USACE / NAVFAC / AFCESA / NASA UFGS-32 01 17 (August 2008) --------------------------- Preparing Activity: USACE Superseding UFGS-32 01 17 (April 2006) UNIFIED FACILITIES GUIDE SPECIFICATIONS References are in agreement with UMRL dated January 2009 SECTION 32 01 17 COLD-MIX RECYCLING 08/08 NOTE: This guide specification covers the requirements for recycled cold-mix asphalt concrete. Edit this guide specification for project specific requirements by adding, deleting, or revising text. For bracketed items, choose applicable items(s) or insert appropriate information. Remove information and requirements not required in respective project, whether or not brackets are present. Comments and suggestions on this guide specification are welcome and should be directed to the technical proponent of the specification. A listing of technical proponents, including their organization designation and telephone number, is on the Internet. Recommended changes to a UFGS should be submitted as a Criteria Change Request (CCR). PART 1 GENERAL 1.1 UNIT PRICE NOTE: This paragraph will be deleted if the work is included in one lump-sum contract price for the entire work covered by the invitation for bids. This paragraph may be revised to combine the payment for cold-mix recycled mixture, rejuvenator (if needed), and emulsified asphalt cement, when separate payment for emulsified asphalt cement material is not considered warranted based on local experience and job conditions. Lump-sum contracts can be used when the total job does not exceed 16,800 square meters (20,000 square yards) or 1000 metric tons (tons). 1.1.1 Measurement NOTE: Where inplace mixing is used, measurement will be in square meters (yards) of accepted work. Cold-mix recycling paid for will be the number of [metric tons tons] [squaremeters yards] used in the accepted work. Aggregates will be paid for by the number of [metric tons tons] [square meters yards] used in the accepted work. The recycling agent will be paid for by the number of [liters gallons] [metric 2000-pound tons] of material used in accepted work. The emulsified asphalt cement will be paid for by the number of [liters gallons] [metric 2000-pound tons] of material used in accepted work. Determine the number of liters gallons of emulsified asphalt cement used either by measuring the material at a temperature of 15.6 degrees C 60 degrees F or by correcting the amount measured at another temperature to liters gallons at 15.6 degrees C 60 degrees F, using a coefficient of expansion of 0.00045 per degree C 0.00025 per degree F for the emulsified asphalt. 1.1.2 Payment The quantities of recycled paving mixture, aggregates, recycling agent, and emulsified asphalt cement, determined as provided above, will be paid for at respective contract unit prices per [metric ton ton] [square meter yard ] for paving mixture and aggregates and per [liter gallon] [metric ton ton] for recycling agent and emulsified asphalt cement. If deficiencies in the finished product exceed specified tolerances, no payment will be made for such areas of pavement until the defective areas are corrected and accepted by the Contracting Officer. 1.2 REFERENCES NOTE: This paragraph is used to list the publications cited in the text of the guide specification. The publications are referred to in the text by basic designation only and listed in this paragraph by organization, designation, date, and title. Use the Reference Wizard's Check Reference feature when you add a RID outside of the Section's Reference Article to automatically place the reference in the Reference Article. Also use the Reference Wizard's Check Reference feature to update the issue dates. References not used in the text will automatically be deleted from this section of the project specification when you choose to reconcile references in the publish print process. The publications listed below form a part of this specification to the extent referenced. The publications are referred to within the text by the basic designation only. ASTM INTERNATIONAL (ASTM)ASTM C 117(2004) Standard Test Method for Materials Finer than 75-um (No. 200) Sieve in Mineral Aggregates by WashingASTM C 131(2006)Standard Test Method for Resistance to Degradation of Small-Size Coarse Aggregate by Abrasion and Impact in the Los Angeles MachineASTM C 136(2006) Standard Test Method for Sieve Analysis of Fine and Coarse AggregatesASTM C 29/C 29M(2007) Standard Test Method for Bulk Density ("Unit Weight") and Voids in AggregateASTM C 88(2005) Standard Test Method for Soundness of Aggregates by Use of Sodium Sulfate or Magnesium SulfateASTM D 140(2001; R 2007) Sampling Bituminous MaterialsASTM D 1556(2007) Density and Unit Weight of Soil in Place by the Sand-Cone MethodASTM D 2041(2003a) Theoretical Maximum Specific Gravity and Density of Bituminous Paving MixturesASTM D 2172(2005) Quantitative Extraction of Bitumen from Bituminous Paving MixturesASTM D 2216(2005) Laboratory Determination of Water (Moisture) Content of Soil and Rock by MassASTM D 2397(2005) Standard Specification for Cationic Emulsified AsphaltASTM D 242(2004) Mineral Filler for Bituminous Paving MixturesASTM D 422(1963; R 2007) Particle-Size Analysis of SoilsASTM D 4643(2008) Determination of Water (Moisture) Content of Soil by the Microwave Oven MethodASTM D 4791(2005e1) Flat Particles, Elongated Particles, or Flat and Elongated Particles in Coarse AggregateASTM D 4944(2004) Field Determination of Water (Moisture) Content of Soil by the Calcium Carbide Gas Pressure Tester MethodASTM D 4959(2007) Determination of Water (Moisture) Content of Soil by Direct HeatingASTM D 6938(2007a) Standard Test Method for In-Place Density and Water Content of Soil and Soil-Aggregate by Nuclear Methods (Shallow Depth)ASTM D 75(2003) Standard Practice for Sampling AggregatesASTM D 977(2005) Emulsified AsphaltU.S. ARMY CORPS OF ENGINEERS (USACE)COE CRD-C 649(1995) Standard Test Method for Unit Weight, Marshall Stability, and Flow of Bituminous MixturesCOE CRD-C 650(1995) Standard Test Method for Density and Percent Voids of Compacted Bituminous Paving Mixtures1.3 SYSTEM DESCRIPTION 1.3.1 General Allow the Contracting Officer access, at any time, to all equipment used to produce the cold-recycled mixture; this can involve checking the adequacy of the equipment used, inspecting the operation of the equipment, and verifying weights, mixture proportions, and the character and physical properties of the materials used for construction. Plant, machines, tools, and miscellaneous equipment to be used on the production and placement of the cold recycled mixture shall be approved by the Contracting Officer. Tentative approval of specific items will be made only after adequacy of the plant, machines, tools, and miscellaneous equipment has been demonstrated in full-scale production. 1.3.2 Central Plant Mixing NOTE: This paragraph and paragraph In-Place Mixing should be left in only when it is desired to give the Contractor a choice between central plant mix and in-place methods. Provide a mixing plant designed, coordinated, operated to produce mixture within the JMF, and capable of producing recycled mixture at a minimum rate of [136] [_____] Mg [150] [_____] tons per hour. The plant shall be equipped with positive means to control the amount of asphalt, water, and time of mixing. 1.3.3 In-Place Mixing Equipment used for in-place mixing construction shall be designed, coordinated, and maintained to produce mixture within the JMF. The mixing equipment used shall be equipped with positive means to control the amount of asphalt and water added and shall be capable of producing a homogeneous mixture. 1.3.4 Straightedge Furnish and maintain at the site, in good condition, one 3.66 meter 12 foot straightedge for each mechanical spreader. Make straightedges available for Government use. Straightedges shall be constructed of aluminum or other lightweight metal with blades of box or box-girder cross section, with flat bottom reinforced to insure rigidity and accuracy. Straightedges shall have handles to facilitate movement on pavement. 1.4 SUBMITTALS NOTE: Review submittal description (SD) definitions in Section 01 33 00 SUBMITTAL PROCEDURES and edit the following list to reflect only the submittals required for the project. Submittals should be kept to the minimum required for adequate quality control. A “G” following a submittal item indicates that the submittal requires Government approval. Some submittals are already marked with a “G”. Only delete an existing “G” if the submittal item is not complex and can be reviewed through the Contractor’s Quality Control system. Only add a “G” if the submittal is sufficiently important or complex in context of the project. For submittals requiring Government approval on Army projects, a code of up to three characters within the submittal tags may be used following the "G" designation to indicate the approving authority. Codes for Army projects using the Resident Management System (RMS) are: "AE" for Architect-Engineer; "DO" for District Office (Engineering Division or other organization in the District Office); "AO" for Area Office; "RO" for Resident Office; and "PO" for Project Office. Codes following the "G" typically are not used for Navy, Air Force, and NASA projects. Choose the first bracketed item for Navy, Air Force and NASA projects, or choose the second bracketed item for Army projects. Government approval is required for submittals with a "G" designation; submittals not having a "G" designation are for [Contractor Quality Control approval.] [information only. When used, a designation following the "G" designation identifies the office that will review the submittal for the Government.] Submit the following in accordance with Section 01 33 00 SUBMITTAL PROCEDURES: _{SD-03 Product Data Aggregates Asphalt Cement Recycling Agent} Notification on sources from which aggregates, emulsified asphalt cement (bituminous materials), and recycling agent are to be obtained within 15 days after contract award. _{Job-Mix Formula (JMF)}[; _G][; _{G, [_____]}] The Job-Mix Formula (JMF) after the award of the contract and at least [30] [_____] days prior to placement of recycled mixture. _{SD-04 Samples Samples} Samples from the existing pavement obtained from at least two locations to provide representative samples of the pavement. _{Cold Recycled Mixtures} A 50 kg 100 lb sample of each aggregate, a 100 kg 200 lb representative sample of the recyclable asphalt pavement, a 20 L 5 gallon sample of recycling agent, and a 20 L 5 gallon sample of emulsified asphalt cement for mix design, not less than [30] [_____] days before material is required in the work. _{SD-06 Test Reports Testing} Copies of test results within 24 hours of completion of tests. Copies of test reports for aggregate source, not less than [30] [_____] days before the material is required in the work. Certified copies of the emulsified asphalt cement and/or recycling agent manufacturer's test reports indicating compliance with applicable specified requirements, not less than [30] [_____] days before material is required in the work. 1.5 QUALITY ASSURANCE 1.5.1 Sampling and Testing Perform sampling and testing by using a commercial testing laboratory or Contractor facilities, upon approval by the Contracting Officer. No work requiring testing will be permitted until the testing facilities have been inspected and approved. The first inspection will be at the expense of the Government. Cost incurred by the Government for any subsequent inspection required because of failure of the facilities to pass the first inspection will be charged to the Contractor. 1.5.2 _Samples Take recyclable asphalt pavement and aggregate samples for laboratory tests in accordance with ASTM D 75. Take samples of the emulsified asphalt cement (bituminous material) in accordance with ASTM D 140. 1.5.3 Sampling and Testing During Construction Perform quality control sampling and testing as required in paragraph ACCEPTABILITY OF WORK. 1.6 ENVIRONMENTAL REQUIREMENTS A recycled cold-mix course shall not be constructed in rain or on a layer which contains free water either within the layer or on its surface. Construct recycled cold-mix courses only when the atmospheric temperature is 10 degrees C 50 degrees F or above. PART 2 PRODUCTS 2.1 RECYCLABLE ASPHALT PAVEMENT (RAP) NOTE: Cold-mix recycling could include the use of existing RAP material stockpiles. If this condition exists, the desired material properties must be included below. The gradation of the existing stockpile will need to be determined. Provide RAP consisting of material obtained from cold milling or from removal and crushing of the existing asphalt concrete pavement. The maximum particle size of the RAP material shall never exceed half the thickness of the compacted recycled pavement. When lifts of 75 mm 3 inches or more are used, the maximum particle size of the RAP material shall not exceed a maximum of 38 mm 1-1/2 inch and a minimum of 90 percent of the RAP shall pass a 25 mm 1 inch sieve. 2.2 _AGGREGATES NOTE: Delete this paragraph when new or additional aggregates are not required as part of the recycling project. When required, new aggregates may be added to produce an aggregate gradation that meets the desired end product. Gradations for base course, stabilized base course or asphalt concrete intermediate course materials should be specified in Table I below. The choice of which gradation to specify should be based on the type, quality, and uniformity of the RAP material available for use. The gradation may require only that a maximum aggregate particle size not be exceeded or it may be more detailed, requiring further processing or adjustment with new aggregates to meet the desired gradation. The tolerances applied to this gradation should follow standard tolerances given for aggregates or asphalt aggregate mixtures when used in similar situations. When the recycled mixture is intended to be used as an intermediate or binder course, the gradation tolerances should follow those given in UFC 3-250-03, Table "Aggregate Gradations for Bituminous Concrete Pavements," for low-pressure tires. When the recycled mixture is to be used as a base course, an exact JMF aggregate gradation is not normally given and therefore tolerances are not required. The only requirement is that the gradation must stay within the gradation range specified. Provide aggregates consisting of crushed stone, crushed gravel, crushed slag, screening, sand, and mineral filler, as required. The portion of materials retained on the 4.75 mm No. 4 sieve will be known as coarse aggregate, the portion passing the 4.75 mm No. 4 sieve and retained on the 0.075 mm No. 200 sieve will be known as fine aggregate, and the portion passing the 0.075 mm No. 200 sieve will be known as mineral filler. The combined recycled aggregate gradation shall conform to the gradation specified in TABLE I. TABLE I is based on aggregates of uniform specific gravity; the percentage passing various sieves may be changed by the Contracting Officer when aggregates of varying specific gravities are used. Adjustments of percentage passing various sieves may be changed by the Contracting Officer when the specific gravity of the aggregates varies by more than 0.2. TABLE I.  COMBINED RECYCLED AGGREGATE GRADATION                    Sieve Size                    Percent Passing          ------------------------------------------------------------                    [_____]                            [_____] 2.2.1 Coarse Aggregate NOTE: The values of percentage of loss will be based on knowledge of aggregates in the area which have been previously approved or that have a satisfactory service record in bituminous pavement construction for at least 5 years. Coarse aggregate consisting of clean, sound, durable particles meeting the following requirements. a. Percentage of loss not exceeding 40 after 500 revolutions, as determined in accordance with ASTM C 131 . b. Percentage of loss not exceeding [_____] after five cycles performed in accordance with ASTM C 88 , using magnesium sulfate. c. Dry weight of crushed slag not less than 1200 kg/cubic m 75 pcf, as determined in accordance with ASTM C 29/C 29M. d. Crushed gravel retained on the 4.75 mm No. 4 sieve and each coarser sieve containing at least 75 percent by weight of crushed pieces having one or more fractured faces with the area of each face equal to at least 75 percent of the smallest midsectional area of the piece. When two fractures are contiguous, the angle between planes of fractures shall be at least 30 degrees to count as two fractured faces. e. Essentially cubical particle shape of crushed aggregates. The quantity of flat and elongated particles in any sieve size shall not exceed 20 percent by weight, when determined in accordance with ASTM D 4791 . 2.2.2 Fine Aggregate Provide fine aggregate consisting of clean, sound, durable particles including natural sand or crushed stone, slag, or gravel that meets requirements for wear and soundness specified for coarse aggregate. Fine aggregate produced by crushing gravel shall have at least 90 percent by weight of crushed particles having two or more fractured faces in the portion retained on the 0.600 mm No. 30 sieve. This requirement shall apply to the material before blending with natural sand, when blending is necessary. Quantity of natural sand to be added to the wearing and intermediate course mixtures shall not exceed 25 percent by weight of coarse and fine aggregate and material passing the 0.075 mm No. 200 sieve. Provide natural sand that is clean and free from clay and organic matter. Percentage of loss shall not exceed [_____] after five cycles of the soundness test performed in accordance with ASTM C 88, using magnesium sulfate. 2.2.3 Mineral Filler NOTE: The tabulated gradation requirements will be used to eliminate undesirable one-size materials. Mineral filler shall conform to ASTM D 242. Determine grain size in accordance with ASTM D 422. Use the tabulated gradation requirements in areas where dune sand or one-size material may be used as mineral filler, unless otherwise directed.                    Particle Size (mm)            Percent Finer               --------------------------------------------------                         0.05                          70-100                         0.02                          35-65                         0.005                         10-22 2.3 _{ASPHALT CEMENT} NOTE: The material being recycled may contain sufficient asphalt binder to meet the specification requirements. In this case, only water will be added as a lubricant to improve compaction. Grade SS-1 or CSS-1 should be specified in moderate or cold climates. Grade SS-1h or CSS-1h should be specified in hotter climates such as the southern or southwestern areas of the United States. Medium set, high float, or other types of emulsions may be used with open graded mixtures or in instances where previous experience with these types of emulsions has provided good results. Asphalt cement, if required, shall be an emulsified asphalt, Grade [_____] conforming to [ASTM D 977] [ASTM D 2397 ]. 2.4 WATER Generally, any potable water will be acceptable. Prior to construction, mix a sample of the water intended for use on the job with a sample of the emulsion at the ratio to be used in the project. If any adverse effect is observed on the emulsion, use a new source of water. 2.5 _{RECYCLING AGENT} NOTE: Depending on the material properties of the existing asphalt cement binder and the type and method of recycling used, an appropriate type of recycling agent (rejuvenator) will be selected. An emulsified rejuvenator which is widely used is reclamite (Golden Bear Division of WITCO Chemical Co., Los Angeles, CA). Non-emulsified recycling agents should be specified according to ASTM D 4552. The type of rejuvenator specified must match the recycling process used. The recycling agent selected should be capable of decreasing the viscosity of the recycled asphalt cement to levels that approach the viscosity values of asphalt cement in new asphalt concrete pavements for that area or region. Delete this paragraph if a recycling agent is not required. The recycling agent shall be [_____] or an approved equal. 2.6 _{JOB-MIX FORMULA (JMF)} NOTE: The mix design primarily establishes the amount of asphalt binder and recycling agent (if used) to be added to the mixture, and then establishes the amount of water to insure optimum compaction conditions. The asphalt content (this includes the recycling agent, if used) is determined based on hot compacted samples because this produces the density that will ultimately be obtained in the field. Ideally, the water content should be selected based on samples compacted at the mixture temperature (ambient air temperature) which will be encountered during construction. This paragraph should be edited where a choice is given between using 50 blows for roads or 75 blows for airfields and heavy duty roads. Prior to bidding the contract, the designer may want to sample and obtain the material properties of the asphalt and aggregates in the existing pavement. This information is required to allow the development of a JMF and to allow for estimates of emulsified asphalt cement and/or recycling agent type and quantities required. The need for new aggregates to meet JMF requirements may also be determined. For lump sum bidding, a reasonable estimate of required quantities of materials will be needed. Furnish the JMF for the recycled mixture to the Contracting Officer for acceptance. The Contracting Officer will verify this JMF through samples of materials submitted by the Contractor. No payment will be made for _{cold recycled mixtures} produced prior to the completion and acceptance of the JMF. The formula will indicate the gradation of the aggregate and a definite percentage of water [,recycling agent] and asphalt to be added to the mixture. 2.6.1 Gradation Tolerances NOTE: Eliminate the corresponding material size and tolerance values to agree with sieve sizes specified in Table 1. Eliminate these completely if no new aggregate is added and no specific JMF gradation is developed. The tolerances allowed on the gradation are as follows:                                                            Tolerance,                    Material                                Plus or Minus   -------------------------------------------------------------------------   Aggregate passing the 4.75 mm or larger sieve                 4 percent   Aggregate passing the 2.36, 1.18, 0.6, and 0.3 mm sieves      3 percent   Aggregate passing the 0.15 and 0.074 mm sieves                1 percent                                                            Tolerance,                    Material                                Plus or Minus   ------------------------------------------------------------------------   Aggregate passing the No. 4 or larger sieve                   4 percent   Aggregate passing the Nos. 8, 16, 30, and 50 sieves           3 percent   Aggregate passing the Nos. 100 and 200 sieves                 1 percent 2.6.2 Asphalt Content The JMF will be allowed an asphalt content tolerance of 0.3 percent. The asphalt content may be adjusted by the Contracting Officer to improve paving mixture, without adjustment in contract unit price. Select the optimum asphalt content to provide the tabulated properties when samples are compacted at 120 degrees C 250 degrees F with [50] [75] blows of standard Marshall hammer on each side of the specimen, according to COE CRD-C 649 and COE CRD-C 650.                                                  Requirement    Requirement          Property                                (75 blows)     (50 blows)   -----------------------------------------------------------------------------   Stability, minimum, Newtons                         8000           2200   Flow, maximum, 25/100-mm                              16             20   Voids in total mix, percent                          3-5            3-5   Voids filled with bitumen, percent                 70-80          75-85                                                  Requirement    Requirement          Property                                (75 blows)     (50 blows)   -----------------------------------------------------------------------------   Stability, minimum, pounds                          1800           500   Flow, maximum, 1/100-inch units                       16            20   Voids in total mix, percent                          3-5           3-5   Voids filled with bitumen, percent                 70-80          5-85 2.6.3 Water Content Select the water content to provide maximum dry density when samples are prepared at the optimum asphalt content and compacted with [50] [75] blows of Marshall hammer at ambient temperature. When no asphalt binder is added to the mixture, select the water content to provide maximum dry density. Prepare samples with water contents, in 0.5 percent intervals, from 0 to 2.5 percent (water content may be increased to achieve maximum density). After compaction, place the samples in an oven at 60 degrees C 140 degrees F for 96 hours. After cooling to ambient temperature, determine the dry density according to COE CRD-C 650. PART 3 EXECUTION 3.1 CONDITION OF EXISTING SURFACE Correct areas in the existing pavement that provide indications of underlying structural deficiencies (alligator cracking or depressions) prior to the completion of the recycling process. 3.2 CONSTRUCTION METHODS NOTE: Depending on the type of recycling desired the following paragraphs should be edited to remove the undesired method. The following can remain in its entirety when the type of construction used is to be a Contractor's option. The RAP material, prior to mixing, shall meet the requirements given in paragraph RECYCLABLE ASPHALT PAVEMENT. 3.2.1 Central Plant Mixing Introduce the required amount of bituminous material for each batch, or calibrated amount of continuous mixing, into the mixer to meet the requirements of the JMF. The mixing process shall provide a uniform dispersion of the emulsified asphalt and water to achieve a thorough coating (visually) of all aggregate particles. If this process requires excessive mixing, resulting in premature breaking of the emulsified asphalt, shorten the mixing times as directed by the Contracting Officer. As a minimum, when the recycled mixture contains fine particles passing the 4.75 mm No. 4 sieve, the mixing process shall provide a thorough coating of these particles. 3.2.2 Test Section NOTE: Use of a test section is recommended for all recycled mixtures, especially for central-plant mix recycling. The following paragraph is written for placing central-plant mix with a paver and must be edited when another type of recycling is used. Prior to the start of the recycling project, prepare a sufficient quantity of mixture to construct a test section at least 15 meters 50 feet long, two spreader widths wide and of thickness to be used in the project. Place, spread, and roll the mixture with the equipment to be used in the project and in accordance with requirements specified above. This test section will be tested and evaluated as a lot conforming to all specification requirements. If approved by the Contracting Officer, the test section may be located in one of the less critical areas of the project pavement construction. Otherwise, it will be located outside the project paving. If tests results are satisfactory, the test section will remain inplace as part of the completed pavement if constructed in the project pavement area. If tests indicate that the pavement does not conform to specification requirements, remove the test section and the material disposed of offsite. Make necessary adjustments to the plant operations and rolling procedures immediately, and construct another test section, all at no additional cost to the Government. Other additional test sections, as necessary and as directed, shall be constructed and will be sampled and tested for conformance with specification requirements. In no case start full production with the recycled mixture without approval of the Contracting Officer. 3.2.3 In-Place-Mixing NOTE: In-place recycling can be divided into either partial- or full-depth recycling. Partial-depth recycling involves only a portion of the asphalt bound layers and normally involves recycling to a depth of 50 to 100 mm (2 to 4 in.). Full-depth recycling involves all asphalt bound layers and often portions of the underlying base course layer. Produce a uniform blend of the RAP, aggregate (when required), asphalt emulsion, water, and a mixture containing the required amounts of emulsified asphalt and water as given in the JMF when using the in-place recycling process. 3.3 PLACEMENT 3.3.1 Spreaders Provide spreading equipment capable of spreading material uniformly; and conforming the surface to the grade and smoothness requirements when compacted. Unless otherwise directed, begin spreading along the centerline of areas paved on a crowned section, or on the high side of areas with a one-way slope, in the direction of major traffic flow. Sprsy contact surfaces of previously constructed pavement, curbs, manholes, and other structures with a thin coat of bituminous material conforming to Section 32 12 10 BITUMINOUS TACK AND PRIME COATS. Place the recycled mixture without segregation; when segregation occurs during placement, suspend the spreading operation until the cause is determined and corrected. When placing by hand, the mixture shall be dumped, distributed into place, and spread with lutes in a uniformly loose layer of such thickness to conform to the required grade and thickness when compacted. During hand spreading, carefully place each shovelful of mixture by turning the shovel over in a manner to prevent segregation. In no case shall mixture be placed by throwing or broadcasting. 3.3.2 Placement with a Paver Place the recycled asphalt mixture with a self-propelled asphalt paver or similar equipment containing a vibrating or tamping screed. Operate the paver so that the surface course being laid will be smooth and continuous without pulling or tearing. 3.3.3 Layer Thickness and Curing NOTE: The minimum layer thickness allowed should be at least twice the size of the maximum aggregate particle of the RAP or aggregate. The maximum layer thickness may vary from 100 to 150 mm (4 to 6 in.). However, a 100 mm (4 in.) layer is recommended. The thicker the layer the more difficult it is to get density, and the cure period increases. The curing period should range from 7 to 14 days, depending on climatic conditions. The hotter and drier the weather, the shorter the curing period. Generally, the cure period should be about 2 days for each 25 mm (1 inch) of lift thickness. The water content of the recycled mixture should be below 1.5 percent prior to placing additional layers or a wearing surface. Construct each layer of compacted mixture at least [_____] mm inches but no more than [_____] mm inches in thickness. Allow each layer of recycled mixture to cure for [_____] days before placing a succeeding layer, unless a shorter curing period is approved in writing by the Contracting Officer. 3.3.4 Windrows When windrows are used, construct them of such size and shape to allow adequate mixing of materials without segregation, ensuring that the required thickness of pavement can be constructed. 3.4 COMPACTION OF MIXTURE Conduct compaction of the mixture to satisfy density, grade, and smoothness requirements. Roll bituminous mixtures until all roller marks are eliminated, and a field density of at least 86 percent of the theoretical maximum density has been obtained when tested in accordance with ASTM D 2041. 3.4.1 Operation of Rollers and Tampers Provide the sufficient number, weight, and type of rollers to obtain the required density. Begin initial rolling of the recycled mixture as the emulsion is starting to break. Where lift thicknesses exceed 75 mm 3 inches, accomplish breakdown rolling with a large 22.5 to 27 Mg 25 to 30 ton pneumatic roller. Use either a pneumatic or a steel-wheel roller to breakdown roll thinner lifts. All rollers shall be equipped with watering devices to prevent material adhesion; however, excess water will not be permitted. Vibratory rolling will be allowed to achieve required density. Use finish rolling with a steel-wheel roller to remove any existing roller marks. 3.4.2 Correcting Deficient Areas Remove mixture that becomes contaminated with foreign material, or is defective in any way, to the full thickness of the course. Cut the hole with sides vertical and perpendicular to each other, with one pair parallel to the direction of traffic. Rolled areas shall not be skin patched to correct low areas and shall not be planed to correct high areas. Place fresh paving mixture in holes in sufficient quantity to produce a finished surface conforming to grade and smoothness requirements. Paving mixture shall be aerated, if necessary, and shall be compacted to the density specified herein. Provide competent workmen capable of performing all work incidental to the correction of deficiencies and defects. 3.5 JOINTS Joints shall present the same texture, density, and smoothness as other sections of the course. Carefully make joints between old and new pavements or between successive days' work to ensure continuous bond between old and new sections of the course. 3.5.1 Transverse Joints Pass the roller over the unprotected end of freshly laid mixture only when laying of the course has been discontinued. Cut back the edge of the previously laid course to expose even, vertical surface for the full thickness of the course. The fresh mixture shall be raked against the joints, thoroughly tamped, and then rolled. 3.5.2 Longitudinal Joints Construct longitudinal joints which are uniform, and without mixture segregation. When directed by the Contracting Officer, cut back the longitudinal joint to expose an even, vertical surface for the full thickness of the course. 3.6 EDGES OF PAVEMENT Edges of pavement shall be straight and true to required lines. After final rolling, cut off square excess material and dispose of as directed. 3.7 TRAFFICKING Trafficking on newly placed recycled mixtures will not be allowed prior to completion of compaction and the curing period. 3.8 ACCEPTABILITY OF WORK 3.8.1 _Testing Perform field tests in sufficient numbers to ensure that the specifications are being met. Testing is the Contractor's responsibility and performed by an approved commercial laboratory. Perform the following tests at the appropriate time, as the minimum acceptable for each type of operation. 3.8.1.1 Mixture Properties NOTE: The mixture should normally be sampled and tested twice a day or for every 4 hours of production or placement. Obtain a sample of the recycled mixture for every [_____] hours of placement of the mix. Extract the asphalt cement from the mix according to ASTM D 2172. The asphalt content of the recycled material shall be within the tolerance given in paragraph JOB-MIX FORMULA. Determine the gradation of the extracted aggregate in accordance with ASTM C 117 and ASTM C 136. The extracted gradation shall meet the JMF and the corresponding tolerances. 3.8.1.2 Density Testing NOTE: The frequency of testing for the maximum theoretical density (ASTM D 2041) should be tied to the frequency of the field nuclear test readings. Depending on the anticipated construction methods used, a nuclear density test should be performed about every 500 square meters (yards) of recycled mixture placed. Generally, one ASTM D 2041 test should be conducted for every 4 nuclear tests and four ASTM D 2041 tests should be performed for each full day of production. Consult CEMP-ET on test method to be used for cold-recycled mixture that is produced without additional bituminous material and fill in the brackets below. Conduct field density tests in accordance with ASTM D 6938, ASTM D 1556 or [_____]. When ASTM D 6938 is used, the testing shall be by the direct transmission method. Accomplish the calibration of the nuclear test device by testing in accordance with ASTM D 1556 as described in paragraph "Calibration" of ASTM D 6938. Tests performed in accordance with ASTM D 6938 result in a wet unit weight of material. Determine the moisture content of the recycled mixture by ASTM D 2216, ASTM D 4643, ASTM D 4944, or ASTM D 4959. The calibration testing shall occur in an area representative of the entire project in regards to materials and compactive effort. Perform a minimum of three of these tests and at least three nuclear readings shall be taken near each of these areas. Calibrate each nuclear device accordingly. Each day the used nuclear devices shall be recalibrated in the manner stated above or the selected area preserved and the devices calibrated in the same approximate locations each day. The field density shall be expressed as a percentage of the maximum theoretical density in accordance with ASTM D 2041 . Furnish all tools, labor, and materials for obtaining samples and refilling sample locations. Perform a minimum of one nuclear field density test for every [_____] [metric tons tons] [square meters yards] of mixture placed. 3.8.1.3 Grade Conformance NOTE: For cold-recycled pavements used only as a base course in aircraft traffic areas, such as airfield runways and taxiways, intervals between grade-conformance and smoothness tests should not exceed 8 meters (25 feet). Take measurements for deviation from grade by running lines of levels at intervals of [_____] meters feet longitudinally and [_____] meters feet transversely to determine the elevation of the completed pavement. The finished and completed surface shall conform within 15 mm 0.05 foot to lines, grades, cross section, and dimensions shown on the drawings. 3.8.1.4 Surface Smoothness Take measurements for deviation from surface smoothness with a 3.66 meter 12 foot straightedge. The finished surface of the pavement shall not deviate more than 10 mm 3/8 inch from the testing edge of the straightedge in the transverse or longitudinal direction. Place the straightedge parallel to the centerline of each lane paved at intervals of [_____] meters feet and perpendicular to the centerline at intervals of [_____] meters feet. Record the locations and deviations from the straightedge of all measurements. Remove defective areas and replace them with fresh paving mixture at no additional cost to the Government. 3.8.2 Material Samples Obtain a sample of all materials used in the recycled mixture under the supervision of the Contracting Officer. The sample will be retained by the Government.