The evaluation of permanent deformation of one fine-grained soil undergoing drying and wetting

Permanent deformation as well as resilient modulus is of paramount importance to pavement design. However, permanent deformation has not been studied so widely as resilient modulus. In this paper the authors report a series of permanent deformation tests of samples which were wetted or dried to reduce or increase the water content (to simulate post-compaction conditions). Samples were tested in three ways: in one phase loading, four phases loading (increasing load), and four phases (reducing load). The results indicate that water content variation has a strong effect on permanent deformation. Data also indicate that samples (with similar water contents) achieve the same level of permanent deformation regardless whether the maximum load is applied in one step or if the load is applied in stepwise fashion. Besides, it was observed that permanent deformation after 5000 cycles – for the case in which load is applied from maximum to minimum – does not change if a load of less magnitude is applied.