Preface Preface to the English edition This book on the Science of Construction Materials is the English version of the Danish textbook Materialefysik for Bygningsingeniorer (Statens Byggefor- ningsinstitut - Danish Building Research Institute, Horsholm, 1995). The tra- lation has been done by a team consisting of Professor Ole Mejlhede Jensen, Technical University of Denmark and Kirsten Aakjaer, BA, Aalborg University. Comments on the English version were kindly supplied by Professor Sidney D- mond,PurdueUniversity.Helpwithreproductionoftheline?gureswasgivenby Trine Bay, MSc student, and help with the ?nal text editing was given by Sara Laustsen, PhD student. Transfer of copyright was kindly granted by the family of Per Freiesleben Hansen. Financial support for the translation was donated by three Danish foundations: COWIfonden, Knud Hojgaards fond, and Larsen & Nielsen fonden. A number of modi?cations were made during the preparation of the English version of the textbook. Some of these have been necessitated by the translation, suchasreferencestosourcesinDanishbeingchangedtointernationalreferences. Other corrections were made concerning a few apparent errors in the text.All line ?gures have been redrawn, and many photos have been substituted. H- ever, in general, the English version is close to the Danish text. In addition to the textbook, a separate book of exercises exists. The exercises di?er in extent and complexity and are organized to further the understanding and use of the subjects in the textbook. Based on this teaching concept, the subject of ba- Per Freiesleben Hansen sic construction materials has been taught successfully in Denmark through 20 (1936-2002) years.