再生沥青中新旧沥青扩散特性
Diffusion characteristics of aged and virgin asphalt in reclaimed asphalt

为掌握再生沥青中新旧沥青扩散特性，以提高再生沥青混合料性能和旧沥青的再生程度，采用老化沥青和新沥青制备双层沥青试样，保温使新旧沥青扩散，在此基础上，建立基于针入度和动态剪切流变（DSR）试验的新旧沥青扩散程度评价方法和指标，进而研究高温和中温条件下扫描保温时间、保温温度、老化沥青类型及老化程度对新旧沥青扩散程度影响，设计正交试验，并使用极差分析和方差分析方法研究各因素影响程度。结果表明：高温条件下新旧沥青扩散程度随保温时间的增加先增加后不变，随老化程度的增加基质沥青扩散程度逐渐增加，SBS改性沥青则基本不变，且老化程度较低时SBS改性沥青扩散程度优于基质沥青，但老化程度严重时正好相反；老化时间、保温温度和保温时间对新旧沥青扩散程度的影响程度依次降低，其中老化时间和保温温度对其有显著影响，而保温时间无显著影响；中温扫描时，新旧沥青扩散程度随扫描时间的增加而增加，随老化程度增加而减小，且基质沥青扩散程度优于SBS改性沥青；高温和中温条件下新旧沥青扩散程度均随温度的增加而增加，且基质沥青的最佳增长温度范围高于SBS改性沥青。故如需提高再生沥青混合料中新旧沥青扩散程度时应主要关注沥青老化程度及适宜的新旧沥青温度。
To evaluate the diffusion characteristics of new and old asphalt in recycled asphalt， and to improve the performance of recycled asphalt mixture, two？？layer asphalt samples were prepared using aged asphalt and virgin asphalt, and thermal insulation was used for the diffusion of virgin asphalt and old asphalt. Based on this, an evaluation method and index for the diffusion degree of virgin asphalt and old asphalts based on penetration and dynamic shear rheology (DSR) tests were established. Next, the influence of scanning insulation time, insulation temperature, type of aged asphalt, and aging degree on the diffusion degree of new and old asphalt was investigated. Orthogonal test using range analysis and variance analysis method was designed to study the degree and significance of the influence degree of each factor. The results show that under the condition of high temperature storage, the diffusion of new and old asphalt first increases with the insulation time and then becomes constant. The diffusion of asphalt increases with the aging degree. the SBS modified asphalt remains constant. The diffusion of SBS modified asphalt is better than that of asphalt when the aging degree is low， however, the opposite occurs when the aging degree is high. The influence of aging time, holding temperature, and holding time on the diffusion degree of new and old asphalt decreases. The aging time and holding temperature significantly influence the asphalt, but the holding time does not. Under the condition of middle temperature scanning, the diffusion degree increases with the increase of the scanning time and decreases with the increase of the aging degree. Further, the diffusion degree of asphalt is better than that of SBS modified asphalt. Under the condition of new and old asphalt the diffusion degree increases with the increase of temperature, and the optimum increase temperature range of asphalt is higher than that of SBS modified asphalt. Therefore, to improve the diffusion characteristics of asphalt in recycled asphalt mixture, the asphalt aging