Aspects of the freezing process in a porous material-water system - Part 1. Freezing and the properties of water and ice

In spite of a large volume of work carried out on the frost damage of conso lidated porous materials such as concrete, the mechanism of damage remains unresolved. As the damage is associated with the freezing of water, so the physical properties of water and ice near the freezing point are reviewed i n this, Part I of the series. The macroscopic process of the freezing of wa ter has also been analyzed. These analyses show that ice is a very strong m aterial and its adhesion to hydrophilic substances like cement and concrete is high. In the normal freezing of water, the initially formed ice forms a jacket around still, unfrozen water. During subsequent freezing, pressure develops within still unfrozen water, and at some point the ice jacket brea ks. The nature of this breakage and the thickness of the ice jacket at the breaking point depend on the initial volume of water. The larger the initia l volume of water, the thicker is the ice jacket and the more explosive is the breakage. The relevance of these properties to concrete breakdown are d iscussed. (C) 1999 Elsevier Science Ltd. All rights reserved.