Evaluation of Tennessee HMA Mixtures Using Simple Performance Tests

Hot mix asphalt (HMA) covers more than ninety percent of paved roadways in the US. Most HMA pavement distresses (such as rutting and fatigue cracking) can be characterized through laboratory performance tests. The NCHRP Project 9-19 has identified several tests as the simple performance tests (SPT) to characterize the performance of HMA mixtures. The paper presents a laboratory study carried out by the Tennessee Department of Transportation and the University of Tennessee. One type of HMA commonly used as surface mixture in the state of Tennessee, USA, was evaluated through the simple performance tests of dynamic modulus and flow number. The Asphalt Pavement Analyzer (APA) test was conducted as comparison to the simple performance testing. The dynamic modulus was tested at 10, 25, and 54 °C and three confining pressures. Three asphalt binders (PG 64-22, PG 70-22, and PG 76-22) were used for comparative purposes. The results from the present study indicated that the simple performance tests generally agreed with APA, i.e., mixtures produced with increased high temperature PG grade of asphalt cement exhibited higher dynamic modulus values, higher flow number values, lower rut depths, indicating potentially high resistance to rutting.