Road surface treatments
Identification and prioritisation
Identification and prioritisation of structural and preventative maintenance schemes is undertaken using the results from highway condition surveys that are undertaken on a regular basis.
A lifecycle planning approach is then adopted to ensure highways benefit from the correct maintenance treatment at the appropriate time within their lifecycle; ensuring the efficient and effective use of available resources.
As the funding for highway maintenance is not proportionate with all of the work required, a further developed value management process is used to prioritise sites that are of an equal or similar condition.
This involves scoring locations against various criteria including the number of safety defects recorded at the site, accident rates and the contribution of the scheme to the sustainability of the area.
How often are preventative maintenance treatments required on roads?
This is dependent upon several factors. Ideally, a new carriageway will be preventatively treated three times at intervals of between ten and fifteen years, followed by replacement after a further ten to fifteen years.
Preventative maintenance treatments
Preventative maintenance treatments such as surface dressing, micro asphalt, footway slurry sealing, etc, are used to preserve and extend the life of roads that are already in a reasonable to good condition.
It is crucial that these treatments are undertaken before serious deterioration has taken place rather than repairing inevitable deterioration through routine and reactive maintenance works and eventually, structural maintenance schemes which cause increased traffic congestion and are much more expensive and time consuming.
If roads did not benefit from preventative treatments they would require replacement three or four times as often. Most preventative treatment applications are usually completed at each site within the same day although some preparation works might be required beforehand with subsequent lining and cat’s eye replacement works following after.
The carriageway preventative maintenance season is from late March or April to September, footway preventative treatments are carried out all year round and these may take place outside of normal working hours or on restricted working days. All preventative treatments are weather dependent which can affect the length of the working day or when they commence.
Preventative maintenance treatment types
There are various surface treatment designs that feature on the below programmes and the following descriptions explain the processes involved in each type which may assist when responding to enquiries.
10/6 Racked in, 6mm single, 10/6 Double Dressed
These are all the basic traditional surface dressing designs that have been around for some years, they are generally completed in one visit apart from any back sweeping that may be required.
This is basically as a 10/6 racked in design above but then after an initial sweep a couple of days later, the team will return to apply the lockdown part of the treatment which is just an emulsion type spray that goes onto the new dressing to “Lockdown” the aggregate.
This is a very fast process and is usually drivable on after around 30 minutes (weather temperature dependent). This treatment can be used on a variety of different sites, such as main roads or rural lanes or spine roads through housing estates.
This is very similar to the above Finagrip 10/6 treatment whereas it is a two-visit treatment but it will only receive a 6mm dressing first and is more often used on housing estate roads or urban streets.
This is a one visit treatment that will usually be laid in two layers, a regulating layer and a top coat. It has more depth than the above surface treatment designs. Once complete the site may have ironwork such as grids and manholes left low, there should be signage up to indicate this and a team following on behind as soon as possible to adjust the low ironwork.
The initial end appearance of micro asphalt can be a little untidy and may need one sweep, but it is a treatment that after a few months settles down.
This is very similar to micro asphalt but is a stronger and more robust treatment and is usually used on busier low speed roads.
This is very similar to the two above treatments but it gives better skid resistance and added texture.
Visit our highways programmes page to view the surface dressing programme. If you have any queries, please visit our frequently asked questions page.