Title:
Frost Resistance, a Critical Look
Author(s):
M. Pigeon
Publication:
Symposium Paper
Volume:
144
Issue:
Appears on pages(s):
141-158
Keywords:
air entrainment; air voids; cracking (fracturing); deicers; durability; freeze-thaw durability; microcracking; microstructure; scaling; Materials Research
DOI:
10.14359/4395
Date:
3/1/1994
Abstract:
It is now commonly accepted that there are two basic frost durability problems: internal cracking due to freezing and thawing cycles, and surface scaling, generally due to freezing in the presence of deicer salts. Although there are still parts of the problem that are not well understood and warrant further investigation, particularly with respect to the differences between laboratory tests and field exposure, the way to make concrete resistant to freezing and thawing cycles is very well known. It is simply to insure that the hardened concrete has an adequate system of entrained air voids. Field experience as well as laboratory data have shown conclusively that internal cracking due to frost in properly air-entrained concrete is almost nonexistent. In the years to come, it will be necessary to increase our knowledge of some of the parameters that influence air entrainment, particularly in the new types of concrete that are being used, such as, for instance, high-strength concrete and roller compacted concrete. Simple methods to determine the characteristics of the air-void system in fresh concrete will also be required. Scaling due to freezing in the presence of deicer salts is a much more complex problem than internal cracking for many reasons, but probably mainly because it is related to the microstructure of the surface layer or "skin" of concrete. Laboratory as well as field data are often contradictory. But if scaling is a complex problem, this does not mean that it is a monumental one. It is only one aspect of the complex question of the durability of concrete structures.