The response of saturated brick masonry units to internal freezing water was studied in an attempt to improve the accuracy of freeze-thaw durability predictions currently described in ASTM C 67. Cryogenic dilatometry was employed to study the change in length, or response, of water-saturated brick during freeze-thaw cycles. In all cases, a permanent, or residual, expansion was observed.
Residual expansion varied from approximately 0.01% to 0.08% for different commercially available brick for a single freeze-thaw cycle. No strong correlation was found between residual expansion and physical properties cited in current ASTM specifications.
Research on lab-fired extruded brick showed that the amount of residual expansion is related to the “maturity,” or amount of “heat work” expended, in firing of the brick. Comparison of lab- and plant-fired brick with similar water adsorption values yielded considerable differences in residual expansion, reflecting a lack of correlation between physical properties and durability.
Residual expansion may be a quantitative index reflecting the freeze-thaw durability of brick, and may result in a more definitive and faster test procedure than that described in ASTM C 67.