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SECTION 32 12 15
SECTION 32 12 15
HOT-MIX ASPHALT (HMA) FOR AIRFIELDS
PART 1 GENERAL
1.1 SECTION INCLUDES
A. Products and procedures for placing and compacting one or more layers of HMA for Airfields comprised of aggregate, asphalt binder, and additives.
1.2 REFERENCES
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.
A. AASHTO M 156: Standard Specification for Requirements for Mixing Plants for Hot-Mixed, Hot-Laid Bituminous Paving Mixtures
| B. | AASHTO M 320: Standard Specification for Performance-Graded Asphalt Binder |
| C. | AASHTO T 308: Standard Method of Test for Determining the Asphalt Binder Content of Hot Mix Asphalt (HMA) by the Ignition Method |
D. AASHTO T 329: Standard Test Method for Moisture Content of Hot Mix Asphalt (HMA) by Oven Method E. AI MS-02 (6th Ed): Mix Design Methods F. ASTM C117: Standard Test Method for Materials Finer than 75-um (No. 200) Sieve in Mineral Aggregates by Washing G. ASTM C1252: Standard Test Methods for Uncompacted Void Content of Fine Aggregate (as Influenced by Particle Shape, Surface Texture, and Grading) H. ASTM C127: Standard Test Method for Density, Relative Density (Specific Gravity), and Absorption of Coarse Aggregate I. ASTM C128: Standard Test Method for Density, Relative Density (Specific Gravity), and Absorption of Fine Aggregate J. ASTM C131: Standard Test Method for Resistance to Degradation of Small-Size Coarse Aggregate by Abrasion and Impact in the Los Angeles Machine K. ASTM C136: Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates L. ASTM C142/C142M: Standard Test Method for Clay Lumps and Friable Particles in Aggregates M. ASTM C29/C29M: Standard Test Method for Bulk Density ("Unit Weight") and Voids in Aggregate M. ASTM C566: Standard Test Method for Total Evaporable Moisture Content of Aggregate by Drying N. ASTM C88: Standard Test Method for Soundness of Aggregates by Use of Sodium Sulfate or Magnesium Sulfate O. ASTM D140/D140M: Standard Practice for Sampling Bituminous Materials
| P. | ASTM D1461: Moisture or Volatile Distillates in Bituminous Paving Mixtures |
| Q. | ASTM D2041/D2041M: Theoretical Maximum Specific Gravity and Density of Bituminous Paving Mixtures |
| R. | ASTM D2172/D2172M: Quantitative Extraction of Bitumen from Bituminous Paving Mixtures |
S. ASTM D2419: Sand Equivalent Value of Soils and Fine Aggregate T. ASTM D242/D242M: Mineral Filler for Bituminous Paving Mixtures U. ASTM D2489/D2489M: Estimating Degree of Particle Coating of Bituminous-Aggregate Mixtures
| V. | ASTM D2726: Bulk Specific Gravity and Density of Non-Absorptive Compacted Bituminous Mixtures |
| W. | ASTM D3203: Percent Air Voids in Compacted Dense and Open Bituminous Paving Mixtures |
X. ASTM D3381/D3381M (2009a) Viscosity-Graded Asphalt Cement for Use in Pavement Construction
| Y. | ASTM D3665: Random Sampling of Construction Materials |
| Z. | ASTM D3666: Minimum Requirements for Agencies Testing and Inspecting Road and Paving Materials |
AA. ASTM D4125/D4125M: Asphalt Content of Bituminous Mixtures by the Nuclear Method
| BB. | ASTM D4791: Flat Particles, Elongated Particles, or Flat and Elongated Particles in Coarse Aggregate |
| CC. | ASTM D4867/D4867M: Effect of Moisture on Asphalt Concrete Paving Mixtures |
| DD. | ASTM D5444: Mechanical Size Analysis of Extracted Aggregate |
| EE. | ASTM D6307: Asphalt Content of Hot Mix Asphalt by Ignition Method |
| FF. | ASTM D6925: Standard Test Method for Preparation and Determination of the Relative Density of Hot Mix Asphalt (HMA) Specimens by Means of the Superpave Gyratory Compactor |
| GG. | ASTM D6926: Standard Practice for Preparation of Bituminous Specimens Using Marshall Apparatus |
| HH. | ASTM D6927: Standard Test Method for Marshall Stability and Flow of Bituminous Mixtures |
| II. | ASTM D946/D946M: Penetration-Graded Asphalt Cement for Use in Pavement Construction |
| JJ. | ASTM D979/D979M: Sampling Bituminous Paving Mixtures |
| KK. | CTM 526: Operation of California Profilograph and Evaluation of Profiles |
| LL. | COE CRD-C 171: Standard Test Method for Determining Percentage of Crushed Particles in Aggregate |
| 1.3 | SUBMITTALS |
| A. | Submit the following in accordance with Section 01 33 00 SUBMITTAL PROCEDURES: |
| 1. | SD-02 Shop Drawings |
| a. | Placement Plan |
| 2. | SD-03 Product Data |
| a. | Mix Design |
| b. | Contractor Quality Control Plan |
| 3. | SD-06 Test Reports |
| a. | Aggregates |
| b. | QC Monitoring |
| 4. | SD-07 Certificates |
| a. | Asphalt Cement Binder |
| b. | Testing Laboratory |
1.4 ACCEPTANCE
| A. | Acceptance sampling and testing of material is as specified herein. |
| B. | Gradation and asphalt binder content |
| 1. | A lot equals the number of tons of HMA placed during each production day. The COR evaluates a lot on the test results of four samples with the following exceptions: |
| a. | Compute disincentive using the test results from three samples if only three samples can be taken for the production day. |
| b. | Add the lot to the next day’s production if three random samples cannot be taken. |
| c. | Add the lot to the previous day’s production for the final day’s production if three random samples cannot be taken. |
| d. | The lot may be increased to include up to three production days when agreed upon in advance by both the Contractor and the COR when less than 900 tons are anticipated per production day. |
| 2. | Aggregate: Verify gradation prior to the drum mixer or after going through the drier. |
| 3. | Asphalt shall meet the requirements specified herein and in Section 32 12 03. |
Table 1: Asphalt Binder Content/Air Voids Pay Factors
| Pay Factor |
| Mean Absolute Deviation from Job Mix Formula |
| 4. | Laboratory air voids will be calculated in accordance with ASTM D3203 by determining the Marshall density of each lab compacted specimen using the laboratory-prepared, thoroughly dry method in ASTM D2726 and determining the theoretical maximum density (TMD) of every other sublot sample using ASTM D2041/D2041M. Laboratory air void calculations for each sublot will use the latest theoretical maximum density values obtained, either for that sublot or the previous sublot. The mean absolute deviation of the four laboratory air void contents (one from each sublot) from the JMF air void content will be evaluated and a pay factor determined from Table 1. All laboratory air void tests will be completed and reported within 24 hours after completion of construction of each lot. |
| a. | Example: Assume that the laboratory air voids are determined from 4 random samples of a lot (where 3 specimens were compacted from each sample). The average laboratory air voids for each sublot sample are determined to be 3.5, 3.0, 4.0, and 3.7. Assume that the target air voids from the JMF is 4.0. The mean absolute deviation is then: |
Mean Absolute Deviation = (|3.5 - 4.0| + |3.0 - 4.0| + |4.0 - 4.0| + |3.7 - 4.0|)/4 = (0.5 + 1.0 + 0.0 + 0.3)/4 = (1.8)/4 = 0.45 The mean absolute deviation for laboratory air voids is determined to be 0.45. It can be seen from Table 1 that the lot's pay factor based on laboratory air voids, is 100 percent.
Table 2: Aggregate Gradation Pay Factors
| Sieve Size |
| Pay Factor |
| Mean Absolute Deviation |
| 1/2 inch and larger |
| 1.00 |
| 0.0 to 5.6 |
| D. | Density and Grade |
| 1. | The Government evaluates a lot on the test results of two samples per lot. Lot size is 1,000 square yards or part thereof. |
| 2. | Contractor obtains cores within two days after the pavement is placed. |
| a. | The Government marks coring locations for in-place density and joint density cores. |
| b. | Move transversely to a point 1 ft from the edge of the pavement for In-place density if the random location for coring falls within 1 ft of the edge of the overall pavement section (outer part of shoulders). |
| c. | Fill core holes with HMA or high AC content cold mix and compact as approved by the COR. |
| d. | The Government witnesses the coring operation and testing the cores begins within 24 hours for density acceptance. |
| 3. | Density Requirements |
| a. | Use the average of the Theoretical Maximum Density (TMD) tests for each lot. |
Table 3: Density Pay Factors
| Pay Factor |
| Density, in Percent |
| Average Mat Density |
| Average Joint Density |
| 1.00 |
| 93.1 to 96.0 |
| Above 92.5 |
| 0.95 |
| 92.8 to 93.0 |
| 91.3 to 92.4 |
| 0.90 |
| 92.4 to 92.7 |
| 90.9 to 91.2 |
| 0.80 |
| 92.1 to 92.2 |
| 90.6 to 90.7 |
| Reject |
| Less than 92 |
| Less than 90.5 |
| 4. | Compaction determinations are full core depth or overlay depth in overlay construction. |
| 5. | Grade Requirements |
| a. | The Government accepts a lot for thickness when: |
| 1) | The final wearing surface of pavement shall conform to the elevations and cross sections shown and shall vary not more than 0.03 foot for runways or 0.05 foot for taxiways and aprons from the plan grade established and approved at site of work.. |
| 2) | Finished surfaces at juncture with other pavements shall coincide with finished surfaces of abutting pavements. |
| b. | Deviation from the plan elevation will not be permitted in areas of pavements where closer conformance with planned elevation is required for the proper functioning of drainage and other appurtenant structures involved. |
| c. | The grade will be determined by running lines of levels at intervals of 25 feet, or less, longitudinally and transversely, to determine the elevation of the completed pavement surface. Detailed notes of the results of the testing shall be kept and a copy furnished to the Government immediately after each day's testing. |
Table 4: Grade Pay Factors
| Pay Factor |
| Percent of Measurements Out of Grade Tolerance |
| d. | Diamond grinding may be used to remove high spots to meet grade requirements. |
| e. | Skin patching for correcting low areas or planing or milling for correcting high areas will not be permitted. |
| E. | Smoothness |
| 1. | Use one of the following methods to test and evaluate surface smoothness of the finished surface of the pavement final grade. All testing shall be performed in the presence of the Government. Detailed notes of the results of the testing shall be kept and a copy furnished to the Government immediately after each day's testing. |
| 2. | Straightedge Testing: |
a. Lot size is 100 linear feet per lane or part thereof. A minimum of two tests per lot shall be taken in both the longitudinal and transverse directions.
b. The finished surfaces of the pavements shall have no abrupt change of 1/8 inch or more, and all pavements shall be within the tolerances specified in Table 5 when checked with an approved 12 foot straightedge.
Table 5: Straightedge Surface Smoothness Requirements
| Category |
| Direction |
| Tolerance, in |
| Runways & Taxiways |
| Longitudinal |
| 1/8 |
| Calibration Hardstands & Compass Swinging Bases |
| Longitudinal |
| 1/8 |
| 3. | Profilograph Testing: |
| a. | Lot size is 200 linear feet per lane or part thereof. A minimum of two tests per lot shall be taken in both the longitudinal and transverse directions. |
| b. | The finished surfaces of the pavements shall have no abrupt change of 1/8 inch or more, and all pavement shall have a Profile Index not greater than specified in Table 6 when tested with an approved California-type profilograph. |
| c. | If the extent of the pavement in either direction is less than 200 feet, that direction shall be tested by the straightedge method. |
Table 6: Profilograph Surface Smoothness Requirements
| Category |
| Direction |
| Maximum Specified Profile Index, in/mile |
| Transverse |
| Use Straightedge |
| Transverse |
| Use Straightedge |
Calibration Hardstands & Compass Swinging Bases
Use Straightedge
4. The computed pay factor for that lot based on surface smoothness will be as indicated in Table 7. High/low spots exceeding the tolerances shall be corrected by acceptable methods or removed and replaced at no additional cost to the Government.
Table 7: Smoothness Pay Factors
| Pay Factor |
| Straightedge Measurement Deviations, in Percent |
| Profilograph Measurement Deviations, in Percent |
| 1.00 |
| 5.0 or Less |
| 1.0 or Less |
| 0.95 |
| 5.1 to 10.0 |
| 1.1 to 2.0 |
| 0.90 |
| 10.1 to 14.9 |
| 2.1 to 3.0 |
| 0.75 |
| 15.0 to 19.9 |
| 3.1 to 3.9 |
| Reject |
| 20 or Greater |
| 4.0 or Greater |
| 5. | Regardless of the above, any small individual area with surface deviation which exceeds the tolerance given above by more than 50 percent, shall be corrected by diamond grinding to meet the specification requirements above or shall be removed and replaced at no additional cost to the Government. |
| F. | For payment of any lot the lowest applicable pay factor shall be applied to the contract line item cost. |
| G. | Tests listed above are the minimum required to conform to the Contract. If there is reason to suspect non-compliance with the requirements herein or with the requirements specified within the Delivery Order, Contractor may be required to perform additional tests at no additional cost to the Government |
1.5 SYSTEM DESCRIPTION
| A. | Perform the work consisting of pavement courses composed of mineral aggregate and asphalt material heated and mixed in a central mixing plant and placed on a prepared course. HMA designed and constructed in accordance with this section shall conform to the lines, grades, thicknesses, and typical cross sections shown on the drawings. Construct each course to the depth, section, or elevation required by the drawings and rolled, finished, and approved before the placement of the next course. Submit proposed Placement Plan, indicating lane widths, longitudinal joints, and transverse joints for each course or lift. |
| B. | Asphalt Mixing Plant: Plants used for the preparation of hot-mix asphalt shall conform to the requirements of AASHTO M 156 with the following changes: |
C. Truck Scales. Weigh the asphalt mixture on approved scales furnished by the Contractor, or on certified public scales at the Contractor's expense. Scales shall be inspected and sealed at least annually by an approved calibration laboratory.
| D. | Testing Facilities. Provide laboratory facilities at the plant for the use of the Contractor's quality control testing. |
| E. | Inspection of Plant. The Government shall have access at all times, to all areas of the plant for checking adequacy of equipment; inspecting operation of the plant; verifying weights, proportions, and material properties; checking the temperatures maintained in the preparation of the mixtures and for taking samples. Provide assistance as requested, for the Government to procure any desired samples. |
F. Storage Bins.
| 1. | The asphalt mixture may be stored in non-insulated storage bins for a period of time not exceeding 3 hours. |
| 2. | The asphalt mixture may be stored in insulated storage bins for a period of time not exceeding 8 hours. |
| 3. | The mix drawn from bins shall meet the same requirements as mix loaded directly into trucks. |
| G. | Hauling Equipment: Trucks used for hauling hot-mix asphalt shall have tight, clean, and smooth metal beds. To prevent the mixture from adhering to them, the truck beds shall be lightly coated with a minimum amount of paraffin oil, lime solution, or other approved material. Petroleum based products shall not be used as a release agent. Each truck shall have a suitable cover to protect the mixture from adverse weather. When necessary to ensure that the mixture will be delivered to the site at the specified temperature, truck beds shall be insulated or heated and covers (tarps) shall be securely fastened. |
| H. | Material Transfer Vehicle (MTV): |
| 1. | Material transfer Vehicles shall be required due to the improvement in smoothness and decrease in both physical and thermal segregation. To transfer the material from the hauling equipment to the paver, use a self-propelled, material transfer vehicle that can deliver material to the paver without making contact with the paver. |
| 2. | The MTV shall be able to move back and forth between the hauling equipment and the paver providing material transfer to the paver, while allowing the paver to operate at a constant speed. The Material Transfer Vehicle will have remixing and storage capability to prevent physical and thermal segregation. |
| I. | Asphalt Pavers: Mechanical spreading and finishing equipment shall consist of a self-powered paver, capable of spreading and finishing the mixture to the specified line, grade, and cross section. |
| 1. | The screed of the paver shall be capable of laying a uniform mixture to meet the specified thickness, smoothness, and grade without physical or temperature segregation, the full width of the material being placed. |
| 2. | The screed will be equipped with a compaction device and it will be used during all placement. |
| 3. | The screed shall effectively produce a finished surface of the required evenness and texture without tearing, shoving, or gouging the mixture. |
| J. | Receiving Hopper: The paver shall have a receiving hopper of sufficient capacity to permit a uniform spreading operation. The hopper shall be equipped with a distribution system to place the mixture uniformly in front of the screed without segregation. |
| K. | Automatic Grade Controls: If an automatic grade control device is used, the paver shall be equipped with a control system capable of automatically maintaining the specified screed elevation. The control system shall be automatically actuated from either a reference line and/or through a system of mechanical sensors or sensor-directed mechanisms or devices which will maintain the paver screed at a predetermined transverse slope and at the proper elevation to obtain the required surface. The transverse slope controller shall be capable of maintaining the screed at the desired slope within plus or minus 0.1 percent. A transverse slope controller shall not be used to control grade. The controls shall be capable of working in conjunction with any of the following attachments: |
1. Ski-type device of not less than 30 feet in length.
2. Taut stringline set to grade.
3. Short ski or shoe for joint matching.
4. Laser control.
| L. | Rollers: |
| 1. | Rollers shall be in good condition and shall be operated at slow speeds to avoid displacement of the asphalt mixture. The number, type, and weight of rollers shall be sufficient to compact the mixture to the required density while it is still in a workable condition. |
| 2. | Equipment which causes excessive crushing of the aggregate shall not be used. |
| 1.6 | SUBMITTALS |
| A. | At a minimum submit the following in accordance with Section 01 33 00 |
SUBMITTAL PROCEDURES:
| 1. | SD-02 Shop Drawings |
| a. | Placement Plan |
| 2. | SD-03 Product Data |
| a. | Mix Design |
| b. | Contractor Quality Control |
| 3. | SD-06 Test Reports |
| a. | Aggregates |
| b. | QC Monitoring |
| 4. | SD-07 Certificates |
| a. | Asphalt Cement Binder |
| b. | Testing Laboratory |
| 1.7 | QUALITY ASSURANCE |
| A. | Testing for acceptability of work will be performed by the Contractor. |
| B. | Acceptance of the plant produced mix and in-place requirements will be on a lot to lot basis. |
| 1. | Where appropriate, adjustment in payment for individual lots of hot-mix asphalt will be made based on in-place density, laboratory air voids, grade and smoothness in accordance with the following paragraphs. |
| 2. | Grade and surface smoothness determinations will be made on the lot as a whole. |
| C. | The Government reserves the right to direct additional samples and tests for any area which appears to deviate from the specification requirements. Any additional testing will be at no additional cost to the Government. |
| 1. | Testing in these areas will be treated as a separate lot. Payment will be made for the quantity of HMA represented by these tests in accordance with the provisions of this section. |
| 1.8 | ENVIRONMENTAL REQUIREMENTS |
| A. | The hot-mix asphalt shall not be placed upon a wet surface or when the surface temperature of the underlying course is less than specified. The temperature requirements may be waived by the Government, if requested; however, all other requirements, including compaction, shall be met. |
| 1. | Mat thickness 3 inches or greater: 40 degrees F. |
| 2. | Mat thickness less than 3 inches: 45 degrees F. |
| PART 2 | PRODUCTS |
2.1 AGGREGATES
| A. | Aggregates shall consist of crushed stone, crushed gravel, crushed slag, screenings, natural sand and mineral filler, as required. |
| B. | The portion of material retained on the No. 4 sieve is coarse aggregate. |
| C. | The portion of material passing the No. 4 sieve and retained on the No. 200 sieve is fine aggregate. |
| D. | The portion passing the No. 200 sieve is defined as mineral filler. |
Submit sufficient materials to produce 90 kg 200 lb of blended mixture for mix design verification.
| E. | All aggregate test results and samples shall be submitted to the Contracting Officer Engineer at least 14 days prior to start of construction. Aggregate testing shall have been performed within 90 days of performing the mix design. |
| F. | Coarse Aggregate: |
1. Coarse aggregate shall consist of sound, tough, durable particles, free from films of material that would prevent thorough coating and bonding with the asphalt material and free from organic matter and other deleterious substances.
2. The coarse aggregate particles shall meet the following requirements:
| a. | The percentage of loss shall not be greater than 40 percent after 500 revolutions when tested in accordance with ASTM C131. |
| b. | The sodium sulfate soundness loss shall not exceed 12 percent, or the magnesium sulfate soundness loss shall not exceed 18 percent after five cycles when tested in accordance with ASTM C88. |
| c. | At least 75 percent by weight of coarse aggregate shall have at least two or more fractured faces when tested in accordance with COE CRD-C 171. Fractured faces shall be produced by crushing. |
| d. | The particle shape shall be essentially cubical and the aggregate shall not contain more than 20 percent, by weight, of flat and elongated particles (3:1 ratio of maximum to minimum) when tested in accordance with ASTM D4791. |
| e. | Slag shall be air-cooled, blast furnace slag, and shall have a compacted weight of not less than 75 lb/cu ft when tested in accordance with ASTM C29/C29M. |
| f. | Clay lumps and friable particles shall not exceed 0.3 percent, by weight, when tested in accordance with ASTM C142/C142M. |
| G | Fine Aggregate |
| 1. | Fine aggregate shall consist of clean, sound, tough, durable particles. |
| 2. | The aggregate particles shall be free from coatings of clay, silt, or any objectionable material and shall contain no clay balls. |
| 3. | The fine aggregate particles shall meet the following requirements: |
| a. | The quantity of natural sand (noncrushed material) added to the aggregate blend shall not exceed 15 percent by weight of total aggregate. |
| b. | The individual fine aggregate sources shall have a sand equivalent value greater than 45 when tested in accordance with ASTM D2419. |
| c. | The fine aggregate portion of the blended aggregate shall have an uncompacted void content greater than 45.0 percent when tested in accordance with ASTM C1252 Method A. |
| d. | Clay lumps and friable particles shall not exceed 0.3 percent, by weight, when tested in accordance with ASTM C142/C142M. |
| H. | Mineral Filler: Mineral filler shall be nonplastic material meeting the requirements of ASTM D242/D242M. |
| I. | Aggregate Gradation |
| 1. | The combined aggregate gradation shall conform to gradations specified in Table 8, when tested in accordance with ASTM C136 and ASTM C117, and shall not vary from the low limit on one sieve to the high limit on the adjacent sieve or vice versa, but grade uniformly from coarse to fine. |
| 2. | The JMF shall be within the specification limits; however, the gradation can exceed the limits when the allowable deviation from the JMF shown in Tables 9 and 10 are applied. |
Table 8: Aggregate Gradations (Percent Passing by Dry Weight of Aggregate)
Control Sieve Size Nominal Maximum Size of Aggregate
| Gradation 1 |
| Gradation 2 |
| Gradation 3 |
| ½ inch |
| 68 – 88 |
| 76 – 96 |
| 100 |
| ⅜ inch |
| 60 – 82 |
| 69 – 89 |
| 76 – 96 |
| No. 4 |
| 45 – 67 |
| 53 – 73 |
| 58 – 78 |
| No. 8 |
| 32 - 54 |
| 38 – 60 |
| 40 - 60 |
| No. 16 |
| 22 – 44 |
| 26 – 48 |
| 28 – 48 |
| No. 30 |
| 15 – 35 |
| 18 – 38 |
| 18 – 38 |
| No. 50 |
| 9 – 25 |
| 11 – 27 |
| 11 – 27 |
| No. 100 |
| 6 – 18 |
| 6 – 18 |
| 6 – 18 |
| No. 200 |
| 3 – 6 |
| 3 – 6 |
| 3 – 6 |
| 3. | Gradations in Table 8 shall be used for the following: | |
| a. | Gradation 1: Intermediate courses. | |
| b. | Gradation 2: Intermediate and surface courses. | |
| c. | Gradation 3: Shoulders and leveling courses. | |
| 2.2 | ASPHALT CEMENT BINDER | |
| A. | Asphalt cement binder shall conform to AASHTO M 320 Performance Grade PG 64 - 34. As an alternate, ASTM D3381/D3381M Table 2, Viscosity Grade AC-20 may be used when required quantities of asphalt are too low to allow for the appropriate supply of PG 64-34 binder. | |
| B. | Test data indicating grade certification shall be provided by the supplier at the time of delivery of each load to the mix plant. Copies of these certifications shall be submitted to the Government. | |
| C. | The supplier is defined as the last source of any modification to the binder. | |
| D. | The Government may require the sampling and testing of the binder at the mix plant at any time before or during mix production. Samples for this verification testing shall be obtained in accordance with ASTM D140/D140M and in the presence of the Government. | |
| 2.3 | MIX DESIGN | |
| A. | The asphalt mix shall be composed of a mixture of well-graded aggregate, mineral filler if required, and asphalt material. | |
| B. | The aggregate fractions shall be sized, handled in separate size groups, and combined in such proportions that the resulting mixture meets the grading requirements of Table 8. | |
| C. | No hot-mix asphalt shall be produced until a JMF has been approved. | |
| D. | Viscosity Grade: The hot-mix asphalt shall be designed using hand-held hammer procedures contained in AI MS-02 and the criteria shown in Table 9. | |
| E. | Performance Grade: The hot-mix asphalt shall be designed using the Superpave gyratory compactor set at 75 gyrations. Samples shall be prepared at various asphalt contents and compacted in accordance with ASTM D6925. | |
| F. | Laboratory compaction temperatures for Polymer Modified Asphalts shall be as recommended by the asphalt cement manufacturer. If the Tensile Strength Ratio (TSR) of the composite mixture, as determined by ASTM D4867/D4867M is less than 75, the aggregates shall be rejected or the asphalt mixture treated with an anti-stripping agent. The amount of anti-stripping agent added shall be sufficient to produce a TSR of not less than 75. If an antistrip agent is required, it shall be provided at no additional cost to the Government. | |
| G. | Submit the proposed JMF in writing, for approval, at least 28 days prior to the start of the test section/paving operations, including as a minimum: | |
| 1. | Percent passing each sieve size. | |
| 2. | Percent of asphalt cement. | |
| 3. | Percent of each aggregate and mineral filler to be used. | |
| 4. | Asphalt viscosity grade, penetration grade, or performance grade. | |
| 5. | Laboratory mixing temperature. | |
| 6. | Lab compaction temperature. | |
| 7. | Temperature-viscosity relationship of the asphalt cement. | |
| 8. | Plot of the combined gradation on the 0.45 power gradation chart, stating the nominal maximum size. | |
| 9. | Graphical plots and summary tabulation of stability, flow, air voids, voids in the mineral aggregate, and unit weight versus asphalt content as shown in AI MS-02. Summary tabulation shall include individual specimen data for each specimen tested. | |
| 10. | Specific gravity and absorption of each aggregate. | |
| 11. | Percent natural sand. | |
| 12. | Percent particles with two or more fractured faces (in coarse aggregate). | |
| 13. | Fine aggregate angularity. | |
| 14. | | Percent flat or elongated particles (in coarse aggregate). |
| 15. | Tensile Strength Ratio and wet/dry specimen test results. | |
| 16. | Antistrip agent (if required). | |
| 17. | List of all modifiers. | |
| 18. | Percentage and properties (asphalt content, binder properties, and aggregate properties) of RAP in accordance with paragraph RECYCLED HOT-MIX ASPHALT, if RAP is used. | |
Table 9: Marshall Design Criteria
Test Property
| Stability, pounds minimum |
| 2150(1) |
| Flow, 0.01 inch |
| 8 – 16(2) |
| Percent voids in mineral aggregate (minimum) |
| See Table 10 |
| Dust Proportion(3) |
| 0.8 – 1.2 |
Notes:
(1) This is a minimum requirement. The average during construction shall be significantly higher than this number to ensure compliance with the specifications.
(2) The flow requirement is not applicable for Polymer Modified Asphalts.
(3) Dust Proportion is calculated as the aggregated content, expressed as a percent of mass, passing the No. 200 sieve, divided by the effective asphalt content, in percent of total mass of the mixture.
(4) Select the JMF asphalt content corresponding to an air void content of 4 percent. Verify the other properties of Table 9 meet the specification requirements at this asphalt content.
Table 10: Superpave Gyratory Compaction Criteria
Test Property
| Percent voids in mineral aggregate (minimum) |
| See Table 10 |
| Dust Proportion(2) |
| 0.8 – 1.2 |
Notes:
(1) Select the JMF asphalt content corresponding to an air void content of 4 percent. Verify the other properties of Table 10 meet the specification requirements at this asphalt content.
(2) Dust Proportion is calculated as the aggregated content, expressed as a percent of mass, passing the No. 200 sieve, divided by the effective asphalt content, in percent of total mass of the mixture.
Table 11: Minimum Percent Voids in Mineral Aggregate (VMA)
| Aggregate Gradation (See Table 8) |
| Minimum VMS, % |
Notes:
(1) Calculate VAM in accordance with AI MS-02, based on ASTM D2726 bulk specific gravity for the aggregate.
| H. | Adjustments to JMF |
| 1. | The JMF for each mixture shall be in effect until a new formula is approved in writing by the Contracting Officer. |
| 2. | Should a change in sources of any materials be made, a new mix design shall be performed and a new JMF approved before the new material is used. |
| 3. | The Contractor will be allowed to make minor adjustments within the specification limits to the JMF to optimize mix volumetric properties. Adjustments to the original JMF shall be limited to plus or minus 4 percent on the No. 4 and coarser sieves; plus or minus 3 percent on the No. 8 to No. 50 sieves; and plus or minus 1 percent on the No. 100 sieve. Adjustments to the JMF shall be limited to plus or minus 1.0 percent on the No. 200 sieve. |
| 4. | Asphalt content adjustments shall be limited to plus or minus 0.40 from the original JMF. If adjustments are needed that exceed these limits, a new mix design shall be developed. |
| 2.4 | RECYCLED HOT MIX ASPHALT |
| A. | Recycled HMA shall consist of reclaimed asphalt pavement (RAP), coarse aggregate, fine aggregate, mineral filler, and asphalt cement. |
| B. | The RAP shall be of a consistent gradation and asphalt content and properties. |
| C. | RAP stockpiles shall be free from contamination, including coal-tar sealers. |
| D. | When RAP is fed into the plant, the maximum RAP chunk size shall not exceed 2 inches. The individual aggregates in a RAP chunk shall not exceed the maximum size aggregate of the gradation specified in Table 8. |
| E. | The recycled HMA mix shall be designed using procedures contained in AI MS-02. The job mix shall meet the requirements of paragraph MIX DESIGN. |
| F. | RAP shall only be used for shoulder surface course mixes and for any intermediate courses. The amount of RAP shall be limited to 30 percent. |
| G. | RAP Aggregates and Asphalt Cement |
| 1. | The blend of aggregates used in the recycled mix shall meet the requirements of paragraph AGGREGATES. |
| 2. | The percentage of asphalt in the RAP shall be established for the mixture design according to ASTM D2172/D2172M using the appropriate dust correction procedure. |
| H. | RAP Mix |
| 1. | The blend of new asphalt cement and the RAP asphalt binder shall meet the viscosity or dynamic shear rheometer at high temperature and bending beam at low temperature requirements in paragraph ASPHALT CEMENT BINDER according to the type of asphalt cement binder used in the JMF. |
| 2. | The virgin asphalt cement shall not be more than two standard asphalt material grades different than that specified in paragraph ASPHALT CEMENT BINDER. |
| PART 3 | EXECUTION |
| 3.1 | CONTRACTOR QUALITY CONTROL |
| A. | General Quality Control Requirements |
| 1. | Hot-mix asphalt for payment shall not be produced until the quality control plan has been approved. The plan shall address all elements which affect the quality of the pavement including, but not limited to: |
| 1. | Mix Design and unique JMF identification code |
| 2. | Aggregate Grading |
| 3. | Quality of Materials |
| 4. | Stockpile Management and procedures to prevent contamination |
| 5. | Proportioning |
| 6. | Mixing and Transportation |
| 7. | Correlation of mechanical hammer to hand hammer. Determine the number of blows of the mechanical hammer required to provide the same density of the JMF as provided by the hand hammer. Use the average of three specimens per trial blow application. |
| 8. | Mixture Volumetrics |
| 9. | Moisture Content of Mixtures |
| 10. | Placing and Finishing |
| 11. | Joints |
| 12. | Compaction, including HMA-PCC joints |
| 13. | Surface Smoothness |
| 14. | Truck bed release agent |
| B. | Testing Laboratory |
| 1. | Provide a fully equipped asphalt laboratory located at the plant or job site. It shall be equipped with heating and air conditioning units to maintain a temperature of 75 plus or minus 5 degrees F. |
| 2. | Laboratory facilities shall be kept clean and all equipment shall be maintained in proper working condition. |
| 3. | The Government shall be permitted unrestricted access to inspect the Contractor's laboratory facility, to witness quality control activities, and to perform any check testing desired. |
| 4. | The Government will advise the Contractor in writing of any noted deficiencies concerning the laboratory facility, equipment, supplies, or testing personnel and procedures. |
| 5. | When the deficiencies are serious enough to adversely affect test results, the incorporation of the materials into the work shall be suspended immediately and will not be permitted to resume until the deficiencies are corrected. |
| C. | Quality Control Testing |
| 1. | Perform all quality control tests applicable to these specifications and as set forth in the Quality Control Program. |
| 2. | The testing program shall include, but shall not be limited to, tests for the control of asphalt content, aggregate gradation, temperatures, aggregate moisture, moisture in the asphalt mixture, laboratory air voids, stability, flow, in-place density, grade and smoothness. |
| 3. | A Quality Control Testing Plan shall be developed as part of the Quality Control Program. |
| 4. | Asphalt Content |
| a. | A minimum of two tests to determine asphalt content will be performed per lot (a lot is defined in paragraph QUALITY ASSURANCE) by one of the following methods: |
| i) | extraction method in accordance with ASTM D2172/D2172M, Method A or B, |
| ii) | the ignition method in accordance with the AASHTO T 308, ASTM D6307, |
| III) | or the nuclear method in accordance with ASTM D4125/D4125M, provided each method is calibrated for the specific mix being used. |
| b. | For the extraction method, the weight of ash, as described in ASTM D2172/D2172M, shall be determined as part of the first extraction test performed at the beginning of plant production; and as part of every tenth extraction test performed thereafter, for the duration of plant production. The last weight of ash value obtained shall be used in the calculation of the asphalt content for the mixture. |
| 5. | Aggregate Properties |
| a. | Aggregate gradations shall be determined a minimum of twice per lot from mechanical analysis of recovered aggregate in accordance with ASTM D5444 or ASTM D6307. |
| b. | For batch plants, aggregates shall be tested in accordance with ASTM C136 using actual batch weights to determine the combined aggregate gradation of the mixture. |
| c. | The specific gravity of each aggregate size grouping shall be determined for each 20,000 tons in accordance with ASTM C127 or ASTM C128. |
| d. | Fractured faces for gravel sources shall be determined for each 20,000 tons in accordance with COE CRD-C 171. |
| e. | The uncompacted void content of manufactured sand shall be determined for each 20,000 tons in accordance with ASTM C1252 Method A. |
| 6. | Temperatures shall be checked at least four times per lot, at necessary locations, to determine the temperature at the dryer, the asphalt cement in the storage tank, the asphalt mixture at the plant, and the asphalt mixture at the job site. |
| 7. | The moisture content of aggregate used for production shall be determined a minimum of once per lot in accordance with ASTM C566. |
| 8. | The moisture content of the mixture shall be determined at least once per lot in accordance with AASHTO T 329. |
| 9. | Laboratory Air Voids, VMA |
| a. | Mixture samples shall be taken at least four times per lot and compacted into specimens. |
| b. | After compaction, the laboratory air voids and VMA of each specimen shall be determined. The VMA shall be within the limits of Table 11. |
| 10. | Conduct any necessary testing to ensure the specified density is achieved. A nuclear gauge or other non-destructive testing device may be used to monitor pavement density. |
| 11. | Conduct the necessary checks to ensure the grade and smoothness requirements are met in accordance with paragraph QUALITY ASSURANCE. |
| 12. | Any additional testing, which the Contractor deems necessary to control the process, may be performed at the Contractor's option at no additional cost to the Government. |
| 13. | Submit all QC test results to the Government on a daily basis as the tests are performed. The Government reserves the right to monitor any of the Contractor's quality control testing and to perform duplicate testing as a check to the Contractor's quality control testing. |
| D. | Sampling: When directed by the Contracting Officer’s Representative, sample and test any material which appears inconsistent with similar material being produced, unless such material is voluntarily removed and replaced or deficiencies corrected by the Contractor. All sampling shall be in accordance with standard procedures specified. |
| E. | Control Charts |
| 1. | For process control, establish and maintain linear control charts on both individual samples and the running average of last four samples for the parameters listed in Table 12, as a minimum. These control charts shall be posted as directed by the Contracting Officer Engineer and shall be kept current at all times. |
| 2. | The control charts shall identify the project number, the test parameter being plotted, the individual sample numbers, the Action and Suspension Limits listed in Table 12 applicable to the test parameter being plotted, and the Contractor's test results. Target values (JMF) shall also be shown on the control charts as indicators of central tendency for the cumulative percent passing, asphalt content, and laboratory air voids parameters. |
| 3. | When the test results exceed either applicable Action Limit, take immediate steps to bring the process back in control. |
| 4. | When the test results exceed either applicable Suspension Limit, halt production until the problem is solved. |
| 5. | When the Suspension Limit is exceeded for individual values or running average values, the Contracting Officer Engineer has the option to require the Contractor to remove and replace the material represented by the samples or to leave in place and base acceptance on mixture volumetric properties and in place density. |
| 6. | Use the control charts as part of the process control system for identifying trends so that potential problems can be corrected before they occur. Decisions concerning mix modifications shall be made based on analysis of the results provided in the control charts. |
| 7. | The Quality Control Plan shall indicate the appropriate action which shall be taken to bring the process into control when certain parameters exceed their Action Limits. |
Table 12: Action & Suspension Limits for the Parameters to be Plotted on Individual and Running Average Control Charts
| Parameter to be Plotted |
| Individual Samples |
| Running Average of Last Four Samples |
| Action Limit |
| Suspension Limit |
| Action Limit |
| Suspension Limit |
| No. 4 sieve, Cumulative % Passing, deviation from JMF target; plus or minus values |
| 6 |
| 8 |
| 4 |
| 5 |
| No. 30 sieve, Cumulative % Passing, deviation from JMF target; plus or minus values |
| 4 |
| 6 |
| 3 |
| 4 |
| No. 200 sieve, Cumulative % Passing, deviation from JMF target; plus or minus values |
| 1.4 |
| 2.0 |
| 1.1 |
| 1.5 |
| Asphalt content, % deviation from JMF target; plus or minus value |
| 0.4 |
| 0.5 |
| 0.2 |
| 0.3 |
| Laboratory Air Voids, % deviation from JMF target value |
| No specific action and suspension limits set since this parameter is used to determine percent payment |
| In-place Mat Density, % of TMD |
| No specific action and suspension limits set since this parameter is used to determine percent payment |
| In-place Joint Density, % of TMD |
| No specific action and suspension limits set since this parameter is used to determine percent payment |
| 3.2 | PREPARATION OF ASPHALT BINDER MATERIAL |
| A. | The asphalt cement material shall be heated avoiding local overheating and providing a continuous supply of the asphalt material to the mixer at a uniform temperature. |
| B. | The temperature of unmodified asphalts shall be no more than 325 degrees F when added to the aggregates. |
| C. | Performance Graded (PG) asphalts shall be within the temperature range of 265 to 320 degrees F when added to the aggregates. |
| 3.3 | PREPARATION OF MINERAL AGGREGATE |
| A. | The aggregate for the mixture shall be heated and dried prior to mixing. No damage shall occur to the aggregates due to the maximum temperature and rate of heating used. |
| B. | The temperature of the aggregate and mineral filler shall not exceed 350 degrees F when the asphalt cement is added. |
| C. | The temperature shall not be lower than is required to obtain complete coating and uniform distribution on the aggregate particles and to provide a mixture of satisfactory workability. |
| 3.4 | PREPARATION OF HOT-MIX ASPHALT MIXTURE |
| A. | The aggregates and the asphalt cement shall be weighed or metered and introduced into the mixer in the amount specified by the JMF. |
| B. | The combined materials shall be mixed until the aggregate obtains a thorough and uniform coating of asphalt binder (testing in accordance with ASTM D2489/D2489M may be required by the Contracting Officer) and is thoroughly distributed throughout the mixture. |
| C. | The moisture content of all hot-mix asphalt upon discharge from the plant shall not exceed 0.5 percent by total weight of mixture as measured by ASTM D1461. |
| 3.5 | PREPARATION OF THE UNDERLYING SURFACE |
| A. | Immediately before placing the hot mix asphalt, the underlying course shall be cleaned of dust and debris. |
| B. | A prime coat or tack coat shall be applied in accordance with the contract specifications. |
| 3.6 | TEST SECTION |
| A. | Prior to full production, place a test section for each JMF used. Construct a test section consisting of a maximum of 250 tons and two paver passes wide placed in two lanes, with a longitudinal cold joint. |
| B. | The test section shall be of the same depth as the course which it represents. The underlying grade or pavement structure upon which the test section is to be constructed shall be the same as the remainder of the course represented by the test section. |
| C. | The equipment used in construction of the test section shall be the same equipment to be used on the remainder of the course represented by the test section. |
| D. | The test section shall be placed as part of the project pavement as approved by the Contracting Officer. |
| E. | Sampling and Testing for Test Section |
| 1. | One random sample shall be taken at the plant, triplicate specimens compacted, and tested for stability, flow, laboratory air voids, and Tensile Strength Ratio (TSR). A portion of the same sample shall be tested for theoretical maximum density (TMD), aggregate gradation and asphalt content. Four randomly selected cores shall be taken from the finished pavement mat, and four from the longitudinal joint, and tested for density. Random sampling shall be in accordance with procedures contained in ASTM D3665. |
| 2. | The test results shall be within the tolerances or exceed the minimum values shown in Table 13 for work to continue. If all test results meet the specified requirements, the test section shall remain as part of the project pavement. If test results exceed the tolerances shown, the test section shall be removed and replaced at no cost to the Government and another test section shall be constructed. |
Table 13: Test Section Requirements for Materials & Mixture Properties
| Property |
| Specification Limit |
Aggregate Garadation – Percent Passing (Individual Test Result)
| No. 4 and larger |
| JMF plus or minus 8 |
| No. 8, No. 16, No. 30, and No. 50 |
| JMF plus or minus 6 |
| No. 100 and No. 200 |
| JMF plus or minus 2.0 |
| Asphalt Content, Percent (Individual Test Result) |
| JMF plur or minus 1.0 |
| Laboratory Air Voids, Percent (Average of 3 specimens) |
| JMF plus or minus 1.0 |
| VMA, Percent (Average of 3 specimens) |
| See Table 11 |
| Tensile Strength Ratio (TSR) |
| 75% minimum |
| Mat Density, Percent of TMD (Average of 4 Random Cores) |
| 92.0 – 96.0 |
| Joint Density, Percent of TMD (Average of 4 Random Cores) |
| 90.5 minimum |
| F. | Additional Test Sections |
| 1. | If the initial test section should prove to be unacceptable, the necessary adjustments to the JMF, plant operation, placing procedures, and/or rolling procedures shall be made. A second test section shall then be placed. |
| 2. | Additional test sections, as required, shall be constructed and evaluated for conformance to the specifications. |
| 3. | Full production shall not begin until an acceptable section has been constructed and accepted. |
| 3.7 | TESTING LABORATORY |
| A. | The laboratories used to develop the JMF, perform Contractor Quality Control testing, and for Government Engineer acceptance testing shall meet the requirements of ASTM D3666. All required test methods shall be performed by an accredited laboratory. |
| B. | Submit a certification of compliance signed by the manager of the laboratory stating that it meets these requirements to the Contracting Officer Engineer prior to the start of construction. The certification shall contain as a minimum: |
| 1. | Qualifications of personnel; laboratory manager, supervising technician, and testing technicians. |
| 2. | A listing of equipment to be used in developing the job mix. |
| 3. | A copy of the laboratory's quality control system. |
| 4. | Evidence of participation in the AASHTO Materials Reference Laboratory (AMRL) program. |
| 3.8 | TRANSPORTING AND PLACING |
| A. | Transporting |
| 1. | The hot-mix asphalt shall be transported from the mixing plant to the site in clean, tight vehicles. |
| 2. | Deliveries shall be scheduled so that placing and compacting of mixture is uniform with minimum stopping and starting of the paver. |
| 3. | Adequate artificial lighting shall be provided for night placements. |
| 4. | Hauling over freshly placed material will not be permitted until the material has been compacted as specified, and allowed to cool to 140 degrees F. |
| B. | Placing |
| 1. | The mix shall be placed in lifts of adequate thickness and compacted at a temperature suitable for obtaining density, surface smoothness, and other specified requirements. |
| 2. | Upon arrival, the mixture shall be placed to the full width by an asphalt paver; it shall be struck off in a uniform layer of such depth that, when the work is completed, it shall have the required thickness and conform to the grade and contour indicated. |
| 3. | Waste mixture shall not be broadcast onto the mat or recycled into the paver hopper. Collect waste mixture and dispose off site. |
| 4. | The speed of the paver shall be regulated to eliminate pulling and tearing of the asphalt mat. Placement of the mixture shall begin along the centerline of a crowned section or on the high side of areas with a one-way slope. The mixture shall be placed in consecutive adjacent strips having a minimum width of 10 feet. |
| 5. | The longitudinal joint in one course shall offset the longitudinal joint in the course immediately below by at least 1 foot; however, the joint in the surface course shall be at the centerline of the pavement. |
| 6. | Transverse joints in one course shall be offset by at least 10 feet from transverse joints in the previous course. Transverse joints in adjacent lanes shall be offset a minimum of 10 feet. |
| 7. | On isolated areas where irregularities or unavoidable obstacles make the use of mechanical spreading and finishing equipment impractical, the mixture may be spread and luted by hand tools. |
| 3.9 | COMPACTION OF MIXTURE |
| A. | General |
| 1. | After placing, the mixture shall be thoroughly and uniformly compacted by rolling. The surface shall be compacted as soon as possible without causing displacement, cracking or shoving. |
| 2. | The sequence of rolling operations and the type of rollers used are at the discretion of the Contractor, with the exception that application of more than three passes with a vibratory roller in the vibrating mode is prohibited. |
| 3. | The speed of the roller shall, at all times, be sufficiently slow to avoid displacement of the hot mixture and be effective in compaction. |
| 4. | Correct at once any displacement occurring as a result of reversing the direction of the roller, or from any other cause. |
| 5. | Furnish sufficient rollers to handle the output of the plant. |
| 6. | Continue rolling until the surface is of uniform texture, true to grade and cross section, and the required field density is obtained. |
| 7. | To prevent adhesion of the mixture to the roller, keep the wheels properly moistened, but excessive water will not be permitted. |
| 8. | In areas not accessible to the roller, thoroughly compact the mixture with hand tampers. |
| 9. | Remove the full depth of any mixture that becomes loose and broken, mixed with dirt, contains check-cracking, or is in any way defective, replace with fresh hot mixture and immediately compact to conform to the surrounding area. This work shall be done at the Contractor's expense. |
| 10. | Skin patching will not be allowed. |
| B. | Segregation |
| 1. | The Government can require the Contractor to sample and test any material that looks deficient. |
| 2. | When the in-place material appears to be segregated, the Government has the option to require the Contractor to sample the material and have it tested and compared to the aggregate gradation, asphalt content, and in-place density requirements. |
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