Assessing the Water and Freeze–Thaw Susceptibility of Hot Mix Asphalt With and Without Hydrated Lime and Polymer-Modified Bitumen, Using the Complex Modulus Test

Climatic conditions expose hot mix asphalt (HMA) to a large number of elements and phenomena that exacerbate its deterioration. Water infiltration into the bitumen–aggregate interface, combined with high temperatures, reduces its cohesion (stiffness) and that of the asphalt mix. In addition, at low temperatures, water seepage into the bitumen–aggregate interface and into the voids of HMA freezes, creating microcracks and increasing future seepage and damage to the HMA. To determine their behavior and damage under water and freeze-thaw cycles (FTCs), it is essential to carry out good mechanical tests. Empirical tests like indirect tensile strength and Marshall stability are widely used to assess HMA behavior and damage, but they lack precise correlation with field performance. Determination testing, like the complex modulus (E*) test, which allows intrinsic material properties to be related to behavior and damage, should be prioritized. Notably, this laboratory study focuses on the use of the E* test to assess susceptibility to water and FTCs, concentrating on the stiffness and phase angle changes of HMA elaborated with or without hydrated lime (HL) and polymer-modified bitumen (PMB). The 2S2P1D model is also used to simulate E* results under four conditions (DRY, WET, 3 FTCs, and 10 FTCs). The results indicate the impact of water, FTCs, and HL on the properties of HMA. Notable changes in stiffness were observed for the mix without HL. This study highlights the importance of determining intrinsic properties through advanced testing methods to better understand and formulate sustainable HMAs.