利用大豆油脂肪酸对重度老化沥青再生研究

Aged Asphalt with Soybean Fatty Acids

为了研究大豆油脂肪酸(Soybean Fatty Acids, SFA)作为生物再生剂对重度老化沥青的再生效果,首先采用SHRP (Strategic Highway Research Program)指标对不同老化程度的再生沥青进行性能表征并分级,然后借助Black Space图对不同再生沥青性能恢复归属于再生还是软化进行分析。流变试验结果表明SFA能够降低沥青的黏度和复数模量,而SFA对沥青相位角的改变与SFA的掺量和沥青的软硬程度相关,对于软质沥青AAM,较高的SFA (大于5%)掺量会降低沥青的相位角;PG (Performance Grade)分级结果显示SFA能够改善老化沥青的高低温等级,但是改善效果与被再生沥青的化学组分相关,且SFA的掺量受再生沥青热稳定性要求(短期老化质量损失和闪点)限制不得超过6%。借助SHRP指标和Black Space图证实SFA对软沥青性能的改性属于软化,而对重度老化沥青性能的改性属于再生。

This research was conducted to study the regenerate effects of soybean fatty acids on heavily aged asphalt.First step,SHRP tests were conducted to characterize the performance of regenerated asphalt with different aging degrees.Meanwhile,PG results of each sample were measured.Afterwards,Black Space diagram was used to determine the recovery mechanism of aged asphalt,namely softening effects or regenerated effect.Rheological test showed that SFA can decrease asphalt s viscosities and complex modulus.However,the changes of phase angles during regeneration depend on the dosages of SFA and the soft and hard degree of asphalt.For soft asphalt(AAM for short),high percentage of SFA(higher than5%)would decrease asphalt s phase angles.PG results showed that SFA can better the high and low temperature grade of asphalt,however,this improvement was speculated to be related to their chemical composition and it is found that the dosage of SFA was limited to be lower than6%due to its negative impacts on asphalts mass loss in short term aging and flash point.From SHRP indexes and Black Space diagram results,this research finds that the recovery of AAM asphalt performance after add SFA is attributed to softening effect and that of heavily aged asphalts performance is attributed to regeneration effect.