0‘quv materiallari (ma’ruza matni)

of a good concrete in its hardened state
are a satisfactory compressive strength and an adequate
durability.
All this has been valid since the first edition of this book appeared in 1963. In its three editions and the 12 languages in which translations have been published, the book seems to have served well those involved in concrete, which continues to be the most important and widespread construction material. However, very significant changes in knowledge and in practice have taken place in recent years, and this is why a fourth edition needed to be written. The extent of these changes has been such that a ‘bolt-on’ approach was not appropriate and, except for its fundamental core, this is, therefore, a new book.
Its coverage has been greatly widened, and it gives a broad as well as a detailed view of concrete as a construction material. But there has been no change for change’s sake. The form, style, approach, and organization of the material in the previous editions have been maintained so that those readers who are familiar with the earlier versions will have no difficulty in finding their way in the new book.
The fourth edition contains much new material on cementitious materials, some of which were not used, or were little used, in the past. Knowledge of these materials should now form part of the engineer’s stock-in-trade. Durability of concrete under various conditions of exposure, including carbonation and alkali-silica reaction, is treated fully. In particular, the behaviour of concrete under the extreme conditions existing in coastal areas of the hot parts of the world, where a great deal of construction nowadays takes place, is discussed. Other new topics are: high performance concrete, recently introduced admixtures, concrete under cryogenic conditions, and properties of the aggregate-matrix interface, to mention but the main ones.
It has to be admitted that the treatment of the various cementitious materials presented quite a challenge which has provoked the following digression. A very large number of papers on these materials and some other topics were published in the 1980s and continue in the 1990s. Many worthwhile papers have elucidated the behaviour of the various materials and their influence on the properties of concrete. But many more reported narrowly construed investigations which described