atch 1 2550 Hot Mix Asphalt.pdf

FA5000-12-R-0001

Attachment 1

2550- 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.

1.1 Military Standard

: MIL-STD-620A Test Methods for Bituminous Paving and Materials.

1.2 Federal Aviation Administration DOT

: FAA Advisory Circular Hot Mix Asphalt Paving Handbook 150/5370-14.

1.3 American Society for Testing and Materials (ASTM)

C 88 Soundness of Aggregates, C 117 Material Finer Than 76-um (No. 200) Sieve, C 127 Spec Gravity and Absorption of Coarse Aggregate, C 128 Spec Gravity and Absorption of Fine Aggregate, C 131 The Los Angeles Abrasion Machine, C 136 Sieve Analysis of Fine and Coarse Aggregates, C 1252 Un-compacted Void Content of Fine Aggregate, D 5 Penetration of Asphalt, D 36 Ring and Ball Softening Point, D 75 Sampling Aggregates, D 113 Ductility of Asphalt, D 140 Sampling Bituminous Materials, D 242 Mineral Filler for Bituminous Paving, D 692 Course Aggregate for Bituminous Paving Mixtures, D 1973 Fine Aggregate for Bituminous Paving Mixtures, D 2170 Kinematic Viscosity of Asphalts, Pavements - IDIQ

FXSB 11-2102

Section 2550 Hot Mix Asphalt for Airfields and Roads

2550- 2

D 2171 Viscosity of Asphalts, D 2172 Quantitative Extraction of Bitumen, D 2216 Moisture Content of Soil, D 2419 Sand Equivalent Value of Soils and Fine Aggregate, D 2950 Density of Asphalt by the Nuclear Method, D 3515 Hot-Mixed Bituminous Paving Mixtures, D 4125 Asphalt Content by the Nuclear Method, D 4867 Effect of Moisture on Asphalt Paving Mixtures (TSR).

1.4 American Assoc of State Highway and Transportation Officials (AASHTO)

: M-226 (modified) Viscosity Graded Asphalt Cement TP-53 Asphalt Content of Hot Mix Asphalt by Ignition Method T-102 Spot Test of Asphaltic Materials.

1.5 The Asphalt Institute (AI)

: MS-2 Mix Design Methods for Asphalt Concrete MS-3 Asphalt Plant Manual.

1.6 National Asphalt Pavement Association

: QIP-97 Quality Control For Hot Mix Asphalt QIP-110 Hot Mix Asphalt Segregation: Causes & Cures.

2.0 PLANT, EQUIPMENT, MACHINES, TOOLS, AND PERSONNEL:

2.1 The asphalt plant shall be of such capacity, as specified hereinafter, to produce the quantities of asphalt mixtures required for the project within the completion time of the contract.

2.2 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 asphalt paving mixtures at a rate equal to the asphalt plant output. A sufficient number of adequately trained personnel shall be available during paving operations to produce a pavement meeting the requirements in this specification.

3. ASPHALT PLANTS:

3.1 The asphalt plant shall be an automatic or semiautomatic controlled commercially manufactured unit designed, coordinated, and operated to consistently produce an asphalt mix meeting the job mix formula (JMF). The asphalt plant shall have a minimum normal operating (actual) capacity of 200 tons per hour

, unless accepted otherwise by the government’s project engineer.

3.2 Drum mixers will be prequalified at the production rate to be used during actual mix

2550- 3 production. The prequalification tests will include extraction and recovery of the asphalt cement.

The penetration of the recovered asphalt binder shall not be less than 60 percent of the original penetration. The asphalt plant capacity will be determined by the manufacturer's rating.

4. ACCESS TO ASPHALT/CRUSHING PLANT AND EQUIPMENT:

4.1 The Contracting Officer or his designated representative shall have access at all times to all parts of the asphalt plant and the crushing 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.

5. OTHER EQUIPMENT:

5.1 All plant equipment, tools, and machines used in the work shall be capable of producing acceptable pavements and be maintained in satisfactory working condition at all times.

6. OPERATION OF BORROW PITS: See 1020-9.

7. ASPHALT HOT MIX:

7.1 The asphalt hot mix provided under this specification shall consist of coarse aggregate, fine aggregate, blend sand, mineral filler, asphalt cement, rubber modifiers, and approved additives, if required, of the qualities and in the proportions meeting the requirements of this specification.

8. ASPHALT AGGREGATES:

8.1 Asphalt Aggregates

: Samples of aggregates shall be furnished by the Contractor to the Government’s project engineer / project inspector for approval of aggregate stockpiles prior to the start of production and at intervals during production of the bituminous mixtures. Intervals and points of sampling will be designated by the government’s project engineer / project inspector.

Samples will be the basis of approval of specific sources or stockpiles of aggregates for aggregate requirements. 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. All tests necessary to determine compliance with requirements specified herein will be made by the Contractor at no additional expense to the Government. The Contractor will take Quality Assurance tests at the direction of the government’s project engineer / project inspector.

8.1.1 Aggregates shall consist of crushed gravel, screenings, sand, and mineral filler, as required.

Coarse aggregate is the portion of materials retained on the No. 4 sieve. Fine aggregate is the portion of materials passing the No. 4 sieve and retained on the No. 200 sieve. Mineral filler is the portion of materials passing the No. 200 sieve. Those aggregates to be used in the wearing course of pavement shall meet the requirements specified for aggregates as well as being free of silt and clay and vegetable matter, and other objectionable materials or coatings. The Elmendorf borrow pit contains silt and clay layers mixed in with the sand and gravel layers. The silt and clay lumps shall not be used in the asphalt wearing course.

Coarse Aggregate

2550- 4

8.2 Coarse aggregate

is the portion of materials passing the 3/4” sieve and retained on the # 4 sieve and shall consist of clean, sound, durable, angular particles produced by crushing gravel that meets the following requirements:

8.2.1 The crushed gravel retained on each coarse sieve, the #4 sieve, the 3/8” sieve and the 1/2” sieve shall contain at least 75 percent by weight of crushed pieces having two or more freshly fractured faces with the area of each face equal to at least 75 percent of the smallest midsectional area of the piece. When two fractures are continuous, the angle between planes of fractures shall be at least 30 degrees to count as two fractured faces.

8.2.2 Percentage of wear shall not exceed 40 after 500 revolutions as determined by ASTM C 131.

8.2.3 Percentage of loss shall not exceed 12 percent weighed average at five cycles when tested for soundness in magnesium sulfate as determined by ASTM C 88. Percentage of loss shall not exceed 9 percent weighed average at five cycles when tested for soundness in sodium sulfate as determined by ASTM C 88.

8.2.4 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.

Fine Aggregate

8.3 Fine aggregate

is the portion of materials passing the # 4 sieve and retained on the #200 sieve, (includes the portion passing the #200 sieve produced by the crushing operation), and shall consist of clean, sound, durable, angular particles produced by crushing gravel that meets the following requirements:

8.3.1 Percentage of wear shall not exceed 40 after 500 revolutions as determined by ASTM C 131.

8.3.2 Percentage of loss shall not exceed 12 percent weighed average at five cycles when tested for soundness in magnesium sulfate as determined by ASTM C 88. Percentage of loss shall not exceed 9 percent weighed average at five cycles when tested for soundness in sodium sulfate as determined by ASTM C 88.

8.3.3 The fine aggregate manufactured by crushing gravel retained on each fine sieve, the #30 sieve (or #40 sieve), the #16 sieve, and the #8 sieve shall contain at least 90 percent by weight of particles having two or more freshly fractured faces.

8.3.3.1 This requirement shall apply to the fine aggregate before blending with natural sand, when blending is necessary.

8.3.4 The fine aggregate should have a sand equivalent

value greater than 45 when tested IAW ASTM D 2419. Provide one test minimum per 2,000 tons of processed fine aggregates.

8.3.5 The fine aggregate portion of the blended aggregate should have an un-compacted void content (angularity) greater than 45 percent when tested IAW ASTM C 1252, Method A. Provide

2550- 5 one test minimum per lot.

Blend Sand

8.4 The blend sand

shall be natural sand with 100% passing the # 4 sieve, which is added to the wearing and intermediate course mixtures and shall be accepted by the government’s project engineer.

8.4.1 The blend sand shall not exceed 15 percent

by weight of the total weight of the coarse aggregate, the fine aggregate, and the material passing the No. 200 sieve.

8.4.2 Natural sand shall be clean and free from clay and organic matter.

8.4.3 Percentage of loss shall not exceed 12 after five cycles of the soundness test performed in accordance with ASTM C 88, using magnesium sulfate.

8.5 Mineral filler

shall conform to ASTM D 242. Mineral filler is typically not required. There is typically sufficient mineral filler generated during the crushing process.

8.6 Maintaining Stockpiles

: The coarse aggregate, the fine aggregate, and the blend sand shall be stockpiled in separate piles for use at the cold feed bins in individual stockpiles. Stockpile blending will not be authorized.

8.6.1 Place the aggregates in horizontal or gently sloping layers to minimize segregation. Keep the coarse aggregate separated from the fine aggregate. Blend the coarse aggregate, the fine aggregate, and the blend sand together in the proper proportion just prior to the asphalt mixing operation.

8.6.2 When segregation occurs, blend the segregated materials together with the rest of the stockpile before the aggregate is delivered into the cold feed bins.

8.6.3 Stockpile materials that cannot be properly blended for conformance to gradation specified shall be rescreened or reprocessed before use at the asphalt plant cold feed storage bins.

8.6.4 Prevent contamination or intermingling of different materials into the stockpiles.

8.7 Sources

: Sources of aggregates shall be selected well in advance of the time the materials are required in the work.

8.7.1 When a previously developed off-JBER source is selected, test results for the aggregate shall be submitted to the Contracting Officer 30 days in advance of production, with evidence that the asphalt pavements constructed with the aggregates have had a satisfactory service record of at least five years under similar climatic and traffic conditions.

8.7.2 When a new off-JBER or on-JBER source is developed, the Contractor shall indicate sources and submit test results and his plan for operation 30 days in advance of production. The Contractor will make such tests and other investigations as necessary to determine whether aggregates meeting

2550- 6 the requirements specified herein can be produced from proposed sources. Approval of source of aggregate does not relieve the Contractor of the responsibility for delivery at the jobsite of aggregate that meet the requirements specified.

Aggregate Gradations

8.8 Aggregate gradation: Table I

is Based on aggregates of uniform specific gravity. The percentage passing various sieves may be changed by the government’s project engineer when aggregates of varying specific gravities are used.

8.8.1 Asphalt Aggregate Gradation for PG-52-28 and for PG-58-28-R (3%SBS) from the on-JBER borrow pit: Gradation shall conform to

Table I.

8.8.2 Asphalt Aggregate Gradation for PG-52-28 and for PG-58-28-R (3%SBS) from an off-JBER gravel source: Gradation shall conform to Table I

TABLE I

Asphalt Aggregate Gradation

9. ASPHALT CEMENT:

9.1 In addition to initial qualification testing of the asphalt cement, samples shall be taken before and during construction when shipments of the asphalt cement are received or when necessary to assure some condition of handling or storage has not been detrimental to the asphalt cement. The samples will be taken and tested by the contractor under the supervision of the government’s project engineer / project inspector.

9.2 Asphalt cement shall be maintained at appropriate temperatures during mixing, storage, and transporting but shall not be heated by application of direct flame to walls of storage tanks or transfer lines. Record the temperature readings

Sieve during the mixing, storage, and transporting on the IQC reports. Storage tanks, transfer lines, and weigh bucket shall be thoroughly cleaned before a

Sieve Percent Size Size Passing 3/4" 19.0 mm 100 1/2" 12.5 mm 76-96 3/8" 9.5 mm 69-89 #4 4.75 mm 53-73 #8 2.36 mm 38-60 #16 1.18mm 26-48 #30 0.60 mm 18-38 #50 0.30 mm 11-27

#100 0.15 mm 6-18 #200 0.075mm 3-6

2550- 7 different type or grade of asphalt cement is introduced into the system.

9.3 The asphalt cement shall show a negative spot when subjected to the spot test in accordance with AASHTO T 102, using standard naphtha specified therein.

Anti-Strip Agent

9.4 Perform the anti-strip test IAW AASHTO T-182 with 95% bitumen coating (minimum) to determine the adequacy for the non-strip additive. The non-strip additive shall be added at the refinery or the mixing plant in the proportions of 0.50, 0.75 or 1.0 percent of the total weight of the asphalt cement. Use 0.50% minimum

. Requires approval by the Government’s project engineer / project inspector.

9.4.1 Determine the Tensile Strength Ratio

(TSR) of the asphalt mix with the anti-strip agent IAW ASTM D 4867, which should be at least 75 unless approved otherwise by the project manager. This test is used to determine the minimum amount of anti-strip agent. Provide data for informational purposes only.

Optimum Asphalt Cement Content

9.4 Asphalt Cement PG-52-28: Asphalt cement shall conform to Superpave performance grade PG- 52-28. The asphalt cement content of the JMF shall be specified as "percent by weight of the total mix". The "optimum asphalt cement content" shall be 5.7% minimum and shall be determined by the IQC based on the Marshall mix design test results and the test strip results. The government’s project engineer will make the final determination on the "optimum asphalt cement content".

9.4.1 The Contractor shall take test samples of the liquid PG-52-28 with the anti-strip to determine compliance of the PG-52-28 to these specifications. The test samples shall be taken in the presence of the IQC or the government’s project engineer or other approved representative. Each PG-52-28 test sample shall be evaluated by an independent test lab or approved equal. The test samples shall be considered representative for purposes of evaluating each requirement for PG-52-28. Provide at least one test sample per batch mixed.

9.5 Asphalt Cement PG-58-28-R (3%SBS) : Asphalt cement with synthetic rubber modified shall conform to Table II. The asphalt cement content of the JMF shall be specified as "percent by weight of the total mix". The "optimum asphalt cement content" shall be 5.7% minimum and shall be determined by the IQC based on the Marshall mix design test results and the test strip results.

The government’s project engineer will make the final determination on the "optimum asphalt cement content". The PG-58-28-R (3%SBS) shall have 3% SBS minimum by total weight of the resulting modified asphalt cement.

9.5.1 For PG-58-28-R (3%SBS) asphalt, the synthetic rubber modifier shall be mixed and digested with the base asphalt cement IAW an approved mixing procedure under supervised and controlled plant-like conditions, such as the asphalt refinery or the asphalt cement manufacturing plant to produce a uniform, homogeneous, and well dispersed mixture. Maintain a 350 degree F minimum temperature with a 390 degree F maximum during the mixing and digestion process. Field mixing to obtain digestion is prohibited. Submit rubber modifier manufacturer's requirements on mixing, 2550- 8 mixing temperatures, and Maximum allowable temperature for approval.

9.6 PG-58-28-R (3%SBS) Sampling and Testing

9.6.1 The Contractor shall take test samples of the liquid asphalt cement mixed with the synthetic rubber modifier to determine compliance of the PG-58-28-R (3%SBS) asphalt cement to these specifications. The test samples shall be taken in the presence of the IQC or the government’s project engineer or other approved representative. Each PG-58-28-R (3%SBS) test sample shall be evaluated by an independent test lab or approved equal who is qualified to perform tests on rubber modified asphalts. The test samples shall be considered representative for purposes of evaluating each requirement shown in Table II for PG-58-28-R (3%SBS). One test sample per 50 tons of PG- 58-28-R (3%SBS) (liquid asphalt cement mixed with synthetic rubber modifier) or one test sample per batch mixed, whichever results in the larger amount of tests.

9.6.1.1 The PG-58-28-R (3%SBS) asphalt cement shall be approved for use by the Contracting Officer or designated representative, based on the evaluation of the test results, prior to being used.

9.6.2 Truck Tickets for Asphalt Cement: Each truckload of asphalt cement used on this contract delivered to the contractor’s asphalt storage tank shall have the asphalt cement test results for that batch of asphalt cement. Provide to the government’s project engineer within 24 hours of unloading the asphalt cement.

9.6.3 SHRP Superpave Binder Tests

9.6.3.1 The contractor shall provide the SHRP Superpave performance grading of the PG-58-28-R (3%SBS) asphalt cement with the anti-strip agent (plant mixed). The contractor shall provide the corresponding Ring and Ball Softening point test results. Test and evaluate 2 samples per each batch of PG-58-28-R (3%SBS) asphalt cement used. The asphalt cement mixing plant shall provide the modified asphalt cements to the test lab.

9.6.3.2 SHRP Binder Tests: Provide the following test results for the PG-58-28-R (3%SBS) and determine the SHRP performance grade designation:

9.6.4 When the PG-58-28-R (3%SBS) asphalt cement does not meet the specifications, then it shall not be used on this project and shall be removed from JBER at the contractor’s expense.

Direct Tension Test DTT [latest]

Bending Beam Rheometer

BBR

Dynamic Shear Rheometer DSR

AASHTO TP3 AASHTO TP1 AASHTO TP5

--PAV-aged Binder @ - 18°C and -24°C

--PAV-aged Binder @ - 12°C and -18°C

Original Binder RTFO-aged Binder PAV-aged Binder *As required per

SHRP

2550- 9

9.6.5 The kinematic viscosity at 275 degrees F for PG-58-28-R (3%SBS) asphalt cement is up to 10X the kinematic viscosity at 275 F for PG-52-28 asphalt cement. The contractor may have to adjust the asphalt plant pumps in order to maintain the required flow (GPM) of asphalt cement.

TABLE II

Asphalt Cement Requirements

PG-58-28-R (3%SBS) MIX

2550- 10

TABLE III

Asphalt Cement Requirements

NO LONGER USED

10. ASPHALT JOB MIX FORMULA (JMF):

10.1 The contractor shall develop and submit a Job Mix Formula for the asphalt pavement for approval by the contracting officer. The minimum optimum asphalt cement content for PG 58-28R shall be 5.8% and for PG 52-28 shall be 5.6% (percent by weight of the total mix). The optimum asphalt cement content will be determined by the IQC based on the Marshall mix design test results and the test strip results. The government’s project engineer will make the final determination on the "optimum asphalt cement content".

10.2 Proportioning of Mixture: New asphalt pavement for payment shall not be manufactured until a Job-Mix Formula (JMF) provided by the Contractor has been conditionally approved by the Contracting Officer.

10.2.1 The JMF receives final approval by the Contracting Officer or the designated representative when the test section has been tested and evaluated as satisfactory by the Contracting Officer or

PROPERTY VISCOSITY GRADE

3% SBS

ASTM TEST

METHOD

1. Absolute Viscosity 140 F.; Poises, Min. N/A D 2171

2. Kinematic Viscosity 275 F.; Cs, Min.

D 2170

3. Penetration 77 F., 100g, 5 sec; dmm, Min.

D 5

4. Penetration 39.2 F., 200g, 60 sec; dmm, Min.

D 5

5. Ductility 77 F., 5cm/min; cm, Min.

D 113

6. Ductility 39.2 F., cm/min; cm, Min.

D 113

7. Flash Point Cleveland Open Cup, F., Min.

D 92

8. Solubility in Trichlorethylene Percent, Min.

99.0

D 2042

9. Pen-vis Number (PVN), Min. -0.1

10. Ring and Ball Softening Pt. Degrees F., Min.

125 D 36

11. Synthetic Rubber Weight, % Solids, Min. 3.0

Tests on Residue/Rolling Thin Film Oven RTFO (ASTM D 2872):

12. Kinematic Viscosity 275 F.; Cs, Min. 550 D 2171

13. Penetration 39.2 F., 200g, 60 sec; dmm, Min. 20 D 5

14. Ductility 39.2 F, 5 cm/min; cm, Min. 30 D 113

2550- 11 designated representative.

10.2.2 The JMF will indicate the percentage of course aggregate, fine aggregate, blend sand and mineral filler, the percentage of each size aggregate, the percentage of asphalt cement, the percentage of rubber modifier, the amount of anti-stripping agent, and the temperature of the completed mixture when discharged from the mixer.

10.3 The JMF will be allowed to vary within reasonable limits. Tolerances are given in Table IV for full payment for asphalt content, temperature, and aggregate grading, etc., 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 TESTING REQUIREMENTS / PERFORMANCE PAYMENTS. The tolerance limits of 25 F for temperature of mixing shall be strictly enforced. Bituminous mix that deviates more than 25 F from JMF shall be rejected.

TABLE IV

JOB-MIX TOLERANCES

10.3.1 For PG-58-28-R (3%SBS) rubber modified asphalt: The JMF shall indicate the percentage of rubber modifier in addition to the requirements shown in 10.1 and shall meet the Marshall Test criteria shown in Table V and Table VI for non-absorptive and absorptive aggregates, respectively.

10.3.2 Samples for Job Mix Formula: The following minimum quantities of material shall be collected by the Contractor under the supervision of the government’s project engineer / project inspector:

Fine aggregate (minus No. 4) 200 lbs Coarse Aggregate (plus No. 4) 200 lbs Mineral filler 50 lbs Asphalt cement 10 gallons

These samples shall be packaged and delivered at the expense of the Contractor to the approved testing laboratory or to the Independent Quality Controller.

Material Tolerance, Plus or Minus

Aggregate Passing 3/4” thru #4 Sieves Aggregate Passing #8 thru #80 Sieves Aggregate Passing #100 thru #200 Sieves Asphalt Cement

6.0 percent

4.0 percent

2.0 percent

0.3 percent

Temperature of Mixing Rubber Modifier

25 degrees F

0.25 percent

2550- 12

10.4 Test Properties of Bituminous Mixtures: Finished mixture shall meet requirements described below when tested in accordance with MIL-STD-620A. All samples will be compacted with 75 blows of specified hammer on each side of sample.

10.4.1 Requirements for stability, flow, and voids are shown in Table V and Table VI for non-absorptive and absorptive aggregates, respectively.

10.4.1.1 With Non-absorptive Aggregate: When water-absorption value of the entire blend of aggregate does not exceed 2.5 percent as determined in accordance with ASTM C 127 and C 128, aggregate is designated as non-absorptive. The apparent specific gravity will be used in computing air voids total mix, voids filled with bitumen, and the mixture shall meet requirements in Table V.

Typically, Table V is utilized for on-JBER aggregate.

TABLE V

Non-Absorptive Aggregate

MARSHALL TEST CRITERIA

10.4.1.2 With Absorptive Aggregate – Not Used

: When water-absorption value of the entire blend of aggregate exceeds 2.5 percent as determined in accordance with ASTM C 127 and C 128, aggregate is designated as absorptive. The bulk-impregnated specific gravity method contained in MIL-STD-620A, Method 105, shall be used in computing percentages of voids total mix and voids filled with bitumen; the mixture shall meet requirements in Table VI.

TABLE VI

Absorptive Aggregate-Not Used

Properties Units Airfield Criteria Road Criteria Stability, Min. Flow, Max. Air Voids Total Mix Voids Filled with Bitumen

LBS

1/100-inch

Percent Percent

2.5-5.0 75-85

2.5-5.0 75-85

Number of Compaction Blows

Each End 75 50

2550- 13

MARSHALL TEST CRITERIA

10.5 Standard JMF: The approval of the JMF by the Contracting Officer establishes the JMF as the standard for the entire paving job. Only one JMF is acceptable per type of asphalt cement and % of rubber modifier, unless accepted otherwise by the government’s project engineer. The JMF shall be the basis for the acceptability of work. The JMF shall not be adjusted by the contractor during construction unless approved in writing by the Contracting Officer. Any adjustments made shall not affect the contract prices.

Test Section

10.6 Test section:

Construct a test section at least 500' long, two spreader widths wide and of each thickness to be used in the project at the location marked by the government’s project engineer / project inspector. Mixture shall be placed, spread, and rolled with the same equipment to be used in the project.

10.6.1 Each test section shall be tested for the joint density, the mat density, the asphalt content, the aggregate gradation, the Marshall mix, grade control, and surface smoothness and evaluated as a lot with 4 sub-lots. The surface texture shall be evaluated for the presence of pavement surface defects, such as tearing, pulling, segregation, checking, cracking, etc., and corrections shall be made to the JMF or the paving equipment to eliminate these problems. The rolling pattern required to obtain the specified mat and joint densities shall be determined.

10.6.2 Additional test sections, as directed, shall be constructed and tested until conformance to specifications occurs. In no case shall the Contractor start full production of the asphalt pavement without acceptance of the Government’s project engineer / project inspector. The test section(s) shall be placed at no additional cost to the Government.

10.7 Adjustments

: When test results indicate that the pavement does not conform to specification requirements, necessary adjustments to plant operations, rolling procedures, placement procedures or fine aggregate/course aggregate/blend sand ratios, shall be made immediately.

11. MIXING AND TRANSPORTATION OF ASPHALT:

11.1 Preparation of Mineral Aggregates: Each aggregate stockpile shall be placed and maintained in such a manner to prevent segregation

Properties

. Rates of feed of aggregates shall be within tolerances

Units Airfield Criteria Road Criteria

Stability, Min.

Flow, Max.

Air Voids Total Mix Voids Filled with Bitumen Number of Compaction Blows

LBS

1/100-inch

Percent Percent

Each End

2.0-4.0 75-85

2.0-4.0 75-85

2550- 14 specified herein. Dry storage shall be provided for mineral filler.

11.2 Preparation of Bituminous Mixtures: 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.

Overheated and carbonized mixtures or mixtures that foam will be rejected.

11.2.1 For PG-52-28: Temperature of asphalt cement at time of mixing shall not exceed 300 degrees F. Temperature of aggregate and mineral filler in the mixer shall not exceed 325 F when bitumen is added. Temperature of mix at point of discharge from drum mixers shall not exceed 275 F.

11.2.2 For PG-58-28-R (3%SBS): Follow rubber modifier manufacturer's requirements. Submit to the Contracting Officer for approval. Typically for PG-58-28-R (3%SBS), temperature of asphalt cement at time of mixing shall not exceed 390 degrees F

11.3 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 g. If water content is determined on hot bin samples, the water content will be a weighted average based on composition of blend.

11.4 Storage of bituminous paving mixture shall conform to the applicable requirements of ASTM D 3515. However, in no case shall mixture be stored for more than four hours.

11.5 Transportation of Asphalt Mix: Transportation from the paving plant to the job 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 will be drained prior to loading.

During adverse weather, 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 asphalt will not be permitted.

12. ASPHALT MIX TEMPERATURE CONTROL:

12.1 The contractor shall provide to the government prior to starting paving, a new infrared heat gun suitable for measuring the asphalt temperature from the range of 0 deg. F to 550 deg. F with a sensitivity of ½ deg. F. The infrared heat gun shall remain the property of the Government.

12.2 Contractor shall use the infrared heat gun to determine the asphalt mix temperatures at the following times:

12.2.1 At the point of asphalt lay down, one temperature test for every 100 tons of hot mix asphalt that is dumped into or laid in front of the mechanical spreader. When asphalt placement is delayed longer than 20 minutes with asphalt trucks waiting, then every truckload that is delayed shall be measured for temperature.

12.2.2 At the point of asphalt compaction during the roller operation to ensure that the optimum rolling temperature is used, that the minimum initial rolling temperature is used, & that the min.

2550- 15 final rolling temperature is used.

12.2.3 At the point on the base course or existing pavement surface where the new asphalt mix is being placed.

13. PLACING OF ASPHALT MIX:

13.1 Base Course: The base course shall be accepted by the government’s project engineer / project inspector prior to the start of placing the asphalt. Preparation of the base course is specified in Section 2230 Crushed Aggregate Base Course for Airfields and Section 2235 Base Course for Roads.

13.2 Surface Preparation of Structures: Contact surfaces of previously constructed pavement, curbs, manholes, and similar structures shall be sprayed uniformly with a thin coat of tack coat.

13.3 Bituminous mixtures shall not be placed without ample time to complete spreading and rolling during daylight hours, unless satisfactory artificial lighting is provided as determined by the government’s project engineer / project inspector.

13.4 Weather Limitations

13.4.1 When the surface to be paved has free-standing water on the surface, do not start paving until the standing water is removed and the surface is dry.

: The following conditions for weather limitations shall be adhered to:

13.4.2 When the surface temperature of the surface to be paved is below 35 F, do not start paving.

13.4.3 When the existing surface to be paved has a wet or damp surface, do not start paving. Only start paving if the surface to be paved is dry with no standing water.

13.4.4 When it starts raining during the paving operation in sufficient quantity to cause the accumulation of standing water or flowing water on the surface to be paved, then the paving operation shall be stopped immediately. Any hot mix truckloads on the road at the time may be allowed to place the asphalt at the discretion of the government’s project engineer / project inspector.

13.4.5 When it starts a misty drizzle during the paving operation, then the paving operation may continue until there is standing water or flowing water on the surface to be paved, then the paving operation shall be stopped immediately. The continuing threat of more rain shall keep the paving operation from starting up again. Any hot mix truckloads on the road at that time may he allowed to place the asphalt at the discretion of the Government’s project engineer / project inspector.

13.4.6 When an intermittent drizzle occurs during the paving operation, then the paving operation may continue until there is standing water or running water on the surface to be paved, then the paving operation shall be stopped immediately. The continuing threat of more rain shall keep the paving operation from starting up again. Any hot mix truckloads on the road at that time may be allowed to place the asphalt at the discretion of the government’s project engineer / project inspector.

2550- 16

13.4.7 When it is snowing, do not pave unless permitted by the Government’s project engineer / project inspector.

13.5 Offsetting Joints in Intermediate and Wearing Courses: 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. Adjacent paving lanes in transverse joints shall be stair stepped so that there is a minimum 3-foot length difference between adjacent paving lanes.

13.6 General Requirements for Material Transfer Vehicle (MTV)

13.6.1 A material transfer vehicle or shuttle buggy 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 asphalt paver without making contact with the paver. 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.

13.7 General Requirements for Use of Asphalt Paver

13.7.1 Provide an asphalt paver that is self-propelled with an activated heated screed and automatic controls. The paver control system shall be automatically actuated by the use of a mobile string line, ski, or other approved grade follower. Placing of mixture shall be as nearly continuous as possible, and speed of placing shall be adjusted to permit proper rolling.

13.7.2 For PG-52-28 asphalt, mixtures having temperatures less than 250 F when dumped into the mechanical spreader will be rejected.

13.7.2.1 For PG-58-28-R (3%SBS) asphalt, mixtures having temperatures less than 310 F when dumped into the mechanical spreader will be rejected unless accepted otherwise by the Government’s project engineer / project inspector based on the manufacturer's instructions.

13.7.3 The mechanical spreader shall he adjusted and 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 asphalt surface will conform to the cross sections and finished grades indicated. 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 unless otherwise permitted by the government’s project engineer, each strip placed shall conform to requirements specified in paragraph TESTING

REQUIREMENTS / PERFORMANCE PAYMENTS.

13.7.4 When segregation occurs

in the mixture during placing, the spreading operations shall be suspended until cause is determined and corrections are made to the JMF or the paving equipment to eliminate the segregation.

13.7.5 Irregularities in alignment left by the mechanical spreader shall be corrected by trimming directly behind machine. Immediately after trimming, edges of the course shall be thoroughly

2550- 17 compacted by tamping laterally with a lute. Distortion during tamping will not be permitted.

13.8 Placing Strips Succeeding Initial Strip: In placing each succeeding strip after initial strip has been spread and compacted as specified below, the screed of the mechanical spreader shall overlap the previously placed strip 1 to 2 inches ( up to 4” when accepted otherwise by the government’s project engineer) and be sufficiently high so that compaction produces a smooth dense joint.

Mixture placed on edge of previously placed strip by the mechanical spreader shall be pushed back to edge of strip being placed by use of a lute. Excess material shall then be compacted into the joint.

Excess material shall not be spread more than 12 inches across the mat

13.9 Handwork 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 required grade, density and thickness. For PG-58-28-R (3%SBS), use 325 degrees F.

as minimum temperature for placement.

13.10 Existing Structures

: Existing manholes, valve covers and all other items, which penetrate the existing pavement surface or are covered up by an existing overlay, shall be raised or lowered so as to be recessed 1/4 inch below the newly finished asphalt surface. Providing extension rings, pavement rings or other approved accessories or lowering is a separate line item. When paving around manholes and valve covers make sure the new asphalt does not cover the manhole or valve covers to allow the removal of the lids, When paving around manholes and valve covers make sure the new asphalt around the lip of the structure is hand tamped in place to form a beveled shape.

14. COMPACTION OF ASPHALT MIX:

14.1 Sufficient rollers (size, type, and number) shall be provided by the Contractor to obtain the specified compaction. Rolling shall begin as soon after placing as mixture will bear roller without undue displacement. Delays in rolling freshly spread mixture will not be permitted. Preliminary tests of crown, grade and smoothness shall be made by the Contractor as soon as possible.

Deficiencies shall be corrected so that finished course will conform to requirements for grade and smoothness specified herein. Crown, grade, and smoothness shall be checked in each lot of completed pavement by the Quality Controller for compliance and shall be evaluated as specified in paragraph TESTING REQUIREMENTS / PERFORMANCE PAYMENTS. After meeting crown, grade, and smoothness requirements, rolling shall be continued until the required mat density and joint density are obtained. The density will be determined and evaluated as specified in paragraph

TESTING REQUIREMENTS / PERFORMANCE PAYMENTS.

Mat Density-Airfields

14.2 Mat Density: The mat density

shall be from a minimum of 97.5% to a maximum of 100.0% of the maximum laboratory density.

Joint Density-Airfields

14.3 Joint Density: The joint density shall be from a minimum of 96.5% to a maximum of 100.0% of the maximum laboratory density.

2550- 18

Mat Density-Roads

14.4 Mat Density: The mat density

shall be from a minimum of 96.5% to a maximum of 100.0% of the maximum laboratory density.

Joint Density-Roads

14.5 Joint Density: The joint density

shall be from a minimum of 95.5% to a maximum of 100.0% of the maximum laboratory density.

14.6 Mat and Joint Temperature

: Contractor shall provide an infrared heat gun to measure the temperature of the mat and the joints during the roller operation. The Contractor shall determine the optimum temperature and working temperatures for starting the breakdown roll, intermediate rolling, and finish rolling. State this information on the Quality Control reports.

14.7 Correcting Deficient Areas

: Mixtures that become contaminated or are defective shall be removed to the full thickness of course. Edges of the area to be removed shall be saw cut so that sides are perpendicular and parallel to direction of traffic and so that edges are vertical. Edges shall be sprayed with tack coat. Fresh paving mixture shall be placed in the excavated areas in sufficient quantity so that finished surface will conform to grade and smoothness requirements.

Paving mixture shall be compacted to the density specified herein. Skin patching of an area that has been rolled will not be permitted.

14.8 Places Inaccessible

: Places inaccessible to rollers shall be thoroughly compacted with hot hand tampers.

14.9 Roller Marks

: No longitudinal or transverse indentations shall remain in the wearing surface of the mix after the final rolling has been completed unless accepted otherwise by the government’s project engineer. At drainage swales in the new asphalt roller marks will be allowed.

15. JOINTS:

15.1 Contractor shall provide hot joints between new pavements where practical. Provide new joints IAW "HMA Paving Handbook", Section 5, "Joint Construction" or as accepted by the project manager. Avoid excessive raking and broadcasting

15.2 Joints between the existing and new pavements or between successive days' work, or joints that have become cold (less than 175 F, unless accepted otherwise by the government’s project engineer), shall be saw cut or wheel cut back 3 to 6 inches from the asphalt pavement edge in a straight line to ensure continuous bond between the cold and the hot sections of asphalt. Tonnage for removed joints is not deducted. Removal of cold joints is a separate line item.

15.3 All joints shall approximate the texture and smoothness of the mat or as accepted by the project manager.

15.4 Contact surfaces of previously constructed pavements covered by dust, sand, gravel or other

2550- 19 objectionable material shall be cleaned by brushing, sweeping or shall be wheel cut back, as directed. The vertical surface against which new material is placed shall be sprayed with a thin, uniform tack coat. Material shall be applied far enough in advance of placement of fresh mixture to ensure adequate curing. Care shall be taken to prevent damage or contamination of the sprayed tack coat surface.

15.5 Transverse Joints

: The roller shall pass over the unprotected end of a strip of freshly placed material only when placing is discontinued or delivery of 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 saw cut or wheel cut back 12 inches to expose an even vertical surface for full thickness of course. In continuing placement of 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 required density and smoothness specified herein. Stagger transverse joints in adjacent paving lanes in same lift by 5 feet.

15.6 Longitudinal Joints: Edges of the previously placed asphalt 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. Overlap of the new mat on the previously placed mat shall be 1" to 2"

(Fig 3-80 of FAA HMA Paving Handbook).

16. PAVEMENT SURFACE DEFECTS:

16.1 Contractor shall repair all areas on the joints and the mats where the surface texture of the newly placed asphalt wearing course has any of the following defects:

16.1.1 A rough and jagged appearance similar to surface erosion.

16.1.2 A pitted surface from lack of asphalt surface fines or asphalt binder having the appearance of a raveled surface.

16.1.3 Any material racked back into the mat. (Fig 3-83 of FAA HMA Handbook).

16.1.4 Excessive material racked back into the joint. (Fig 3-83)

16.1.5 Non-uniform mat or joint texture (Fig 3-102).

16.1.6 A segregated surface, which is defined as the separation of the coarse material from the fine material or rock pockets.

16.2 In addition, the Contractor shall also repair all areas on the joints and the mats with the following surface defect problems as defined in the FAA HMA Paving Handbook:

16.2.1 Surface waves, tearing, checking, shoving, bleeding, segregation, roller marks, joint problems, and screed marks.

16.3 Contractor shall provide remedial action immediately to resolve the above pavement surface defects. The Contracting Officer or the IQC has the option of stopping the paving operation until

2550- 20 the contractor rectifies the paving problems which cause the pavement surface defects.

16.4 Contractor shall repair the surface defect areas with Thortex Chemi-Tech E.P., Hallemite Black Amazite, or approved equal, or with the specified asphalt cement blended with fines rolled into the pavement surface as required by the Government’s project engineer / project inspector.

The defect areas shall be marked in the field by the CQC or IQC person. Repairs will be performed by the contractor at no additional cost to the Government.

16.5 Contractor shall complete all pavement surface defect repairs for work performed on each delivery order prior to submitting that delivery order for payment.

17. SURVEY REQUIREMENTS:

17.1 The Contractor shall provide all the field surveying

with appropriate notebook required to:

17.1.1 Properly place the new asphalt overlay

which includes:

17.1.1.1 Determine the existing

finish grade elevations of the pavement to be cold-planed; determine the existing finish grade elevations of the adjacent pavement that the new asphalt overlay will butt up against.

17.1.1.2 Determine the proposed

new finish grade elevations of the new asphalt overlay to make sure it has proper drainage.

17.1.1.3 Determine the actual

new finish grade elevations of the new asphalt overlay.

17.1.1.4 Provide elevations at 100' stationing (less spacing may be required in some areas) along the centerline and at every 25' interval off the centerline. Where new pavement ties into existing pavement provide elevations at 10’ stationing in areas that are within 50’ of the existing pavement.

17.1.1.5 Submit as a shop drawing to the contracting officer a copy of the existing elevations and proposed new elevations for evaluation prior to overlaying. Submit as a shop drawing to the contracting officer a copy of the actual new elevations.

17.1.2 Properly place the new asphalt pavement

17.1.2.1 Determine the

and new base course, which includes:

existing finish grade elevations, centerline profiles, vertical curves, and horizontal curves of the asphalt pavement to be removed and replaced; determining the existing finish grade elevations of the adjacent pavement (such as the hardstands and shoulders) that the new asphalt pavement will butt up against;

17.1.2.2 Determine the proposed

new finish grade elevations, new centerline profiles, new vertical curves, and new horizontal curves of the new asphalt pavement to make sure it has proper drainage;

17.1.2.3 Determine the actual new finish grade elevations, new centerline profiles, new vertical curves, and new horizontal curves of the new asphalt pavement; and setting the blue tops for the finish grade elevation of the new base course.

2550- 21

17.1.2.4 Provide elevations at 100' stationing (less spacing may be required in some areas) along the centerline and at every 25' interval off the centerline. Where new pavement ties into existing pavement provide elevations at 10’ stationing in areas that are within 50’ of the existing pavement.

17.1.2.5 Submit as a shop drawing to the contracting officer a copy of the existing elevations, profiles, and curves, and proposed new elevations, profiles, and curves for evaluation prior to paving. Submit as a shop drawing to the contracting officer a copy of the actual new elevations, profiles and curves.

17.1.3 Portions of each road contain several horizontal curves which shall be maintained by the contractor during construction. The existing centerlines of all replacement work shall be maintained by the contractor.

17.1.4 The paving line items that do not include surveying as a separate line item are indicated in specifications section 1020-1.7.1 “Surveying” Requirements.

17.2 Grade Control

: Lines and grades shown on contract drawings shall be established and maintained by means of line and grade stakes placed at site of work by the Contractor. Elevations and locations of permanent bench marks to be used by the Contractor for controlling airfield pavement operations at site of work will be provided by the Government. Finished pavement gradelines and elevations shown on the drawings shall be established and controlled at site of work by the Contractor in accordance with permanent bench mark elevations information furnished by the government’s project engineer / project inspector.

17.3 All overlay grade control shall be with a minimum 40-foot long ski attached to the paving machine or by means of lines & grade stakes as required to meet the grade criteria specified in paragraph: TESTING REQUIREMENTS / PERFORMANCE PAYMENTS.

18. REQUIREMENTS / PERFORMANCE PAYMENTS:

Lot Size

18.1 Lot Size: A lot shall be that unit of construction that will be evaluated for compliance with specification requirements. A lot shall be equal to 1,000 tons per lot of asphalt production unless approved otherwise by the government’s project engineer.

Sub-lot Size

18.2 Sub-lot Size: A sub-lot shall be that unit of construction that will be evaluated for compliance with specification requirements. A sub-lot shall be equal to 250 tons per sub-lot of asphalt production. A lot is subdivided into 4 equal sub-lots of 250 tons each, unless approved otherwise by the government’s project engineer.

Lowest Percent Payment

18.3 When a lot of material fails to meet the specification requirement, that lot shall be removed and replaced or accepted at a reduced price for only those items shown in tables. The lowest

2550- 22 percent payment for any pavement characteristic (i.e.