Testing asphalt concrete in diametral tension-compression

Testing of asphalt concrete in diametral tension-compression is suggested. Given that asphaltic layers experience stress reversals in the field, the underlying motivation is reducing systematic characterization errors. The required experimental setup is shown to be composed of usual testing gear with slight modifications. It is described in detail, validated on an aluminum disk, and then demonstrated for an asphalt concrete specimen. The application of force history that includes several load-unload-rest cycles is advocated. So doing allows separation of the measured response into recoverable and irrecoverable components with only the former being consistent with viscoelastic solid behavior. Reversing the direction of applied force is also beneficial; it effectively confines the accumulation of irrecoverable deformations to a narrow 'band', thereby protecting the mechanical integrity of the specimen. The resulting directional differences in mechanical behavior are demonstrated.