Coaxial Shear Test and Wheel Tracking Tests for Determining Porous Asphalt Mechanical Properties

ABSTRACT Performance oriented test procedures are compared and discussed with respect to their suitability for porous asphalt optimization and for development of improved mix design. Coaxial shear tests and wheel tracking tests were carried out in order to compare the properties of both theoretically and empirically designed porous asphalt specimens. The specimens were produced using an improved theoretical mix design approach for porous asphalt. This method is based on a packing theory for aggregate grading optimization, reducing the post compaction effects on the pavement under traffic. The problems with porous asphalt arise from premature aging and therefore laboratory aging of the mix was used for the simulation of in-situ condition. As presented in this paper the test results vary significantly with aging as seen in the rutting behavior and shear modulus. The packing theory leads, in many cases, to porous asphalt mixes with superior quality as compared to traditional standard mixes provided that the influence of the binder is considered accordingly.