This paper is to report the results of mock-up test for concrete during severe cold weather. The temperature is fixed at -20℃. The mock-up specimens were fabricated simulating slab, wall and column. Heating coil with different heat capacity with 5 W and 15 W were embedded at slab specimen. Test results revealed that at -20 ℃, temperature dropped below 0℃ since around 70 hours. It takes 7 days to gain 45 °D·D of maturity for avoiding frost damage at early age.