This paper aims to report the mechanical behaviour of hydrated cement treated crushed rock base (HCTCRB) as granular road base material subjected to repeated cyclic loads from Repeated Loads Triaxial (RLT) tests with various stress paths in order to improve more understanding of such Western Australian roads based materials on mechanistic-empirical pavement design and analysis. As known, pavement surface rutting, longitudinal and alligator cracks are normally the main cause of damage in flexible pavements. Factors contributing to such damage are the excessive irreversible and reversible deformation of a base layer including the behaviour of a mechanical response of unbound granular materials (UGMs) under traffic load is not well understood. In this study, the shakedown concept was utilized to describe and determine limited use of HCTCRB subjected to different stress conditions. The concept is the theoretical approach of the UGMs used to describe the behaviour under RLT tests. The shakedown concept utilizes macro-mechanical observations of the UGM’s response and the distribution of the vertical plastic strain in the tested material. While the shakedown limit of an UGM is known, whether the limitation of the accumulated plastic strain in an unbound granular layer causing rutting in pavements can be predictable. In this paper, compacted HCTCRB samples were subjected to the various stress condition defined by the stress ratio (the ratio of a vertical major stress, σ1 and a horizontal minor stress, σ3) in order to simulate the real condition of pavement. The study reports that HCTCRB was defined the working stress ratio of 11 in pavement structure and will be achieved stable state at the large number of load cycles. Moreover, the mechanical responses were investigated and the limit ranges of using HCTCRB in pavements were determined.