Concrete antifreezing agent

The invention discloses a concrete antifreezing agent, and belongs to the field of building materials. The antifreezing agent is characterized by being prepared by employing a polyethylene terephthalate (PET) hydrolysate as a main antifreezing component, adding a high-performance polycarboxylate water reducer, an early strength accelerator, an air-entraining agent and water and mixing uniformly. The antifreezing agent can be constructed at -5 DEG C to -20 DEG C, has the characteristics of being low in cost, non-toxic, free of alkali, free of chloride, good in adaptability with cement and the like, and is widely applicable to concrete winner construction.