The most serious disadvantage in the use of concrete in industrial processes is the length of time taken to reach a sufficient degree of maturity. This disadvantage can be avoided by the use of dry mixes for products such as pipes, blocks, tiles and the like, which may be demoulded immediately after compaction. For wet-cast reinforced or prestressed concrete, however, existing processing methods are characterised by the necessity of taking curing time into account. Processing cycles vary from one or more per day to several days, all depending on the required degree of maturity and the number of products of each type. The acceleration of curing to reduce these cycles, preferably to fit within daily production planning, is therefore of importance.

The aim of this Guide to Good Practice is to summarise the current knowledge available on the acceleration of curing by means of increased temperatures. Different methods of raising the temperature are therefore discussed, and factors influencing the quality of the concrete and the final product are described. Good practice is especially important in the use of thermal curing, as mistakes may well lead to serious problems with strength, cracking and durability.

It is hoped that these guidelines will be of special interest not only to those involved in the manufacture and control, especially of precast products, but also to those who use thermal curing on site, and that they may also assist in the preparation of national specifications or recommendations.

This Guide to Good Practice has been prepared by Mr J. Dardare (France), Chairman of the Working Party, consisting of Mr E. Damm (Denmark), Dr A. Erdélyi (Hungary), Mr T. B. Jarosz (Poland), Prof. R. Malinowski (Sweden), Mr J. K. Wellman (UK) and Mr J. B. Whittaker (New Zealand). Comments and criticisms of this document are most welcome for use in any future work and should be addressed to Mr J. Dardare, CERIB, Boîte postale 42, 28230 Épernon, France.