Reducing Traffic Noise with Quieter AC Pavements

Transcription

1 Reducing Traffic Noise with Quieter AC Pavements By Paul R. Donavan 36 th Annual ROCKY MOUNTAIN Asphalt Conference & Equipment Show

2 Reducing Traffic Noise with Quieter AC Pavements What s the interest in quieter pavements? What examples are there of quieter pavement applications? What makes pavement quieter? How long does pavement stay quieter? How does performance vary?

3 Drivers of Quiet Pavement Interest Public concern over noise from freeways Extensive use of sound walls for noise abatement 1800 km in US

4 $$$ $2+ million per mile Can not be used everywhere Limits future highway expansion Not necessarily effective Blocks views

5 ADOT Application of Quieter Pavement 79 dba 70 dba Original Uniform Transverse Tine 1 Rubberized AC Overlay

6 Interest in Quiet Pavement Questions: Does it Last? Does it work for a traffic mix?

7 I-80 Pavement Project Location: I-80 just east of Davis and west of Sacramento, CA Traffic: 140,000 ADT (almost 10% trucks) Existing - Aged DGAC surfacing Quiet Overlay - Applied OGAC in July 1998

8 Measurements & Environment Distant Microphone Locations at 140m Reference Microphone Locations at 20m

9 Old Asphalt Surface 78.6 db Initial Reduction 6.4 db 72.2 db New Quieter Overlay

10 On-Board Sound Intensity Measurement Measure of propagating energy from tire Rejects flow noise Directional Isolates tire/road noise Vehicle adaptability AASHTO, SAE, ASTM Standards Sound Intensity Vectors I = pu

11 OBSI Measurements Windscreens

12 Caltrans Data Base - California & Arizona 110 OG/RAC Pavements 109 PCC Pavements 108 DGA Pavements 107 Sound Intensity Level, dba

13 ADOT/FHWA Arizona Quiet Pavement Pilot Project 185 km of freeway overlaid with ARFC FHWA allowed 4 db credit for pavement Long term research project to measure performance over 10 years Measurements 1. On-board measurements at each milepost 2. Wayside time average measurements

14 Pre & Post Overlay Site 3D ARFC Overlay (25mm Thick) Random Transverse Tined PCC

15 Noise Reduction with ARFC Overlay Tire/Pavement & Traffic Noise Reduction, db Sound Intensity Site 3D 15m x 4m 15m x 1.6m 30m x 1.6m 76m x 1.6m Wayside Microphone Distance and Height

16 Reductions at Other Sites Tire/Pavement & Traffic Noise Reduction, db Site 3E Site 3A Sound Intensity 15m x 4m 15m x 1.6m 30m x 1.6m Wayside Microphone Distance and Height

17 I-280 in San Mateo County, CA

18 New & Existing Pavements on I-280

19 I-280 in San Mateo County, California 1 to 2 db Quieter (Ground) 6 db Quieter RAC(O)

20 Las Vegas I-515 ROGFC Overlay

21 Las Vegas I-515 Pre & Post Levels Original PCC New ROGFC Overall OBSI Level, dba db Reduction N-1 N-2 N-3 S-1 S-2 S-3

22 Pre & Post Rehabilitation Project

23 6½ db Reduction (OBSI)

24 Roadway 5½ db Reduction In Backyards

25 On the Road in Europe Noise Intensity Testing in Europe: The NITE Study

26 Scope First definitive comparison of European & US pavement 4 countries, 68 pavements Compliment to the AASHTO/FHWA Scan Objectives Measure the quietest pavement of all types Measure the range of pavements in use The NITE Project

27 Caltrans Data Base - California & Arizona 110 OG/RAC Pavements 109 PCC Pavements 108 DGA Pavements 107 Sound Intensity Level, dba

28 Sound Intensity Level, dba European Pavements at 97 km/h PA PCC DGA DLPA SMA

29 Sound Intensity Level, dba Comparison of Quietest Pavements Europe California Arizona DLPA 2/6 DLPA 4/8 PA 4/8 PCC (P/G) LA 138 OGAC LA 138 RAC ARFC

30 What Makes AC Pavements Quieter? Smaller aggregate size Less displacement input to the tire Other surface characteristics also important

31 Coarse & Fine SMA Surfaces 8/10mm dba 0.8/1.5mm 99.7 dba

32 Stone Mastic Asphalt Surfaces of Varying Aggregate Size 0/5mm 0/3mm 0.8/1.5mm 0/8mm 0/8mm 0/11mm 0/8mm 0/14mm 8/10mm Sound Intensity Level, dba

33 Extreme Surfaces Chip Seals California SR db db Replica of California Pavement

34 Extreme Surfaces Fine Texture Caltrans Test Track 95.7 db 94.6 db Ultra-Smooth Test Track Pavement

35 What Makes AC Pavements Quieter? Smaller aggregate size Less displacement input to the tire Other surface characteristics also important Porosity Sound absorption in the pavement Reduction of some tire noise mechanisms

36 Porous & Non-Porous AC Surfaces 0/10mm Dense Grade dba 0/10mm Porous 98.5 dba

37 Propagation of Tire Noise over Absorptive Pavement Potential: ~3 db Reduction

38 Typical 2-Layer Porous Asphalt the Netherlands Small Aggregate Size Coarse Aggregate Size

39 Double Porous Layer Asphalt Surfaces of Varying Aggregate Size Sound Intensity Level, dba DLPA 2/6 DLPA DLPA 4/8 DLPA 2/6 DLPA 4/8 DLPA 4/8

40 What Makes AC Pavements Quieter? Smaller aggregate size Less displacement input to the tire Other surface characteristics also important Porosity Sound absorption in the pavement Reduction of some tire noise mechanisms Added rubber content

41 Rubber & Non-Rubber OGAC of Similar Aggregate Size/Gradation OGAC 98.0 dba Rubberized OGAC 97.1 dba

42 What Makes AC Pavements Quieter? Smaller aggregate size Less displacement input to the tire Other surface characteristics also important Porosity Sound absorption in the pavement Reduction of some tire noise mechanisms Added rubber content Surface compliance?

43 Issues Acoustic Longevity Variation in pavement performance

44 Overall Sound Intensity Level, dba Caltrans LA 138 AC Research Sites Oct 02 Oct 03 Oct 05 Oct 06 Oct 07 Oct-08 2½ to 3 db in 6 Years DGAC OGAC (75mm) OGAC (30mm) RAC BWC Test Pavement Surface Type

45 Sacramento I-5 RAC(O) Overlay

46 I-5 Sac RAC(O) Performance over Time SOUTHBOUND NORTHBOUND PCC Avg 12/2/2004 8/18/2005 8/15/ /2/2007 8/14/2008 PCC Avg 12/2/2004 8/18/2005 8/15/ /2/2007 8/14/2008 Overall Sound Intensity Level, dba

47 I-80 Davis Long-Term Performance ~ 2 db in 10 years Old DGAC New OGAC 1 Month 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 Year Traffic Noise Level, dba

48 San Mateo I-280 Performance Overall Sound Intensity Level, dba SB OGAC Shoulder SB RAC(0) Travel Lane NB RAC(0) Travel Lane

49 Performance of AZ ARFC over Time Site 3D Traffic Noise Level, dba Pre- Overlay 1 Year 1.5 Years 2 Years 2.5 Years 3 Years 3.5 Years 4 Years

50 Average Performance of AZ ARFC Overall Sound Intensity Level, dba All Mileposts 94 PCC 2004 Mar 2005 Mar 2006 Nov 2006 Mar 2007 Oct 2007 Mar 2008 Oct 2008

51 Acoustic Longevity of PCC at Mojave 107 Ground PCC 106 Burlap Drag Longitudinal Tined 105 Overall OBSI Level, dba Mar 03 Jun 03 Jun 05 Oct 08 Date of Test

52 Levels for Zebra Sections in the Netherlands Sound Intensity Level, dba A15 #1 A15 #2 A15 #3 A15 #4 A15 #5 A15 #6 A59 #1 A59 #2 A59 #3 A59 #4 A59 #5 A59 #6 Double Layer Porous 4/8mm ~ 2 db

53 Variation of ARFC Tire/Pavement Noise Source Levels at Arizona Site 3 s 100 Sound Intensity Level, dba ~ 2 db 94 Site 3A WB Site 3A EB Site 3C-1 Site 3C-2 Site 3C-3 Site 3D WB Site 3D EB Site 3E SB Site 3E NB

54 Variation of RAC(O) Tire/Pavement Noise on I-5 in Sacramento Southbound Northbound Sound Intensity Level, dba db Segment 1 Segment 2 Segment 3 Segment 1 Segment 2 Segment 3

55 Summary Reductions of 5 to 12 db possible Quietest pavements between US and Europe Perform almost equally Aggregate size & porosity patter Quieter AC performance can degrade at 0.2 to 0.5 db/yr Performance varies up to 2 to 3 db