Lightweight expanded clay infill from maxit UK provided the solution to a range of challenges during the construction of a new bridge over the Leeds and Liverpool Canal.

The new 21-metre span Henhurst Canal Bridge at the £6.4 million Westwood Link Internal Access Road near Wigan has been constructed for Wigan Metropolitan Borough Council with Birse Civil Engineering as main contractor and Faber Maunsell, Altrincham, consulting engineers.

In addition to its primary function as a dual carriageway road bridge, Henhurst Bridge also provides a conduit over the canal for services including high and low voltage cables, water and gas supplies

By using fine grade maxit LWA lightweight aggregate as an infill for service trenches within the bridge structure, the contractors were able to ensure that the various service pipes and cables received support, protection and insulation while limiting superimposed loading on the new bridge structure.

The free-draining qualities of the material also ensured that any water or moisture could escape from the structure, removing the risk of freezing in winter and the self-compacting nature of LWA also provided a quick and convenient method of filling the trench section.

Because of its light weight, the material was easily loaded into a hopper for direct placement to the point of use, enabling each service bay to be filled quickly and efficiently as work progressed. Some 30m³ of maxit 0-5 R was delivered to the site in a high-sided HGV and tipped to form a stockpile close to the point of use.

Henhurst Canal Bridge is a single span composite steel beam and reinforced concrete deck, which is integral with reinforced concrete abutments. The abutments are supported on single rows of CFA piles.