1. Scope

Keywords

Rationale

This standard describes the procedure for determining the tensile creep compliance, tensile failure limits, and energy ratio of asphalt mixtures. These material properties and parameters are determined using the following Superpave IDT tests: tensile creep test and tensile fracture test. Tensile creep test—The tensile creep test is performed in a load-controlled mode. Creep compliance is determined by applying a static load in the form of a step function along the vertical diametral axis of a test specimen and then holding it for 1000 seconds. The resulting horizontal and vertical deformations measured near the center of the specimen are used to calculate tensile creep compliance as a function of time. The magnitude of the load applied is selected to maintain the material response within the linear viscoelastic range throughout the test. By measuring both horizontal and vertical deformations in regions where stresses are relatively constant and away from the localized non-linear effects induced by the steel loading heads, Poisson’s ratio can be accurately determined. Note that creep compliance is sensitive to Poisson’s ratio measurements. Tensile fracture test—The tensile fracture test is performed in a displacement-controlled mode. The test specimen is loaded along its vertical diametral axis at a constant displacement rate of 50 mm/minute (2 in/minute) until failure occurs.