Viscoelastic properties of warm recycled asphalt mixture based on S-φ model

Abstract In order to study the influence of temperature, frequency and RAP content on the viscoelastic properties of warm mix recycled asphalt mixture, the viscoelastic properties of asphalt mixture with different RAP content (0%, 50%, 70%) at four temperatures and six frequencies were studied by dynamic modulus test. The results show that under the condition of high temperature and low frequency, the dynamic modulus of the two kinds of asphalt mixture after warm mix regeneration is higher than that of hot mix asphalt mixture ; under the condition of low temperature and high frequency, the dynamic modulus of the two kinds of asphalt mixture after warm mix regeneration is not significantly different from that of hot mix asphalt mixture, which indicates that the elasticity of asphalt mixture after warm mix regeneration is still higher than that of hot mix asphalt mixture at high temperature, and there is no significant difference between flexible and hot mix asphalt mixture at low temperature. Compared with 70% RAP warm mix recycled asphalt mixture, when the RAP content is 50%, the dynamic modulus increases the most at high temperature (50°C), and the phase angle decreases the least at low temperature (5°C). Therefore, 50% RAP warm mix recycled asphalt mixture has better high and low temperature performance. According to the principle of time-temperature equivalence, S (GMS model) andφ ( improved phase angle model ) with auxiliary parameter ρ are fitted synchronously to realize parameter sharing, and S andφ models can well fit the variation of dynamic modulus and phase angle with frequency.