The complex modulus ($E^{*}$ ) is a fundamental material property extensively used for characterizing the viscoelastic behavior of asphalt concrete. In recent years, numerous micromechanics-based models have been proposed for predicting the asphalt concrete $E^{*}$ . Unfortunately, few of them are capable of rationally considering the aggregate interlocking effect that plays a vital role in the reinforcement mechanisms of asphalt concrete. To address this issue, this study presents a new approach, in which the asphalt mastic matrix phase in the traditional models is substituted with a new equivalent matrix phase that incorporates both the viscoelastic properties of asphalt mastic and the effect of aggregate interlock reinforcement. Two interlock factor functions, which were initially proposed for characterizing the confinement dependency of the triaxial $E^{*}$ of asphalt concrete, are introduced into the two springs, two parabolic elements and one dashpot (2S2P1D) model representing the complex shear modulus ($G^{*}$ ) of the original asphalt mastic matrix phase. The feasibility and effectiveness of the approach is demonstrated by means of the traditional two-layer built-in (TLB) and generalized self-consistent (GSC) micromechanics models. The results show that the proposed method overcomes the shortcomings of underpredicting the storage and loss moduli of asphalt concrete over the intermediate- and low-frequency range in the traditional micromechanics methods. Also, without changing any original geometries, the advantages of simplicity and practicability of the traditional models remain. Finally, recommendations for future research are discussed in brief.

Under low-temperature conditions in winter, asphalt pavement is prone to cracking, icing and other distresses, which affect its safety and comfort. Therefore, by incorporating phase-change materials into asphalt and conducting relevant performance studies, the aim is to alleviate low-temperature distress and regulate road surface temperature and expand the application of phase-change materials in asphalt pavement. We mixed the selected phase-change materials with different dosages into the matrix asphalt to prepare phase-change temperature-regulating asphalt and tested the four basic indicators: road performance, latent heat characteristics, temperature-regulating performance, and rheological properties of phase-change asphalt and its mixture. The research results indicate that with the increase in phase-change material content, the penetration, softening point, ductility, and dynamic viscosity of phase-change high-viscosity asphalt gradually increase. Under the constant temperature test conditions of −2.5 °C and −5 °C, the surface icing speed of asphalt binder specimens mixed with phase-change materials is slower than that of specimens without phase-change materials. Adding phase-change materials can improve the high-temperature and low-temperature PG grading of high-viscosity asphalt, effectively improving its high-temperature rutting resistance and low-temperature cracking performance. According to the temperature regulation test results, phase-change temperature-regulating asphalt has a certain regulating effect on temperature under low-temperature conditions, which can slow down the cooling rate of asphalt, reduce the thermal conductivity of permeable asphalt mixture by more than 50%, increase the temperature regulation rate by more than 30%, and improve the ice-melting and snow-melting ability by more than 20%. Phase-change materials have almost no effect on the porosity of permeable asphalt mixtures and can effectively improve the water stability, low-temperature crack resistance, and antiflying performance of permeable asphalt mixtures. Their Marshall stability and rutting stability decrease, but still meet the requirements of the specifications. Applying phase-change materials to permeable asphalt pavement can automatically adjust the temperature of the pavement, reduce the cooling rate of the asphalt pavement during cooling, alleviate the problem of snow and ice accumulation on the asphalt pavement in winter, and thereby improve the performance of permeable asphalt pavement against freeze–thaw cycles.