Abstract: In order to investigate the relationship among unconfined compressive strength of expansive soil improved by waste rubber particles, rubber particle ratio and freeze-thaw cycle times,we conducted unconfined compressive strength test on expansive soil samples improved by waste tire rubber particles at given water content. Results show that adding rubber particles could improve the unconfined compressive strength to some extent and reduce the stiffness. When the number of freeze-thaw cycle was the same, the unconfined compressive strength of the improved expansive soil increased and then decreased with the increasing of rubber particle ratio. In particular, unconfined compressive strength reached the maximum when rubber particle ratio was 3%.When rubber particle ratio was the same, unconfined compressive strength of the expansive soil and the influence of single freeze-thaw cycle on strength weakening both decreased with the increase of freeze-thaw cycle times. When water content was 20%,the rate of change in expansive soil size increased in general with the increase of rubber particle ratio in freeze-thaw cycles. Finally, when rubber particle ratio was low (≤7%), the size of the expansive soil shrank under freezing and expanded under thawing; while when rubber particle ratio was higher (=9%), the change was the opposite.

Key words: waste tire rubber particles, expansive soil, freeze-thaw cycle, unconfined compressive strength, rate of size change