2013 Session: 785

• Mixture Design Optimization of Low-Noise Pavements
  Abstract: The aim of this paper is to propose a tool to be used for the optimization of mix design of Low Noise Pavements (LNP). This aim has been achieved by developing an experimental model to predict rolling noise of a reference car tire as a function of composition and volumetric characteristics of mixes from in service pavements. By this way, the model enables to identify which composition parameters to operate on in order to improve acoustic performances of LNP.In order to define the experimental model, several types of asphalt surface layers, composed of hot asphalt mixes with different void contents, different aggregate grading and different bitumen percentages have been analyzed by in situ and laboratory tests. Acoustical properties of pavement surfaces have been evaluated by the Close Proximity Method (CPX) measurements. The model has been defined by using a multivariate non-linear regression technique to relate composition and volumetric characteristics of asphalt mixtures with rolling noise levels recorded at different speeds. This model - which is function of some significant parameters of the asphalt mixture composition and tire speed – has proven to be highly reliable in predicting car tire rolling noise; as it enables to identify mixture characteristics to be modified in order to reduce noise, in relation to the specific value of the mean traffic speed, it is particularly useful for the optimization of the mix design of LNP.
  Authors: Losa, Massimo; Leandri, Pietro; Licitra, Gaetano
  Authors: Losa, Massimo; Leandri, Pietro; Licitra, Gaetano
  Year: 2013
  Document Type: Paper
  Subject: Environment; Pavements
  Session: 785
  Paper Number: 13-4240
• Mix Design Factors to Reduce Noise in Hot-Mix Asphalt
  Abstract: Noise generating from high trafficked roadways is a significant source of noise pollution in urban environments. As population centers continue to expand, so too does the demand for quiet, serviceable pavements. Traffic noise is derived from two basic origins: standard vehicle engine operation and the tire-road interaction. Reduction of the former has been a goal of automobile manufacturers since their introduction nearly a century ago, while little focused research has been applied to the latter, especially within the United States. Furthermore, research allocated to determining the mix design factors that significantly influence noise generation in asphalt pavements is almost non-existing. This study investigates the mix design and construction factors that influence noise generation in dense graded HMA by means of noise prediction models. Laser profiling systems are used to measure pavement surface texture parameters. Models that predict noise generation as a function of these surface texture parameters are used to demonstrate the sensitivity of noise generation to commonly encountered mix design and construction variables for HMA. After characterizing a wide range of mixtures produced in the lab and profiling a number of field sections, statistical analysis was conducted to determine the effect of mix variables on texture and estimated noise. Results indicate that reduction in noise at the tire-pavement interface can be achieved with simple consideration of specific mix design parameters including gradation, asphalt content, and nominal maximum aggregate size. The percentage of air voids in the mixture (compaction effort) was also found to significantly influence tire-road noise emission.
  Authors: Cong, Ling; Swiertz, Daniel; Bahia, Hussain U.
  Authors: Cong, Ling; Swiertz, Daniel; Bahia, Hussain U.
  Year: 2013
  Document Type: Paper
  Subject: Environment; Pavements
  Session: 785
  Paper Number: 13-3983
• Investigation of Effects of Porous Pavement on Traffic Noise and Traffic Noise Prediction
  Abstract: The U.S. DOT / Federal Highway Administration (FHWA) Traffic Noise Model® (TNM®) is currently missing the effect of sound absorbing pavements on predicted noise levels, since a single EFR value representing acoustically hard ground is used in the sound propagation/ground reflection algorithms. With acoustically hard ground, most of the sound from vehicles is reflected. For porous pavements (pavements with more 15% interconnected air voids), sound incident on the pavement is partially absorbed, potentially reducing the noise level for receivers along the roadway relative to that for a non-porous surface. Results of the investigations described in this paper indicate that the sound absorption produced by porous pavements will have an effect on both measured and predicted traffic noise levels. The work shows that more accurate TNM-predicted sound levels can be achieved by properly accounting for the sound absorption of pavement, the effect of sound absorbing pavement is not insubstantial, and predictions can be made as to the effect of sound absorbing pavement by using modeling and/or measurement techniques.
  Authors: Rochat, Judith L.; Donavan, Paul
  Authors: Rochat, Judith L.; Donavan, Paul
  Year: 2013
  Document Type: Paper
  Subject: Environment; Pavements
  Session: 785
  Paper Number: 13-5069
• Influence of Quieter Pavement and Absorptive Barriers on US-101 in Marin County, California
  Abstract: A highway-widening project was recently completed on US 101 near San Rafael in Northern California. The project consisted of adding two high occupancy vehicle lanes each direction, relocating the southbound existing sound wall, and adding a multi-purpose path. As there was an existing sound wall in the northbound direction, additional conventional noise abatement was not considered under feasible under Caltrans and FHWA policy for this Type 1 project. However, two elements were included to improve aspects of the existing noise environment. These included overlaying all lanes of the completed project area with quieter, open graded asphalt and applying absorptive treatments to the traffic side of both barriers. To document any potential benefit of these features, the Transit Authority of Marin commissioned a study of the pre and post project noise levels. These included measurements of wayside noise levels above and behind the northbound sound wall and of tire/pavement noise using the on-board sound intensity method. These measurements indicated that 6 to 7 dB reductions in wayside noise levels both above and behind the barrier could be accounted for by the reduction in tire/pavement noise. As the effectiveness of the added absorption could not be directly isolated in the measurements, the benefit of this feature was assessed through acoustic modeling. The results of this analysis indicated that additional reductions of 3 to 5 dB could occur for receptors elevated above the roadway, shielded from the ongoing traffic, but with view of the opposing sound wall, and at distances of 500 ft or more away. Near the highway, the reduction provided by the absorptive was 1 to 1½ dB or less.
  Authors: Donavan, Paul; Lodico, Dana M.
  Authors: Donavan, Paul; Lodico, Dana M.
  Year: 2013
  Document Type: Paper
  Subject: Environment; Pavements
  Session: 785
  Paper Number: 13-4640
  Practice-Ready: Yes
• Mix Design Factors to Reduce Noise in Hot-Mix Asphalt
  Authors: Swiertz, Daniel
  Authors: Swiertz, Daniel
  Year: 2013
  Document Type: Presentation
  Subject: Environment; Pavements
  Session: 785
  Paper Number: 13-3983
• Investigation of Effects of Porous Pavement on Traffic Noise and Traffic Noise Prediction
  Authors: Rochat, Judith
  Authors: Rochat, Judith
  Year: 2013
  Document Type: Presentation
  Subject: Environment; Pavements
  Session: 785
  Paper Number: 13-5069
• Influence of Quieter Pavement and Absorptive Barriers on US-101 in Marin County, California
  Authors: Donavan, Paul
  Authors: Donavan, Paul
  Year: 2013
  Document Type: Presentation
  Subject: Environment; Pavements
  Session: 785
  Paper Number: 13-4640