沥青老化再生过程中的流变与化学特性

Rheological and Chemical Characteristics of Asphalt During Aging and Regenerating

为了给再生剂研发指明方向,从流变和化学角度分析沥青的老化再生过程。对沥青样品进行了动态剪切流变试验和傅里叶变换红外光谱试验,测定了原样沥青、老化沥青及抽出油改性沥青的复数剪切模量、蠕变恢复率R、不可恢复蠕变柔量Jnr、G-R参数和老化官能团指数。结果显示:沥青老化后复数剪切模量提高,抗永久形变能力增强,但中温抗疲劳能力减弱;添加抽出油会减弱沥青的高温性能,但会增强其抗疲劳能力;沥青老化会产生大量的羰基和亚砜基官能团,抽出油可以使得短期老化和长期老化沥青的羰基指数分别下降48.6%和32.6%,亚砜基指数分别下降4.3%和32.7%。研究证明,抽出油可以使老化沥青的中温疲劳性能得到一定恢复,降低老化相关化学官能团浓度,从而起到再生效果。

In order to indicate the direction for the rejuvenator development,the aging and regenerating process of asphalt were analyzed from the rheological and chemical view.The Dynamic Shear Rheological(DSR)tests and Fourier Transform Infrared Spectroscopy(FTIR)tests were conducted on the asphalt samples.The complex shear modulus,creep recovery rate(R),unrecoverable creep flexibility(Jnr),G-R parameters and aging functional group index of the original asphalt,aged asphalt and asphalt modified by extraction oil were measured.The results show that:the complex shear modulus and the permanent deformation resistance of asphalt increase after aging,but the fatigue resistance of asphalt at medium temperature decreases;the high temperature property of the asphalt will be weakened and the fatigue resistance will be enhanced after adding the extraction oil;a lot of carbonyl and sulfoxide functional groups will be generated during asphalt aging,the extraction oil can reduce the carbonyl index of the short-term aging asphalt and the long-term aging asphalt by 48.6%and 32.6% respectively,and the sulfoxide index of the asphalt will be reduced by 4.3% and 32.7%.It proved that the extraction oil can restore the medium-temperature fatigue property of aged asphalt and reduce the concentration of chemical functional groups related to aging,thus having a regenerative effect.