Abstract：In order to explore the effect of red mud on the unconfined compressive strength, frost resistance and fatigue properties of cement composite soil, the microstructure of the specimen was observed by means of scanning electron microscope, and the change rule of element composition inside the specimen was investigated by energy dispersive spectrometer. The results show that under the same number of freeze-thaw cycles, when the cement content is 12%, the unconfined compressive strength of the red mud-cement composite soil increases first and then decreases with the increase of the red mud content. When the content of red mud is 16%, the peak value is reached, and when the content of cement is 20%, the unconfined compressive strength of red mud-cement composite soil increases linearly with the content of red mud. The uncondined compressive strength of red mud cement composite soil decreases with the increase of fatigue times and loading frequency, but the effect of loading frequency is relatively small. The changes of the microstructure and element composition of the specimens show that the increase of the red mud content can effectively enhance the bonding strength between particles and improve the density of the skeleton.
