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maxit LWA GeotechnicAL Fill

Civil Engineering

A 4 1 7 G l o u ce s te r B y p a s s m a x i t Prov i d e s L i g ht we i g ht S o l u t i o n Contractors seeking a lightweight infill for a bridge abutment on a new £18 million by-pass scheme identified maxit LWA lightweight aggregate as the optimum solution for speed and cost. Main Contractor Norwest Holst Construction Ltd, used some 840m 3 of maxit LWA expanded clay aggregate to provide the infill behind sheet piling for the northerly abutment of the twin span Castlemeads Bridge carrying the new A417 Gloucester South West by-pass over the River Severn.

maxit Building Products Ltd. The Heath, Runcorn Cheshire WA7 4QX Tel.: +44 (0)1928 515656 Fax: +44 (0)1928 576792 Web: Email:

Initially, polystyrene-based fill had been considered for the project, but in a value engineering review maxit LWA emerged as the preferred option both for the cost-effectiveness and convenience. The material can be fully submerged and is freedraining, making it ideal for applications adjacent to watercourses.

A spokesman for Norwest explained: “Earlier in the project we used polystyrene, but it is difficult to handle and needs protection from contaminants such as diesel. A value engineering exercise showed us that using the LWA made commercial sense because it provided a quicker and more costeffective solution.”

The sheet piles were retained using tie rods, which were installed in perforated ducts to protect the rods and assist drainage. maxit LWA in 10-20mm rounded pellets was then tipped in 60m 3 loads prior to compacting using traditional infill methods.

maxit LWA is approved for both general fill and structural backfill applications by the Highway Agency. The new Gloucester South west By-pass is being built for Gloucestershire County Council with the first phase open in Spring 2005.