生物基再生剂对老化沥青流变特性的恢复效果及再生机理

Effect of bio-based rejuvenator on restoring rheological characteristics of aged asphalt and its rejuvenation mechanism

为探究油脂行业下游底物作为生物基再生剂(BR)对老化沥青流变特性的恢复效果及再生机理,制备不同针入度等级的老化沥青(P50、P30及P15),分别掺入不同比例的BR使其针入度恢复至未老化水平,通过频率扫描及流动性扫描试验,研究老化沥青流变特性的恢复效果,并基于沥青特征官能团及微观结构变化,分析对应的再生机理。结果表明:BR对不同老化程度沥青流变特性的恢复效果不同,P50再生后各项指标完全恢复,对于老化程度较重的P30和P15,尽管掺入较高比例的BR后针入度得以恢复,但流变指标与未老化沥青仍存在较大差别。BR在调节老化沥青组分比例的同时,通过稀释、溶解沥青质胶团,恢复了沥青胶体结构的稳定性,但该过程并不涉及沥青组分的化学可逆恢复,此为沥青再生的主要机理。

To explore the effect of bio-based rejuvenator(BR, from the downstream substrate in the oil industry) on restoring rheological characteristics of aged asphalt and its rejuvenation mechanism, aged asphalts with different penetration grades(P50, P30, and P15) were prepared firstly, which were mixed with different dosages of BR to restore their penetration to the unaged level. The restoration of rheological characteristics of the aged asphalts was studied through frequency sweep and flow sweep tests, and the corresponding rejuvenation mechanism of the asphalts was analyzed based on the functional groups and microstructure changes. The results show that the restoration effect of BR on the rheological characteristics of asphalt with different aging degrees is diverse. All testing indexes of P50 are completely restored to their unaged level, as for the P30 and P15 with the heavier aging degree, although their penetrations are completely restored after adding a higher proportion of BR, however, there is still a large gap between their rheological indexes and the unaged one’s. BR not only can adjust the fractions proportion of aged asphalt but also restores the stability of the asphalt colloidal structure by diluting and dissolving asphaltene micelles, nevertheless, the rejuvenation does not involve the chemical reversible recovery of asphalt components, which is the main mechanism of asphalt rejuvenation.