§ Mr. Macfarlaneasked the Secretary of State for the Environment what is the nature of the problems caused by the use of high alumina cement.
§ Mr. KaufmanConcrete made with high alumina cement undergoes changes in its crystalline structure, known as conversion, causing a loss of strength which is sometimes serious. This can occur for a number of reasons related to the conditions of manufacture and the environmental circumstances of the building in which it is used. The loss in strength is difficult to assess, and its effect depends on the overall design of the building. It is, therefore, not proving easy to identify those buildings where remedial work is needed.
§ Mr. Michael Morrisasked the Secretary of State for the Environment when the Government expect to complete their full report on buildings containing high alumina cement.
§ Mr. KaufmanThe Building Research Establishment's report on its current research is expected next month, and we shall issue further recommendations about the structural use of high alumina cement concrete as soon as we have considered its findings. It is not yet possible to say how long it will take to carry out all the research which may prove necessary, but interim reports will be issued as the work progresses.
§ Mr. Michael Morrisasked the Secretary of State for the Environment how many buildings in Northamptonshire are known to be affected by high alumina cement problems.
§ Mr. KaufmanThe latest available information is that 288 buildings in Northamptonshire have so far been identified as containing high alumina cement404W concrete, but it is not yet known how many of these will require remedial measures. It will be some time before all the buildings concerned have been identified and appraised.