Project Outline:

The existing A428 is a major link road between Bedford and Cambridge. It is single carriageway and regularly experiences congestion. The aim of the scheme was to improve three major junctions - Black Cat, Cambridge Road and Caxton Gibbet – as well as upgrading the road to dual carriageway along its length.

Most of the work was undertaken off-line, allowing the existing road to remain open, reducing disruption to traffic during the construction.

The project was designed to provide regional economic growth, helping local villages and improving the environment for walkers, cyclists and horse riders.

Project Delivery:

Walters were contracted to undertake the earthworks for the project, with the work commencing in February 2024. The earthworks comprised the excavation and filling of over 2.5million m³ of material, including the removal of 200,000m³ of soft ground and 50,000m³ of silt from two redundant quarry lagoons.

Walters worked collaboratively with Skanska to optimise the design and reduce material wastage and road wagon usage. This included the design and incorporation of landscape bunds on site to accept over 500,000m³ of excess unsuitable material which would have otherwise gone to landfill.

Walters also excavated four borrow pits close to fill areas at Black Cat and Caxton Gibbet, reducing the volume required to be transported in road wagons from 1.2million m³ to 400,000m³. This reduced costs, saved time, lowered the carbon footprint of the project and reduced pressure on the local road network.                                         

Added Value & Client Partnerships:

In conjunction with Skanska, Walters produced a detailed water and silt management strategy, based around early excavation of 21nr large attenuation ponds and 30km of new ditches to slow and store water and silt. The management plan also included other specific silt control measures, such as silt fencing, silt matting, silt curtains, silt socks and silt settlement tanks.

By using HVO (Hydro-treated Vegetable Oil) instead of standard diesel to fuel the 100nr items of large earthmoving plant, Walters reduced the carbon footprint of the plant by 85% over the 3-year project.

Walters carried out specialist environmental training that allowed the staff to carry out ecology checks before vegetation was removed, increasing efficiency and improving the team’s knowledge of the local environment.

Walters donated easter eggs, raffle prizes and food for local charities and attended the A428 open day together with Skanska. 

“The A428 is providing many challenges, but working collaboratively with the stakeholders has meant that to date, the project has run  without any major issues”….Andrew Burder, Walters Contracts Manager for Major Projects.