LAUSR

Abstract Road base is usually subjected to cyclic traffic loadings as well as environment loads. Evidence shows that excessive permanent deformation of the road base may occur under the action of traffic loads and the complicated suction history induced by climate change. Currently, how the suction history of road base affects its long-term deformation remains unclear. To gain a deep understanding of the long-term deformation of road base, cyclic loading tests were conducted on the road base aggregates (mixture of crushed tuff aggregates and clay fines) under controlled suction and suction histories. A large-size soil-water characteristic curve (SWCC) test apparatus was designed and manufactured for the water retention test of the large-size specimen, and the large-diameter cyclic triaxial testing system (LDCTTS) was upgraded with the unsaturated control system to control the matric suction and suction history during the cyclic loading test. Test results show that the permanent axial strain of the mixture has a negative correlation with the current suction and maximum suction history. The effect of drying-wetting cycles on the permanent axial strain is significant. The permanent axial strain decreases with drying-wetting cycles at the drying path, while increases with drying-wetting cycles at the wetting path. The resilient modulus increases significantly with the current suction magnitude while is independent of the suction history.