The Road Surface Treatments Association (RSTA) has welcomed news by the Road Emulsion Association (REA) that indicates an increasing trend in the amount of surface dressing carried out by local highway authorities in 2024, following a twelve year decline, and lowest reported use of surface dressing in 2023.
But the association also said there was ‘still much progress to be made’
The use of surface dressing and other preventative treatments including preservation, rejuvenation, and micro surfacing as part of a preventative maintenance strategy, offer significant financial savings both in the short and medium to longer term as part of a whole lifecycle approach, and similarly huge carbon savings also.
Surface dressing (like micro surfacing) seals the road surface, restores texture, and keeps roads in good condition for longer, prolonging the life of the road and preventing potholes.
Responding to this, Mike Hansford, Chief Executive of the RSTA said: “There has been much discussion within the industry, especially with very experienced individuals within the RSTA and the REA, who recognise how critical it is to seal road surfaces from the damaging effects of water ingress. Therefore the decline in the use of surface dressing from 64.4million m2 in 2012, to 35.3million m2 in 2023 is very alarming, and it’s no surprise that we are in a position of poor road condition and increasing numbers of potholes. So it’s encouraging that the trend is starting to turn, with increasing figures for 2024.”
Mr Hansford said there were other surface treatment options such as preservation, rejuvenation and microsurfacing which similarly protect against water ingress and keep roads in good condition for longer, but use of these treatments have remained fairly static, and not seen the sort of growth anticipated by the implementation of the Incentive Fund, which promoted an asset management approach and therefore development of preventative maintenance strategies.
Mr Hansford added: “All of these surface treatments support a preventative asset management strategy for roads, and those local highway authorities that have developed this approach and adopted these treatments can demonstrate how effective they are at managing road condition and preventing potholes.
Use of data and asset management systems is incredibly powerful, and through whole lifecycle modelling will demonstrate the positive impact of preventative treatments, and this can be presented to senior decision makers, to support the case for policy and strategy change.
“Trying to understand what the reason might have been for this decline in the use in surface dressing over this time; this may be related to historic experiences or reputation, or a lack of knowledge or understanding about surface dressing, and more widely about preventative maintenance strategies and treatments.”
He went on to say that any historic failures in surface dressings might have been due to poorly designed dressings, materials selected, or not having considered suitability for dressing in the first place. So educating and informing engineers about this treatment, is essential.
Surface dressing has developed considerably in recent times with polymer modified binders, super premium grade binders that are more resistant to heat, and encapsulation systems (see photo) that make the dressing more resilient. Encapsulations address many of the issues the public complain about in relation to loose chippings, aesthetics (it looks like a conventional asphalt), stripping etc.
There are also fabrics being used under surface dressings to address roads that may have low to medium levels of bleeding or cracking, which might otherwise have been deemed to be unsuitable, according to the RSTA.
The association offers extensive advice and CPD training on how to prepare a road for surface dressing, as well as site selection.
It is important to understand the limitations of all treatments, so if the deterioration of a road has progressed to a point where it’s no longer suitable for surface dressing, then an alternative treatment such as micro surfacing (Cold Applied Ultra Thin Surfacing (CAUTS) for 250> cv/d) might be more appropriate, which will regulate out any minor surface defects and seal and regularise the road, whilst also restoring texture.
Understanding that if these opportunities for treatment are missed and the road becomes unserviceable, in-situ recycling may be more appropriate, where the existing asphalt is pulverised and repurposed, with the addition of binders to form a solid bound layer on which to lay a new surface (which could be a surface dressing, micro surfacing or even a conventional asphalt).
If replacement of asphalt layers is selected, use of geosynthetic layers may reduce the thickness with which this needs to be reinstated.
Its important that engineers understand the full range of treatment options, when they might be appropriate, and when another treatment might be a better solution.
But ignoring surface treatments, and only basing a maintenance strategy on pothole fixing and asphalt replacement:
• is a negative cycle – only leads to more potholes which are unpredictable and expensive
• does not offer best financial return on investment
• is significantly more carbon hungry,
• and only addresses a very small proportion of the network.
The RSTA is offering support and guidance to local highway authorities to improve knowledge and aid these decisions, which will improve the condition of our road network.
PIC-KILEY BROS
