4-46 Sectio N 407 – Bonde D Wearin G Course
407.0 1 DESCRIPTION . This work shall consist of applying a bonded wearing course pavement. This work shall be performed in conformance with the lines, grades, thicknesses, and typical cross -sections shown on the Plans or established by the Engineer. 407.0 2 MATERIALS . Materials shall meet the requirements of the following subsections: Performance -Graded Asphalt Binder ................................ ................................ ......... 702.01 Polymer -Modified Emulsified Asphalt ................................ ................................ ......702.02(c) Anti-Strip Additives ................................ ................................ ................................ ...702.04 Aggregate for Bituminous Concrete Mixtures ................................ ........................... 704.10 General Bituminous Concrete Mixture Design Requirements ................................ ..716.02(a) Bonded Wearing Course Mixtures ................................ ................................ ............. 716.02(c) Bituminous Mixing Plant and Laboratory ................................ ................................ .716.03 Prepari ng and Mixing Bituminous Concrete Mixtures ................................ .............. 716.04 407.0 3 AGENC Y MATERIA L EVALUATION . Bonded wearing course will be sampled and tested on a statistically random basis for both quality control and acceptance in accordance with the specified requirements, and the material quality will be evaluated based on the results of these tests. The act ual mixture produced shall not vary from the job mix formula target values by more than production tolerances specified in Table 407.03A . For the purposes of verification sampling, the tolerances given in Table 407.03A will be considered the specification limits for an individual sample. Continued production outside these ranges will be grounds to halt production and rescind the mix design. TABLE 407.03A – MIXTURE PRODUCTION TOLERANCES Material Property Lower Mixture Tolerance Upper Mixture Tolerance Aggregate, percent passing the 3/8 inch (9.50 mm) or larger sieves (dry sieve) JMF – 4% JMF + 4% Aggregate, percent passing the No. 4 (4.75 mm) sieve through the No. 16 (1.18 mm) sieves (dry sieve) JMF – 3% JMF + 3% Aggregate, percent passing the No. 30 (0.600 mm) sieve through the No. 100 (0.150 mm) sieves (dry sieve) JMF – 2% JMF + 2% Fines, percent passing the No. 200 (0.075 mm) sieve (dry sieve) JMF – 1.5% JMF + 1.5% Mixture temperature 1 JMF – 20°F JMF + 20°F Asphalt binder content JMF – 0.4% JMF + 0.4% 1 The m ixture temperatures shall not exceed 355°F.
4-47 Material may be sampled at either the production facility or on the project site and may be tested at either
the production facility ’s qualified lab, or at the Agency’s Materials Testing and Certification Section Central Laboratory .
a.Lots and Sublots . The entire quantity of a single mix design of bonded wearing course will constitute a lot. Sublots for quality control shall be a max imum of 500 tons. For acceptance, a sublot will be 1,000 tons. Samples will be taken once per sublot. Agency sublot size may be adjusted by the Engineer to sample more frequently for material quality issues.
b.Evaluation Method . The percent within limit s (PWL) method will be used to determine the quality of the material produced based on the specification limits listed in Table 407.03A . This PWL will be used to determine a pay factor for the material but will not be used to accept or reject the material. Detailed documentation on the PWL method is available in the Agency’s Bituminous Concrete Policy Manual . If mix design JMF changes cause there to be multiple lots, the quantity weight average PWL will be used to determine the project pay factor.
c.Quality Characteristics . Type A bonded wearing course will be evaluated using the No. 4 (4.75 mm), No. 8 (2.36 mm), No. 50 (0.300 mm), and No. 200 (0.075 mm) sieves, and asphalt binder content. Type B and Type C bonded wearing course will be evaluate d using the 3/8 inch (9.50 mm), No. 4 (4.75 mm), No. 8 (2.36 mm), No. 50 (0.300 mm), and No. 200 (0.075 mm) sieves, and asphalt binder content.
d.Pay Factor . A composite weighted pay factor combining the PWL of each quality characteristic will be calcu lated to account for the overall quality of the lot. If mix design JMF changes cause there to be multiple lots, a quantity weight average PWL will be used to determine the project pay factor. 407.0 4 CONTRACTO R QUALIT Y CONTROL .
a.Control of Mixture . The Contractor shall be responsible for maintaining control of the mix production process. The mix production methods and technologies shall generally be at the Contractor’s discretion, but will be limited to proven, Agency and industry accepted p ractice. Upon approval of the Engineer and at no additional cost to the Agency, the Contractor may use innovative equipment or techniques not included in the specifications to produce or monitor the production or placement of the mixture.
4-48 The plant sh all be operated so that no intentional deviations are made from the approved job mix
formula. T he continual production of non -conforming work at a reduced price, in lieu of making adjustments to bring work into conformance, will not be allowed. The Contractor shall provide process control adequate to produce work of acceptable quality. At a minimum, the Contractor shall perform sampling and testing at the frequencies specified in Table 407.04A as applicable for the mixture type, and shall calculate the cumulative weighted PWL using the equation specified in Subsection 407.06(a)(1) after each quality control sublot . The Engineer will not sample or test for process control or assist in controlling t he Contractor’s production operations. TABLE 407.04A – QUALITY CONTROL TESTING AND SAMPLING CRITERIA Parameter Test Method Minimum Frequency (Select the Least Frequent) Mixture gradation AASHTO T 30, AASHTO T 308 1 per 500 tons Mixture temperature Verified thermometer 1 per 250 tons at plant (truck) Asphalt binder content AASHTO T 308 1 per 500 tons Cold feed gradation AASHTO T 27 1 per day Cold feed percentage fractured face 1 AASHTO T 335 1st day of paving, 1 per week or 5,000 tons Cold feed flat and elongated particles 2 ASTM D4791 1 per month Fine and coarse aggregate moisture content 3 AASHTO T 255 2 per day Stripping 4 ASTM D3625 1 per week 1 Fractured faces for crushed gravel sources only. 2 Flat and elongated percentage for all material retained on or above the No. 4 (4.75 mm) sieve. 3 For drum -mix and continuous mixing plants only. 4 Stripping testing for stripping prone aggregates only. Testing will be witnessed by Agency staff. Control over production shall follow the control limits established for the mix design for quality control samples. A single result outside the control limit will necessitate the Contractor take action to return production to in control. Production shall be suspended if two out of three values in row exceed the control limits , or if the quality control cumulative weighted PWL falls below 60%.
4-49 After suspens ion, a passing quality control test from a trial drop shall be used to show the mix has
been returned to in control, and production may resume. Following a PWL suspension, three tests will be conducted before reevaluating for suspension of production based on the total project PWL, however, production shall be suspended if two out of those three tests exceed the control limits. Failure or inaction by the Contractor to maintain control over the mix production will result in mix design suspension.
b.Contractor Quality Control Plan . The Contractor shall provide, maintain, and operate in accordance with a quality control plan for the plant and the field, hereafter referred to as the plant QC plan and field QC plan, to ensure the production of material t hat meets the Contract requirements. The Contractor shall develop and submit program -wide QC plans annually in advance of the paving season, to document the QC practices, personnel, facilities, and equipment to be used by the Contractor. Additionally, the Contractor shall submit project -specific supplements to both the plant and field QC plans to provide specific details applicable to each project. No paving shall occur until both QC plans and their supplements have been approved for the project. Project su pplements to the QC plans shall be submitted at least 10 working days before the start of paving on the project.
1.Plant QC Plan . Bituminous concrete mixture plants shall submit a program wide plant QC plan to cover all mix production, as detailed in the Agency’s Bituminous Concrete Policy Manual . A project -specific supplement shall be submitted to apply the plant QC plan to the pr oject and provide specific details, including, but not limited to, the mix designs to be used, the use of silos, changes in personnel, and other project specific requirements.
2.Field QC Plan . The Contractor shall submit a comprehensive field QC plan to cover paving practices in the field, as detailed in the Agency’s Bituminous Concrete Policy Manual . A project -specific supplement shall be submitted to apply the field QC plan to the project and provide specific details, including, but not limited to, pa ving personnel and equipment identification, QC personnel, mixing, loading, transportation, intended paving sequence, emulsion application procedure and rate, and other project -specific requirements.
3.Non-Compliance with the QC Plans . The Contractor shall comply with the approved QC plans and shall take all other steps necessary to ensure a high -quality product. Failure of the Contractor to comply with the approved QC plans may result in the Agency ordering the Contract or to cease pro duction or paving, revoking approval of the QC plan, or taking other actions as necessary.
4-50 407.0 5 Constructio N Requirements
a.Equipment .
1.Hauling Equipment . To prevent the mixture from adhering to the beds, trucks used for hauling bituminous mixture shall have tight, clean, and smooth metal beds which have been thinly coated with a bond release agent. Petroleum -based products will not be permitted. Each truck shall have a cover of canvas or other suitable material of sufficient size to extend over all sides of the haul vehicle to properly protect the mix from the weather. Covers shall be securely fastened to ensure placement of the material at the specified temperature. The trucks used for hauling bituminous mixture shall be compati ble with the equipment used for placing the bituminous mixture. Trucks shall not to be cleaned or emptied on surfaces to be paved.
2.Placing Equipment . The Contractor shall use a self -priming paver as approved by the Engineer. The self -priming paver s hall be capable of spraying the polymer -modified emulsified asphalt, applying the bonded wearing course, and smoothing the surface of the mat in one pass at a rate of at least 35 feet per minute. The paver shall provide means for obtaining a sample of th e emulsified asphalt, and as needed, the lines shall be flushed prior to sampling to ensure there are no residual cleaning solvents in the sample. The self -priming paver shall be equipped with a receiving hopper, feed conveyor, emulsion storage tank, metered high -pressure emulsion spray bar calibrated per the manufacturer’s recommendations, and a variable width, heated, ironing -type screed. The screed shall have the ability to be crowned at the center both positively and negatively and have verti cally adjustable extensions to accommodate the desired pavement profile.
3.Compaction Equipment . The Contractor shall use steel -wheeled double -drum rollers weighing at least 10 tons, equipped with functioning water systems and scrapers to prevent materia l from adhering to the roller drums.
b.Weather And Seasonal Limitations . Bonded wearing course shall not be placed unless both the ambient air temperature and the temperature of the existing surface at the paving site, in the shade and away from artifici al heat, are greater than 50°F. Bonded wearing course shall not be placed on a wet or frozen surface, or when weather or other conditions would prevent the proper handling, finishing, or compacting of the material, unless otherwise approved by the Engineer . Placement of bonded wearing course shall not occur between September 16th and May 1 5th, inclusive.
4-51 (c) Preparation of Surfaces . The existing bituminous concrete pavement surface shall be prepared as
shown on the Plans and as directed by the Engineer prior to applying the polymer -modified emulsified asphalt. This shall include patching, pothole repairs, raveling repairs, crack seali ng, and other repairs directed by the Engineer and performed in accordance with Subsection 406.08 and Subsection 417.05(c) . Surface preparation material shall be a bituminous material or mixture approved by the Engineer or as otherwise specified. The sur face of the area to be overlaid shall be thoroughly cleaned and free of dirt, oil, debris, other foreign materials, and standing water. All utility structures within the area to be paved shall be covered with material approved by the Engineer and referenc ed for location and adjustment, if necessary, after paving.
d.Placing and Finishing .
1.Polymer -Modified Emulsified Asphalt . Polymer -modified emulsified asphalt shall be applied in accordance with Subsection 404.06(c) . Production of bonded wearing cours e shall be suspended if the actual application rate of the polymer -modified emulsified asphalt is outside of the required application rate range specified in Subsection 404.06(c) .
2.Bonded Wearing Course . Equipment shall not come in contact with the polymer -modified emulsified asphalt before the bonded wearing course is applied. Immediately after the polymer -modified emulsified asphalt has been applied, the bonded wearing course shall be placed across the full width of the emulsion within the temperature range specified on the approved mix design. A load ticket shall accompany each vehicle supplying bonded wearing course. One legible copy of the load ticket shall be made available to the Engineer prior to placement of the mixture.
3.Finishing . Finishing shall begin immediately after application of the bonded wearing course using a minimum of two static passes. Vibratory equipment shall not be used unless otherwise approved by the Engineer. The rollers shall not stop on the freshly placed bonded wearing c ourse. The Contractor shall use an adequate number of rollers to complete finishing before the pavement temperature falls below 185°F. Once finished, traffic will not be permitted on placed material until the material has cooled to 140°F, unless otherwise authorized by the Engineer.
4-52 407.0 6 MIXTUR E PROPERTIE S PAY ADJUSTMENT . The Mixture Properties Pay Adjustment will
be based on the Mixture Properties Pay Factor calculated using the equations specified below.
a.Mixture Properties Pay Factor Determinatio n. For bonded wearing course, the Mixture Properties Pay Factor will be calculated based on the weighted PWL for gradation and asphalt binder content.
1.Weighted PWL . The weighted PWL for gradation and asphalt binder content will be calculated using the equation below. For Type A 𝑃𝑊𝐿 𝑊=0.20( 𝑃𝑊𝐿 #4+𝑃𝑊𝐿 #8+𝑃𝑊𝐿 #50+𝑃𝑊𝐿 #200 +𝑃𝑊𝐿 𝐴) For Type B and Type C 𝑃𝑊𝐿 𝑊=0.15( 𝑃𝑊𝐿 3/8+𝑃𝑊𝐿 #4+𝑃𝑊𝐿 #8+𝑃𝑊𝐿 #50)+0.20( 𝑃𝑊𝐿 #200 +𝑃𝑊𝐿 𝐴) where: PWL W = Weighted percent within specification limits PWL 3/8 = Percent within specification limits for the 3/8 inch (9.5mm) sieve PWL #4 = Percent within specification limits for the No. 4 (4.75 mm) sieve PWL #8 = Percent within specification limits for the No. 8 (2.36 mm) sieve PWL #50 = Percent within specification limits for the No. 50 (0.300 mm) sieve PWL #200 = Percent within specification limits for the No. 200 (0.075 mm) sieve PWL A = Percent within specification limits for asphalt binder content
4-53 (2) Mixture Properties Pay Factor . Once the weighted PWL for gradation has been determined,
the Mixture Properties Pay Factor will be calculated using the formulas below. For 85% ≤ PWL W ≤ 100% 𝑃𝐹𝑀𝑃=0.00067 𝑃𝑊𝐿 𝑊−0.05700 For 50% ≤ PWL W < 85% 𝑃𝐹𝑀𝑃=0.00286 𝑃𝑊𝐿 𝑊−0.24310 For PWL W < 50% 𝑃𝐹𝑀𝑃=0.00800 𝑃𝑊𝐿 𝑊−0.50000 where: PWL W = Weighted percent within specification limits PFMP = Mixture Properties Pay Factor
b.Mixture Pro perties Pay Adjustment Determination . The Mixture Properties Pay Adjustment will be calculated using the equation below. 𝑃𝐴 𝑀𝑃=𝑃𝐹𝑀𝑃×𝑄×𝐵 where: PAMP = Mixture Properties Pay Adjustment (dollars) PFMP = Mixture Properties Pay Factor Q = Quantity of material (square yards) B = Contract bid price (dollars/square yard) The quantity of material (Q) will be the number of square yards compacted in place for each lot. This quantity will include material used for shoulders.
4-54 407.0 7 METHO D OF MEASUREMENT . The quantity of Bonded Wearing Course of the type specified
to be measured for payment will be the number of square yards of mixture complete in -place in the accepted work. The quantit y of all applicable Pay Adjustments will be calculated according to the appropriate subsection. 407.0 8 BASIS OF PAYMENT . The accepted quantity of Bonded Wearing Course of the type specified will be paid for at the Contract unit price per square yard. Payment will be full compensation for furnishing, mixing, hauling, and placing the material specified, and for furnishing all labor, materials, and equipment necessary to complete the work. The costs of furnishing testing facilities and supplies at the plant will be considered included in the Contract unit price for Bonded Wearing Course. Surface preparation, patching, and crack sealing will be paid for separately in accordance with Section 406 and Section 417 . The quantity of all Pay Adjustments will be debited or credited against the Contract dollar amounts for those items. Payment will be made under: Pay Item Pay Unit 407.0100 Bonded Wearing Course, Type A ................................ ............................. Square Yard 407.0200 Bonded Wearing Course, Type B ................................ ............................. Square Yard 407.0300 Bonded Wearing Course, Type C ................................ ............................. Square Yard 407.9100 Pay Adjustment, BWC, Mixture Properties (N.A.B.I.) ............................ Dollar
4-55 Sectio N 410 – Materia L Transfe R Vehicle
410.0 1 DESCRIPTION . This work shall consist of furnishing and using an approved material transfer vehicle (MTV) in bituminous concrete paving operations. 410.0 2 CONSTRUCTIO N REQUIREMENTS . An approved MTV shall be used to transfer the bituminous material from the hauling equipment to the paver . The MTV shall operate independently from the paver and shall be a commercially manufactured unit specifically designed for the transfer of mix from the hauling equipment to the paver without depositing the mix on the roadway surface . The MTV or separate hopper shall be designed such that the deposited mix is remixed prior to placement on the roadway . The minimum storage capacity of the MTV, not including any separate hopper, shall be 12 tons. The MTV shall be capable of swing ing or offsetting the material transfer delivery system to side discharge into the paver. If the MTV and associated actions do not effectively eliminate mat segregation as determined by the Engineer, the Engineer may require a hopper insert with remixing c apabilities or other measures . When the MTV traverses a bridge that is not a buried structure, it shall be as near to empty as possible and shall not exceed 5 mph while on any structure . 410.0 3 METHO D OF MEASUREMENT . The quantit y of Material Transfer Vehicle to be measured for payment will be the number of tons of bituminous pavement transferred by the MTV to the paver in the completed and accepted work , as determined by the weigh slips. 410.0 4 BASIS OF PAYMENT . The accepted quan tity of Material Transfer Vehicle will be paid for at the Contract unit price per ton . Payment will be full compensation for the equipment as specified and for furnishing all labor, tools, equipment , and incidentals necessary to complete the work . Payment will be made under: Pay Item Pay Unit 410.10 00 Material Transfer Vehicle ................................ ................................ ......... Ton
Source: Vermont Standard Specifications for Construction, 2024 Edition. Pages 364–372 of 1,380.