§ Mr. John GarrettTo ask the Secretary of State for Transport (1) who specified the mix of materials which has been found to be faulty in the construction of the Norwich southern bypass; and if(a) his Department, (b) the consulting engineers or (c) the contractors are liable for the resulting cost;
(2) what is the estimate of the cost of remedial work on the Norwich southern bypass following the discovery of a faulty mix of materials in its construction.
§ Mr. Chope[holding answer 27 January 1992]: The Department's specification for highway works which incorporates British standards is used on all its trunk road contracts including Norwich southern bypass. It lays down criteria for road materials which allow contractors and suppliers a wide choice to encourage the use of local and low cost sources of raw materials to minimise transportation and environmental costs. At Norwich each of the four contracts is using a different combination of ingredients for the bituminous mix. The sources of supply for each varies and some local Norfolk aggregates are being used.
The particular combinations of aggregates and bituminous binder used in the heavy duty macadam exhibited unexpected deformation causing a suspension of work while the possible causes were investigated.
Adjustments have been made to the mixes within the British standard to provide a material which has greater resistance to deformation.
The extent and apportionment of any additional costs will be resolved under the terms of the contract.
Present indications are that the completed bypass will be opened to traffic by the original contract completion date.