The road ahead is concrete

Whole life cost benefits mean the Highways Agency “want to see concrete solutions on the strategic road network”. Our latest report from Britpave’s Steve Elliott.

At the recent ‘Low maintenance highway pavements’ seminar, the concrete pavement sector outlined the options  that can enable the Highways Agency to meet the challenges of operating and maintaining a strategic road network faced with a forecast traffic growth of 46% by 2040.

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The seminar, organised by The Concrete Centre in partnership with Britpave, heard from Mike Wilson, Chief Highway Engineer at the Highways Agency, how road traffic congestion on the UK motorways and ‘A’ trunk roads costs the UK economy some £2 billion a year.

He also reported that so far in 2014, 224 people have been killed and many more injured, traffic noise adversely impacts 4.3 million, traffic air pollution is increasing and that road user satisfaction of the performance and maintenance of roads continues to decline.

However it is not all bad news. Wilson explained how the planned restructure of the Highways Agency into a customer-focused, government-owned Strategic Highways Company offers a very real opportunity to address these issues thanks to a tripling of investment to £24 billion by 2021.

Critically, in future the Highways Agency will plan investment over a five year period. This will offer long-term funding certainty and clarity that will be welcomed by those involved with planning, building and maintaining the strategic road network.

However, in return for this funding certainty the Agency is seeking to save £2.6 billion of the cost of running the road network over the ten years. To help realise this, there needs to be an increased focus on whole life costing, long-term performance, minimum maintenance and interventions, and the adoption of a more product-based approach. 

To forward this the Agency will seek to work closer with the supply chain to develop new delivery models that are focused not only on value and cost but also on delivering the road network that road users’ demand.

Concern for customers

The emphasis on delivering a road network that carries traffic safety, comfortably, economically and with minimal disruption was underlined by Ramesh Sinhal, chief pavement engineer, Highways Agency.  He explained how the strategic road network exists to meet the needs of road users - the customers - and stakeholders. Those needs drive the objectives of the Highways Agency.

Challenging the seminar audience, HA chief pavement officer Ramesh Sinhal stated: “We want to see concrete solutions on the strategic road network.”

Meeting those objectives calls for road pavement surfaces that provide good friction at all traffic speeds, have good longitudinal and transverse profiles, low noise and dust emissions and provide a good interface with road markings. They should be durable and resilient, require minimal maintenance and offer sustainable recyclability. Crucially, they should offer good whole life costing and long-term performance that translates into good asset management.

He outlined the way forward as being based on closer liaison with the concrete pavement industry that allows the development of cost efficient, high performance, low noise, long lasting concrete solutions. Challenging the seminar audience, Sinhal stated: “We want to see concrete solutions on the strategic road network.”

Concrete and DBFOs

His challenge was taken up by John Donegan, chairman of the Britpave Roads Task Group. Donegan outlined how concrete road pavements can offer more-for-less in terms of price certainty, better long term performance and less maintenance. This translates into more reliable journeys for road users, less interventions therefore less need for road workers to work on live carriageways, less congestion due to road works so reduced traffic emissions and, above all, better use of the road network asset. In addition, there is the certainty of material supply and ready availability of multi and single-lane slipform pavers plus mobile concrete plants.

As proof of this, Donegan asked why is it that DBFO road projects are predominately concrete pavements? The answer is that they provide better journey reliability, need less maintenance interventions and offer lower whole life costs. Furthermore, with the confirmed upward trend of bitumen prices, increasingly concrete offers comparable if not better initial construction costs.

There is a range of proven concrete pavement solutions that meet the requirements of the Highways Agency and the demands of traffic and road users. These include rigid concrete options for inlays to flexible pavements, lane replacement and hard shoulder upgrade for all-lane running.  Continuously Reinforced Concrete Pavements (CRCP) with Thin Surface Course offers the lowest maintenance option currently approved.  CRCP with Exposed Aggregate Concrete Surface (EACS) for low noise and even less maintenance, will be an option available without a Departure from Standards from 2015. All of these options are enshrined within existing HA specifications. There are no reasons against their widespread adoption.

M6 J10A-13 

Demonstrating that the proof is in the pudding, Jeff Curry from Carillion provided a case study on the M6 Junctions 10A – 13. The £70 million contract called for turning this section of the M6 into a Smart Motorway using a range of innovative technologies and operating procedures to actively control traffic flow. The challenges faced included getting the best from an existing infrastructure asset, enabling all lane running, and providing accelerated delivery with a fast investment return.

Key to this was the reconstruction of the hard shoulder to allow its use to reduce congestion and improve journey times and safety. On a typical UK motorway, 77% of all heavy good vehicles use the inside lane, therefore, the use of the hard shoulder calls for a pavement solution that has the strength to cope with this traffic load.

A range of construction solutions was examined. Carillion choose a full depth, flexible/rigid reconstruction that could be built during a series of six hour windows and provided guaranteed pavement longevity. The success of the project proved that concrete pavement parity is achievable and the lessons learnt from this project underline the material’s ability to deliver solutions for future motorway widening and full lane running projects.

Connect concrete

Concrete’s long-term performance means that it is well suited to Design, Build, Finance and Operate (DBFO) contracts. As explained by Ali El Jaber of Connect Roads, this is where a company takes on the responsibility, over a 30 year period, for the maintenance of a section of the motorway network including the structures and the carriageway. A key feature of this is the focus on whole life costs – an area where concrete excels.

Jaber outlined the maintenance management strategy adopted by Connect Roads. It has three main approaches: condition survey; probabilistic scenario; risk management. All three are used to work together to verify each other with onsite verifications of one year, five year and 30 year life cycles being undertaken.

Experience of DBFO maintenance contracts has shown that with a CRCP road base the second and third lanes are invariably in good condition, with only the inside lane showing damage to the surface course from HGVs. The main maintenance expense came from renewing the top flexible surface course layer. Furthermore in terms of maintenance costs, those of concrete have flatlined while the cost of asphalt continues to rise.

Low noise

Further proof of the ability for concrete pavements to deliver was given by Joe Quirke of VolkerFitzpatrick. Traffic noise is a major issue for the Highways Agency. Examining the use of Exposed Aggregate Concrete Surface (EACS) on the A449 in South Wales, Quirke explained how concrete can provide a long term quiet road surface.

The A449 Coldra to Usk rehabilitation scheme constructed in 1998/9, was one of the most innovative highway projects of the time, involving the first overlay in the UK of a life expired rigid carriageway with a continuously reinforced concrete pavement (CRCP). The project also incorporated the UK’s first full scale use of two-layer EACS and it remains the largest such project in the UK.

TRL has carried out an assessment of the noise characteristics of the surface after 15 years. The long term acoustic performance of the EACS was assessed by repeating noise measurements originally taken in 1999. The testing showed that the surface is degrading acoustically at a very slow rate, when compared with other asphaltic low noise surfaces, such that noise levels from EACS are ultimately lower than asphaltic surface courses.

The road surface is performing very well in terms of skidding resistance with the latest SCRIM results indicating levels considerably above intervention point, and the possibility of 10 to 15 year’s further service in hand.

This is very encouraging news for clients and contractors seeking a low maintenance, low noise pavement solution for heavily trafficked roads. It is evident that EACS can be expected to provide up to 30 years maintenance free operation. With the HA design manual now being updated, EACS will no longer require a Departure from Standards for use in England and is a very viable option for road pavements.

This was an interesting seminar that saw the client, the Highways Agency, outlining its objectives, investment plans and ongoing future requirements and inviting the supply chain to work with it to develop solutions. The Agency underlined the challenges to meet the demands for long life pavements that require minimum maintenance, offer low traffic noise and low emissions and provide good whole life cost.  They are challenges that the concrete pavement sector is fully ready and able to meet in order to ensure that the road ahead is concrete. This article appears in the latest edition of Britpave News.

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