Book excerpt: The report has been prepared by the Joint Working Group on High Strength/High Performance Concrete, set up by CEB and FIP and comprising 15 experts from Europe, North America, Japan and Australia. Part one 'Recommended Extensions to Model Code 90' identifies the lacuna in existing regulations and proposes supplementary or alternative solutions to be applied with caution for concrete grades above C 50. In order to facilitate its use the report is edited in two columns following the numbering of the CEB-FIP Model Code 1990. It will be presented for approval to the 30th CEB Plenary Session in Berlin, September 1995. Part two identifies the research needs resulting from those clauses of Model Code 90 which needed amendments. Also more basic research needed for a better understanding of mechanical, physical and chemical processes which cannot be connected directly to a short-term application has been included."--Back cover.