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18 QA/QC Test Results--Aggregate properties, fresh and · Friction (micro-texture) hardened mix properties, surface properties (initial DF Tester (ASTM E 1911)--DFT(20) (also capable of texture dimensions and direction, initial smoothness). generating friction numbers at other speeds, such as · Historical Data DFT(40), DFT(60), and DFT(80)). Traffic--Initial year ADT and %trucks, subsequent year · Noise ADTs and %trucks, traffic growth rate, direction and lane Near-Field Noise (GM standard), as measured with pro- distribution factors. prietary single-probe receptor and noise equipment, and Texture--Subsequent texture depth measurements, Goodyear Aquatred III test tire, mounted on an all-wheel texture measurement device/method. drive Honda CR-V test vehicle (see Figure 3-2)--SI. Friction--Subsequent friction measurements, fric- Interior Vehicle Noise (SAE J1477), as measured with tion equipment/method (device, tire type, test speed), proprietary receptor and noise equipment mounted in the friction test conditions (air temp, wind, sun), equip- interior of the Honda CR-V test vehicle--Leq. ment calibration (date, location, speed, 524 conver- Far-Field CPB Noise (in accordance with ISO 11819, but sion intercept and slope). with fixed vehicle), as measured with proprietary wayside Accidents--Wet-to-dry crash rates. receptor and noise equipment--Lmax. Noise--Near-field SI, interior vehicle noise Leq, far-field pass-by noise. Collection of high-speed texture data and the three forms Smoothness--Subsequent IRI measurements, smooth- of noise data required no lane closure, whereas collection of ness measuring equipment/method. micro-texture (DF Tester) and macro-texture (CT Meter) Distress--Faulting, cracking, spalling. required traffic control and full lane closure. The following protocols were developed and followed for these tests: Test Section Descriptions Brief descriptions of the 57 selected test sections are pro- · High-Speed Texture--Macro-texture measurements will be vided in Appendix C. The sections represent an array of made in the right wheelpath (18 to 30 in. [460 to 760 mm] formed and cut (fresh and hardened) concrete pavement sur- from the outside lane edge, depending on lane width) at face textures, as well as some asphalt surfacings with different 60 mi/hr (97 km/hr). If it can be safely accomplished, tex- mix characteristics. The sections are mostly new (<5 years in ture measurements also will be collected in the lane center age) and typically are located on 2- or 4-lane highway facili- to evaluate the effects of wear on texture durability. Steps in ties. The sections represent a range of traffic and climatic con- the macro-texture measurement process will include ditions. Several of the sections were built as part of an agency 1. Set markers at the roadside to define the test section study on pavement texturing. limits. 2. Warm up tires for at least 10 minutes and check the tire Texture, Friction, and Noise Testing pressure. of Existing Texture Test Sections 3. Make three passes over the site. Field Testing Protocol The following specific texture, friction, and noise tests (and their corresponding outputs) were planned for the selected test sections: · Texture (macro-texture) CT Meter (ASTM E 2157)--MPD and RMS. High-Speed Texture Profiler (International Cybernetics Corporation [ICC] Model MDR 4081-T 64-Hz laser texture system mounted on Honda CR-V test vehi- cle)--MPD, EMTD (also capable of generating Interna- tional Roughness Index [IRI] and Ride Number [RN]). EMTD computed according to ASTM E 1845: EMTD = 0.0079 + 0.8 × MPD (U.S. Customary units ) Eq. 3-1a EMTD = 0.2 + 0.8 × MPD ( SI units ) Eq. 3-1b Figure 3-2. SI horizontal single-probe configuration.
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19 4. Collect data with the right wheel in the lane center, 6. Record the wind speed and direction, air temperature, where this can be safely accomplished. and driving direction. 5. Review the texture depths and profiles for each pass for 7. Collect data while passing the test site at 60 mi/hr reasonableness and precision; make repeat runs, as (97 km/hr). appropriate. 8. Check data for reasonableness and completeness. 6. Back up the data. 9. Ensure that the measured noise is at least 10 dB greater · Near-Field Noise Measurement (SI)--Prior to data collec- than the background noise level. tion, the equipment will be calibrated according to the 10. Repeat tests until three sets of precision data are manufacturer's recommendations. SI noise testing will obtained. be conducted at a speed of 60 mi/hr (97 km/hr) using a 11. Compute the overall average "A" weighted sound level. Goodyear Aquatred III test tire (ASTM E 1136) aligned in 12. Compute the overall average 1/3 octave A-weighted sound the right wheelpath (18 to 30 in. [460 to 760 mm] from the levels. outside lane edge, depending on lane width). If it can be 13. Compute the FFT frequency spectrum using a 3-5 Hz safely accomplished, SI measurements also will be collected resolution frequency analyzer. with the test tire aligned in the lane center. The process 14. Back up the data. includes the following steps: · Far-Field CPB Noise Measurement (Lmax)--The CPB sys- 1. Set markers at the roadside to define the test section tem will be calibrated according to the recommended limits. manufacturer's procedures. Testing will be done using the 2. Position the microphone probe at the front of the same vehicle and test tires (Aquatred III tires mounted on test tire. both the front and rear on the side closest to the far-field 3. Warm up tires for at least 10 minutes at highway speeds microphone) used in the SI testing. Steps that will be fol- and check the tire pressure. lowed in this data collection effort include the following: 1. Confirm roadside location selection meets the require- 4. Make three passes over the site with the test tire aligned ments of ISO-11819-1. in the right wheelpath. 2. Ensure that the environmental conditions are adequate 5. Collect additional data with the test tire aligned at the for testing. lane center. 3. Set up the microphones at 25 ft (7.5 m) from the vehicle 6. Re-position the microphone probe to the rear of the center at an elevation of 5 ft (1.5 m) above the outside test tire. lane elevation. 7. Make three passes each with the test tire aligned in the 4. Ensure that the entire surface between the vehicle and right wheelpath and at the lane center, respectively. microphone has consistent attenuation using plywood 8. Review the noise spectra and SI levels for each pass for strips as necessary. reasonableness and precision; make repeat runs, as 5. Set up a calibrated thermometer for air temperature appropriate. measurements. 9. Back up the data. 6. Set up an anemometer for wind speed and direction · Interior Noise Measurement (Leq)--Interior noise equip- measurement. ment will be calibrated according to the manufacturer's rec- 7. Set up the data collection and storage board. ommendations. Noise data will be collected using a single 8. Make three vehicle passes with the same tires used in microphone above the passenger seat, in accordance with the near-field measurements. SAE J1477. This method entails the following anticipated 9. Check the data for reasonableness and precision; make setup and steps: repeat runs, as appropriate. 1. Make sure all windows are up and all vehicle ventila- 10. Back up the data. tion and the radio are turned off. · CT Meter Macro-texture Measurements--Longitudinal 2. Adjust the seat and headrest to mid position. and transverse macro-texture measurements will be made 3. Position the microphone securely 2.25 ft (0.7 m) above in at least five locations in both the right wheelpath (18 to the intersection of the passenger seat surface and the 30 in. [460 to 760 mm] from the outside lane edge, depend- seat back. Orient the microphone facing forward. ing on lane width) and the lane center, in accordance with 4. Check and document the background noise (stationary ASTM E 2157. Areas of the pavement with sufficient length and vehicle off). and consistent noise and texture qualities will be singled- 5. Ensure that wind speed is less than 11 mi/hr (18 km/hr) out as a test section. Representative measurements will and that ambient air temperature is between 23 and be collected at locations that exhibit different tine channel 95°F (-5 and 35°C). If not, wait until winds die down dimensions, texture properties, or noise properties. All data sufficiently and/or temperature is in range. will be checked for reasonableness and precision, and tests