§ Dr. Kim HowellsTo ask the Secretary of State for Scotland what is the estimated cost in Scotland of undertaking remedial work to counteract the effects of concrete cancer on structures associated with motorways, trunkroads and major road bridges in 1990–91, 1991–92 and 1992–93.
§ Lord James Douglas-Hamilton[holding answer 26 February 1991]: Concrete cancer is a term used to describe the deterioration of existing concrete in bridges due to long-term alkali silica reaction.
This problem occurs only with certain combinations of cement and aggregate types which are rarely encountered in Scotland. However, a very limited number of bridges contain precast concrete beams manufactured in England. The bridges concerned are being closely monitored. No expenditure is envisaged to counteract the effects of concrete cancer in Scotland in 1990–91, 1991–92 and 1992–93.
Revised specifications for new concrete bridge construction should avoid problems in future years although, in the present state of world-wide knowledge of this phenomenon, it is impossible to eliminate all risks.