The road ahead should be concrete: whole life costs benefits of concrete roads

Britpave, the infrastructure industry association, believes that it is time for the UK take note of why other countries increasingly prefer concrete pavements over asphalt.

With traffic in the UK forecast to grow by nearly 50% by 2040, the 40 year long-term, minimum maintenance performance of concrete is increasingly attractive to UK highway authorities especially when those benefits are combined with the reduced whole life costs over a 40 year period compared with the more frequent maintenance and re-construction interventions necessary for other road solutions.

This whole life consideration of costs has resulted in concrete pavements being increasingly the road solution of choice for many countries. In Germany, France, Austria, Belgium, Netherlands and Switzerland, concrete roads represent a considerable length of the most heavily trafficked routes. In USA, nearly 60 per cent of the interstate highway system are concrete roads. In the UK concrete tends to be limited to Design Building Finance and Operate (DBFO) rather than for the motorway and trunk road network as a whole.

The UK Design Manual for Roads and Bridges (DMRB) HD26/06 describes whole life costing as examining “the costs of a project from inception to disposal, including the direct costs of constructing and maintaining highway and the indirect costs imposed on society and the environment by its use and operation (e.g. traffic delay, accidents at roadworks, skidding accidents, fuel consumption and tyre wear)”. Analysis of DRMB fully flexible, flexible composite, continuously reinforced concrete pavement (CRCP) and Exposed Aggregate Concrete Surface (EACS) pavement options for a heavily trafficked >80msa roads built on a green field site or substantial reconstruction in Class 3 foundations demonstrates significant whole life cost savings for concrete roads with the EACS option being 30% cheaper than the fully flexible asphalt option.

Further whole life cost analysis of fully flexible and flexible composition pavements that are resurfaced after ten years and fully reconstructed at 40 years, compared with CRCP with thin course surfacing that is resurfaced at 15 years and reconstructed at 40 years and with a EACS concrete pavement resealed at 15 years and replacing the thin wearing course at 40 years, shows that the fully flexible pavement will be almost 2.5 times more expensive than the exposed aggregate concrete surface.

The potential long-term savings of concrete pavements have been analysed and calculated by research undertaken by Eupave, the European Concrete Paving Association. In their report ‘A guide on the basic principles of Life-Cycle Cost Analysis (LCCA) of pavements, Eupave examined ways to calculate the various parameters required to undertake a Life Cycle Cost Analysis of roads. They compared a concrete and an asphalt pavement option for the reconstruction of 8,360m2 of 80 year old pavement on Diversey Boulevard, Whitefish Bay, Winconsin. The concrete option was a 175mm pointed plain concrete pavement with a 100mm granular subbase on a subgrade foundation base compare with a 125mm asphalt pavement on a 250mm granular base on a subgrade foundation base. The life cycle cost analysis found that found that over 90 years the concrete option would be 29 per cheaper. The concrete option’s initial construction and on-going maintenance costs were calculated to be $384,250 whilst the costs for the asphalt road were $542,254.