Influence of the pavement surface on the vibrations induced by heavy traffic in road bridges

The irregularity of the pavement surface governs the traffic-induced vibrations in road bridges, but it is either ignored or simulated by means of ideal pavements that differ significantly from real cases. This work presents a detailed dynamic analysis of a heavy truck crossing a 40-m span composite deck bridge using on-site measurements of different existing road profiles, as well as code-based ideal pavements. By activating or deactivating certain spatial frequency bands of the pavement, it is observed that the ranges 0.2 - 1 and 0.02 - 0.2 cycles/m are critical for the comfort of the pedestrians and the vehicle users, respectively. Well maintained roads with low values of the displacement Power Spectral Density (PSD) associated with these spatial frequency ranges could reduce significantly the vibration on the sidewalks and, specially, in the vehicle cabin. Finally, a consistent road categorisation for vibration assessment based on the PSD of the pavement irregularity evaluated at the dominant frequencies is proposed

Ultrathin porous pavement made with high viscosity asphalt rubber binder: A better acoustic absorption?

his work presents a non-destructive technique applied to ultrathin porous asphalt pavements that allows us to characterize their internal structure. Comparison between acoustic absorption data from experimental tests with an impedance tube and analytical simulation leads to an optimization of intrinsic parameters, such as tortuosity, airflow resistivity and porosity. The studied ultrathin specimens are of a high air void content porous mixture made with conventional polymer modified bituminous binder and high viscosity rubber binder. It has been found that one of the studied mixtures presents less air void con- tent than specified by the manufacturer, and thus absorbs less noise as foreseen. Finally, in this case it appears that using a high viscosity asphalt rubber binder has no influence on maximum acoustic absorp- tion but on the frequency of appearance of this maximum, tortuosity and airflow resistivity

Impact of the Use of Crumb Rubber Modified Binder on Tire/Road Noise Generation

The recycling of waste material produced by human activity is one of the challenges of our generation. One of the most serious environmental problems of the recent years is mass production of tire and the diculty of disposing of them. The material and energetic valorization of the wasted tires is possible through the extension of green roads. The incorporation of crumb rubber from wasted tires in bi- tuminous binders allows the design of new asphalt pavements with a higher viscosity. A preliminary study to determine the impact of the use of crumb rubber modied bituminous binder in the sound generation level for a thin layer type BBTM11A, has been carried out by the LA2IC. These results are compared with sound level from a BBTM11A with a conventional binder. This work presents the acoustical characterization performed on the regional road CM-3102 in Ciudad Real (Castilla- La Mancha), based on the close proximity methodology (Tiresonic Mk4-LA2IC ). In addition, mea- surements of supercial macrotexture prole have been realized with the LaserDynamicPG-LA2IC to study the relationship with close proximity road noise. Furthermore, sound absorption measurements of BBTM11A compacted samples have been analyzed to understand the mechanisms involved in the sound generation. The results show that addition of crumb rubber by the wet process leads, in this case (20% crumb rubber content), to a decrease in the sound level emitted by the interaction between tire and road surface, at low frequency by muing the vibrations and by sounf absorption at high frequency

Road pavement rehabilitation using a binder with a high content of crumb rubber: Influence on noise reduction

Although performance of pavements depend on the characteristics of materials used, design accuracy and construction quality, crumb rubber modified binders (CRMB) are materials with an increasing use in road pavements due to their enhanced properties and to the environmental protection by re-using a waste material. This paper presents the laboratory characterization and the evaluation of field performances of a gap-graded mix with 20% of crumb rubber by weight of bitumen, added by a wet process. Acoustical field characterization has been performed by determining, at different speeds, sound levels and noise spectra measured in close proximity. Road profiles along the test sections and sound absorption of compacted sample cores also have been studied to analyze their relationship with the noise emitted. Results show that the use of a binder modified with a high content of crumb rubber reduces the noise emitted by the tyre/pavement interaction

Pavement temperature influence on close proximity tire/road noise

The aim of this work is to analyze the influence of the surface temperature on the acoustical behaviour of a semidense asphalt pavement located in an urban area. The sound levels emitted by the interaction between a reference tire and the asphalt pavement at different surface temperatures were measured with the trailer Tiresonic Mk4 LA2IC-UCLM rolling at a speed of 50 km/h. The analysis of the results shows that increasing pavement temperature leads to a reduction in the close proximity sound levels assessed at a rate of 0.06 dB(A)/°C. Moreover, spectral analysis confirms that both the mechanisms associated with vibration and impacts and those related to the friction and adhesion between tire and pavement in the contact patch could be affected by the variation of the surface temperature