The effect of temperature distribution in mortar on frost scaling

Abstract

Thermal boundary conditions are rarely studied in relation to frost scaling. However, in literature, several examples point out that some thermal boundary conditions and resulting temperature distributions may change the extent of frost scaling. Salt concentration, test liquid layer thickness on test surface, and surrounding temperature were considered variables that influence the thermal boundary conditions. A factorial design of experiments was followed to assess the influence of these variables on frost scaling. Statistical results indicate that salt concentration and surrounding temperature have strong effects on frost scaling, whereas the effect of the test liquid layer thickness was not significant. A possible physical explanation of the results is that certain temperature distributions promote liquid transport either from the surface reservoir or from unfrozen parts of the specimen to freezing parts of the specimen. In both cases, liquid transport feeds ice formation close to the test surface and therefore increases frost scaling.