IDT Creep Compliance Test ResultsFig. 6 presents the creep compliance mastercurves for the HMAand SMA field cores at the 20°C reference temperature. The measuredcreep compliance values of the HMA and SMA field cores ateach temperature are compared and shown in Table 3. The HMAfield core shows a lower creep compliance value at most temperaturesthan the SMA field core, which indicates that the SMA fieldcore has a better ability to relax the thermal stress at a low temperaturedue to its lower relaxation modulus (Park and Kim 1999)and thus resists thermal cracking better than the HMA field core.At 30°C, the creep compliance value for the SMA close to that ofthe HMA.