Renewing road surfaces

Road surfaces become worn out due to the volume of traffic that use them and the different extremes of weather that affect them. We carry out a series of nationally approved surveys each year using specialist vehicles to determine the condition of the local road network.

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Road surface treatments

Different surface treatments are used according to the condition of the road, how busy the road is and the most efficient treatment.

Below we've explained when each type of dressing is used, as well as an explanation of what it involves.

When specific surface treatments are used:

surface dressing is used where the surface is in reasonably good condition but needs sealing to prevent water damage - we can cover a large area very quickly at relatively low cost - we use surface dressing on most of our surfacing programme
micro surfacing is a slightly more durable and more expensive process which places a thin layer of new surface on the road - it takes longer than surface dressing but is used where roads are busier, and the road needs more levelling
asphalt preservation is a sustainable and cost-effective solution to improve roads by sealing the surface layer, extending the resilience and performance of a road surface
machine resurfacing is where the existing surface is removed and a new surface is laid as a replacement (between 30 to 105mm of new asphalt) - sometimes the existing road will be overlaid with the new surface, but generally the existing surface will be removed and replaced
grouted macadam provides enhanced structural performance, as the excellent aggregate interlock and specialist heavy duty grout provides a durable surface in high stress areas
retexturing is used to improve skid resistance and extend the life of road networks - it is used when a road's surface layer is aging, but the structure is in otherwise good condition
joint and crack sealing protects the joints where sections of surfacing meet and prevents damage to the road by stopping water getting below the surface and vehicles wearing away at the edges of exposed cracks

Surface dressing

Surface dressing involves the application of stone chippings onto a layer of bitumen binder. The chippings are rolled into the bitumen to form a water-resistant protective layer which makes the road less slippery and extends its life.

Surface dressing takes place during the spring and summer months, although we will carry out preparation works throughout the year. The treatment is very weather dependent, so the date of works can change at short notice if conditions are too cold, hot, or wet.

For further information, watch the Road Surface Treatment Association's surface dressing video on YouTube.

We sweep the road to remove any loose chippings, but the nature of the treatment means there will be some loose chippings on the road surface until it beds down. During treatment, we will set temporary speed limits of 20mph and avoid sharp turns, to allow the surface to stabilise and prevent damage to vehicles.

We will replace the road markings and studs that were on the road before laying the new surface on the completion of road sweeping.

Micro surfacing

Micro surfacing is laid on top of the existing road surface and restores the surface texture and improves skid resistance. It forms a water resistant, protective layer which extends the life of the road. It is applied cold and consists of a thin layer of bitumen, fine aggregates, cement and water.

There may be some loose material on the road for a short while after it has been laid. We will sweep up any loose materials when we return to replace all road markings and studs that were on the road before laying the new surface.

Machine surfacing

Machine resurfacing will usually involve removing existing road layers. This process is known as 'milling' or 'planing' and is carried out by large machinery which breaks up the existing road before removing it.

The planed area will have the manholes and gullies adjusted and replaced if required. A bitumen spray coat will then be applied, and the new surfacing laid. The surfacing will consist of either one or two separate layers, depending on the shape and condition of the road structure.

We will replace the road markings and studs that were on the road before laying the new surface after compaction and when the road surface temperature has cooled.

Grouted macadam

Similar to machine resurfacing, the treatment involves removing existing road layers and adjusting or replacing existing manholes and gullies if required.

There are two main types of grouted macadam surfacing - those grouted with an asphaltic grout and those with a cementitious grout:

asphaltic grouted macadam: a hot, open-graded asphalt laid (by an asphalt paver) to a depth of between 30mm and 50mm, which is then sealed with an asphaltic grout - sealing the surface course reinforces its strength
cementitious grouted macadam: a hot, open-graded asphalt typically laid (by an asphalt paver) to a depth of between 35mm and 50mm with a 'controlled void content' which is then filled with a resin cementitious grout - a flexible, heavy-duty surface course is capable of withstanding intense traffic loads and fuel contamination

Both high-strength materials provide complete sealing against water and flexibility to withstand underlying movement.

We will replace the road markings and studs that were on the road before laying the new surface after grouting is completed.

Retexturing

Road retexturing involves blasting and cleaning the road using specialised vehicles with ball bearing or water blast equipment attached.

The vehicle travels along the road first removing excess debris, and then blasts the carriageway with high pressure to refresh the surface material. This increases the surface texture of the road, making the surface more skid resistant.

Joint and crack sealing

Joint and crack sealing involves removing the existing road layer. This process is known as 'milling' or 'planing' and is carried out by small machinery that cuts a section of road 200mm wide and 20mm deep.

The cut section is mechanically swept and cleaned before applying a joint sealer. This is poured into the cut and screeded to a smooth level finish, to seal the edges and provide a watertight seal. Finally, aggregate is applied to leave a skid resistant finish.

Footway resurfacing and preservation

We resurface and preserve our footways, kerbs, blocks and slabs where necessary, depending on their condition, usage and defects. We use a variety of treatments, from applying a thin surface, such as slurry sealing, to a full reconstruction.

Footway resurfacing

Footway resurfacing is similar to road resurfacing. Resurfacing is the most expensive treatment option available and involves the replacement of the surface and substructure where it has deteriorated extensively. The existing layers are removed, and a new surface is laid.

Footway preservation

Footway preservation (slurry seal) is a low-cost, preventative maintenance process. It is designed to seal the surface of a structurally sound footway to extend its life. It fills in minor depressions and holes and provides a more even surface.

Slurry is a mixture of bitumen emulsion, aggregate and water, which is spread over the existing footway. Before laying, we may have to prepare the existing surface by cleaning, weed spraying, minimal patching and raising ironwork (manholes and gullies).