p06-09_MiMagazineFEB/MAR.qxp_Layout 1 23/01/2024 17:42 Page 6
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POTHOLES – the big, the bad and the ugly… By Melanie Wooding Jones – Redbourn Auto Solutions – Caring for you, and your car
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here are an estimated one million potholes across the UK, causing breakdowns to rise to a fiveyear high at a cost to drivers of £474 million. So, why do we have so many and how can we avoid any unnecessary motoring costs?
Why do potholes occur? Potholes are formed by three elements: surface cracks, water ingress, and movement. They then expand according to weather conditions and the amount of distress caused over the weakened area. Surface cracks appear when there is an inadequate road structure. The layers are defined for the applied level of traffic loading allowing the road to flex under defined parameters. However, repeated strain at the bottom of the asphalt can result in the initiation of fatigue cracks which are exacerbated when the defined wheel load is exceeded. Our roads have become busier, so it is no surprise that these loads are regularly surpassed. Other contributory factors are
poor drainage, ageing asphalt, shrinkage, reflective cracking (where a new asphalt covers old), or where utility trenches have been excavated and the disruption of soil creates movement. Water seeps into the cracks, saturating the asphalt layers and softening the soil below, damaging the infrastructure. Movement from traffic pounding the road, fractures the surface which continues to expand and deepen contaminating the layers beneath, creating further weakened areas. This is most likely to occur under where wheels regularly travel and usually closest to the kerb where water drains. Rainfall and freeze/thaw cycles accelerate development, which is why we see an increase of potholes forming in the winter months. Why are there so many potholes? There are several reasons why we are suffering with an increase of potholes across the UK:
