Estimation of ice formation in mortar saturated with sodium chloride solutions

Frost damage of concrete is usually caused by ice expansion, therefore, the ice formation of NaCl solutions is of significant importance for predicting the mechanical degradation of concrete under the combined frost action and NaCl attack. In this study, the ice formation in cementitious materials saturated with different concentrations of NaCl solution is theoretically investigated first. Then the ice formation in mortar is further studied experimentally by electrical measurements. To estimate the ice amount based on the electrical measurements, the relationship between temperature, saturation degree, solution concentration and the electrical conductivity of mortar specimen is clarified. With regard to ice formation and salt crystallization during freeze-thaw, the ice content estimation model is proposed for mortar specimens. In addition, electrical response of meso-scale mortar specimens saturated with NaCl solutions with freeze-thaw cycles (FTCs) is measured. The electrical test results are interpreted with the proposed model and the ice formation is estimated with FTCs. The results from electrical measurements are compared with the theoretical calculations, and acceptable agreement is observed.