Influence of suction stress on the resilient modulus model for unsaturated aggregate base

• Suction stress can be used as an influence factor of moisture conditions in the resilient modulus model. • The effect of suction stress on resilient modulus was examined via approaches using ASS and ISSV models. • The suction stress model accurately estimated the resilient modulus of aggregate base materials. The resilient modulus of the aggregate base material is crucial in mechanical pavement design. The resilient modulus is affected not only by the stress state but also by the moisture state, which must be considered during modeling to properly estimate the resilient modulus. Regarding the moisture state, the suction stress as a stress state variable accounts for the effect of suction and saturation can be incorporated into the resilient modulus model. In this study, the effect of suction stress on the resilient modulus was investigated, and the behavior of suction stress was considered based on the concept of average skeletal stress and independent stress state variables to estimate the resilient modulus. The results revealed that the established model appropriately estimates the resilient modulus of the aggregate base materials and that suction stress affects the resilient modulus independently.