EVALUATING CREEP COMPLIANCE OF ASPHALTIC PAVING MIXTURES USING A HOLLOW-CYLINDER TENSILE TESTER

摘要

A novel approach for measuring the creep compliance of viscoelastic solids in tension is presented. A prototype hollow cylinder tensile tester (HCT) has been developed, which applies pressure to the internal cavity of the specimen, and the resulting time-dependant strain is measured. In a previous study, the device was shown to produce reliable measures of complex modulus for asphalt concrete. In this study, the accuracy of creep compliance measurements from the HCT was assessed by conducting parallel tests on identical materials using an indirect tensile test (AASHTO TP-9). The creep compliance obtained with the two test devices were found to be in good agreement across a modest range of materials, test temperatures, and loading times, including nominal maximum aggregate sizes (NMAS) up to 19 mm. These findings suggest that both of the devices investigated are capable of measuring fundamental properties of viscoelastic media, such as asphalt concrete creep compliance. The data suggested a slight tendency for the indirect tension test to underestimate compliance relative to the HCT when measuring at high compliance values. Additional testing is needed to thoroughly examine the accuracy and repeatability of the HCT, particularly at higher compliance levels and for mixtures with NMAS exceeding 9.5 mm.