The Road Emulsion Association recently published its 2024 surface dressing volumes. After a 12-year decline of this specific preventative measure, the summer of 2024 revealed an uptick in the amount of bitumen emulsion manufactured for the use of surface dressing.  

9% more surface dressing was carried out across England between April and August 2024 compared to the same period in 2023. Circa 38.5 million m2 of surface dressing was applied over the surface treatments season in 2024. 

This could be a sign of market recovery and potential change in the focus amongst local highway authorities who are investing more in preventative maintenance, which is what we have been calling for as part of our campaign, Futureproofing Our Local Roads.  

However, this upturn is still significantly below the typical volume of surface dressing used before the decline that we have experienced over the last 12 years.

In this article, we explore the benefits of surface dressing and the extortionate costs the country will now face repairing roads that will most likely need full resurfacing following a 12-year period of deterioration. 

What is surface dressing

Surface dressing is a surface treatment that supports a preventative road maintenance strategy, keeping roads in good condition for longer, and preventing the onset of aging that leads to asphalt deterioration and eventually potholes. 

Surface dressing is a combination of an emulsion binder (black sticky stuff), and chippings, which can be applied to a structurally sound, good profiled road, whilst still either in sound condition or with only a small number of defects, (typically by around years 7-8). 

This seals the road surface, preventing the damaging effects of water ingress, whilst restoring surface texture.

Why is surface dressing a useful preventative treatment?

There are many ways to keep good roads in good condition. There is no one-size-fits-all approach because roads across the UK are characteristically different. 

For roads that are not drastically defected, surface dressing can be applied to prevent further deterioration.  

Low carbon emissions

There is a significant carbon benefit to be gained using surface dressing as part of a robust preventative maintenance strategy. 

If the 12-year decline (since 2024) in surface dressing had been prevented, and we had continued to surface dress roads at the same rate, an extra 182.5 million sqm of road would have been preserved. These roads are now likely in need of full resurfacing due to deterioration, creating an extra 760 Million Kgs of CO2 per m2 – a  circa 700% increase. The opportunity of saving those carbon emissions has been lost. 

Cost effective

Similarly, the opportunity to save financially has been lost. To surface dress 182.5m of roads, it would have cost £730m. But to now resurface those roads due to lack of investment and inevitable deterioration, it will cost £3.6Billion. This is a staggering 500% increase. The whole lifecycle costs of early preventative maintenance methods such as surface dressing are £39m2. This is based on a 90-year life of a typical lightly trafficked road and includes one asphalt surfacing intervention over this life period.

Safety

Over time the travelling of vehicles on the road surface can polish the aggregate on the surface of the asphalt layer. This can reduce the skidding resistance of the road surface even if the road surface is intact, therefore applying a surface dressing at the correct time improves the safety of the road in relation to the ability of the surface to help vehicles stop under braking. 

Surface dressing provides a new skid resistant surface, with added water protection to seal the road and prevent potholes. The application of a new layer of fresh aggregate in the process of laying surface dressing ensures the skid resistance of the road surface is renewed. 

The use of encapsulation provides an additional surface coating and water proofing layer when first applied with the appropriate initial texture required for the surface to provide skid resistant properties. The appearance is similar to that of a newly laid thin asphalt surfacing.

Resilience

The predominance of Polymer Modified Emulsion binders in surface dressing provides extra elasticity and resilience to the binder (glue) which the aggregate is bonded to in the surface dressing process. Surface dressing provides an important waterproof coating to the original road surface enabling the road to become more resilient to worsening weather conditions because of climate change. Encapsulation ensures a double layer of waterproofing and therefore increases the resilience of the existing road to recover from extremes of cold and wet weather together with warmer summers.

It is possible for local authorities to futureproof their roads at a lower cost and more sustainably. It just requires a different mindset and an understanding that, while there will always be a need for reactive maintenance, this can be massively reduced with investment up-front in preventative measures. 

Notes to Editor:

The Road Emulsion Association (REA) is a UK trade association representing manufacturing businesses that supply a wide range of bitumen emulsion products used in the highways, airfield and construction sectors.
 
We aim to provide a good member intelligence network to understand what issues are on the agendas of policy-makers and businesses as well as those issues that are important in central and local government policy making. We attempt to identify the effects of policy measures on our sectors and contribute to government consultations.
 
This Association has an extensive knowledge of our industry and we believe trade associations can form effective partnerships with governmental and academic bodies to bridge mutual gaps in understanding.