Abstract: To achieve the scientifically designed gradation composition of a salt rock aggregate base in an inland dry salt lake, this study focused on the salt rock in Lop Nur as the research subject. The analysis examined the particle breakage evolution of a single particle group of salt rock aggregate under different particle sizes and brine contents. A gradation transition model for salt rock aggregate under complex gradation was constructed, and a gradation composition design method for salt rock aggregate base was proposed. The rationality of this design method was verified, and the engineering properties of the rock salt aggregate were compared under different gradations and water loss rates. The results demonstrated that all particle groups of the salt rock aggregate experienced breakage during compaction. The gradation of uniformly graded salt rock aggregate tended to stabilize with increasing compaction work. The presence of brine reduced the particle breakage rate of uniformly graded salt rock aggregate. The Weibull distribution effectively characterized the particle breakage distribution characteristics of the salt rock aggregate. The recommended gradation composition design method of salt rock aggregate base successfully deduced the gradation characteristics of salt rock aggregate base and realized the gradation correction considering the influence of brine. Salt crystallization of brine among salt rock particles was conducive to promoting the strength formation of salt rock aggregate base. The unconfined compressive strength of the salt rock aggregate with a water loss rate of 75% reached 4.1 MPa, indicating its suitability for road base engineering in dry salt lake areas.

Key words: road engineering, salt rock aggregate, grading composition design, base, particle breakage, Lop Nur