基于热分析质谱联用技术的沥青老化机理研究

Aging mechanism of asphalt based on thermal property and mass spectrum analysis

利用热分析质谱联用技术研究不同老化状态的沥青微观组成、结构与宏观路用性能之间的联系。首先制备沥青结合料短期老化和长期老化试样,然后采用热重-差热分析-质谱联用技术,分析不同老化状态沥青的热性质及逸出物质结构。研究结果表明:基质沥青、短期老化和长期老化的沥青试样分解过程的温度范围及峰值对应温度基本一致;低于300℃的温度范围内,试样老化程度对热重损失速率影响较小;沥青高温分解阶段,长期老化质量损失速率最低,基质沥青最高,短期老化试样居中;3种老化状态的沥青试样热分解产物主要有CO、H2O、CH4、CO2,该产物主要来源于沥青中大分子烷烃的高温分解和碳元素氧化;热重曲线残留质量比与沥青复数模量有较好的联系,随着沥青老化程度增大,TG曲线上残留质量比逐渐增加,在宏观上表现为复数模量增大。

The thermal analysis and mass spectrometry were used to study the microstructure and thermal property of asphalt composition. The base asphalt sample, short term aging sample, and long term aging sample were prepared for the combined differential scanning calorimetry（DSC）- Thermal gravimetric（TG）-Mass spectrum（MS） test. The results show that the pyrolysis temper- ature range and the peak temperature of the three different aging type samples are similar. Within a temperature range below 300 ~C, the degree of aging has a small effect on weight loss rate in TG curve. In asphalt pyrolysis stage, the weight loss rate of long-term aging sample is the low- est, base asphalt sample＇s weight loss rate is the highest, and the short term aging sample＇s is medium. The decomposition products of three aging type asphalt samples are CO, H20,CH4 and CO2, which are mainly from alkane oxidation and pyrolysis of carbon element. For the TG curve, the residual quality ratio and complex modulus have a good relationship. With the increase of as-phalt aging degree,the residual quality ratio on TG curve gradually increases, which presents the increase of complex modulus on a macro-scale. 3 tabs, 9 figs, 16 refs.