Use of crushed brick in reinforced earth railway structures

Abstract

The Bermondsey Dive-Under (BDU) scheme is a fundamental part of UK's Thameslink Programme. The scheme involves extensive demolition of 900 m of masonry viaduct followed by the construction of 900 m of new structures, 200 m of reinforced earth structures and 200 m of embankment modifications. Crushed brick is typically not used as a structural fill material in the UK due to concerns over its friability and associated long-term performance. This paper describes a study undertaken in 2012 that examined the viability of recycling the demolished brickwork material into a crushed engineered fill material for use in the BDU permanent works. The overarching objective of the study was to seek to reduce the scheme's significant volumes of both imported fill and exported demolition material, with associated sustainability advantages in addition to the environmental and safety benefits resulting from the significantly reduced lorry movements from London's streets. The paper details the sampling and testing of brickwork that was undertaken and presents the findings from the study. The paper also discusses some of the issues associated with introducing innovation within major work programmes. The BDU scheme is currently under construction and is scheduled for completion in 2017.