An investigation into methods of carrying out accelerated freezing and thawing tests on concrete

Abstract

Summary It was noted in earlier investigations that accelerated freezing and thawing tests on concrete carried out using a continuously refrigerated room produced results more rapidly than similar tests using a cabinet-type refrigerator, although in each case the specimens reached the same limiting temperatures of about 5° and 60°F. Attempts have therefore been made to modify the technique so that results can be obtained more rapidly in the refrigerator. The tests show that damage occurs more rapidly when specimens are frozen immersed in water than when frozen in air, although the rate offreezing is lower. This suggests that evaporation of water from the surface of the specimens before freezing may mitigate the damage by reducing the stresses developed near the surface when the water freezes. Little was gained by the use of a brine bath surrounding the water-immersed specimens. Measurements of the temperatures of the specimens during freezing and thawing suggest that two cycles per day could be carried out successfully in the refrigerator in place of the one cycle per day formerly used.

Rock moisture content in the field and the laboratory and its relationship to mechanical weathering studies

“…It is this applicability of experiments to the real world which is the main problem. Wright and Gregory (1955) showed that accelerated freezing and thawing produced more rapid results and that when specimens were frozen immersed in water then damage occurred more rapidIy than when the specimens were frozen in air. Unless the study environment is one of rapid freeze-thaw cycles with rocks immersed, or partially immersed, then the experiments show little or no relevance to the study site.…”

Frost susceptibility of concrete in near-saturated states

“…Also, the results depend on which procedure is used. Procedure A generally is found to be more severe than procedure B [34,67,76,83].…”

“…Wright and Gregory [83], in explaining the reason for the lesser severity of procedure B, suggested that the evaporation of water from the specimen surface before freezing mitigates damage by reducing the stresses developed near the surface when water freezes. They also investigated and compared the evaluation of the durability of concrete by dynamic modulus of elasticity and pulse velocity measurements and found them to be equally suitable.…”