关键词: 纤维改性滨海水泥土;干湿循环;无侧限抗压强度;脆性指数;

Abstract: In order to study the effect of polypropylene fiber on the mechanical properties of coastal cement-soil, the unconfined compression test for coastal cement-soil modified by polypropylene fiber（PFCC）under dry-wet cycles was carried out, considering two curing ages of 7d and 28d and six dry-wet cycles of 0, 1, 3, 5, 7 and 9. Moreover, a new PFCC brittleness index model which can consider both the pre-peak stress growth rate and the post-peak strength drop rate was established to evaluate the brittle failure characteristics of PFCC. The test results showed that the compressive strength of PFCC specimens increased with the increasing of dry-wet cycles. The brittleness index of PFCC samples also increased with the increasing of dry-wet cycles, and the brittleness index of the samples under 7d curing age after 5 times of dry-wet cycles was greater than that of the samples under normal curing at the same age, while the brittleness index of the samples under 28d curing age in dry-wet cycles was always greater than that of the samples under normal curing at the same age. With the increase of dry-wet cycles, the brittleness index of PFCC increased gradually, and the reinforcement effect of fiber on cement soil samples decreased gradually.

Key words: PFCC; dry-wet cycles; unconfined compression strength; brittleness index