Pass-by Noise on Different Concrete Surfaces - A Canadian Experiment 2001-01-1567
A comprehensive study was undertaken to evaluate the effectiveness of different proposed low-noise surface treatments for concrete road pavements. The acoustical results of that study are described in this paper.
Several consecutive 500 metre long trial sections were integrated as part of a newly constructed concrete freeway. These trial sections included several control sections of regular transversely tined concrete, a randomly tined section, and a number of different exposed aggregate concrete (EAC) surfaces of different aggregate types and sizes, all surfaced using a shotblasting method.
Controlled tests were performed prior to opening of the highway, and uncontrolled tests were performed just after the highway was opened using the statistical pass-by (SPB) method. Both sets of this initial data indicated that the shotblasted surfaces were all approximately ½ dB quieter than the transversely tined control pavements, although it was noted that the variability between the different control surfaces was on this same order. It was also found that the control sections were among the quietest of Portland Concrete Cement (PCC) pavements, having an emission level almost 2 dB quieter than the FHWA average for PCC, and that the randomly tined surface was almost 2 dB louder than the controls.
Follow-up testing performed a year after the highway opened indicated only subtle changes relative to the initial results, with most trial pavements including the control sections becoming slightly (½ dB) quieter.