Resilient Modulus at the Limits of Gradation and Varying Degrees of Saturation

011150292007Final ReportPDFTech ReportRC -149703-0063Aggregate gradationBase course (Pavements)Granular materialsModulus of resilienceMoisture contentPercent saturationQuality controlStiffnessHighwaysMaterialsI36: AggregatesMichiganUnited StatesMichigan. Dept. of Transportation. Construction and Technology DivisionHodek, Ralph J.{44756}Mayrberger, TorstenMichigan Technological University. Dept. of Civil and Environmental EngineeringMichigan. Dept. of Transportation. Construction and Technology DivisionMichigan Tech Transportation InstituteUS Transportation CollectionThis report details a laboratory study which was intended to evaluate the 4G aggregate specification as a quality control specification. The study variables were the gradation, the material, and the moisture condition. The characteristic to be controlled was the stiffness, and the stiffness of each compacted unbound granular material was measured by the resilient modulus. Findings showed that the stiffness is dependent on material type. As a generalization, natural gravel is always softest, dolomite and slag behave similarly and are stiffest, and crushed concrete occupies an intermediate position. The stiffness is also dependent upon the ratio of fine to coarse aggregate within the specification. As the ratio increases, the material\u2019s compacted stiffness decreases. Significant stiffness differences occur within the limits of the 4G specification band; stiffnesses could vary by up to 50%. For every material type it was also observed that the effect of moisture content increases as the ratio of fine to coarse fraction increases. An increase in moisture content was shown to decrease stiffness