Temperature rising and anti-freezing performance of gravel-clay mixed with PCM applying infrared radiation during winter construction

Freeze–thaw cycles could easily cause the structural damage and mechanic performance deterioration of clay. In order to prevent the freeze–thaw cycles problem in the core-wall zone of the high core-wall rock-fill dam in cold regions, gravel-clay mixed with phase change material (GC-PCM) can be used as damming material and present a certain level of anti-freezing performance during winter construction. However, GC-PCM construction work area is still likely to run a risk of freezing under the severe cold and strong wind weather. In order to solve the freezing problem of GC-PCM, this study developed an infrared radiant heating device without interfering with the original construction procedure and conducted an indoor test to investigate the temperature rising performance of GC-PCM after receiving infrared radiation. Also, a numerical simulation method was proposed for the temperature rising and anti-freezing performance of the GC-PCM construction work area and the effects of different factors (including radiant pass, moving speed of infrared device and wind speed) on the anti-freezing performance were analysed subsequently. Main results show that: (1) the effectiveness of proposed numerical simulation method is validated by the indoor test; (2) after receiving 8-pass infrared radiation, the GC-PCM construction work area at 4 % PCM content remains unfrozen in 24 hours under the typical weather in December; and (3) instead of increasing radiant passes, reducing the moving speed of infrared device can better improve the anti-freezing performance of GC-PCM. This study validates the feasibility of applying infrared radiant heating method on GC-PCM, providing a potential technical means for gravel-clay anti-freezing during winter construction.