Abstract: The aim of this study is to investigate the influence of sulfate content on compressive strength and microstructure of solidified saline soil with solid waste materials. The impact of salinity on compressive strength of solidified saline soil was examined from the viewpoint of pozzolanic products and quantities via compaction test and unconfined compressive strength test in association with scanning electron microscopy (SEM), energy dispersive spectrom(EDS), X-ray diffraction (XRD) and thermogravimetric analysis. Results demonstrated that when the content of sulfate was lower than 2.7%, the compressive strength of solidified saline soil increased at first and then decreased with the increase of salinity. When salinity was 1.8%, compressive strength reached peak value. The major pozzolanic products of solidified saline soil are C-S-H and AFt. When the content of sulfate augmented from 0.3% to 1.8%, the reaction products increased obviously, resulting in the rising of compressive strength of solidified soil; however, when the content of sulfate increased from 1.8% to 2.7%, the internal pores of the specimen were completely filled by expansive AFt, giving rise to cracks and the decline of compressive strength. The research findings laid a foundation for the engineering application of solidified sulphate saline soil.

Key words: solidified saline soil, all-solid waste material, sulfate content, unconfined compressive strength, microstructure