The results are presented of a laboratory study that was carriedout to investigate the stability of thin layers of coarse single-sized (open-graded) highway aggregates under dynamic plate loading. The investigation considered a range of aggregates having variable quality as defined by the aggregate index number. The aggregate index number is a quantitative measure of the combined durability of an aggregate that is based on the aggregate's resistance to fracture and abrasion as measured in the los angeles abrasion and mill abrasion tests. Other variables between tests were gradation size and support compressibility. The test results showed that for the coarest gradation investigated, the semi-logarithmic permanent deformation rate could be reduced significantly by increasing aggregate quality and/or increasing underlying support stiffness. The sensitivity of deformation rate to aggregate quality and underlying support compressibility decreased for parallel but finer gradations. Finally, implications to selection criteria for aggregate used in unbound open-graded drainage layers below highway and airfield pavements are identified. Thispaper appears in transportation research record no. 1278, Dynamic testing of aggregates and soils and lateral stress measurements 1990.
Samenvatting