4−35
d.Adjust Water Gates.
e.Adjust Gas Gates.
f.Gravel Borrow Subbase (to adjust the gravel base and/or subgrade or to replace unsuitable materials).
g.Coarse or Fine Aggregate from outside sources.
h.Water for Compaction Control.
i.Calcium Chloride for Pavement Rehabilitation.
j.Adjust Catch Basins or Manholes to Grade.
k.Trimming and Fine Grading (to adjust the gravel base or subgrade).
407.01 DESCRIPTION. This Specification provides the Contractor with the option of recycling
reclaimed asphalt pavement (RAP) into the composition of the following mixes or applications.
a.Bituminous Concrete; Base Course b. Bituminous Concrete; Binder Course If the Contractor chooses this recycling option the following modifications to SECTION 401; DENSE GRADED HOT MIX ASPHALT (HMA) PAVEMENTS , shall apply.
407.02 MATERIALS. Reclaimed Asphalt Pavement (RAP) shall consist of asphalt pavement
recovered by cold milling or other removal techniques approved by the Engineer. New aggregate and asphalt cement shall be added to meet the required composition. 407.02.1 Composition of Mixtures. No more than 30 percent RAP will be allowed in the bituminous mixture. The recycled mixture of RAP, new aggregate and added asphalt cement shall meet the requirements specified in Subsection M.03.01; Bituminous Concrete Pavements , for aggregate gradation and asphalt cement content. AASHTO TP2 shall be used for extracting and recovering the binder from the RAP. The added asphalt cement grade shall be selected so that the requirements for PG 64-28 specified in Subsection M.03.02.1; Performance Graded Asphalt Cement, shall be met.
a.Job Mix Formula. For any bituminous mixture containing RAP, the Contractor shall formulate and submit to the Engineer a Job Mix Formula (JMF) which shall include: 4−36
1.Gradation and asphalt content of the RAP.
2.Gradation of recycled mixture.
3.Percentage of RAP added.
4.New aggregate source(s).
5.Total asphalt cement content (based on total mixture weight).
6.Added asphalt cement content (based on total mixture weight).
7.Grade of added asphalt cement.
8.Recycling Agent Additive (Type and Amount; optional if needed)
407.02.2 Bituminous Material. The added asphalt cement may be PG 64-28, PG 58-28, PG 58-
34, PG 52-34 or other asphalt cement grades approved by the Engineer. 407.02.3 Reclaimed Asphalt Pavement (RAP). The aggregate component of the RAP shall meet the requirement of Subsection M.03.02.2 of these Specifications. The bitumen component of the RAP shall be asphalt cement and shall be free of significant contents of solvents, tars or other contaminating substances that will make the RAP unacceptable for recycling as determined by the Engineer. The RAP shall be separated according to specific pavement sources by the Contractor unless otherwise permitted by the Engineer.
a.Approval of RAP Quality. The Engineer will use one of t he following criteria to approve the RAP quality:
1.RAP obtained from a pavement which was constructed with asphalt cement and aggregates that meet the current requirements of Subsection M.03.02.2 of these Specifications.
2.If the source of the RAP or its quality is not known, the Contractor shall submit to the Department at least 15 calendar days prior to the start of paving the following:
a.Designated use of the RAP and approximate proportions.
b.A five-pound (minimum) sample representing the RAP to be incorporated into the recycled mixture.
c.The absolute viscosity (140 OF) of the bituminous material recovered from the RAP. The Engineer will determine the acceptability of t he RAP for the designated use. Details for sampling and testing the RAP are available from the Engineer.
b.Acceptance Requirements. The RAP will be accepted on the basis of the following:
1.Certification from the Contractor stating the source of the RAP, if known.
2.Analysis of RAP and its components conduc ted by the Contractor and approved by the 4−37Engineer. This will be submitted as required to insure the consistency of the RAP.
c.Stockpile Requirements. RAP from similar pavement types and sources shall be stockpiled on a free draining base separated from other aggregates and RAP sources and shall be free of foreign materials. The stockpile must contain at a minimum the amount projected to be used in five days or necessary to complete the project. Prior to entry into the mixer, the RAP shall have a consistent gradation from coarse to fine with 100 percent passing the maximum size sieve allowed by the job mix formula. 407.02.4 Recycling Agent Additives. The recycling agent additive shall be approved by the Engineer and shall be chemically and physically com patible with asphalt cement. Recycling agent additive material shall be composed of selected maltene and asphaltene fractions derived from petroleum crude. The additive when mixed with aged asphalt shall restore the properties of the aged asphalt to a level that is reasonably consistent with the requirements of current specifications for the new asphalt. 407.03 CONSTRUCTION METHODS.
407.03.1 Batch Plant. The plant shall meet all the applicable requirements of Subsection
401.03 1; HMA Mixing Plant , with exceptions and additions as noted below. It shall be modified as
required to permit recycling in conformance with all local, state and federal air pollution standards. The recycling modification shall be such that it provides a separate, independent, controlled cold feed system to introduce the salvaged bituminous pavement material into the weigh box for automatic proportioning, with new (virgin) aggregates , liquid asphalt and additives as required. This cold feed system shall also be equipped with a scalping screen to ensure that all bituminous pavement material being recycled will be 100 percent passing the maximum size sieve allowed by the job mix formula. The recording equipment shall be capable of automatically recording the batch weight of the salvaged bituminous pavement material along with other batch components, on the required delivery tickets. The new (virgin) aggregates shall be dried and heated to a sufficiently high temperature to produce a recycled mixture with a discharge temperature of at least 280 OF or as approved by the Engineer. The salvaged bituminous pavement materi al to be recycled shall be added to the heated aggregates in the weigh box at a rate that will minimize heat loss and provide for efficient plant operations. The salvaged bituminous pavement mate rial to be recycled s hall not be preheated prior to being added to the weigh bin. The combined aggregate and pavement material shall be mixed in the pugmill for approximately 20 seconds, after which the mixture shall be sprayed with the asphalt cement and additives, as required, and mixed for approximately 25 seconds more. The mixing time may be increased if, in the opinion of the Engineer, the aggregate is not sufficiently coated with asphalt. These components shall be proportioned and mixed so as to fall within the limits of the approved job mix formula. 407.03.2 Drum Dryer Mixing Plant. The plant shall meet all the applicable requirements of Subsection 401.03.1; HMA Mixing Plant, with exceptions and additions noted below. The plant shall consist of a dryer with a dual entry system capable of drying, heating and mixing new aggregate and salvaged bituminous pavement material to the temperature and gradation requirements established in the job mix formula. At no time shall the RAP material be in contact with the flame of the burner. It shall be capable of recycling in conformance with all local, State and Federal air pollution standards. This type plant shall also conform to the following 4−38 Specifications:
a.Cold Feed System. The plant shall have an adjustable feed rate control for the salvaged bituminous pavement feeder, as well as for the cold aggregate feeder and the mineral filler feeder.
b.Mixer Unit.
1.The Drum Mix Plant shall utilize a center entry system for recycling purposes.
2.The moisture content of the mixture upon discharge from the mixer shall not exceed 1.5 percent by weight and the mixture shall have a minimum temperature of 280 OF.
c.Automated Blending System.
1.The plant shall have an automated blending system for proportioning virgin aggregate, liquid bitumen, additives as needed, and recycled material.
2.The blending system shall include a hardcopy strip printer; capable of totaling and printing at intervals quantities of virgin aggregate, liquid bitumen, additives as needed, and recycled material. 407.04 METHOD OF MEASUREMENT. "Base Course" and "Binder Course" which have been produced utilizing the Hot Recycle Option will be measured according to Subsection 401.04 of these Specifications. 407.05 BASIS OF PAYMENT. The accepted quantities of "Base Course" and "Binder Course" which have been produced utilizing the Hot Recycle Option will be paid for according to Subsection 401.05 of these Specifications. SECTION 408 CLEANING AND SEALING CRACKS IN BITUMINOUS CONCRETE PAVEMENTS
408.01 DESCRIPTION. This work shall consist of performing all operations and furnishing all
materials, labor, and equipment necessary in connection with the cleaning and sealing of cracks and open joints in bituminous concrete pavements at the locations indicated and as directed by the Engineer, all in accordance with these Specifications. In this specification, the terms “crack” and “open joint” are used synonymously. All cracks shall be designated as follows: • Cracks 1/16-Inch to Less than One Inch in Width; • Cracks One Inch and Over in Width; • Alligator Cracks, which are cracks in any area where the density and/or severity of cracking forms a chicken wire or alligator pattern.
Source: Rhode Island Standard Specifications (Bluebook), 2024 Edition. Pages 213–216 of 826.