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Pothole repair

Potholes - a big problem

Potholes are a HUGE problem both in the UK and around the world.

At Thermal Road Repairs, we have produced the perfect solution to beat this scourge that threatens almost everyone in some way, pedestrians, cyclists and motorists alike.

Our patented technology offers a right first time, low emission, zero waste, cost effective, permanent solution to this problem.

But in case you wanted to know more about potholes, please see our simple guide below:

Everything you ever wanted to know about potholes but were too afraid to ask

1. When should you treat a pothole?

Before it even exists. As soon as cracks begin to appear, consider applying some form of surface treatment. 

Surface dressing, where a bitumen binder is sprayed onto the road and then stone chippings spread on top, is better for busy urban or rural roads.  Micro surfacing (also called micro asphalt or thin surfacing) involves the application of a base and top layer of slurry – a water-based mix of stones and bitumen – onto the road surface. It is best for less-busy roads.

2. What is a pothole?

There’s no formal definition of a pothole. They are usually between 40mm and 60mm deep and cover an average area of 0.35m2. Most treatments are effective up to these depths. (Shameless plug: Thermal Road Repairs technology is effective up to 100mm deep).

Any defect in the road should be treated because it is only going to get bigger and bigger. Cold joints over reinstated utility trenches and infills around utility covers are commonly occurring weak spots which some councils choose to treat early.

3. What causes potholes?

Over time, the bitumen that holds the aggregate in a road surface becomes less elastic which means that it is more susceptible to cracking. The higher the volume of traffic and the heavier that traffic, the sooner this point will be reached. Once a defect has formed, as described above, water can get into it. When water freezes, it expands, pushing the crack further open (freeze-thaw action).

Sometime freeze-thaw can attack from below as well. For instance, if a thinnish layer of asphalt has been laid over cobbles or compacted stone in a country road. In these cases, larger areas of asphalt may delaminate.

4. What are the methods of repairing potholes and which one is best?


Patch with hot asphalt

Traditional method which involves squaring up the edges of the pothole, taking loose material away, bringing in hot asphalt to fill the hole and compacting.

  • Where: any road

  • Pros: quick, familiar

  • Cons: joint between old and new material is a weak point for water ingress, high carbon emission, risk of HAVS, noise pollution, prone to failure, extra asphalt required, multiple vehicle movements required


Thermal road repairs

Heat the loose material in the pothole and the surrounding area with a specialist heater, top up and mix with missing asphalt, compact.

  • Where: any road

  • Pros: permanent, no joints (seamless), zero waste, low carbon, no HAVS risk, only asphalt to replace missing amounts required, minimal road disruption, low noise, 1 self contained vehicle

  • Cons: requires specialist unit

(Shameless plug: not all systems are created equal. Thermal Road Repairs’ patented system heats the road in a very controlled way to optimise the bond at the perimeter of the pothole. It also uses solar energy to partially power the heater, further lowering the carbon footprint of the repair).


In-situ thermal recycling

Loose material is removed from the road, heated and mixed in a purpose-made vehicle with new material before being returned to the pothole and compacted.

  • Where: anywhere, needs high volume to be cost effective

  • Pros: reduced waste, lower carbon

  • Cons: specialist operation, cold joint remains a weak spot for water ingress and failure, significant space and traffic management required


Spray injection patching

A specialist machine applied cold emulsion asphalt into potholes under high pressure. The same machine is used to prepare the pothole by blowing out any loose material and then to apply a bitumen emulsion before aggregate is added to the stream to fill up the pothole. It is self-compacting.

  • Where: rural roads

  • Pros: fast, lower cost, no waste, no HAVS risk

  • Cons: specialist unit, durability may be a problem


Cold-applied instant material

Pothole is prepared by squaring up the edges and applying a primer to the bottom and primer. The material is then applied and compacted, possibly in layers, and a primer applied around the edges.

  • Where: ideal for lower trafficked roads

  • Pros: fast, good for temporary repairs, lower carbon

  • Cons: durability not great for trafficked roads


All in one cutting machines

There are various machines in the market that claim they are an all in one fix to potholes. But is that really the case? These machines generally cut around the pothole, straighten the edges and clean the hole in preparation for the hole to then be filled. But they then require extra stages to fill the potholes.

  • Where: ideal for larger roads

  • Pros: fast for cutting, making edges and cleaning potholes

  • Cons: it doesn't fill the pothole, they cause extra waste material, multiple vehicles and crews are required on site to undertake different stages of the repair process, machines are large so need to be transported to site if too far to drive, larger machines mean extra disruption to roads, potentially high carbon emissions and footprint for the entire process, produces a joint which could allow water ingress and failure of the repair


5. How can I lower the carbon footprint of my pothole repair?

There are six questions to consider when looking at ways to reduce the carbon footprint of a pothole repair.

  • Is there any waste material to be taken away?

  • Does the patching medium contain recycled material?

  • How much heat is used in the process?

  • Does energy come from a renewable source?

  • How many vehicle movements are needed?

  • What is the patch’s longevity? This is perhaps one of the most important aspects. Mending a pothole twice is spending the carbon twice.

(Shameless plug: Thermal Road Repairs’ system ticks all these boxes)


6. What are the other considerations when repairing a pothole?

The responsible authority has a statutory responsibility to keep its roads as safe as possible, under Section 41 of the Highways Act 1980. It may be that speed of repair is the number one consideration due to concerns about the safety of car users or cyclists. Some councils are also facing hefty claims from motorists looking to recoup the cost of damage to their vehicles.

Access and width of the road will also dictate what methods are possible, and what aren’t. Residential streets with parked vehicles will require a different approach to main roads, country lanes demand a different approach again.

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