Case Study: Colas – West Midlands Project

Celtest rapid response ensures timely completion for significant West Midlands project

Project / Client

Colas is an ambitious, award-winning business, which delivers sustainable solutions for the design, building and maintenance of the UK’s transport infrastructure. In operation for almost a century (it was founded in 1923), the company’s unrivalled expertise is a result of wide experience gathered over those years, along with the strength derived from being part of the world-leading Colas Group. 

The Colas Group operates in every aspect of construction and maintenance for roads and other types of transport infrastructure (air, rail and marine transport), as well as on projects involving urban development and recreational facilities. The Group’s excellent R&D facilities provide Colas with access to innovative new products, processes and ideas. 

While Colas’ head office is in West Sussex, it has more than 20 offices and depots across the UK, and employs more than 2,000 people. Clients include the Highways Agency, local authorities, MoD, aviation industry and the private sector: contractors, consultants, architects and utility companies. 


Following a competitive tender process run by Birmingham City Council in 2012, two companies were chosen as the preferred joint venture contractors for two major West Midlands construction projects – the A45 Transport Corridor Improvement Scheme and the Runway Extension at Birmingham Airport. Colas formed a joint venture with VolkerFitzpatrick to deliver the runway extension at Birmingham Airport and realign the A45 dual carriageway adjacent to Birmingham Airport. 

The previous runway was only 2,600m long, restricting the airport’s capacity to handle direct long- haul routes to destinations such as China and South Africa. The project was planned to increase the runway length by 405m runway, and constructing new taxiways and tie-ins. 

Colas’ responsibility included the provision of expertise to supply and lay the asphalt for both highway and airfield works. This required the supply and erection of the largest mobile asphalt plant in the country – 280 tonnes per hour – supplying in excess of 1000 tonnes per shift. Where possible, all the asphalt was laid in echelon using up to three paving machines at the same time. 

Colas has previously contracted with Celtest on similar work. As Steve Cant, Colas’ Technical Manager – Asphalt & Quarries, says, “Colas has used Celtest services for several years. Since 2006, the company has worked closely with us on numerous airfield projects, supplying site and laboratory staff and equipment.” 

The Celtest team on this Colas West Midlands project included: Bruce Johnstone (testing bituminous material in the Celtest mobile laboratory, adjacent to the mobile bituminous plant); Nigel Wager (lab and site testing); and, Rhydian Jones and Richard Wyn Jones, both involved in site testing. 

A major challenge for the four-man team was to work within the tight schedules demanded by airfield schedules and operations. This meant day-time sleeping, to enable working night- time shifts, with operational hours restricted to between 23:00 to 06:00. 

Steve Cant says: “Airfield work is always challenging: limited possession and immovable hand back times means constant pressure to ensure work continues as planned, with the airfield able to open on time the following morning and operate on schedule.” 


Close liaison with Celtest during the tendering and early contract-award stages ensured Colas’ needs were understood, and potential challenges anticipated, with solutions planned in advance. 

The design and formulation of Marshall Asphalt and Stone mastic asphalt (SMA) was undertaken at Celtest’s Bangor laboratories. At the on-site mobile laboratory, compliance testing included: stability and flow, maximum density, percentage refusal density, flakiness index, moisture content, and binder and grading analysis. 

To assess performance and compliance, additional in-situ work included testing for compaction control, surface regularity using rolling straight edge and three-metre beam, surface texture by macro texture method, sampling for air voids, and laying records/temperature control. 

As Steve Cant adds: “Celtest is sufficiently resourced to quickly adapt to the changing needs of the contract, particularly where programme has been changed and working plans altered.” 


In 2014, Birmingham Airport welcomed the UK’s first direct flight from China into a non- London airport – inaugurating its recently extended runway as the service departed for its five thousand mile journey back to Beijing. 

Steve Cant comments: “We have worked with Celtest on major contracts for the past eight years, and have built up a unique working relationship with the company and staff. This close relationship enables us to progress preliminary works at tender stage and swiftly resolve problems as they arise. 

Celtest is uniquely placed in the industry with their range of UKAS accreditation, and the ability to provide all of our needs without recourse to other sub-contractors.

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