Characterizing resilient behavior of naturally occurring bituminous sands for road construction

Oil sand is a generic name given to natural deposits of bituminous sand materials that are mined for crude oil production. These materials are currently used as subgrade materials of temporary and permanent roads in oil sand fields for operating large capacity haul trucks and shovels. This paper focuses on determining in laboratory the resilient behavior of three oil sand materials with bitumen contents of 8.5, 13.3, and 14.5% by weight. The resilient modulus (M_R) properties were obtained using a newly established repeated load triaxial test procedure. From the test results, nonlinear M_R models were successfully developed in the forms of K-theta, Witczak-Uzan, and the mechanistic empirical pavement design guide (MEPDG) models to properly characterize temperature and stress dependent resilient behavior. The modified K-theta model predicted the overall M_R dependency on applied stress states and temperature quite satisfactorily for all the three oil sands when compared to the modified Witczak-Uzan and MEPDG models. The M_R results presented and the models developed can be practically used to estimate the field stiffness behavior of oil sands as subgrade materials.