Potential asphalt-mix parameters that influence susceptibility of a mix to rutting during its service life are identified. Seven highways were selected where sections have suffered from rutting and where other sections, with identical loading conditions, have been rut free. Field samples, includinng both cores and slabs, were collected mainly from areas where original mix properties were assumed not to have varied in both sections. An extensive laboratory program was conducted to establish the properties of both the mix and its components (asphalt cement and aggregates). Because slabs were collected from the wearing course only, tests related to asphalt cement and aggregates were only established for the wearing course. Cores were used to determine the characteristics of both wearing and base courses. Statistical analysis by using the t-test was utilized to determine major factors in both wearing and base courses that affect rutting. The significant wearing-course tests were hveem stability and modulus of resilience. Forthe base course, in addition to those two parameters, both marshall stability and compactness showed a significant impact on rutting of asphalt mixes. This paper appears in transportation research record no. 1259, Chip seals, friction courses, and asphalt pavement rutting 1990.
Abstract