An integrated approach to motorway design from Brett

A combination of specialist kerbs and a roadbase of cement-bound granular material (CBGM) has provided the Channel Tunnel approach from Junction 11a of the M20 with an effective pavement construction and a safe carriageway thanks to the integration of engineering and products from the Brett Group.

Brett Aggregates was initially approached by contractor BAM Nuttall to provide a CBGM roadbase for the carriageway and a foundation for Brett Landscaping’s Trief containment kerbs, running adjacent to the roadbase.

This was a high-specification application as the carriageway has to be able to cope with the movement of over a million articulated lorries a year on the approach to the very busy channel tunnel entrance.

Over 7,000 tonnes of CBGM were supplied by Brett for this project. 

Trief kerbs were an obvious choice as the go-to solution for this situation as they provided a safe boundary to the carriageway but with the additional ability to contain and redirect any stray vehicles.

Brett provided an innovative solution with a refined roadbase design, allowing the roadbase’s width to be extended beneath the Trief. Through a clever approach, this allowed a safer, faster, simpler construction method to be employed, saving cost throughout, whilst achieving the performance demands of the carriageway and the Trief kerb foundation.












Trief kerbs have been tried and tested by the TRL to help keep vehicles away from pedestrians

The integration with the Brett Aggregates team made co-ordination of the engineering and the installation very straightforward.

In all, Brett supplied some 7,000 tonnes of CBGM material to the project which involved the construction of 1.5km of carriageway.

BAM Nuttall was the main contractor involved in the project, with consultancy provided by Campbell Mains.