Preparation and Performance Testing of EC-PEG/EC-MA for Asphalt Mixtures

Asphalt pavements are significantly affected by high temperatures. Incorporating phase-change materials into asphalt can effectively absorb heat and reduce pavement temperatures. In this study, we prepared two PCMs—ethyl cellulose–polyethylene glycol (EC-PEG) and ethyl cellulose–myristic acid (EC-MA)—using ethyl cellulose (EC) as the shell material and polyethylene glycol 2000 (PEG) and myristic acid (MA) as the core materials via the counter-solvent method. The particle size, morphology, functional groups, and thermal properties of EC-PEG and EC-MA were characterized using a laser particle size analyzer, SEM, FTIR, and TG-DSC. By incorporating 5–30% EC-PEG and EC-MA into asphalt mixtures, mechanical properties were analyzed to determine the optimal phase-change particle content. Through temperature cycling tests on asphalt mixtures, the reduction in the cooling rate at the optimal dosage was determined. The test results have indicated the following: EC-MA exhibited a larger particle size than EC-PEG; EC-PEG forms loosely packed particles, while EC-MA adopted a blocky structure; EC-PEG and EC-MA formed a physical mixture without creating new chemical bonds; the PCMs phase-change enthalpies were 57.05 J/g and 89.15 J/g, respectively, with EC-MA exhibiting a higher encapsulation efficiency than EC-PEG. The optimal dosage of EC-PEG in asphalt mixtures was 15%, while that of EC-MA was 20%. At their respective optimal dosages, EC-MA demonstrated superior temperature control performance compared to EC-PEG, achieving a reduction in maximum temperature of 7.23 °C.