198 SECTION 410 ASPHALT BASE AND WEARING COURSES, PERCENT WITH LIMITS (PWL)
410.1 -DESCRIPTION : 410.1.1 -General: The Contractor shall note that this Section is to be used for Square Yard Paving operations; however, the proposal and / or plans may contain 401 and 402 items to be paid and measured by the Ton (TN). In instances where those items occur, they shall be constructed and measured in accordance with the applicable sections of the West Virginia Division of Highways Standard Specifications Roads and Bridges, current edition, and the Supplemental Specifications current when the contract is let. Additionally, the following Materials Procedures (MP’s) for Square Yard Paving can be found on the Materials Control, Soils and Testing (MCS&T) Division website: https://transportation.wv.gov/highways/mcst/Pages/WVDOH -Materials -Procedures.aspx .
410.1.2 -PWL Paving Description: This work shall consist of constructing one or more courses of asphalt, mixed mechanically in a plant, composed of aggregate and asphalt material designed in accordance with either the Marshall or Superpave Design System as specified in the contract documents, on a prepared foundation in accordance with these specifications and in reasonably close conformity with the lines, grades, weights or thicknesses, and cross sections shown on the Plans or established by the Engineer. The unit of measurement for asphalt will be by the ton, square yard, or cubic yard. The work will be accepted in accordance with these Specifications and the applicable requirements of Sections 105, 106, and 109.
199 410.2 -MATERIALS : The materials shall conform to the following requirements:
MATERIAL SUBSECTION Coarse Aggregate 703.1 thru 703.3 Note 1 & Note 2 (See MP 401.02.28 for exceptions and additions required for Superpave Items.) Fine Aggregate 702.3 (See MP 401.02.28 for additions required for Superpave Items) Mineral Filler 702.4 Performance Graded Binders 705.5 Note 1 The total shale, coal and other lightweight deleterious material and friable particles shall not exceed 3%. Note 2 When slag is specified in the contract, the coarse aggregate shall be slag which meets the requirements of 703.3, except as amended in this subsection.
410.2.1 -Performance Graded Binder Grade: The standard grade for Performance Graded (PG) binders shall be PG 64S -22, any deviation will be noted in the contract documents. PG 64H -22 shall be used on projects specified with over 20 million ESALs over the de sign life. PG 64S -22 binder may be used in asphalt placed below the top two lifts in any pavement section, scratch course and patching -and-leveling are not identified as lifts.
CONSTRUCTION METHODS
410.3 -GENERAL : Construction methods to be used in performing the work shall be submitted to the Engineer for review prior to the start of work. This review may require modification of the proposed methods to provide the desired end product. All equipment, tools, machinery, and plant shall be maintained in a satisfactory working condition.
410.4 -COMPOSITION OF MIXTURES : 410.4.1-General : The aggregate for use in the designated mixture shall consist of a mixture of aggregate (coarse, fine, reclaimed asphalt pavement (RAP) if desired, or mixture thereof) and mineral filler if required. It shall be the responsibility of the Con tractor to determine the percentage of RAP to be used in the mix. The amount and grade of virgin PG Binder to be used in the RAP designs shall be determined in accordance with Materials Procedure (MP) 401.02.24 and MP 401.02.28.
410.4.2 -Job Mix Formula : Job Mix Formula (JMF) is the specification for a single mix produced at a single plant. This mix may be specific to a single project or be used on multiple projects if the basic design criteria (design compaction level and PG Binder grade) are the same. The Contractor shall submit a proposed JMF for each combination of aggregate and asphalt material for each asphalt mixture to be produced. Depending on the design type, the JMF gradations shall be within the tolerances set forth in either Table 410.4.2A or Table 410.4.2B. Marshall mix designs shall be developed in accordance with MP 401.02.22. Superpave mix designs shall be developed in accordance with MP 401.02.28.
200 Each proposed JMF must be documented on the Division Form T400 or T400SP and the entire JMF package shall be forwarded for review to the District Materials Engineer/Supervisor. After the District reviews the T400/T400SP and JMF package shall then be transmitted to the Materials Control, Soils and Testing Division for final review. If t he JMF requires revision, it will be returned to the designer through the District. The T400/T400SP Form shall contain the following information:
ii. The aggregate blend percentages and the percentage for each sieve fraction of aggregate considered the desirable target for that fraction. iii. The percentage of virgin asphalt binder to be blended with RAP and the total asphalt binder representing the optimum asphalt content for the JMF submitted, which is to be considered the desirable target percentage. iv. The temperature of the completed mixture at the plant which shall be within ± 25°F of the median mix temperature established by the temperature -viscosity chart or as recommended by the asphalt supp lier.
Marshall mixes the ratio is defined as the percentage of aggregate passing the No. 200 (75 µm) sieve, divided by the percentage of asphalt content calculated at the percentage optimum asphalt content of the design. For Superpave mixes the ratio is defined as the percentage of aggregate passing the 75 µm (No. 200) sieve, divided by the percentage of effective asphalt content calculated at the percentage optimum as phalt content of the design.
TABLE 410.4.2A Design Aggregate Gradation Requirements for Marshall Mix Designs Type of Mix Base -I Base -II (Patch & Level) Wearing IV Wearing -I (Scratch -I) Wearing -III (Scratch -III) Sieve Size Nominal Maximum Size 1 ½ in (37.5 mm) ¾ in (19 mm) ¾ in (19 mm) 3/8 in (9.5 mm) No. 4 (4.75 mm) 2 in (50 mm) 100 – – – – 1 ½ in (37.5 mm) 90-100 – – – – 1 in (25 mm) 90 max 100 100 – – ¾ in (19 mm) – 90-100 90-100 – – ½ in (12.5 mm) – 90 max 90 max 100 – 3/8 in (9.5 mm) – – – 85-100 100 No. 4 (4.75 mm) – – 47 min 80 max 90-100 No. 8 (2.36 mm) 15-36 20-50 20-50 30-55 90 max No. 16 (1.18 mm) – – – – 40-65 No. 30 (600 µm) – – – – – No. 50 (300 µm) – – – – – No. 200 (75 µm) 1-6 2-8 2-8 2-9 3-11
201 TABLE 410.4.2B Design Aggregate Gradation Requirements for Superpave Mix Designs Type of Mix 37.5 25 19 Note 1 (Patch & Level) 12.5 9.5
(Scratch) Standard Sieve Size Nominal Maximum Size 37.5 mm (1 ½ inch) 25 mm (1 inch) 19 mm (3/4 inch) 12.5 mm (1/2 inch) 9.5 mm (3/8 inch) 4.75 (No. 4) 50 mm (2”) 100 – – – – – 37.5 mm (1½”) 90-100 100 – – – – 25 mm (1”) 90 max 90-100 100 – – – 19 mm (3/4”) – 90 max 90-100 100 – – 12.5 mm (1/2”) – – 90 max 90-100 100 100 9.5 mm (3/8”) – – – 90 max 90-100 95-100 4.75 mm (No.4) – – – – 90 max 90-100 2.36 mm (No.8) 15-41 19-45 23- 49 28-58 32-67 1.18 mm (No.16) – – – – – 30-60 600 µm (No.30) – – – – – – 300 µm (No. 50) – – – – – – 75 µm (No.200) 0-6 1-7 2-8 2-10 2-10 6-12
Note 1 When a 19 mm mix is specified for use as a heavy duty surface mix, it shall be designed as a fine graded mix with the additional requirement of a minimum of 47% passing the 4.75 mm (No.4) screen.
If it becomes necessary to change aggregate sources, a new mix design shall be developed and submitted for approval. When using neat (unmodified) PG Binders, the binder grade must always remain the same for each design, however the binder source may be changed without requiring a new mix design given that the replacem ent binder is provided from an approved source. If a source change results in the use of an additive enhanced modified binder of the same grade, a new mix design will be required. If a modified binder source is changed or if the modification process is c hanged, a new mix design shall be developed and submitted for approval. A source change to a new location with the original manufacturer/supplier and the original modification process will not require a new mix design. At no time shall different grades o f PG Binders be mixed together in the same storage tank. When it is necessary to switch to a new binder grade the tank shall be drawn down as far as possible, normally to the top of heating coils, before refilling with the new binder. The new binder shall be circulated thoroughly before restarting production.
410.4.2.1 -Warm Mix Asphalt: When the Contractor chooses to use an approved asphalt design to be produced as warm -mix asphalt (WMA) using the water injection system, the temperature of the completed mixture at the plant may be lowered to an
202 established range that has previously been determined through trial production. The allowable temperature range specified on the approved T400 mix design form shall be adjusted accordingly when producing WMA. In ad dition, all references to the minimum compaction temperatures in Sections 410.10.3 and 410.10.4 of this specification, may be waived if it can be established that additional density can be obtained at lower temperatures without damaging the pavement. All t esting requirements established for Hot Mix Asphalt mix designs and quality assurance/quality control testing shall also apply to WMA.
410.5 -TESTING : 410.5.1 -Test Methods: MP 700.00.06 Aggregate Sampling Procedures AASHTO T168 Sampling Hot -Mix Asphalt AASHTO T11 Materials Finer than No. 200 (75 µm) Sieve in Mineral Aggregates by Washing AASHTO T27 Sieve Analysis of Fine and Coarse Aggregates AASHTO T30 Mechanical Analysis of Extracted Aggregate AASHTO T164 Quantitative Extraction of Bitumen from Bituminous Paving Mixtures AASHTO T308 Asphalt Content of HMA by the Ignition Method (Test Method A) AASHTO T245 Resistance to Plastic Flow of Bituminous Mixtures Using Marshall Apparatus ASTM D5581 Resistance to Plastic Flow of Bituminous Mixtures Using Marshall Apparatus (For Base -I Marshall designs only) AASHTO T166 Bulk Specific Gravity of Compacted Bituminous Mixtures AASHTO T209 Maximum Specific Gravity of Bituminous Paving Mixtures AASHTO T312 Determining the Density of HMA Specimens by Means of the Superpave Gyratory Compactor AASHTO T331 Bulk Specific Gravity and Density of Compacted HMA Using Automatic Vacuum Sealing Method ASTM D7227 Rapid Drying of Compacted Asphalt Specimens Using Vacuum Drying Apparatus MP 401.02.31 Quality Control and Acceptance of Asphaltic Mixtures MP 401.07.20 Sampling Loose Asphaltic Mixtures in the Field MP 401.07.21 Sampling Compacted Asphaltic Mixtures in the Field MP 401.07.22 Measuring Thickness of Asphalt Pavement using Drilled Cores MP 401.07.23 Measuring Bond Strength of Cored Specimens MP 401.07.24 Measuring Asphaltic Pavement Macrotexture MP 401.07.25 Evaluation of Pavement with Substandard Properties MP 401.13.50 Determination of Percent Within Limits
410.6 -CONTRACTORS QUALITY CONTROL : 410.6.1 -Quality Control Testing : Quality control of the asphalt pavement is the responsibility of the Contractor. The Contractor shall maintain equipment and qualified personnel including at least one certified Asphalt Plant Technician at each plant. The technician shall be in charge of all plant quality control activities such as mix proportioning and adjustment and all sampling and testing activities necessary to maintain the various properties of asphalt within the limits of the specification.
203 The Contractor shall maintain necessary equipment and qualified personnel including at least one certified Asphalt Field and Compaction Technician at each project during paving operations. Additionally, a certified Asphalt Field and Compaction Technician with certification to perform nuclear density testing of asphalt pavements shall perform all testing necessary to assure compaction of the asphalt meets spe cification requirements.
410.6.2 -Job Mix Formula Field Verification : For each JMF, a mix design field verification shall be conducted during the first days of plant production. For Marshall and Superpave designs, the verification shall be in accordance with the guidelines established in MP 401.02.31. The field verification is for the purpose of demonstrating that the JMF can be produced within the specified tolerances set forth in the MP 401.02.31. If the mix cannot be produce within these requirements, a new mix design will be required.
410.6.3 -Quality Control Testi ng Requirements: After the JMF design field verification has been successfully completed, sampling frequency and test requirements for quality control shall be as set forth in MP 401.02.31 for Marshall and Superpave designs. If the Division determines th at a mix cannot be consistently produced within the tolerance limits of the specified design properties, approval of the mix may be revoked and the contractor will be required to provide a new mix design.
410.7 -ACCEPTANCE TESTING : 410.7.1 -Acceptance Testing of Asphalt: For Interstates and divided National Highway System (NHS) Highways, material from the paving of the traveled lanes and shoulders will be accepted in the field on a lot -by-lot basis. Lots will be established cumulatively and will be specific for each JMF. Each lot consists of five equal sublots (n=5). A completed sublot will have cores obtained for Pavement Density, and Bond Strength and a L oose Mixture sample for gradation and asphalt content. Samples for mat density and bond strength shall also be used to measure lift thickness prior to any preparation for density or bond strength. All field samples shall be obtained from locations determined as per MP 401.07.20 and MP 401.07.21. A normal lot size is 2,500 tons with five, 500 -ton sublots (n=5), unless operational conditions or project size dictate otherwise. If operational conditions or project size dictate, readjustment of the lot will be made as specified in Table 410.7.1. When lots are adjusted, all sublots shall be of equal size. Breakdowns or stoppages of short periods due to such causes as weather or equipment failure will not be considered as reason to adjust the lot size. The original lot will be continued when work resumes after stoppages of less than 5 days. If a lot is terminated due to a stoppage of 5 days or more, adjust the lot size and number of sublots as specified in Table 410.7.1. For two lane and non -divided NHS Routes, refer to Section 410.13.7.1.