Freezing of aqueous solutions in a porous medium Part I. Freezing of air-entraining agent solutions

✍ Scribed by S. Chatterji

• Publisher: Elsevier Science
• Year: 1985
• Tongue: English
• Weight: 485 KB
• Volume: 15
• Category: Article
• ISSN: 0008-8846
• DOI: 10.1016/0008-8846(85)90003-1

✦ Synopsis

In this investigation, a pre-formed, autoclaved porous material, of stable pore characteristic, was used to study the freezing characteristics of wet porous materials. Prior to freezing, prisms made from this material were filled with solutions of air-entraining agents. The results show that (i) a major part of a solution could be frozen without any dilation of the matrix, (ii) the dilation, when it occurs, is connected with the later stages of the freezing process when only a limited amount of ice forms, (iii) initially, ice forms on the surfaces of large air-filled pores, (iv) ice formation strengthens the matrix.

It is proposed that the initially ~o~med ice-layers on the pore surfaces seal in the remainder of the solutions. Continued ice formation generates a bursting pressure within the unfrozen solution . When this bursting pressure exceeds the tensile strength of the icestrengthened matrix, it fails.

Attention has been drawn to the relevance of the above observations and the hypothesis to freezing of cement paste.