Atch_12_Spec_Section_32_12_15_HMA_Airfield.doc

MAINTAIN/REPAIR PAVEMENTS IDIQ

IFB No.: F26600-99-R-C118

RKMF 04-0075

Contract No.:

PAVING IDIQ

Solicitation: FA4861-16-R-A300

SECTION 32 12 15

HOT MIX ASPHALT (HMA) FOR AIRFIELD PAVEMENT

1. PART 1 - GENERAL

1.1. APPLICABLE PUBLICATIONS: The publications listed below form a part of this specification to the extent referenced. The publications are referred to in the text by the basic designation only.

American Society for Testing and Materials (ASTM) Publications:

C 29

Unit Weight of Aggregate

C 88

Soundness of Aggregates by Use of Sodium Sulfate or Magnesium Sulfate

C 117

Materials Finer than 75 um (No. 200) Sieve in Mineral Aggregates by

Washing

C 127

Specific Gravity and Absorption of Coarse Aggregate

C 128

Specific Gravity and Absorption of Fine Aggregate

C 131

Resistance to Degradation of Small-Size Coarse Aggregate by Abrasion and Impact in the Los Angeles Machine

C 136

Sieve Analysis of Fine and Coarse Aggregates

C 566

Total Moisture Content of Aggregate by Drying

C 1252

Standard Test Method for Uncompacted Void Content of Fine Aggregate

D 75

Sampling Aggregates

D 140

Sampling Bituminous Materials

D 242

Mineral Filler for Bituminous Paving Mixtures

D 1188 Standard Test Method for Bulk Specific Gravity and Density of Compacted Bituminous Mixtures Using Parrafin-Coated Specimens

D 1559

Resistance to Plastic Flow of Bituminous Mixtures Using Marshall

Apparatus

D 2041

Theoretical Maximum Specific Gravity of Bituminous Mixtures

D 2172

Quantitative Extraction of Bitumen from Bituminous Paving Mixtures

D 2419

Sand Equivalent Value of Soils and Fine Aggregate

D 2489

Degree of Particle Coating of Aggregate Mixtures

D 2726

Bulk Specific Gravity of Compacted Mixtures Using Saturated Surface

Dry Specimens

D 2950

Density of Concrete in Place by Nuclear Method

D 3203

Percent Air Voids in Compacted Density and Open Paving Mixture

D 3665

Random Sampling of Paving Materials

D 3666

Inspection and Testing Agencies for Paving Materials

D 4125

Asphalt Content of Mixtures by the Nuclear Method

D 4318

Liquid Limit, Plastic Limit, and Plasticity Index of Soils

D 4791

Flat or Elongated Particles in Coarse Aggregate

D 4867

Effect of Moisture on Asphalt Concrete Paving Mixtures

E 178

Practice for Dealing with Outlying Observations

The Asphalt Institute’s Manual No. 2 (MS-2)

AASHTO MP-1

Performance Graded Asphalt Cement

1.2. PLANT, EQUIPMENT, MACHINES, AND TOOLS:

1.2.1. General: The bituminous plant shall be of such capacity, as specified herein to produce the quantities of bituminous mixtures required for the project. Hauling equipment, paving machines, rollers, miscellaneous equipment, and tools shall be provided in sufficient numbers and capacity and in proper working condition to place the bituminous paving mixtures at a rate equal to the plant output.

1.2.2. Mixing Plants: The mixing plant shall be an automatic or semiautomatic controlled, commercially manufactured unit designed and operated to consistently produce a mixture within the job-mix formula (JMF). Drum mixers shall be prequalified at the production rate to be used during actual mix production. The prequalification tests will include extraction and recovery of the asphalt cement in accordance with ASTM D 2172 and ASTM D 1856. The penetration of the recovered asphalt binder shall not be less than 60 percent of the original penetration, as measured in accordance with ASTM D 5.

1.2.3. Straightedge: The Contractor shall furnish and maintain at the site, in good condition, one 12-foot straightedge for each bituminous paver. Straightedge shall be made available for possible Government use. Straightedges shall be constructed of aluminum or other lightweight metal and shall have 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.

1.2.4. Bituminous materials spreaders shall be self-propelled type, equipped with hoppers, tamping or vibrating devices, distributing screws, adjustable screeds, and equalizing devices. The spreader shall be capable of spreading hot bituminous mixtures without tearing, shoving, or gouging, and capable of producing a finished surface conforming to the smoothness requirements specified hereafter. The spreader shall be capable of confining the edges of the strips to true lines without the use of stationary side forms, and of placing the course to the required thickness. Spreaders shall be designed to operate forward at variable speeds and in reverse at traveling speeds of not less than 100 feet per minute. The use of spreader that leaves indented areas or other objectionable irregularities in the fresh laid mix during operations will not be permitted. Bituminous materials spreaders shall be equipped with electronic sensing devices for grade control. The devices shall be capable of utilizing the stringline, long ski sled, joint matcher (short ski sled), and automatic transverse grade control methods for controlling grades. The long sled shall have a minimum length of 25 feet.

1.2.5. Saws shall be of the power type, capable of rapidly cutting pavement and trimming joints and edges on pavement.

1.2.6. Small tools available on the work shall consist of the following: rakes, lutes, shovels, tampers, smoothing irons, pavement cutters, portable heater for heating small tools, wood sandals and stilt sandals or standard type, and other small tools as may be required. A sufficient number shall be available at all times. The lutes shall be constructed of metal and shall consist of a plate or sheet 36 x 4 inches attached to handle properly braced. Hand tampers shall weigh not less than 25 pounds and have a tamping face not larger than 50 square inches.

1.2.7. Rollers. The minimum number of rollers for each spreader shall be of 3-wheel roller, one 2-axle tandem roller and one pneumatic-tired roller, with separate operator for each.

1.2.7.1. Steel wheel rollers shall be self propelled, 3-wheel roller and 2-axle tandem roller weighing less than 10 tons. The rollers shall have adjustable wheel scrapers, water tanks and sprinkling apparatus to keep the wheels sufficiently wet to prevent the bituminous mixture from sticking to the wheels. The roller shall be capable of reversing without backlash and shall be free from worn parts. The roller wheels shall not have flat or pitted areas of projections that will leave marks on the pavement.

1.2.7.2. Pneumatic tired rollers shall be self propelled and shall consist of two axles on which are mounted multiple tired wheels in such a manner that the rear group of wheels will not follow in the tracks of the forward group but mounted in a rigid frame provided with a loading platform or body suitable for ballast loading. Tires shall be smooth and capable of being inflated to at least 90 psi. Construction of roller shall be such that each wheel can be loaded to a minimum of 4500 pounds.

1.3. WEATHER LIMITATIONS: Bituminous courses shall not be constructed when the temperature of the surface of the existing pavement or base course is below 40 degrees F.

1.4. PROTECTION OF PAVEMENT: After final rolling, no vehicular traffic of any kind shall be permitted on the pavement until the pavement has cooled to 140 degrees F, or 6 hours.

1.5. GRADE AND SURFACE-SMOOTHNESS REQUIREMENTS: Finished surface of pavements, when tested as specified below and in paragraph 1.9, ACCEPTABILITY OF WORK, shall conform to elevations shown and to the surface smoothness requirements specified.

1.5.1. Plan Grade: Finished surfaces shall conform within tolerances specified to the cross sections indicated. Finished surfaces shall vary not more than 0.03 foot from the plan elevation established and approved at site of work, in accordance with paragraph 1.6, GRADE CONTROL. Finished surfaces at juncture with other pavements shall coincide with finished surfaces of abutting pavements. Deviations 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. Grade will be determined and evaluated as specified in paragraph 1.9, ACCEPTABILITY OF WORK.

1.5.2. Surface Smoothness: Finished surfaces shall not deviate from the testing edge of a 12-foot straightedge more than tolerances shown for the respective pavement category in Table I. Surface smoothness will be determined and evaluated as specified in paragraph 1.9, ACCEPTABILITY OF WORK.

1.6. GRADE CONTROL: Lines and grades shown on the contract drawings shall be established with the new overlay surface. The Contractor shall use bituminous material spreaders equipped with electronic sensing devices for grade control. The devices shall be capable of utilizing the string line, long ski sled, joint matcher (short ski sled) and automatic transverse grade control methods for controlling grades. The long sled shall have a minimum length of 25 feet. Contractor shall be required to use a stringline (wire) set to grade for the initial paving lanes. Subsequent paving lanes shall use the short ski to match joints and the long ski or stringline to maintain required grades. Stringlines shall be set and maintained by the Contractor in a manner that will insure that the average new overlay thickness shall not exceed 2 1/2 inches. The stringline will be supported every 12 1/2 feet. Supports will be provided by pins driven into the joints and/or chairs in between joints. The stringlines will be set to the precise grade line by the Contractor to result in a finish grade that will permit free drainage of the areas. The supports shall be designed to allow the stringline to be secured to the pins without any protrusion above the stringline. The supports shall not interfere with the electronic grade sensing finger. Stringline tension shall be maintained at not less than 75 pounds to prevent sag. The stringlines shall be tied to supports at a maximum of 125 foot centers. The Contactor shall provide the services of a registered surveyor to establish and maintain grade control at all times.

TABLE I. SURFACE-SMOOTHNESS TOLERANCES

Tolerance for Tolerance for

Direction Intermediate Wearing

Pavement Category of Testing Course, inch Course, inch

Runways and taxiways Longitudinal 1/4 1/8

Transverse 1/4 1/4

Calibration hardstands Longitudinal 1/4 3/16 and compass swinging Transverse 1/4 3/16 bases

All other airfields and Longitudinal 1/4 1/4 helicopter paved areas Transverse 1/4 1/4

1.7. SAMPLING AND TESTING: All sampling and quality control testing is the responsibility of the Contractor and shall be performed by an approved material testing laboratory at the expense of the Contractor.

1.7.1. Aggregates: The Contractor shall have the aggregates that are intended to be used in the bituminous mixture tested for conformance to Paragraph 2.1.1 Table V, Aggregate Gradation, and the results furnished to the Contracting Officer for approval. Sources of all aggregates shall be identified. The test results on aggregates shall include gradations, percentages of materials such as natural sand, wear tests, fracture faces analysis, specific gravities, absorbtion tests, and mineral filler analysis as identified in Paragraphs 14.12.1.3 and 2.1.4. Samples of aggregates shall be furnished by the Contractor to the Contracting Officer, if requested, for additional testing at any time during production of the bituminous mixtures. Times and points of sampling will be designated by the Contracting Officer. Unless otherwise directed, ASTM D 75 shall be used in sampling coarse aggregate and fine aggregate, and ASTM C 183 shall be used in sampling mineral filler. If a sample of material from a source fails to meet specification requirements, the material represented by the sample shall be replaced, and the cost of testing the replaced sample will be at the expense of the Contractor. Approval of source of aggregate does not relieve the Contractor of the responsibility for delivery at the jobsite of aggregates that meet the requirements specified.

1.7.2. Bituminous Materials: Samples of bituminous materials shall be obtained by the Contractor; sampling shall be in accordance with ASTM D 140. Tests necessary to determine conformance with requirements specified herein will be performed by the Contractor and shall be submitted for approval. In addition to initial qualification testing of bituminous materials, samples shall be taken before and during construction when shipments of bituminous materials are received or when necessary to assure that handling or storage has not been detrimental to the bituminous material.

1.8. DELIVERY, STORAGE, AND HANDLING OF MATERIALS:

1.8.1. Mineral Aggregates: Mineral aggregates shall be delivered to the site of the bituminous mixing plant and stockpiled in such manner as to preclude fracturing of aggregate particles, segregation, contamination, or intermingling of different materials in the stockpiles or cold-feed hoppers. Mineral filler shall be delivered, stored, and introduced into the mixing plant in a manner to preclude exposure to moisture or other detrimental conditions.

1.8.2. Bituminous Materials: Bituminous materials shall be maintained at appropriate temperature during storage but shall not be heated by application of direct flame to walls of storage tanks or transfer lines. Storage tanks, transfer lines, and weigh bucket shall be thoroughly cleaned before a different type or grade of bitumen is introduced into the system. The asphalt cement shall be heated sufficiently to allow satisfactory pumping of the material; however, the storage temperature shall be maintained below 300 degrees F.

1.9. ACCEPTABILITY OF WORK: Acceptibility of work shall be determined per each delivery order and upon receipt of testing results. See UFGS SECTION 32 12 15.13 Hot Mix Airfield Pavement Novemeber 2012 or most current version at the time of delivery order.

1.9.1. General: A lot shall be that quantity of construction that will be evaluated for compliance with specification requirements. A lot shall be equal to 500 tons. Acceptability of work will be based on the test results submitted by the Contractor from the quality control laboratory. These results are subject to confirmation by quality assurance testing performed by, and at the expense of the Government. Additional tests required to determine acceptability of nonconforming material will be performed by the Contractor. No payment will be made for areas of pavement defined as rejectable because of deficiencies in composition, density, or thickness until they are removed and replaced by the Contractor as directed by the Contracting Officer. Quality assurance testing will be done as necessary, as determined by the Contracting Officer.

1.9.1.1. In order to evaluate aggregate gradation, asphalt content, and density, each lot shall be divided into four equal sublots. For density determination, one random sample shall be taken from the mat, and one random sample shall be taken from the joint of each sublot. Randomly select the test sites in accordance with ASTM D 3665. Each random sample shall weigh at least 1250 grams. After air drying to a constant weight, random samples obtained from the mat will be used for density determination using ASTM D 1188 or D 2950. Samples for determining asphalt content, laboratory reference density, and aggregate gradation shall be taken from loaded trucks within each sublot. Asphalt content will be determined in accordance with ASTM D 2172, Method A or B. Gradation of the aggregate shall be determined from the recovered aggregate according to ASTM C 136 and ASTM C 117. In addition, at the beginning of each day's operation and at least once more during the afternoon of each day, a complete Marshall Method Test (stability, flow, unit weight, percentage voids total mix, and percent voids filled with bitumen) shall be performed in accordance with ASTM D 1559. Samples will be taken from trucks chosen at random.

1.9.1.2. When a lot of material fails to meet the specification requirements, that lot shall be removed and replaced or accepted at a reduced price. The lowest percent payment determined for any pavement characteristic (i.e., gradation, asphalt content, density, grade, and smoothness) discussed below shall be the percent payment for that lot.

1.9.1.3. The Contracting Officer reserves the right to sample and test any area which appears to deviate from the specification requirements. Testing in these areas will be in addition to the lot testing, and the requirements for these areas will be the same as those for a lot.

1.9.2. Aggregate Gradation: The mean absolute deviation of the four sublot aggregate gradations from the JMF for each sieve size will be evaluated and compared with Table II. The percent payment based on aggregate gradation shall be the lowest value determined for any sieve size in Table II. All tests for aggregate gradation will be completed and reported within 24 hours after completion of construction of each lot. The computation of mean absolute deviation for one sieve size is illustrated below:

Example: Assume the following JMF and sublot test results for aggregate gradation.

Percent by Weight Passing Sieves

Sieve Test Test Test Test

Size JMF No. 1 No. 2 No. 3 No. 4

3/4 inch 100 100 100 100 100

1/2 inch 88 87 88 90 88

3/8 inch 75 72 77 78 74

No. 4 64 60 65 67 62

No. 8 53 50 56 57 52

No. 16 42 39 44 45 41

No. 30 32 30 34 35 32

No. 50 20 17 20 22 21

No. 100 10 8 10 10 11

No. 200 6 4 7 8 6

Mean Absolute Deviation = |4 - 6| + |7 - 6| + |8 - 6| + |6 - 6|

(for No. 200 Sieve) 4

= 2 + 1 + 2 + 0

= 1.25

The mean absolute deviation for other sieve sizes can be determined in a similar way for this example to be:

Sieve 3/4 1/2 3/8

Size inch inch inch No. 4 No. 8 No. 16 No. 30 No. 50 No. 100

Mean 0 0.75 2.25 2.50 2.75 2.25 1.75 1.50 0.75

Absolute

Deviation

The least percent payment based on any sieve size listed in Table II would be 98 percent for the No. 200 sieve. Therefore for this example the percent payment based on aggregate gradation is 98 percent.

TABLE II. PERCENT PAYMENT BASED ON MEAN ABSOLUTE DEVIATION

OF AGGREGATE GRADATIONS FROM JMF

Sieve Percent Payment Based On Mean Absolute Deviation from JMF

Size 0.0-1.0 1.1-2.0 2.1-3.0 3.1-4.0 4.1-5.0 5.1-6.0 Above 6.0

3/4 inch 100 100 100 100 98 95 90

1/2 inch 100 100 100 100 98 95 90

3/8 inch 100 100 100 100 98 95 90

No. 4 100 100 100 100 98 95 90

No. 8 100 100 100 98 95 90 reject

No. 16 100 100 100 98 95 90 reject

No. 30 100 100 100 98 95 90 reject

No. 50 100 100 100 98 95 90 reject

No. 100 100 98 95 90 90 reject reject

No. 200 100 98 90 reject reject reject reject

1.9.3. Asphalt Content: The mean absolute deviation of the four asphalt contents from the JMF will be evaluated and compared with Table III. The percent payment based on asphalt content shall be the value determined in accordance with Table III. All asphalt content tests will be completed and reported within 24 hours after completion of construction of each lot.

TABLE III. PERCENT PAYMENT BASED ON ASPHALT CONTENT

Mean Absolute Deviation of Extracted

Asphalt Content from JMF Percent Payment less than 0.20

0.21-0.30

0.31-0.35

0.36-0.40

Above 0.40 reject

1.9.4. Density: The average mat density and the average joint density will be expressed as a percentage of the laboratory density. The laboratory density for each lot will be determined in accordance with ASTM D 1559 from four sets of laboratory samples. One sample will be obtained from each of the four sublots and will be divided into three specimens to produce one set of laboratory samples. Laboratory samples will be prepared from asphalt mixture which has not been reheated in the laboratory. Samples will be compacted within 2 hours of the time the mixture was loaded into trucks at the asphalt plant.

1.9.4.1. The field density will be determined and compared with Table IV. The percent payment based on density will be the lowest value determined from Table IV. The percent payment based on mat density will be for all of the material placed in the lot. The percent payment based on joint density will be for the amount of material represented by an area equal to the lot joint length by 10 feet wide not to exceed the lot size.

TABLE IV. PERCENT PAYMENT BASED ON DENSITY

Average Mat Density Percent Average Joint Density

(4 Cores) Payment (4 Cores)

98.0-100.0 100.0 Above 96.5

97.9 100.0 96.4

97.8, 100.1 99.9 96.3

97.7 99.8 96.2

97.6, 100.2 99.6 96.1

97.5 99.4 96.0

97.4, 100.3 99.1 95.9

97.3 98.7 95.8

97.2, 100.4 98.3 95.7

97.1 97.8 95.6

97.0, 100.5 97.3 95.5

96.9 96.3 95.4

96.8, 100.6 94.1 95.3

96.7 92.2 95.2

96.6, 100.7 90.3 95.1

96.5 87.9 95.0

96.4, 100.8 85.7 94.9

96.3 83.3 94.8

96.2, 100.9 80.6 94.7

96.1 78.0 94.6

96.0, 101.0 75.0 94.5 below 96.0, or above 101.0 reject below 94.5

1.9.4.2. All density results on a lot will be completed and reported as specified after the construction of that lot. When the Contracting Officer considers it necessary to take additional samples for density measurements, sampling will be done in groups of four (one for each sublot). The percent payment shall be determined for each additional group of four samples and averaged with the percent payment for the original group to determine the final percent payment. The Contractor shall fill all sample holes with hot mix and compact.

1.9.5. Grade: The finished surface of the pavement will be determined from a topographical survey conducted by the Contractor. Within 5 working days after the completion of the survey, the results shall be submitted to the Contracting Officer for evaluation. When more than 5 percent of all measurements made within a lot are outside the specified tolerances, the payment for that lot will not exceed 95 percent of the bid price. In areas where the grade exceeds the plan-grade tolerances given in paragraph GRADE AND SURFACE-SMOOTHNESS REQUIREMENTS by more than 50 percent, the Contracting Officer shall require removal of the deficient area and replacement with fresh paving mixture. Sufficient material shall be removed to allow at least 1 inch of asphalt concrete to be placed. Skin patching for correcting low areas or planing for correcting high areas shall not be permitted on the wearing course.

1.9.6. Surface Smoothness: After the completion of final rolling of a lot, the compacted surface will be tested by the Contractor in the presence of the Government representative with a 12-foot straightedge. Measurements will be made perpendicular to and across all joints at equal distances along the joint not to exceed 25 feet. Location and deviation from straightedge for all measurements will be recorded and submitted to the Contracting Officer. When more than 5 percent of all measurements along the joints or along the mat within a lot exceed the specified tolerance, the unit price for that lot shall not exceed 95 percent of the bid price. Any joint or mat area surface deviation which exceeds the surface-smoothness tolerances referenced in UFGS 32 12 13.15 paragraph 1.6.4.1 Table 3 Straighedge Surface Smoothness--Pavements by more than 50 percent shall be corrected to meet the specification requirements. The Contractor shall remove the deficient area and replace with fresh paving mixture at no additional cost the Government. Sufficient material shall be removed to allow at least 1 inch of asphalt concrete to be placed. Skin patching for correcting low areas or planing for correcting high areas shall not be permitted.

1.10. ACCESS TO PLANT AND EQUIPMENT: The Contracting officer shall have access at all times to all parts of the paving plant for checking adequacy of equipment in use; inspecting operation of plant; verifying weights, proportions, and character of materials; and checking temperatures maintained in preparation of mixtures.

1.11. WAYBILLS AND DELIVERY TICKETS: If requested, waybills and delivery tickets shall be submitted to the Contracting Officer during progress of the work. Before the final progress report is allowed, the Contractor shall file with the Contracting Officer certified waybills and certified delivery tickets for all aggregates and bituminous materials actually used in the construction and covered by the contract.

1.12. MEASUREMENT: Asphaltic concrete will be measured in place in the completed and accepted pavements in accordance with the dimensions given on the contract drawings.

1.13. PAYMENT: The total contract amount for AC pavement will be paid only if the completed pavements meet or exceed the area and thickness dimensions as given on the contract drawings, and only if all the 100 percent payment requirements are attained as specified in paragraph 1.9, ACCEPTABILITY OF WORK. Otherwise, sections of the completed AC pavement may be accepted at a reduced price or rejected altogether, as defined in paragraph 1.9, ACCEPTABILITY OF WORK. Payment shall constitute full compensation for preparing or reconditioning the base course or existing pavement, prime coating and tack coating, for furnishing all materials, equipment, plant, and tools, and for all labor and other incidentals necessary to complete work required in this section of the specifications.

2. PART 2 - PRODUCTS

2.1. BITUMINOUS HOT MIX shall consist of coarse aggregate, fine aggregate, mineral filler, bituminous material, and approved additives, if required, of the qualities and in the proportions specified and shall conform to requirements contained in paragraphs 2.2, PROPORTIONING OF MIXTURE and 1.9, ACCEPTABILITY OF WORK.

2.1.1. Aggregates: Aggregates shall consist of natural sand, crushed stone, crushed gravel, crushed slag, screenings, sand, and mineral filler, as required. The portion of materials retained on the No. 4 sieve shall be known as coarse aggregate; the portion passing the No. 4 sieve and retained on the No. 200 sieve as fine aggregate; and the portion passing the No. 200 sieve as mineral filler. Aggregate gradation shall conform to gradation(s) specified in Table V. Table V 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 percentages passing various sieves may be directed by the Contracting Officer when aggregates vary more than 0.2 in specific gravity.

TABLE V. AGGREGATE GRADATION

Sieve Wearing Course, Intermediate Course, Size Percent Passing Percent Passing

1”

3/4" 100 90-100

1/2" 90-100 68-88

3/8" 69-89 60-82

No. 4 53-73 45-67

No. 8 38-60 32-54

No. 16 26-48 22-44

No. 30 18-38 15-35

No. 50 11-27 9-25

No. 100 6-18 6-18

No. 200 3-6 3-6

2.1.2. Coarse aggregate shall consist of clean, sound, durable particles meeting the following requirements.

2.1.2.1. Percentage of loss shall not exceed 40 after 500 revolutions, as determined in accordance with ASTM C 131.

2.1.2.2. Percentage of loss shall not exceed 18 after five cycles performed in accordance with ASTM C 88, using magnesium sulfate.

2.1.2.3. The dry weight of crushed slag shall not be less than 75 pcf, as determined in accordance with ASTM C 29.

2.1.2.4. Crushed gravel retained on the No. 4 sieve and each coarser sieve listed in Table V shall contain at least 75 percent by weight of crushed pieces having two or more fractured faces with the area of each face equal to at least 75 percent of the smallest midsectional area of piece. When two fractures are contiguous, the angle between planes of fractures shall be at least 30 degrees to count as two fractured faces.

2.1.2.5. Particle shape of crushed aggregates shall be essentially cubical. 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.

2.1.3. Fine aggregate shall consist of clean, sound, durable, angular particles produced by crushing 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 No. 30 sieve. This requirement shall apply to 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 15 percent by weight of coarse and fine aggregate and material passing the No. 200 sieve. Natural sand is defined as pit or bank-run material that had not been derived by crushing larger aggregate. Natural sand shall be clean and free from clay and organic matter. Percentage of loss shall not exceed 18 after five cycles of the soundness test performed in accordance with ASTM C 88, using magnesium sulfate.

2.1.4. Mineral filler shall conform to ASTM D 242.

2.1.5. Bituminous Materials: Asphalt cement shall conform to AASHTO MP1 PG Grade 70-16.

2.1.6. Additives: The use of additives such as antistripping and antifoaming agents is subject to approval.

2.2. PROPORTIONING OF MIXTURE:

2.2.1. Job Mix Formula: The JMF for the bituminous mixture will be furnished by the Contractor to the Contracting Officer for approval. No payment will be made for mixtures produced prior to the approval of the JMF. The formula will indicate the percentage of each stockpile and mineral filler, the percentage passing each sieve size, the percentage of bitumen, and the temperature of the completed mixture when discharged from the mixer. Tolerances are given in Table VI for asphalt content, temperature, and aggregate grading for tests conducted on the mix as discharged from the mixing plant; however, the final evaluation of aggregate gradation and asphalt content will be based on paragraph 1.9, ACCEPTABILITY OF WORK. Bituminous mix that deviates more than 25 degrees F. from JMF shall be rejected. The JMF may be adjusted during construction to improve paving mixtures, as directed, without adjustments in the contract unit prices.

TABLE VI. JOB-MIX TOLERANCES

Tolerance, Material

Plus or Minus

Bitumen 0.20 percent

Temperature of mixing 25 degrees F.

2.2.2. Test Properties of Bituminous Mixtures: Finished mixture shall meet requirements described below when tested in accordance with ASTM D 1559. All samples will be compacted with 75 blows of specified hammer on each side of sample. When bituminous mixture fails to meet the requirements specified below where below? State specifically, the paving operation shall be stopped until the cause of noncompliance is determined and corrected.

2.2.3. Requirements for stability, flow, and voids are shown in Table VII .

TABLE VII. NONABSORPTIVE-AGGREGATE MIXTURE

Intermediate

Wearing Course Course

Stability minimum, pounds 2200 2200

Flow maximum, 1/100-inch units 8-16 8-16

Air Voids, percent 3-5 3-5

% Voids in Mineral Aggregate (minimum) 13

The Contracting Officer may permit deviations from limits specified when gyratory method of design is used to develop the JMF and he may permit deviation from limits specified for voids filled with bitumen in the intermediate course in order to stay within limits for percent voids total mix.

2.2.4. If the Tensile Strength Ratio (TSR) of the composite mixture, as determined by ASTM D 4867, is less than 75, the aggregates shall be rejected or the asphalt mixture treated with an approved 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 will be provided by the contractor at no additional cost.

3. PART 3 - EXECUTION

3.1. BASE COURSE CONDITIONING: Surface of the base course will be inspected for adequate compaction and surface tolerances specified in SPECIFICATION SECTION 02233. Unsatisfactory areas shall be corrected.

3.2. PREPARATION OF BITUMINOUS MIXTURES: Rates of feed of aggregates shall be regulated so that moisture content and temperature of aggregates will be within specified tolerances. Aggregates, mineral filler, and bitumen shall be conveyed into the mixer in proportionate quantities required to meet the JMF. Mixing time shall be as required to obtain a uniform coating of the aggregate with the bituminous material. Temperature of bitumen at the time of mixing shall not exceed 300 degrees F. Temperature of aggregate and mineral filler in the mixer shall not exceed 325 degrees F. when bitumen is added. Overheated and carbonized mixtures or mixtures that foam shall not be used.

3.3. WATER CONTENT OF AGGREGATES: Drying operations shall reduce the water content of mixture to less than 0.75 percent. Water content test will be conducted in accordance with ASTM D 2216; weight of sample shall be at least 500 grams. If water content is determined on hot bin samples, the water content will be a weighted average based on the composition of the blend.

3.4. STORAGE OF BITUMINOUS PAVING MIXTURE: Storage of bituminous paving mixture shall conform to the applicable requirements of ASTM D 3515; however, in no case shall the mixture be stored for more than 4 hours.

3.5. TRANSPORTATION OF BITUMINOUS MIXTURE: Transportation from the paving plant to the site shall be in trucks having tight, clean, smooth beds lightly coated with an approved releasing agent to prevent adhesion of mixture to truck bodies. Excessive releasing agent shall be drained prior to loading. Each load shall be covered with canvas or other approved material of ample size to protect mixture from weather and prevent loss of heat. Loads that have crusts of cold, unworkable material or have become wet by rain will be rejected. Hauling over freshly placed material will not be permitted.

3.6. SURFACE PREPARATION OF UNDERLYING COURSE: Prior to the placing of intermediate or wearing course, the underlying course shall be cleaned of all dust and other foreign or objectionable matter with power brooms and hand brooms other specs allow power blowers also; are they allowed in this instance?.

3.7. PRIME COATING: Surface of previously constructed base course shall be sprayed with a coat of bituminous material conforming to SECTION: BITUMINOUS PRIME AND TACK COAT What is the spec number/where is this spec?.

3.8. TACK COATING: Contact surfaces of previously constructed pavement, curbs, manholes, and other structures shall be sprayed with a thin coat of bituminous material conforming to SECTION: BITUMINOUS PRIME AND TACK COAT What is the spec number/where is this spec?.

3.9. PLACING: Bituminous courses shall be constructed only when the base course or existing pavement has no free water on the surface. Bituminous mixtures shall not be placed without ample time to complete spreading and rolling during daylight hours, unless approved satisfactory artificial lighting is provided lighting is not the only issue; duty hours should be addressed.

3.9.1. Offsetting Joints: The wearing course shall be placed so that longitudinal joints of the wearing course will be offset from joints in the intermediate course by at least 1 foot. Transverse joints in the wearing course shall be offset by at least 2 feet from transverse joints in the intermediate course.

3.9.2. General Requirements for Use of Mechanical Spreqder: The Bange what? of temperatures of mixtures, when dumped into the mechanical spreader, shall be as determined by the Contracting Officer. Mixtures having temperatures less than 225 degrees F. when dumped into the mechanical spreader shall not be used. The mechanical spreader shall be adjusted and the speed regulated so that the surface of the course being laid will be smooth and continuous without tears and pulls, and of such depth that, when compacted, the surface will conform to the cross section indicated. Placing with respect to areas with one-way slope shall begin on the low side. Each lot of material placed shall conform to requirements specified in paragraph 1.9, ACCEPTABILITY OF WORK. Placing of the mixture shall be as nearly continuous as possible, and the speed of placing shall be adjusted, as directed, to permit proper rolling. When segregation occurs in the mixture during placing, the spreading operation shall be suspended until the cause is determined and corrected.

3.9.3. Placing Strips Succeeding Initial Strips: In placing each succeeding strip after the initial strip has been spread and compacted as specified below, the screed of the mechanical spreader shall overlap the previously placed strip 2 to 3 inches and be sufficiently high so that compaction produces a smooth dense joint. Mixture placed on the edge of a previously placed strip by the mechanical spreader shall be pushed back to the edge of the strip by the use of a lute. Excess material shall be removed and wasted.

3.9.4. Hand spreading in Lieu of Machine Spreading: In areas where use of machine spreading is impractical, the mixture shall be spread by hand. Spreading shall be in a manner to prevent segregation. The mixture shall be spread uniformly with hot rakes in a loose layer of thickness that, when compacted, will conform to the required grade, density, and thickness.

3.10. COMPACTION OF MIXTURE: Rolling shall begin as soon after placing as the mixture will bear a roller without undue displacement. Delays in rolling freshly spread mixture will not be permitted. After initial rolling, preliminary tests of grade and smoothness shall be made by the Contractor. Deficiencies shall be corrected so that the finished course will conform to requirements for grade and smoothness specified herein. Grade and smoothness will be checked for compliance in each lot of completed pavement by the Contractor and will be evaluated as specified in paragraph 1.9, ACCEPTABILITY OF WORK. After the grade and smoothness requirements have been met, rolling shall be continued until a mat density of 98.0 to 100.0 percent and a joint density of 96.5 to 100.0 percent of density of laboratory-compacted specimens of the same mixture are obtained. The density will be determined and evaluated as specified in paragraph 1.9, ACCEPTABILITY OF WORK. Places inaccessible to rollers shall be thoroughly compacted with hot hand tampers. The speed of the rollers shall not exceed 3 miles per hour and rolling shall be performed in such a manner to avoid cracking, shoving, or displacement of the hot mixture.

3.10.1. The use of vibratory steel wheel roller for breakdown and finish rolling is subject to prior approval by the Contracting Officer. A vibratory roller shall be operated with the vibratory units off for finish rolling. The maximum weight of the roller shall not exceed 5 tons.

3.10.2. The maximum compacted thickness per lift shall not be more than 3.0 inches.

3.10.3. No compaction effort will be allowed after finish rolling is complete, as the mix will be too cold to gain additional density without crushing aggregates.

3.11. TEST STRIP: At the start of the plant operation, a quantity of mixture shall be prepared sufficiently to construct a test section at least 50 feet long, two spreader widths wide and of thickness to be used in the project. Mixture shall be placed, spread, and rolled with the equipment to be used in the project and in accordance with requirements specified above. This test section shall be tested and evaluated as a lot and shall conform to all specified requirements. If test results are satisfactory, the test section shall remain in place as part of the completed pavement. If tests indicate that the pavement does not conform to specification requirements, necessary adjustments to the plant operations and rolling procedures shall be made immediately, one test section will be evaluated as specified in paragraph 1.9, ACCEPTABILITY OF WORK. Additional test sections, as directed, shall be constructed and sampled for conformance with specification requirements. In no case shall the Contractor start full production of an intermediate or wearing course mixture without approval.

3.12. CORRECTING DEFICIENT AREAS: Mixtures that become contaminated or are defective shall be removed to the full thickness of the course. Edges of the area to be removed shall be cut so that the sides are perpendicular and parallel to the direction of traffic and so that the edges are vertical. Edges shall be sprayed with bituminous materials conforming to SECTION: BITUMINOUS TACK AND PRIME COAT What is the spec number/where is this spec?. Fresh paving mixture shall be placed in the excavated areas in sufficient quantity so that the finished surface will conform to the grade and smoothness requirements. Paving mixture shall be compacted to the density specified herein. Skin patching of an area that has been rolled shall not be permitted.

3.13. JOINTS: Joints between old and new pavements, between successive days' work, or joints that have become cold (less than 175 degrees F.) because of any delay, shall be made to insure continuous bond between the old and new sections of the course. Longitudinal joints on bituminous airfield pavements which are irregular, damaged, uncompacted, or cold (less than 175 degrees F at the time of placing the adjacent lane), or otherwise defective, shall be cut back a maximum of 3 inches from the top edge of the lift with a cutting wheel to expose a clean, sound vertical surface for the full depth of the course. All joints shall have the same texture and smoothness as other sections of the course. Contact surfaces of previously constructed pavements coated by dust, sand, or other objectionable material shall be cleaned by brushing or shall be cut back as directed. When directed by the Contracting Officer, the surface against which new material is placed shall be sprayed with a thin, uniform coat of bituminous material conforming to SECTION: BITUMINOUS TACK AND PRIME COAT What is the spec number/where is this spec?. Material shall be applied far enough in advance of the placement of fresh mixture to insure adequate curing. Care shall be taken to prevent damage or contamination of the sprayed surface.

3.13.1. Transverse Joints: The roller shall pass over the unprotected end of a strip of freshly placed material only when the placing is discontinued or the delivery of the mixture is interrupted to the extent that material in place may become cold. In all cases, prior to continuing placement, the edge of previously placed pavement shall be cut back to expose an even vertical surface for full thickness of the course. In continuing placement of the strip, the mechanical spreader shall be positioned on the transverse joint so that sufficient hot mixture will be spread to obtain a joint after rolling that conforms to the required density and smoothness specified herein.

3.13.2. Longitudinal Joints: Edges of a previously placed strip shall be prepared such that the pavement in and immediately adjacent to the joint between this strip and the succeeding strip meets the requirements for grade, smoothness, and density as described in paragraph 1.9, ACCEPTABILITY OF WORK.

END OF SECTION

Page 32 12 15-1 (22 Mar 99)

HMA Airfield

Page 32 12 15-2 (7 Feb 2016)