Platform Extension - St Margaret’s Station, London

The ability to blow the equivalent of five lorry loads of traditional hardcore direct to a construction site made Leca® LWA lightweight aggregate the ideal choice for extension work to a busy railway station platform.

Following approval from Network Rail, contractors Walker Construction (UK) Limited, of Folkstone, specified Leca® LWA infill to overcome time and storage constraints.  Some 45m3 of Leca® LWA delivered in just one load was pneumatically pumped into place in less than three hours to form the base for the 110m2 central platform extension at St Margaret’s Station, South West London. A totally natural product, Leca® LWA is made from pure clay, which is expanded to form small, lightweight granules with a honeycomb core. Its use for the station project allowed placement to be completed in a tight time frame during a single overnight possession. Walker Construction specified Leca® LWA after assessing the logistical difficulties of storing and transferring traditional hardcore to the site. The use of traditional fill would have required five HGV deliveries to the site, which was in a busy residential area, followed by manual transfer of the hardcore to the platform by barrow. The tracks would also have needed protection, extending the timescale. By specifying Leca® LWA 10-20mm, the contractor was able to complete the fill in one limited closure of the live tracks, compact it, then apply a sub base followed by a dense bitumen base course topped off by a 20mm wearing course. Explains Peter Maddox, of Walker Construction said: “Using traditional hardcore in this location, with the possession times available, would have presented severe difficulties. Leca® LWA proved ideal for this application and was realistically the only option once we had been given approval.”