Low-temperature aliphatic eutectic phase change materials for asphalt: Design and characterization

Cost and thermal stability are critical for the application of low-temperature phase change materials (PCMs) in asphalt pavements. Aliphatic eutectic phase change materials (AEPCMs) are expected to be potential candidates for new low-temperature PCMs. The objective of this study was to develop a set of low-temperature AEPCMs with a phase transition temperature of − 3.58 to 16.21 °C and a latent heat of 144.01 to 195.96 J/g in an attempt to replace tetradecane (TD). To fully evaluate the properties of low-temperature AEPCMs and TD, and the impacts of their direct incorporation into asphalt, the chemical structures, enthalpies, mass retention, economic costs, and changes in the physical and rheological properties of the modified asphalt were investigated. The results showed that AEPCMs with a phase transition temperature similar to that of TD could be obtained by eutectic crystallization and retained the chemical properties of their components. However, the latent heat decreased progressively with the increase in the number of components. The AEPCMs exhibited higher thermal stability than TD, with a maximal increase in mass retention from 37.24% to 86.66% at 180 °C. In addition, AEPCMs exhibited significant cost advantages. The most inexpensive AEPCMs synthesized in the laboratory is only 112.01 ¥/kg and an enthalpy cost of 0.57 ¥/kJ, accounting for 30.1% and 35.8% of TD cost, respectively. Incorporation of AEPCMs and TD increased the lightweight component of asphalt binders and caused damage to the conventional physical and rheological properties of asphalt binders, but polar AEPCMs had fewer deleterious effects on asphalt compared to nonpolar TD. •A set of low-temperature AEPCMs were synthesized to replace tetradecane.•AEPCMs outperform tetradecane in terms of heat stability and material cost.•AEPCMs is polar and enhances asphalt resin, whereas TD is non-polar and increases saturant.•Tetradecane impacts asphalt binder characteristics more than AEPCMs.