Strength, Stiffness, and Compressibility of RAP/Aggregate Blends

摘要

The strength, stiffness, and compressibility characteristics of the material underlying an asphalt surface can have a significant influence on pavement performance and long-term maintenance. Subgrade and base layers must be strong enough to resist shear failure and have adequate stiffness to limit vertical deflections. This study examines changes that occur in the engineering properties of aggregate materials when mixed with reclaimed/recycled asphalt pavement (RAP). Laboratory tests were conducted using four different aggregates blended with milled asphalt over a broad range of mix percentages. Laboratory test results indicate that at higher levels of RAP, the characteristics of the asphalt millings increasingly control the behavior of the blend. This results in decreased stiffness and reduced shear strength. The decreases observed in laboratory tests may not be significantly detrimental, and do not necessarily preclude the use of RAP/aggregate blends in highway pavement sections. However, the implications of this study should be further investigated by examining projects in which RAP mixtures have already been used, and by constructing and evaluating the performance of controlled test sections