Academic research by two universities in the same UK city shows that patch repairs on potholes could be far more durable if a few simple techniques were consistently used. Guy Woodford reports.
Repairing pothole damage to highways and vehicles across Europe costs responsible authorities and individual motorists hundreds of millions of euros each year.Yet it has cost just €20,204 to make the potentially crucial first step in identifying a method of keeping highways across the continent and beyond pothole free for a much longer period of time.
An initial Institution of Civil Engineering (ICE) and industry partners funded study by
It was also confirmed that a hot mix repair – in which asphalt is heated to 140°C or more - was the best option for repairing potholes with a depth of more than 2.5cms.
“The [UK] public purse carries a huge burden with the cost of pothole repairs as so many of them have to be repaired again and again. It’s essential, therefore, that we understand more about how they are created and how they can be repaired in a more efficient and a better way,” said Dr Mujib Rahman, a senior lecturer in civil engineering at Nottingham Trent University’s School of Architecture, Design and the Built Environment.
“As an initial study, we have found that if a few simple and cost-effective measures are applied with each repair then there may be less need for as many repeat repairs.”
The initial study, which was funded by the
During the study it was also found that the presence of water accelerated pothole cracks significantly increased a pothole’s permeability.
Dr Nicholas Thom, of the University of Nottingham, said: “This study to some extent confirms what many practitioners will have always thought, but until now virtually no scientific work has been done to prove this. This study holds the promise of transforming general understanding into a usable design approach, based on both experiment and computation.
“The key requirement is a means of predicting the life of different types of repair, allowing informed decisions to be taken by highway authorities, and progress has certainly been made towards this end. The recently completed study will feed into follow-on research at both universities, acting co-operatively, so while we haven’t seen the last of the pothole there is hope that it could one day become a rarer sight.”
Some of the follow-on research mentioned by Thom has already begun: a PhD student at the University of Nottingham has received funding for a three-year study into the pothole foundation mechanism. It is hoped that another PhD student will receive funding for a three-year study at Nottingham Trent University from September 2013 into the evaluation of asphalt pothole patch repairs under laboratory conditions.
Speaking about the aim of the continued pothole repair research, Rahman said: “We want standardised repair guidelines that will make sure nine out of ten repairs actually last for a specified period of time. At the moment the guidelines are quite loose, we need to tighten them. These guidelines need to be backed up by research, like ours.
“We have climate change and every year potholes are increasing by 10 to 15%. If we can avoid or delay a repeat repair there’s not only cost savings but environmental benefits also.”
Institution of Civil Engineers vice president, Geoff French, said potholes present an “on-going frustration” for the public.
He added: “More preventative maintenance that lasts is needed to ensure our roads are more resilient and this is an approach that is likely to be more cost-effective in the long run. We are therefore pleased that this initial study shows the potential for a repair method that could achieve these aims in the future.”
Survey highlights UK’s ‘crumbling roads’
The recently published annual national survey of UK local road network condition and funding claims there is a crumbling road crisis of increasing concern, prompting renewed calls for increased and longer-term Government funding.
Commissioned by the
The AIA, an alliance of the
The cost of filling the estimated 2.2 million potholes across England and Wales came to around US$168.69 million (£113 million), while $47.77 million (£32 million) was paid out in compensation claims and the cost of staff time spent on claims amounted to over $19.40 million (£13 million). The survey found that councils have paid out 50% more last year than the previous year in compensation claims from road users for damage or injury due to poor road condition.
While the cost of filling potholes is not increasing significantly overall, they indicate poor road condition that is costing the country heavily in many other ways. This year, local authorities in England (including London) report a shortfall in their annual budgets of $1.23 billion (£829 million). Across England and Wales, authorities estimate that $15.67 billion (£10.5 billion) would be needed to bring their roads back into reasonable condition.
“It’s time to stop the rot. The Government needs to make sufficient funding available now that will enable local authorities to get their roads back into a condition that will quickly and directly boost the economy, help businesses and improve local communities,” says AIA chairman Alan Mackenzie.
