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Tire/Pavement Noise and other Surface Characteristics from Highway Pavements in California. Erwin Kohler. CHILE. Presented at CONINFRA 2009, Sao Paulo, Brazil. Acknowledgements. John Harvey – UCPRC Linus Motumah - Division of Pavements, Caltrans. Propiedades del pavimento vs textura.
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Tire/Pavement Noise and other Surface Characteristics from Highway Pavements in California Erwin Kohler CHILE Presented at CONINFRA 2009, Sao Paulo, Brazil
Acknowledgements John Harvey – UCPRC Linus Motumah - Division of Pavements, Caltrans
Projetos UCPRC sobre ruído e textura • UCPRC é a Universidade da Califórnia Pavement Research Center (Centro Pesquisar Pavimentos) • Em 2005 começou um projeto para avaliar o ruído e outras características superfície do pavimento • Temos até 3 anos de medições de ruído e da macrotextura em pavimentos de asfalto • Estou trabalhando agora no 4º ano da recolha de dados em asfalto e 2º ano en concreto • Medições acústicas com método “OBSI”
Content • OBSI method of testing noise • Asphalt Pavement Research • Concrete Pavement Research
The OBSI method AASHTO TP 76-08 - Standard Method of Test for Measurement of Tire/Pavement Noise Using the On-Board Sound Intensity (OBSI) Method
OBSI Details • It measures the noise near the source, at two locations (front and rear) • It captures noise in a range of frequencies and an overall index is calculated • OBSI uses a standard test tire, and the test speed is 60 miles per hour (96.5 Km/h)
Quieter Pavement Research Purpose is to answer: • What properties/materials impact pavement noise levels and how? • How long can the acoustic benefits of the pavement last? • How do quieter pavements perform over time with regard to friction, smoothness, traffic loading, and maintenance needs?
Asphalt sections • Target: 80 pavement sections throughout California
Asphalt Pavements Sections Total number of sections 2006 76 2007 71 2008 65 By mix type OGAC: 18 (Open Graded Asphalt Concrete) RAC-O: 20 (Rubberized AC Open Graded) RAC-G: 13 (Rubberized AC Gap Graded) DGAC: 18 (Dense Graded AC) Other: 7 (BWC, F-mixes, Euro gap graded, MB) Represent entire population of AC pavements
Data collection Traffic speed Laboratory Traffic closure 150m long test section Cores #1 and #2 Cores #3 and #4 Cores #5 and #6 Cores #7 and #8 Cores #9 and #10 Cores #11 and #12 Detail segment Direction of traffic Center of the lane Friction and permeability zones 3.6m Core #4 Core #6 Wheelpath Core #3 Core #5 25m between cores
Work in a traffic closure Traffic Control: Caltrans Maintenance Condition survey: cracks & distresses, pictures Cores: drill, extract, label, backfill Friction: BP (& DFT) Permeability: epoxy seal, place, pour water, time
OBSI vs Pavement Age & by Mix Type • no AC section older than 8 years has OBSI <100 dB(A)
Asphalt Pavements 3-year Results • OBSI results in California on all sections by year
Concrete Pavements • From early Arizona and California database: • “at least in the US, the absolute level of quiet PCC does not approach that of quiet AC” • The concrete pavement industry responded with testing and building test sections • 4 “families” of concrete pavements - Diamond Grinding - Drag - Longitudinal Tining - Transverse Tining
State-wide AC & PCC OBSI studies • Range of climates, traffic levels, pavement types AC PCC
Comparison of PCC and AC • Cumulative distributions of OBSI levels • PCC: CP Tech Center, from several states, custom equipment, shorter interval • AC: UCPRC, only California, AASHTO TP-76 equipment, 5 seconds
Conclusions • Diamond ground surfaces are the quietest PCC. • It is important to establish goals for tire/pavement noise. A noise level of 100.0 dB(A) measured at 60 mph seems reasonable. • The UCPRC study shows that after two years, the average noise from about 70 sections has increased from 100.8 dB(A) to 102.1 dB(A). This is an increase of 1.3 dB(A) over a two-year period. • It must be noted that many RAC-O sections that are less than 8 years old are still between 98 and 100 dB(A).
Thanks Erwin Kohler +56 (2) 581-3940 ekohler@dynatest.com