Significant advances in technology mean road building in the twenty-first century will be very different to the last 100 years. But how sustainable will these highways surfaces be and how will innovation come against a climate of cost-cutting? James Evison reports.
The advancements in road building across the UK and globally has resulted in amazing progress in recent generations however we are now entering a new era where efficiency and sustainability is key.
The Highways Agency has helped lead on this agenda. Its sustainability plan includes specific criteria for the creation of ‘green’ roads – albeit ones still created using the traditional mix of materials.
The Highways Agency aims to drive down carbon emissions and increase levels of sustainability – as outlined in its 2012-15 plan – through reducing waste and increasing the efficiency of construction methods.
All this will help, but the UK’s dependence on the oil industry – and within the next decade solelyimported oil at that – means that the highways sector has to move towards new surfacing materials and techniques or risk huge increases in costs.
Highway construction has always used industrial waste and other by-products as a material base to reduce costs and to manage materials that were hard to dispose of.
The current challenge has been to use these materials in ways that do not compromise critical performance properties.
Rubber from old tyres has been used as an additive in hot-mix asphalt, and fly ash, a residue from coal-burning power plants, and silica fume, a residue from metalproducing furnaces, have also been used as additives to Portland cement concrete. Another example on the M6 was to use old books - in this case, pulped romance novels.
A new approach has also been highlighted in the last month to cut costs: re-texturing and re-profiling roads. The technique involves the mechanical reworking of an existing road surface to improve its frictional skid resistance and the re-use is effectively 100% recycling in situ.
The Road Surface Treatments Association (RSTA) has even established a new sub-committee to forward best practice specification and installation of the technique, which aims to give local authorities a viable new highways construction and maintenance solution, against a backdrop of limited road budgets. The technique can also help extend the life of existing roads significantly, the RSTA claims.
For the successful and widespread introduction of the technique, amendments to the Highways Agency’s design manual for roads are required alongside a code of practice. With the current funding squeeze, the will is there to ensure this happens.
Martin Leech, chair of the new sub-committee, said: ‘Re-texturing and re-profiling have considerable potential for cost-effective and sustainable road maintenance.’
Another key example for local authorities on how to maintain highways in the future comes from Blackpool. Recent research by Ipsos MORI for the National Highways and Transport (NHT) Network, exclusively unveiled by Surveyor’s sister publication, Transport-network.co.uk, suggested Blackpool was the only council in the UK to see improvements in all strands of highway maintenance in the last year.
The local authority chalks much of this up to its Project 30 scheme. The highways work saw an investment of £30m across more than 40 miles of roads. It saw detailed and accurate condition report created for every single square metre of the network. Because data on the condition of the roads was not considered significant enough to target costs, assumptions were then also made on the worst case scenario for the highways surface.
Will Britain, principal engineer at Blackpool Council, said: ‘It was designed to respond to public views on deteriorating roads while aiming to save money in the long term.
‘There is much more to do but we our widely improved ratings show the public are already experiencing and valuing the improvements.’
The eventual plan at Blackpool is to have a highways department with no backlog, arrest the decline of the highway network, carry out all maintenance on a proactive and planned basis, drastically reduce tripping claims and subsequently save the authority £100m over the next 25 years. In other words, create an ideal scenario for any local authority roads team.
So maybe the solution for dealing with spiralling pothole backlogs, roads maintenance regimes and general highways maintenance isn’t to go rushing to new technologies or cheaper surface mixtures.
Instead, it is simple management: invest in resolving the ‘to-do’ list and look at each road in the local area carefully. This isn’t even a hypothesis. Blackpool proves it works.
