Quiet asphalt for a main road

For routine resurfacing on a low-speed stretch of the A4020 Oxford Road the client, London Borough of Hillingdon, sought not only to improve the condition of the carriageway but reduce noise levels for local residents. The carriageway was showing signs of reflection cracking from the underlying layers and deterioration of the surface course.

After discussion with the client Tarmac proposed using 10mm ULTIFLEX, a thin asphalt surface course made with polymer modified binder to provide enhanced rutting resistance and noise reduction. Around 200 tonnes of ULTIFLEX and a flexible binder course were laid by our team along 225m of the northbound carriageway of the A4020 during three night-time possessions. To ensure minimal disruption to road users and local residents, we carried out the works under full carriageway closures between 20.00hrs and 06.00hrs over three days.

Testing after the work was completed measured average LAeq and LA10 noise levels were 76.9 and 81.0 dB respectively before resurfacing and 70.4 and 73.4dB after resurfacing - giving reductions of 6.5 and 7.6 dB respectively. This significant noise reduction was also noted by local residents. The findings of the study open new possibilities for the type of resurfacing material selected for low speed roads.