Slipform extrusion of drainage channels using ggbs

This article describes the design and implementation of drainage channels along an upgraded section of motorway in north-east England. The concrete channel was cast in situ using a slipform paver: the concrete included cement replacement ground-granulated blast furnace slag (ggbs) to enhance its plastic properties and provide the extended working time required by the slipform process. The contractors and suppliers operated a pre-supply agreement to minimise concrete supply problems and ensure continuity. Quality was assured by regular testing of the product. The finished channel allows run-off via petrol/oil interceptors to a watercourse, with balancing ponds constructed to control flooding.