基于再生剂/新沥青扩散行为的老化沥青再生规律

采用试管法模拟再生剂/新沥青在老化沥青中的扩散,截取不同扩散位置处混溶形成的再生沥青,通过常规指标、流变性质及感温性分析,评价再生沥青性能指标随再生剂/新沥青扩散行为发展的变化规律,并探究不同温度及时间条件对再生剂/新沥青扩散行为的影响机制。结果表明:随再生剂/新沥青在老化沥青中的扩散,各层位混溶形成的再生沥青性能得到不同程度的恢复,且随层位呈现梯度变化趋势,距新旧沥青界面越远,再生沥青性能与老化沥青越接近;相同扩散位置处,RA-1型再生剂比SK-90新沥青具有更好的扩散能力和再生效果,尤其可显著提高再生沥青的低温抗裂性能;在一定范围内提高拌和温度和延长扩散时间,有助于提升再生剂/新沥青在老化沥青中的扩散能力,促进新旧沥青的融合。

Recycling Law of Aged Asphalt Based on Diffusion Behavior of Rejuvenator/Virgin Asphalt

Tube method was used to simulate the diffusion of rejuvenator/virgin asphalt in aged asphalt. The formed rejuvenated asphalt in different layers were cut out for testing of conventional indexes, rheological properties and temperature susceptibility, so as to evaluate the variation laws of technical performance for rejuvenated asphalt with diffusion process of rejuvenator/virgin asphalt. In addition, the influencing mechanism of temperature and time on diffusion behavior of rejuvenator/virgin asphalt was also carried out. The results show that the performances of rejuvenated asphalt in different layers are restored to varying degrees and display gradient trend with the diffusion of rejuvenator/virgin asphalt. The farther away from the interface between virgin asphalt and aged asphalt, the closer the performance is to the aged asphalt. In the same diffusion position, RA-1 rejuvenator shows better diffusion ability and rejuvenating effect than virgin asphalt SK-90, especially in terms of improvement of cracking resistance at low temperature for rejuvenated asphalt. The increase of mixing temperature and extension of diffusion time within certain range are conducive to enhancing the diffusion ability of rejuvenator/virgin asphalt in aged asphalt and promoting the blending between virgin and aged asphalt.