659HIGH FRICTION SURFACE TREATMENT (HFST)

659.1DESCRIPTION—This work is the furnishing and applying a High Friction Surface Treatment (HFST)

on asphalt and concrete pavements.

659.2MATERIALS—

binder resin system. If serrated squeegees are used, they must be designed to apply a Wet Film Thickness

in Table A; and listed in Bulletin 15.

Table A Physical Binder Requirements Property Test Method Requirements Low Modulus Epoxy Polyester Apparent Viscosity, mixed components (cP), minimum ASTM D2556 modified/AASHTO MP 41-22* 1,000 1,000 Flash Point ASTM D3278/AASHTO MP 41-22 See Safety Data Sheet See Safety Data Sheet Gel Time (minutes), minimum ASTM C881/AASHTO MP 41-22*, prepare a 60 g sample 10 10 Compressive Modulus (psi), maximum 7-day cure ASTM D695/AASHTO MP 41-22* 130,000 - Compressive Strength (psi), minimum 3 hours cure 24 hours cure ASTM C579 Test Method B/AASHTO MP 41-22*, prepare specimen according to Method "B", 2-inch cube, using 2.75 parts of sand to one part of mixed binder by volume. Use sand conforming to ASTM C778, 20-30 sand 1,000 3,000 1,000 3,000 **Tensile Strength (psi) 7-day cure ASTM D638/AASHTO MP 41-22* 2,000-5,000 2,000-5,000 **Tensile Elongation (%), minimum 7-day cure ASTM D638/AASHTO MP 41-22* 30 30 Absorption (%), maximum 14 days cure ASTM D570/AASHTO MP 41-22* 1 1 Type D Hardness 7 days ASTM D2240/AASHTO MP 41-22* 60-80 50-60 Thermal Compatibility 7-day cure

ASTM C884/AASHTO MP 41-22* PASS PASS Infrared Spectrum ASTM E152/AASHTO MP 41-22 Combined & Components Combined & Components * Perform testing at a temperature of 73 ± 2F. Prepare the specimens according to the manufacturer mixing recommendations. If applicable, cure specimens at 73 ± 2F and relative humidity at 50% ± 10%. ** At MTL request, prepare and priority ship twelve Epoxy sample specimens as indicated in Bulletin 15, Section 659.

and meets the physical and chemical requirements of Table B.

Table B Physical and Chemical Requirements of Refractory Grade Calcined Bauxite Aggregate Properties Test Method Requirements Resistance to degradation ASTM D7428 modified*/AASHTO MP 41-22 Micro-Deval 3% maximum loss Aggregate Grading AASHTO T 27 % Passing: No. 4 Sieve 100 No. 6 Sieve 95-100 No. 16 Sieve 0-5 No. 30 Sieve 0-0.2 Moisture Content AASHTO T 255 0.2% maximum Aluminum Oxide ASTM E1621 85% minimum * Test sample must be washed and dried in accordance with ASTM D7428. Do not separate into individual sized fractions. Instead of the grading required in ASTM D7428, obtain the aggregate for the test sample by collecting a 500 ± 5-g sample passing the No. 4 sieve and retained on the No. 8 sieve.

Section 659.3(g), and only reclaimed over the binder treated area. Do not reclaim aggregate on adjacent untreated areas as they are contaminated. If the same equipment collects aggregate from treated and untreated areas, all collected material will be considered contaminated and cannot be reused. Reclaimed aggregate may not be reused if dust control is not maintained to the satisfaction of the Representative.

For aggregate, provide independent testing to verify Table B requirements are met. Independent testing must be less than 12-months-old and be from an AASHTO Certified Laboratory at the time aggregate is furnished to the project. Submit for project specific, local approval by the Representative as specified in Section 106.02(a)2.c.

659.3CONSTRUCTION—

similar treatments such as Epoxy or Polyester Overlays. Submit a minimum of three projects including the

installer’s contact information. The three projects must have a cumulative minimum of 10,000 square yards and must have been placed within the past 3 years. HFST projects must have a friction reading of at least 65 SN40S within 120 days of the installation tested according to ASTM E274/E274M (AASHTO T 242). An installer who does not meet these minimum requirements will be allowed to perform the installation operation if approved in writing by the binder manufacturer.

plan is approved. Discuss the QC Plan at the pre-construction meeting. The QC Plan must include key personnel, equipment, materials, proposed methods of installation and operation, and the following requirements:

successful operation of the QC Plan and is responsible for the following:

• Identify and provide contractor procedures for:

ͦ Documenting quantities used for binder and aggregate at each HFST site so application rates may be confirmed to be according to the specification. ͦ Moisture control methods of aggregate. ͦ Dust control methods during application.

ͦ Cleaning and maintenance schedule for machinery and equipment. ͦ Corrective actions for unsatisfactory construction practices and deviations from the specifications. Any deviation from the approved QC Plan will be cause for immediate suspension of operations.

• Contractor performance of required field QC sampling, testing and record keeping according to the approved QC Plan and contract documents.

• Maintain and make available upon request, complete records of sampling, testing corrective actions, and QC inspection result.

• Train and provide recommendations to construction personnel in the safe handling and proper application of materials before placing the HFST.

• Must be present at each site if the installer does not meet the minimum requirements as specified in Section 659.3(a).

• Must be present for the first 2 days of installation, for installers that do meet the minimum requirements as specified in Section 659.3(a).

• Must be present at any job site that requires corrective work due to unacceptable Skid Number (SN) values as specified in Table E.

• Must be present as required in the approved QC Plan.

the manufacturer’s recommendations. Do not expose the aggregate to rain or moisture. Obtain and post at the storage areas the Safety Data Sheet (SDS), Product Data Sheet, and other information from the manufacturer pertaining to the safe practices for the storage, handling, and disposal of the materials, and to their health hazards. Provide to the Representative a copy of this information. Storage containers must have the manufacturer’s name, date of manufacture, batch/lot number, trade name, quantity, and mixing ratio printed on the label.

is below manufacturer’s recommendation, or if the anticipated weather conditions would prevent the proper application of the surface treatment. Protect freshly applied HFST from sudden or unexpected rain. Stop all application operations if it starts to rain. The Representative may order removal and replacement of any material damaged by rainfall or placed below the manufacturer’s recommended temperature.

holes/inlets) that are adjacent to the HFST site as directed before performing surface preparation. Remove thermoplastic pavement markings that conflict with the HFST installation and other pavement markings that are one year old or newer, as specified in Section 963.3. Prepare all pavement surfaces immediately before the installation of HFST. Wash pavement surfaces with a mild detergent solution to remove oils, greases, or other deleterious materials that remained after the surface preparation, rinse with clean potable water, and dry using a hot compressed air lance. Where cracks are present, remove loose material with compressed air and pre-treat cracks 1/4 inch or greater in width with the mixed binder. Do not overfill cracks. If cracks are overfilled, scarify the material to make it flush with the adjacent pavement after the binder material is cured. Install HFST after the binder in the pre-treated cracks has gelled.

air wash with sufficient oil traps. Mechanically sweep all surfaces to remove dirt, loose aggregate, debris, and

deleterious material. Vacuum sweep or air wash, using a minimum of 180 cubic feet per minute and 80 pounds per square inch of clean and dry compressed air, all surfaces to remove all dust, debris, and deleterious material. Do not apply HFST applications on new asphalt pavements until after a mandatory 30-day cure period.

blast all surfaces to remove all curing compounds, loosely bonded mortar, surface carbonation, and deleterious material. Comply with the International Concrete Repair Institute (ICRI) standard for surface roughness (CSP) 5. Provide the necessary concrete surface profile chips to visually verify the surface preparation. After shot blasting, vacuum sweep or air wash using a minimum of 180 cubic feet per minute and 80 pounds per square inch of clean and dry compressed air, all surfaces to remove all dust, debris, and deleterious material. Do not apply HFST on concrete surfaces or repairs that are less than 28 days of age.

size of each individual HFST installation site. Control operations to minimize and maintain a safe and unobstructed passageway through the work zone for all traffic. The Representative may suspend all operations if there are any safety concerns, such as excessive dust or poor visibility. Do not allow the mixed binder material to be exposed, separate, cure, dry, or otherwise harden in such a way as to impair retention and bonding of aggregate. Remove and replace any binder that becomes contaminated at no additional expense to the Department. Immediately remove loose aggregate that falls onto any part of an active adjacent travel lane after the traffic is temporarily held. Contractor equipment and traffic are not allowed on the HFST during the curing period.

Table C Allowable Application Methods Site Size (Square Yards) Application Method Less than 300 Section 659.3(f)1 Hand Mixing and Manual Application, Section 659.3(f)2 Semi Mechanized Application, or Section 659.3(f)3 Automated Continuous Application 300 to 2,000 Section 659.3(f)2 Semi Mechanized Application or Section 659.3(f)3 Automated Continuous Application * Larger than 2,000 Section 659.3(f)3 Automated Continuous Application * * Hand Mixing and Manual Application is allowed at sites as an alternate method only where the automated continuous or Semi-Mechanized equipment cannot physically be used because of access and geometry related constraints.

binder components. Provide a clean, dry, container large enough to blend and mix the proper proportions of the binder. Uniformly mix the binder components to within ± 2% of the manufacturer’s specifications (by volume) using a low-speed, high-torque drill fitted with a helical stirrer, moving the stirrer around to all the edges of the mixing container, or as approved by the manufacturer’s technical person. Do not use wheel mixers or paddle mixers. Immediately after the binder application, use a serrated squeegee to distribute a uniform binder thickness of 50-65 mils (25-32 square foot per gallon), then mechanically or manually spread the aggregate onto the wet, uncured binder at a uniform rate of 12-15 pounds per square yard. Completely cover the wet, uncured binder with aggregate to achieve a uniform surface with no exposed binder remaining visible on the surface. Spread the aggregate without displacing the wet binder film during placement. Minimize walking or standing on the binder. Do not allow loose aggregate onto any part of the adjacent, active travel lanes.

work to distribute mixed binder, and machine application of aggregate. Use equipment to continuously mix, meter, and monitor the binder. If recommended by the binder manufacturer, use a heated metering pump. Mix the b inder according to the manufacturer’s specifications (± 2% by volume). Immediately after the b inder application, use a serrated squeegee to distribute a uniform binder

thickness of 50- 65 mils (25 -32 square foot per gallon) . Mechanically spread the aggregate onto the wet, uncured binder at a uniform rate of 12-15 pounds per square yard. Do not allow loose aggregate onto any part of the adjacent, active travel lanes. Hand spread aggregate is allowed as a secondary method if the mechanized equipment cannot physically be used as approved by the Representative. Completely cover the wet, uncured b inder with aggregate to achieve a uniform surface with no exposed binder remaining visible on the surface. Spread the aggregate without displacing the wet binder film during placement. Minimize walking or standing on the binder.

application of binder, and machine application of aggregate. No hand squeegee work allowed. Do not apply HFST if wind speed is above 15 mph or if wind gusts of 20 mph or higher are anticipated during the placement of the treatment. Perform automated application using equipment that mixes, meters, monitors, and applies the binder followed by application of the aggregate by use of equipment capable of placing binder and aggregate in one continuous pass up to a 12-foot width. If recommended by the binder manufacturer, use a heated metering pump. Blend and mix the binder in accordance with the manufacturer’s specification (± 2% by volume) and place a uniform binder thickness of 50-65 mils (25-32 square foot per gallon). Apply the aggregate mechanically at a rate of 12-15 pounds per square yard (achieving saturation) by vertical drop onto the wet, uncured binder. Do not allow loose aggregate onto any part of the adjacent, active travel lanes. Use equipment capable of continuously monitoring b inder and aggregate application rates, and capable of placing HFST at a minimum rate of 2,000 square yards per hour. In sloped areas, minimize the weight of the application truck by filling the bauxite hopper and resin tanks halfway. No walking or standing on the binder is allowed.

first aggregate cleanup. Remove all excess aggregate broadcasted to adjacent areas. If contaminated aggregate is mixed with virgin aggregate, all the aggregate in the container will be considered contaminated and not acceptable for use in the HFST. Between 15 to 30 days after placing the HFST, perform a second aggregate cleanup, including aggregate in the shoulder area using a vacuum sweeper.

659.3(g), localize all the untreated areas where bare asphalt or concrete pavement is showing, prepare them and reapply HFST. Remove, prepare, and retreat with HFST areas with poor aggregate retention, areas that show signs of delamination and areas with color discoloration. Perform all repairs at no additional cost to the Department. The Department will conduct a calibrated skid test a minimum of 31 days after the HFST is applied. The

Engineering District will request the Skid Testing from the Department’s Roadway Inventory and Testing Section. Skid Testing for each HFST site will be performed according to ASTM E274/E274M (AASHTO T 242) using a smooth tire lock-wheel apparatus, and Table D.

Table D Number of SN40S Skid Tests per HFST Site, per Lane HFST Site Length Number of Runs per Lane Skid Tests to Obtain per Run Less than 100 feet N/A No Testing Required 100 feet to 350 feet 2 Run 1 – 2 Skid Tests Run 2 – 1 Skid Test Greater than 350 feet 1 3 Note: The Department’s Roadway Inventory and Testing Section will determine what location can or cannot be tested.

659.4MEASUREMENT AND PAYMENT—Square Yard

Payment will be processed after the first aggregate cleanup is completed. Acceptance payment will be determined utilizing the factors in Table E.

Table E Acceptance and Payment Factor per HFST Site Average SN40S (per HFST site) HFST Acceptance Item Pay Factor (%) SN ≥ 70 Yes 100 SN 65 - 69 Yes 90 SN < 65 No Remove and replace, or reapply, at no additional cost to the Department to obtain acceptable SNs. Manufacturer’s technical person must approve any proposed reapplication treatments and be present during all corrective work. Representative must approve all corrective work plans before