Tees barrage: Durability assessment of concrete

A barrage has been constructed on the River Tees, near Stockton in the UK, by the Teesside Development Corporation. Ground granulated blastfurnace slag cement was specified to meet the durability requirements of a 120-year life. The Building Research Establishment was commissioned to monitor the performance of the concrete in the barrage so that the body adopting the barrage can be given assurance that the structure will meet its design specifications. Upstream of the barrage the water is non-saline and will be maintained at a constant level. Downstream where the water is saline and tidal, epoxy-coated reinforcing bars have been used. Concrete test blocks have been cast on site from a concrete mix equivalent to that used in the barrage and these are exposed in upstream and downstream environments. The development over time of carbonation, chloride ingress, permeability and strength will be determined. Corrosion probes have been cast into test blocks and the walls of the upstream and downstream navigation lock waiting bays. Corrosion is not expected to occur within the time-scale of the initial project (four years) but these probes allow for the possibility of much longer term monitoring and will provide valuable baseline data for non-corroding steel.