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maxit LWA Geotechnical Fill

Civil Engineering

A 1 2 M a r s h l a n d Ro a d S c h e m e m a xi t P rovi d e s S o l i d Fo u n d a t i o n maxit LWA has been used to construct an extension to a coastal road scheme where its lightweight properties reduced the time required for settlement by at least 75%. A roundabout was extended from one lane to two to accommodate traffic using a new Tesco supermarket on the outskirts of Great Yarmouth. The challenge for engineers was that the coastal location is low lying, its condition is naturally marshy and the water table rises and falls with the tides.

The roundabout sub-base and pavement were extended onto the existing verge and a new embankment was built using maxit LWA. The roads contractor was Jackson Civil Engineering, working on the adopted roads, on behalf of RG Carters (Builders) and Tesco Stores Limited. Civil engineering designer, Boreham Consulting Engineers Limited, had specified the use of a lightweight aggregate to minimise differential settlement. Jacksons cut away the existing embankment at a right angle to the line of the new outside edge of the carriageway. Services were then

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

installed, including 14 feet deep wick drains and a drainage blanket. The maxit LWA, in conjunction with the wick drains, accelerated settlement to completion within six months, compared to an expected 2 - 3 years using conventional fill. The LWA was tipped over a geotextile membrane and ‘tracked’ in place using a mini excavator to minimise any surface movement. The geotextile was then rolled over the LWA, creating a ‘sausage’, preventing migration of the material. This was then soiled and seeded. A total of 1,500m 3 of LWA was used on the Gapton Hall roundabout.