London Orbital Motorway M25

Introduction

When opened in 1986, the M25 or London Orbital Motorway was the longest ring road in Europe (188 km or 117 mi). Since then, the motorway has been continuously serving Greater London’s growing traffic demands.

Challenge

Recognizing the finite nature of resources for road building and the growing needs related to pavement maintenance, one of Britain’s leading infrastructure companies FM Conway was searching for a better way to provide maintenance service to M25.

Resolution

In collaboration with Toppesfield, FM Conway designed a special mix for resurfacing an M25 motorway section. The innovative design allowed for 50 percent recycled asphalt use. To enable such high recycled material content in the surface mix, bespoke premium polymer modified bitumen (PMB) was used. According to FM Conway, “The PMB was added to significantly improve the surface course durability by improving rutting and cracking resistance.”

FM Conway conducted an extensive laboratory evaluation of their new mix. They proved that such a far more sustainable solution could achieve the performance level of conventional surface treatment, which contains only up to 10 percent recycled material. As a result, the company’s new 50 percent recycled content asphalt mix solution was the first of its kind to be used on the UK’s strategic road network. In September 2019, FM Conway applied the mix solution to an M25 section between junctions 25 and 26, laying a 4.5 cm (1.8 in) thick layer.