Study on failure mechanism of concrete subjected to freeze-thaw condition in airport deicers

The rapid freeze-thaw test about ordinary Portland cement concrete (PCC) was performed in the deicers of water, 3.5% ethylene glycol, 3.5% NaCl and 3.5% calcium magnesium acetate (CMA). The ice pressure (I-P) of deicer was tested, and the concept of the ice pressure impulse (IPI) was proposed. A crack density model was employed to describe the freeze-thaw damage process of concrete. Results indicated that the freeze-thaw damage of PCC in CMA deicer was the mildest. The I-P value of water was the highest but its IPI value was the lowest. The freeze-thaw microcracks inside concrete was induced by the I-P of deicer restrained in concrete pores. The freeze-thaw crack density decreased with the relative depth of specimen. The value of superficial critical crack density was 0.85 similar to 0.88, when the exterior mortar of concrete began spalling. The value of central critical crack density was 0.32 similar to 0.34, when the interior freeze-thaw failure of concrete occurred.