Abstract: all described as “shrinking in frost and expanding in thaw”. The bigger the cement ratio was, the less the variation of volume change was, and the smaller the maximum frozen shrinkage and maximum thaw expansion were. Yet there was an optimum cement ratio. Freeze-thaw cycles had a great effect on the mechanical properties of cement-modified expansive soil, especially for the initial freeze-thaw cycle. With the increasing of freeze-thaw cycles, strength and elastic modulus of samples with different cement ratios decreased gradually and then tended to be stable. The larger the cement ratio was, the smaller the attenuation of strength and elastic modulus were. The toughness of cement-modified expansive soil improved after freeze-thaw cycles.

Key words: expansive soil, cement modification, freeze-thaw cycles, volume change, stress-strain curve, unconfined compressive strength, elastic modulus