Abstract: The use of curing additives and the cement to solidify the plain soil can make the full use of the abandoned soil of the project, reduce the cost of sand and gravel, reduce the use of cement and protect the ecological environment. The unconfined compressive strength test, splitting tensile strength test, and scanning electron microscope test were utilized to investigate the mechanical properties and the microscopic features of soilcement after the solidification. The mechanical test shows that the unconfined compressive strength and the splitting tensile strength of the solidified soil-cement can be enhanced by the extension of curing age, the increase of cement content and the addition of curing agent. The specimen containing 0.04% curing agent and 10% cement content exhibits greater strength compared to the specimen without curing agent but with 10% cement content and is nearly equivalent to the strength of the specimen without curing agent but with 12% cement content. The microscopic examination reveals that the introduction of a curing agent and an increase in cement content result in improved hydration reaction, elevated levels of hydration products, as well as reduced surface porosity and pore diameter of the sample at 28 days old. The results show that the road performance of solidified soil-cement is better than that of soil-cement, which meets the needs of road engineering.

Key words: Curing Additives, SoilCement, Unconfined Compressive Strength, Splitting Tensile Strength, Microscopic Characteristics