Aybike Ongel

Pavement characteristics affecting the frequency content of tire/pavement noise

Tire/pavement noise is a major contributor to traffic noise at highway speeds. Annoyance is more closely related to frequency content than to overall A-weighted noise levels, therefore spectral content analysis of tire/pavement noise is an important consideration. A study conducted in California measured the noise levels of different mix types and the pavement characteristics affecting noise levels as determined by on-board sound intensity (AASHTO TP 76-08). Data was collected on dense-graded asphalt concrete mixes (DGAC), conventional open-graded mixes (OGAC), open-graded rubberized asphalt concrete mixes (RAC-O), and gap-graded rubberized asphalt concrete mixes (RAC-G) with ages less than 8 years old. This paper evaluates the effects of pavement characteristics including the air-void content, gradation properties, rubber inclusion, roughness, texture, pavement surface condition, and age on one-third octave band noise levels. This research confirmed that macrotexture and IRI, which are associated with the impact and shock mechanisms, increase the noise levels at lower frequencies. Higher air-void content, associated with the air pumping mechanism, reduces the noise levels at higher frequencies.

Comparison of Surface Characteristics and Pavement/Tire Noise of Various Thin Asphalt Overlays

ABSTRACT Traffic noise has become a major concern in the last decade and many countries have been looking for solutions to reduce noise levels. The California Department of Transportation (Caltrans) has been using different open graded mixes to reduce highway noise levels and improve wet weather driving conditions. There is a need to identify their noise reduction properties, durability, and safety, and to compare these with other asphaltic mixes. Caltrans initiated a long-term program to investigate and monitor field performance of different open graded mixes and other commonly used asphalt surface mixes. This paper summarizes part of the first-year measurements of relevant parameters from asphalt pavements with different surface mixes. It was confirmed that open graded mixes generally reduce the tire/pavement noise level, and the amount of reduction is correlated with air-void content and surface texture.

Acoustical Absorption of Porous Pavement

Acoustical absorption coefficients of more than 140 pavement cores were obtained by the impedance tube method with two microphones and cross-spectral analyses. The effectiveness of the impedance tube in predicting noise reduction for different mixes was evaluated by comparing the correlations between onboard sound intensity levels and absorption. Theoretical predictions of acoustical absorption due to friction between air and porous matrix and thermal relaxation were compared with measured results for an idealized porous structure. The model was used to infer porosity, tortuosity, and pore size from measured acoustical absorption spectra for manufactured porous asphalt and extrapolate test results to nonnormal angles of incidence, assuming isotropy of the porous structure. This model will help improve mix designs to increase the absorption of pavement surfaces and can be used to estimate porous pavement properties.

Higway traffic noise effects on annoyance

Noise pollution has been a major issue in the last decade. Noise was shown to cause adverse health effects including noise-induced hearing impairment, annoyance, sleep disturbance, and cardiovascular diseases. Transportation noise has been the most common one among all noise sources in urban areas. A study has been initiated in Istanbul, Turkey in order to evaluate the effects of highway noise on annoyance and myocardial infarction. A total of 2000 surveys will be conducted in 6 hospitals in Istanbul. The highway noise levels are obtained from the noise maps prepared by Environmental Protection Department of Istanbul Metropolitan Municipality. This manuscript presents the highway noise exposure levels in Istanbul and early findings regarding the annoyance effects of highway traffic noise.

Evaluation of effects of pavement characteristics on the OBSI levels using Principal Components Regression

Tire/pavement noise is a major contributor to traffic noise at highway speeds. Tire/pavement noise is affected by different pavement properties. A study conducted in California measured the noise levels of different mix types and the mix characteristics affecting noise levels. In this study, tire/pavement noise was measured using the on‐board sound intensity (OBSI) method. Data was collected on four different types of pavement mixes: conventional open graded asphalt concrete (OGAC), rubberized asphalt concrete that are open graded (RAC‐O), rubberized asphalt concrete that are gap graded (RAC‐G), and dense graded asphalt concrete mixes (DGAC). A total of 72 field pavement sections were included in the study, all of which were less than 8 years old at the time of the measurements. This paper evaluates the pavement characteristics affecting noise levels using principal components regression. This technique was used due to the multicollinearity found among the variables. Two principal components were extracte...