A Practical Look at the Simple Performance Tests: Louisiana’s Experience

摘要

The Superpave volumetric mix design procedure developed during the Asphalt Research Program of the Strategic Highway Research Program did not include a mechanical “proof” test similar to the ones commonly used in the Marshall mix design or Hveem mix design such as the Marshall stability and flow tests or the Hveem stabilometer method, respectively. The Superpave mix design method, however, did use strict requirement to material specifications and volumetric mix criteria to ensure satisfactory performance of mix designs that were intended for low volume traffic. In addition, the original Superpave mix design protocol required mix verification for intermediate and high volume traffic through advanced materials characterizations tests utilizing the Superpave Shear Tester test protocols. It was quickly recognized the complexity of those test protocols for routine mix design application and that a simple performance test is needed to complement the Superpave volumetric mix design procedure. In response to this need, NCHRP Project 9-19, Superpave Support and Performance Models Management, recently recommended three candidate Simple Performance Tests (SPTs) to complement the Superpave volumetric mixture design method. These are flow time (FT), flow number (FN), and dynamic modulus |E*| tests. In addition, the dynamic modulus test was selected for the HMA materials characterization input utilized in the 2002 Empirical and