水光耦合老化对橡胶改性沥青性能影响研究

Effects of Water-light Coupling Aging on Performance of Crumb Rubber Modified Asphalt

为研究水光耦合老化对橡胶改性沥青的性能影响,对橡胶改性沥青进行光老化与水光耦合老化,通过常规性能试验、动态剪切流变试验与凝胶渗透色谱法试验,分析了橡胶改性沥青在光老化和水光耦合老化作用下的高低温性能变化,并结合灰色关联分析法,对沥青微观组成和宏观性能关系进行分析。试验结果表明:橡胶改性沥青光老化导致沥青的延度均匀下降,软化点不断增大且后期趋缓。相较于光老化,水光耦合老化作用下的延度和软化点变化趋势相同,但对前期变化更为显著,说明水加速了橡胶改性沥青的前期老化速率。随着试验温度升高,车辙因子呈现指数状降低,且沥青车辙因子的温度敏感性降低。相位角随温度增大而增大,但老化条件对变化规律有影响。随着老化时间延长,光老化的橡胶改性沥青车辙因子、相位角与临界温度均增长,水光老化的变化规律与水老化一致,但变化幅度更为显著。橡胶改性沥青光老化导致沥青分散度D与大分子含量LMS均逐渐增长,但水光耦合老化的变化幅度更为显著,其中对前期变化影响更为明显。不同老化环境下,与LMS关联度最高的宏观指标不同,光老化的LMS与64℃车辙因子关联度最高,但光热老化的LMS与临界温度关联度最高。

In order to study the effect of water-light coupling aging on the performance of rubber modified asphalt,the light aging and water-light coupling aging of rubber modified asphalt were carried out.Through conventional index test,dynamic shear rheological test and gel permeation chromatography test,the high and low temperature performance changes of rubber modified asphalt under the action of light aging and water-light coupling aging were analyzed.Combined with grey correlation analysis method,the relationship between micro-composition and macro-performance of asphalt was analyzed.The test results show that the light aging of rubber modified asphalt leads to a uniform decrease in the ductility of asphalt,and the softening point continues to increase and slows down later.Compared with light aging,the change trend of ductility and softening point under water-light coupling aging is the same,but the change is more significant in the early stage,indicating that water accelerates the early aging rate of rubber modified asphalt.As the test temperature increases,the rutting factor decreases exponentially,and the temperature sensitivity of the asphalt rutting factor decreases.The phase angle increases with the increase of temperature,but the aging conditions have an effect on the change rule.With the extension of aging time,the rut factor,phase angle and critical temperature of light-aged rubber modified asphalt increase.The change rule of water-light aging is consistent with that of water aging,but the change range is more significant.The light aging of rubber modified asphalt leads to the gradual increase of D and LMS of asphalt,but the change range of water-light coupling aging is more significant,and the influence on the early change is more obvious.Under different aging environments,the macro indicators with the highest correlation with LMS are different.The LMS of photo-aging has the highest correlation with the rutting factor at 64°C,but the LMS of photo-thermal aging has the highest correlation with the critical temperature.