SECTION 403: OPEN GRADED FRICTION COURSE
403.1 Description
This Work consists of construc ting an Open-Graded Friction Cour se (OGFC), which includes Standard OGFC , Warm Mix Open-Graded Friction Course (WOGFC), or Rubberized Open-Graded Friction Course (ROGFC) on a prepared surface.
403.1.1 Definitions
Open-Graded Friction Course (OGFC) – type of asphalt surface mi xture whose function is to provide a free-draining lay er that permits surface water to migrate laterally through the mixture to the edge of the pavement. Warm Mix Open-Graded Fricti on Course (WOGFC) – OGFC th at utilizes a single or combination of Department approved WMA technologies to reduce t he production, placement and compaction temperatures of the OGFC mixture. Rubberized Open-Graded Friction Course (ROGFC) – OGFC that utilizes a Department approved tire rubber modifier ( TRM) in the asphalt binder.
403.2 Materials
403.2.1 General
The Contractor shall provide OGFC, WOGFC, or ROGFC composed of aggregate, asphalt binder, and mineral admixture.
403.2.2 Aggregate
The aggregate is crushed stone or crushed gravel, composed of h ard durable particles or fragments. Accepted aggregate Material must meet the following requirement s: 1. Have a minimum of 75% two (2) Fractured Faces as determined in accordance with AASHTO T 335, Fractured Face Determination for Coarse Aggregate; 2. Be free of organic matter, lumps of clay, or other Material that prevents thorough coating with asphalt binder; 3. Have an Aggregate Index (AI) of 20 or less when determined i n accordance with Section 910, “AGGREGATE INDEX;” and 4. The Department will allow the combination of Materials from two (2) or more sources if each source independently meets the requirements of items tw o (2) and three (3), above. The Contractor shall ensure the aggregate meets the gradation r equirements in Table 403.2.2:1, “OGFC Gradation Requirements,” when tested in accordance with AASHTO T 11 and AASHTO T 27. The Department will determine agg regate combined aggregate gradation acceptance by testing samples of the combin ed aggregates and mineral admixture taken before adding asphalt Materials. Table 403.2.2:1 OGFC Gradation Requirements Sieve size % passing OGFC Gradation Requirements Sieve size % passing 1/2 inch 100 3/8 inch 90 – 100 No. 4 25 – 55 No. 8 4 – 20 No. 16 0 – 10 No. 50 0 – 6 No. 200 0 – 4
403.2.3 Asphalt Material
The Contractor shall use the binder type and grade as specified in the Contract, in accordance with Section 402, “As phalt Materials and Mineral Adm ixture.”
403.2.4 Mineral Admixture Material
The Contractor shall provide hydrated lime, Portland cement, or anhydrite based Material in accordance with Section 402, “ Asphalt Materials and Mineral Admixture.”
403.2.5 Mix Design
The Contractor shall develop t he mix design at no additional co st to the Department. The OGFC, WOGFC, or ROGFC mix design shall be developed in acco rdance with ASTM D 7064, “Standard Practice for Open Graded Friction Course (OGFC) Mix Design,” as modified by the New Mexico Department of Transportation State A sphalt Engineer by a Department-approved testing Laboratory. A list of approved pri vate testing laboratories is available from the State Materials Bureau. The mix design will establish: 1. A combined gradation (compr ised of aggregate and mineral adm ixture) showing the percent passing each required siev e size that provides a JMF gr adation that is within the master range as listed in Table 403.2.2:1, “OGFC Gra dation Requirements” for the specified type of OFGC listed in the Cont ract; 2. A single target asphalt cont ent (a minimum of five and one h alf percent (5.5%) asphalt Material is required); and 3. A single target mineral admixture content (a minimum of one percent (1%) mineral admixture is required). The Mix Design shall identify t he minimum and maximum mixing an d placement temperatures of the mix. The mix design shall be reviewed by a Professional Engineer lic ensed by the New Mexico Board of Registration for Professional Engineers and Lan d Surveyors. The Contractor shall summarize the mix design results in a form at approved by the State Materials Bureau and submit t he design and supporting documenta tion for review and concurrence to the State Asphal t Engineer. Department concurre nce of a mix design will not relieve the Contractor of full responsibility of producing an A cceptable mixture. When Department Reviewed Commercial Mix Designs are used on the P r o j e c t , t h e Section 403: Open Graded Friction Course Page 165 Contractor shall submit a copy of proposed commercial mix desig n to the State Asphalt Engineer with the Project information to verify the proposed co mmercial mix design is appropriate for use and meets all the requirements for the for the specific Project. If the proposed commercial mix design meets all the requirements for t he specific Project, the State Materials Bureau may re-issue t he proposed commercial mix desig n as the Project specific mix design for that specific Project. The State Materials Bureau may allow the Contractor to use a mi x design up to one (1) year from the date of review by the State Materials Bureau, bas ed upon the validity of the Aggregate Index. If the Aggregate Index expires before the one (1) year time frame, the review of mix design will expire on the date as indicated on th e Summary of Design Sheet and may be renewed by submitting an updated Aggregate Index. The Contractor may use or re-submit the design before the expir ation of the one (1) year period. The Contractor shall: 1. Not use a Mix Design beyond one (1) year after the State Mat erials Bureau’s review date; 2. Submit Acceptable evidence to the State Materials Bureau ver ifying that the component Materials have not changed; 3. Submit a new mix design if c hanging the source of Materials; and 4. Obtain concurrence from the State Materials Bureau before us ing the new Materials.
403.2.6 Warm Mix Open-Graded Friction Course (WOGFC)
Only Warm Mix (WM) additives or technologies approved by the P roduct Evaluation Program and currently listed on the Approved Products List (APL ) shall be used on Department Projects. For foamed asphalt systems, water used as directed by the foame d asphalt system manufacturer shall be considered the Warm Mix additive. Only f oamed asphalt systems approved by the State Asphalt Engineer shall be used. To be placed on the APL, the WM additive Supplier shall verify that the asphalt binder with the warm mix additive meets the PG grade of the specified binder listed in the Contract. The potential additive Supplier shall demonstrate this to the D epartment by evaluating the Asphalt Binder and WM additive for compliance with the rheologi cal properties for low and high temperatures for the specified PG grade in accordance with AASHTO M320, Table 1 and Section 402.2.1.1, “Polymer-Modified Asphalt Binder.” A technical representative of W arm Mix Additive Supplier, inclu ding contact information shall be designated in writing vi a the mix design submittal pro cess. The representative is expected to ensure that the Warm Mix Additive is handled proper ly. The representative does not have the authority to allow any deviation from the Departme nt Specifications and Project requirements. Warm Mix additive dosage rates shall not deviate from those de signated by the Warm Mix Additive Supplier. If a terminal blend Warm Mix additive i s used, the dosage rate shall be shown on the Materials Certificate of Compliance. The WM Additive supplier and the Asphalt Binder supplier will b e consulted when establishing recommend mixing, c ompaction and maximum allowable temperatures to be used Section 403: Open Graded Friction Course Page 166 for the development of the mix design. Some modification to HMA plants may be necessary to accommodate the WMA technologies.
403.2.7 Rubberized Open-Graded Friction Course (ROGFC)
ROGFC shall be produced with te rminal blended asphalt rubber bi nder. Terminal blended asphalt rubber b inder shall consist of a homog eneous mixture of tire rubber obtained from recycled tires and compatible with PG 70-2 8 + asphalt binders or as specified in the Contract. A ll binder components shall be thor oughly blended and reacted prior to use. The PG 70-28 + asphalt Material or as specified in the Contract for the asphal t rubber binder shall comply with the requirements of Section 402, “Asph alt Materials and Mineral Admixtures” for PG 70-28R + or as specified in the Contract.
403.3 Construction Requirements
403.3.1 General
The Contractor shall use the “strap method” or “meter reading” to determine the quantity of asphalt Material, and maintain the percentage of asphalt Mat erial specified in the mix design in accordance limits shown in Table 403.3.6.2:1, “Accept ance Limits and Factors.”
403.3.2 Preparation of Roadbed
Before placing OGFC, WOGFC, or ROGFC the Contractor shall clean Deleterious Materials from the existing surface.
403.3.3 Temperature and Weather Limitations
The Contractor shall: 1. Not place OGFC, WOGFC, or ROGFC on wet surfaces or when the Project Manager determines that the weather conditions prevent proper h andling and finishing; and 2. Place OGFC or ROGFC when the Chill Factor is at least 60 °F and 55 °F for WOGFC. If the ambient air temperature is ≥90 °F the Chill Fact or will not be applied.
403.3.4 Mixing Requirements
The Contractor shall ensure that: 1. Hot mix plants conform to the requirements of Section 423, “ Hot-Mix Asphalt (HMA) (Major Paving)” or Section 424 , “Warm Mix Asphalt (WMA);” 2. The mineral aggregate is fr ee of deleterious coatings; 3. The moisture content of the combined aggregate and mineral a dmixture Material is in compliance with the “Combined Aggregate Water Absorption @ S SD” shown on the approved mix design; 4. The aggregate is mixed with asphalt Material until the aggre gate particles are thoroughly and uniformly coated; Section 403: Open Graded Friction Course Page 167 5. The mixture temperature does not does not exceed the asphalt binder Supplier’s recommendation; 6. The placement temperature for the mixture does vary by more than 20 °F from the temperature established on the approved Mix Design, or fall bel ow 220 °F; and 7. Mineral admixture, shall be added to the aggregate in accord ance with Section 423, “Hot-Mix Asphalt (HMA) (Major P aving)” or Section 424, “Warm Mi x Asphalt (WMA)” within the production tolerances specified in Table 403.3.6.2:1 , “Acceptance Limits and Factors.”
403.3.5 Placement and Finishing
The Contractor shall: 1. Place the OGFC, WOGFC, or ROGFC with a paving machine in acc ordance with Section 423.3.4.3, “Pavers;” 2. Roll the surface immediately following OGFC placement with a steel-wheeled, self- propelled roller that weighs enough to achieve adequate consoli dation of the aggregate without excessive breakage. The finished surface sha ll be in accordance with Section 401, “Pavement Smoothness Measurement” and the Pav ement Smoothness Category identified in the Contract Plans. For pave ments that are not subject to Section 401. “Pavement Smoothness Measurement” the C ontractor shall use a ten (10) foot straightedge to ensure the surface is free of irregularities larger than 1/4inch; and 3. Remove low and defective areas immediately, replace them wit h new OGFC, and compact the corrected Work to conform to the surrounding area.
403.3.5 1 Plan Surfacing Depths
The Contractor shall monitor and record Plan depths throughout the surfacing operations at intervals specified by the Project Manager. The Department will not pay for any excess course depth. Courses will be rejected, if less than 1/2 inch.
403.3.6 Sampling and Testing
403.3.6 1 Contractor Quality Control
After the mix design has been reviewed and issued, the Contract or shall control the mixture production on the project such that the tolerances of T able 403.3.6.2:1 “Acceptance Limits and Factors” are met. The Contractor shall perform Quality control processes in accor dance with Section 902 “Quality Control” and Section 906 “Minimum Testing Requirements .”
403.3.6 1.1 Suspension of Operations
If one (1) or more properties listed in Subsection 403.3.6.2, “ Department Quality Assurance,” fail to meet the Specification requirements for a p eriod of one (1) Day or a maximum production of 1000 tons ; the production will be halted by the Project Manager. The Contractor shall: 1. Use the gradation information to determine causes or factors t h a t m a y b e a contribution to the problem and prepare a plan to solve the pro blem. Approval of the Plan must be obtained from the Project Manager before resum ption of paving operations. Upon approval of the proposed Plan, the Contractor may resume Section 403: Open Graded Friction Course Page 168 operations to determine if the ac tions taken have corrected the problem; 2. Limit production to 1000 tons that will be tested in 500-ton increments. If that testing indicates that the problem has been corrected, the Contractor m ay resume full operations. If the problem has not been corrected, reduced pro duction rates and testing as described above will be required; and 3. Take corrective action to remedy any property of the mix tha t is out of Specification. Contractors who elect to produce Material that is not within th e Specification limits do so at their own risk. Price reductions due to out of Specif ication Material being placed will be deducted from the unit price of the item in acco rdance with the Department’s current Acceptance and Price Reduction Procedures. All Material that is rejected shall be removed a nd replaced with Specification Ma terial at the Contractor’s expense. Material that is improperly graded or se gregated or fails to meet the requirements herein provided shall be corrected or rem oved and disposed of immediately as directed by the Project Manager at the Contra ctor’s expense.
403.3.6 2 Department Quality Assurance
403.3.6 2.1 Acceptance
The Department will conduct Quality Assurance sampling, testing , and monitoring to ensure that the Contractor provides a mix that meets the tolera nces. Acceptance for gradation will be based on testing of samples ob tained from combined aggregates and mineral admixture , before addition of asphaltic Materials. Acceptance for asphalt content will be based on strap method or meter reading. Acceptance for mineral admixture content will be based on daily meter reading totals. The testing will be conducted in accordance Section 906, “Minimum Testing Requirements.” Accept ance test results will be provided to the Contractor’s Quality Control Representative or designee by the end of the Workday after the samples are taken. Table 403.3.6.2:1 Acceptance Limits and Factors Characteristic Specification limits Asphalt Content ± 0.3%a Mineral Admixture Content ± 0.2%a 1/2 inch 100 3/8 inch 90-100 No. 4 25-55 No. 8 4 - 20 No. 16 0-10 No. 50 0-6 No. 200 0-4 aPercent difference from TV listed on approved JMF.
403.4 Method of Measurement
403.4.1 Ogfc, Wogfc, and Rogfc
OGFC, WOGFC, AND ROGFC will be measured by the square yard or t on. The average width of the OGFC in place will be used in computing the quanti ties. The length used in Section 403: Open Graded Friction Course Page 169 computing the area shall be station to station along the center line of the Roadway. All dimensions shall be as shown on t he typical section of the Plan s.
403.5 Basis of Payment
The Accepted quantities of the OGFC, WOGFC, or ROGFC will be pa id for at the Contract unit price per square yard or ton. Pay Item Pay Unit Open-Graded Friction Course Complete Square Yard or Ton Warm Mix Open-Graded Friction Course Complete Square Yard or Ton Rubberized Open-Graded Friction Course Complete Square Yard or Ton
403.5.1 Price Adjustments
A price reduction in accordance wi th the Department’s Price Red uction Guidelines will be applied if the OGFC, WOGFC, or ROGFC, asphalt Material, or mine ral admixture are not produced, mixed, or placed in accordance with the Contract requ irements.
403.5.2 Work Included in Payment
The Department will consider as included in the payment for th e pay item(s) listed in this section and will not measure or pay separately for the followin g Work: 1. Crushing and stockpiling of Material; 2. Asphalt Material, mineral adm ixtures, warm mix additives, an d tire rubber modifiers; 3. Mix design; 4. Mixing, hauling, placement on a prepared surface; and 5. Process control testing and providing cold feeds. Section 405: Detour Pavements Page 170