This study investigated the mechanistic climatic constitutive behaviour of granular materials from Saskatchewan, Texas, and Finland. This research employed triaxial frequency sweep testing to characterize various quality granular materials with and without cement modification. Cement stabilization showed a consistent improvement in the response of poor and well graded granular materials, relative to untreated granular materials in terms of both mechanical behavior and climatic durability. As a result, when cement stabilized, poorly graded (or dirty bases) with high fines and (or) fine sand content can be engineered to perform better in the field than well graded (or clean) bases. This research showed that climatic conditioning of laboratory samples significantly influences the mechanical behavior of both unstabilized and cement treated granular materials. Therefore, when characterizing granular base materials for structural design purposes, the mechanistic properties and the effect of climatic conditioning of granular materials representative of field state conditions are needed to provide accurate structural design purposes.