Aspects of freezing process in porous material-water system Part 2. Freezing and properties of frozen porous materials

摘要

In Part 1 of this series it has been shown that ice isa strong material and adheres well with hydrophilic materials. Inthis part of the series the strengths of ice-infiltrated porous, bothunconsolidated and consolidated, materials have been reviewed.Ice-infiltrated porous materials are much stronger than theoriginal materials. The contribution of ice to strengths of frozenmaterials is higher than is expected from strengths of bulk iceitself. The disruptive pressure needed to cause damage duringfreezing of porous materials has also to be much higher, this faceseems not to have been considered in often-quoted mechanismsof frost attack. Ice infiltrates porous bodies in the form ofdendrites and in the process encapsulates still unfrozen water inmany places. During further cooling unfrozen water developshigh hydrostatic pressure capable of causing damage. Differentproposed mechanisms of frost damage have been examinedagainst the above background.