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About road surface dressing and micro asphalt

What is the difference between surface dressing and micro asphalt?

Surface dressing is designed for roads with heavy traffic whilst micro asphalt is used on residential roads with slower moving traffic.


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What is surface dressing?

Surface dressing involves spraying bitumen binder (a sticky tar-like substance) on a clean, dry road surface, over which stone chippings are spread (small, consistently-sized aggregate). The surface is rolled to embed the stones into the bitumen although some loose stones will remain on the road surface for about a week. The weight of vehicles passing over these loose stones will force them in to the bitumen to finish the new road surface.

We will sweep the area again approximately one week after the new surface has been laid and again if necessary. To be successful, surface dressing relies upon warm dry weather, and for this reason work is usually carried out between May and August.

Getting a grip on surface dressing video

Please see the short video below (less than 5 minutes) which gives further information on the surface dressing process and the loose chipping issues.

View on YouTube.com

Why do we use surface dressing?

Surface dressing has three main purposes:

  • To provide a safer, non-skid road surface
  • To seal and waterproof the road
  • To extend the life of the road surface, it could prolong the life of a road by over 10 years.

In addition:

  • it is a relatively quick treatment as 1km of road can be completed in about 2 hours, which minimises delays to traffic;
  • it is more environmentally friendly, as we re-use materials to conserve natural resources wherever possible;
  • it is up to three to four times cheaper than alternative ways of maintaining a road;
  • it can improve the appearance of heavily patched roads.

When can road markings be replaced?

Road markings will not be able to be replaced until after the final sweep has taken place. This can take up to three weeks.

Does surface dressing create a noisier road?

Surface dressing can produce a little more tyre noise than some other road surface treatments. This noise will reduce in time as chippings are embedded into the surface.

We cannot always use quieter treatments because, in many situations, a good road surface texture and excellent skid resistance are crucial for the safety of road users and outweigh the need for reduced noise.

Why is there a temporary speed limit after surface dressing?

Surface dressing is vulnerable to fast or turning traffic immediately after laying. This is why there are temporary signs asking you to keep your speed down to 20mph. Travelling any faster than this may prevent the chippings from becoming properly embedded in the binder – as well as risking broken windscreens and chipped paintwork.

If the chippings do not become properly embedded, then the work will need to be repaired or replaced much earlier than usual.

Please help us to make sure that the resurfacing is successful by:

  • Driving at low speeds over new works until all warning signs have been removed
  • Not parking your car in the area to be resurfaced when work is planned
  • Letting us know if there continues to be a problem with loose chippings following the treatment.

Why are we surface dressing a road that was only resurfaced a few years ago?

Many surface dressing schemes are carried out as 'lifecycle' schemes, due to some surface materials having a lifespan of only 7 years before they may let in water, which can lead to deterioration and increase the likelihood of potholes. Surface dressing reseals and waterproofs these surfaces, preventing this deterioration and extending the road life for up to a further 10 years.

What is micro asphalt?

Micro asphalt surface treatment is a preventative maintenance treatment, used to seal the existing road surface, improve the texture and helps water evaporate. This type of surface treatment can prolong the life of a road by up to 10 years. It is mostly used in residential areas with slower moving traffic.

The work involves applying a base and top layer of slurry to the existing road surface. The treatment acts as liquid when first applied, but this dries within 30 minutes and is then ready for traffic.

Following the treatment, loose stones may remain on the road surface for a period and temporary road signs are used to advise motorists and motorcyclists to drive carefully.

When can I park on the road?

When the micro-asphalt has set, you can drive on the road and park on it again. It can take anything from 30 minutes to over an hour to set depending on the weather conditions at the time.

Will the road be monitored after the initial work?

We will monitor the road over the following seven days and return to sweep if required.

For a few days after the work and during prolonged spells of hot weather, the surface may still be sticky and could easily be carried into your home on shoes. Please be careful and check your shoes.

Are there any circumstances that will stop this work taking place?

This type of work is weather dependent and bad weather means the work will be rescheduled. If we're unable to work on the date specified, please keep the road clear of vehicles the following working day.

When will the road markings be replaced?

Road markings can only be replaced after the final sweep has taken place which can be a few weeks after the works. Where needed, temporary signs are put in place reminding the public that road markings have been removed.

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