed material shall be automatically weighed and proportioned according to the job mix formula requirements. The combined aggregate materials shall be dry mixed in the mixer as directed by the Engineer prior to introduction of additional asphalt cement, and then mixing shall continue until a uniform, adequately coated mixture is obtained.
When a dryer-drum mixer plant is used to produce the recycled mixture, provisions shall be made to accurately and automatically proportion the combined materials according to job mix formula requirements at varying production rates. Convenient and accurate means shall be provided to check the blend proportions.
611-6 CONSTRUCTION REQUIREMENTS.
The production, spreading, finishing, weather limitations, joints, etc., of the recycled asphalt plant mix shall conform with applicable requirements of Sections 605, 610, 615, 620, 622, 630, 640, 645, and 654, except as modified herein.
Payment at the contract unit prices for the various items covered by Sections 630, 640, 645, and 654 will be full compensation for all work covered by this section except as otherwise provided below.
Furnishing asphalt cement for the mix will be paid for as provided in Article 6205 for "Asphalt Cement for Plant Mix".
Furnishing non-strip additive will be paid for as provided in Article 6225 for "Non-Strip Additive".
Furnishing asphalt laboratory facilities will be paid for as provided in Article 6153 for "Field Laboratory Rental, Asphalt Plant Mix".
Where samples of reclaimed asphalt pavement are obtained by milling, removal of the milled pavement will be paid for as provided in Section 612. The plant mix used for replacing the milled pavement will be paid for as provided by the section of the Specifications covering the type of plant mix used.
The above prices and payments will be full compensation for all
work covered by this section, including but not limited to sampling,
producing, weighing, transporting, placing, and compacting the
recycled plant mix; furnishing new aggregate, reclaimed asphalt
materials, additional asphalt cement, non-strip additive, and
all other materials for the plant mix; handling and processing
the reclaimed asphalt materials; furnishing and applying tack
coat as specified in Section 605; furnishing scales; maintaining
the plant mix until final acceptance of the project; and making
any repairs or corrections to the plant mix that may become necessary.