The best porous asphalt pavement in Sweden so far

摘要

In 2010 a double-layer porous asphalt concrete (DPAC) pavement was constructed in various versions on the E4 motorway through the Swedish city Huskvarna. As a result of a court decision the Swedish Transport Administration had to reduce noise emission by applying a low noise road surface that would reduce A-weighted noise levels by 5 dB, as an average. Earlier experience in Sweden indicated that it was possible to obtain a high initial reduction but due to the widespread use of studded tyres in winter, clogging and ravelling created a loss of around 2 dB per year, with an acoustical lifetime of only 3 years. However, the improved pavement in Huskvarna has exceeded lifetime and durability expectations by at least 100 %. The first three years noise reduction fell from the initial 7-8 dB by about 1 dB, compared to an SMA 16 pavement, and now in its 4th year the main pavement still performs well. This paper presents results of noise measurements over a 4-year period on various versions of the DPAC and single-layer porous asphalt which were tried at the site. This includes the effects of grinding, cleaning, and rejuvenation. Measurements were made by TUG using the CPX method and two reference tyres.