Towards Comparing Critical Degree of Moisture Saturation (SCrit) in Historic Brick Samples for Different Freezing Rates and Minimum Temperatures
As more historical buildings are being retrofitted, it is becoming more important to have an efficient procedure to test historic masonry’s capacity to withstand freeze-thaw cycling. Frost dilatometry testing focuses on establishing a critical degree of saturation (Scrit) at which masonry will fail if subjected to freeze-thaw cycles. Past studies in frost dilatometry attempt to reduce the total laboratory testing time by modifying different parameters, such as the freezing rate. This MRP focuses on the relationship between Scrit and freezing temperature, and Scrit and freezing rate. Brick samples from three historic masonry sites in Toronto were saturated at varying moisture contents between 60% and 100%. Three freezing temperatures, -2C, -6C and -15C, and three freezing rates, -5C/hr, -12C/hr and -21o C/hr, were tested. The samples were initially subjected to 12 cycles; however, upon discovering that there was little correlation in the data, an additional 30-cycle frost dilatometry tests were performed. As a result of this study, it was found that there is repeatable correlation between Scrit and freezing rate, with lower freezing rates resulting in higher Scrit values. While freezing temperatures also affect Scrit values, a definitive correlation between Scrit and freezing temperature was not established as part of this work. However, it was noted that the lowest freezing temperature (-15C) produced data that was more precise, and therefore it was generally easier to establish a linear trend to determine the Scrit values at the lowest freezing temperature.
History
Language
engDegree
- Master of Building Science
Program
- Building Science
Granting Institution
Ryerson UniversityLAC Thesis Type
- MRP