沥青结合料的热老化机理研究

发布时间：2018-03-28 12:12

本文选题：天然沥青　切入点：老化　出处：《长安大学》2014年硕士论文

【摘要】：沥青老化是影响道路沥青使用性能的重要因素，老化后会导致路用性能的劣化。研究沥青的热老化机理，评价和预测道路沥青的老化性能，为提高其抗老化性能提供理论基础。本文利用多设备同步联用技术对沥青结合料的微观组成与结构进行测试，，分析沥青老化过程中微观组成、结构变化与宏观流变特性、路用性能之间的作用关系。首先制备基质天然沥青改性沥青、TFOT短期老化后天然沥青改性沥青、TFOT+PAV长期老化天然沥青改性沥青，对制备的沥青结合料进行宏观性能试验，得出天然沥青最佳掺量在4%和6%之间，并发现老化后针入度和延度均减小，软化点增大。其次分别对老化前后的沥青结合料进行红外光谱分析，动态剪切流变试验和频率扫描分析。得出原样沥青和改性沥青短期老化（TFOT）和长期老化（PAV）后复数剪切模量均增大，相位角均减小；老化程度越大，则沥青结合料的高温稳定性能就越好，高温抗变形能力越强。天然沥青改性沥青结合料的复数模量数值随着频率的增大而变大，相位角随着频率的增大而减小，高频区域和低频区域速率不同。然后利用热分析（DSC、TG）、质谱（MS）同步联用技术，对沥青结合料进行热分析和质谱联用分析，分析了DSC曲线分解峰特征和TG曲线质量损失温度范围。对不同掺量改性沥青的DSC曲线分解峰面积进行积分，结合离子流强度分析得出天然沥青最佳掺量在4%和6%之间；对于老化前后的DSC曲线分解峰进行积分，短期老化后峰面积明显减小，说明短期老化后沥青结合料的热性能变得比较稳定了。对TG曲线进行一阶微分得到DTG曲线图，发现沥青结合料质量损失的速率有三个台阶式的变化，比较未老化、短期老化和长期老化DTG曲线峰值的大小，得到未老化最大，短期老化次之，长期老化相对较小。最后从热分析、质谱分析联用的角度考虑，TG-DSC-MS具有一致性，分解峰、热重损失速率最大处和离子流强度值最大处的温度是相互对应的。
[Abstract]:Asphalt aging is an important factor affecting the performance of road asphalt, which will lead to the deterioration of road performance. The thermal aging mechanism of asphalt is studied, and the aging performance of road asphalt is evaluated and predicted. In order to provide a theoretical basis for improving the anti-aging properties of asphalt binders, the microstructure and structure of asphalt binders were tested by using multi-equipment synchronous technique, and the microstructure, structural changes and macroscopic rheological properties of asphalt during aging were analyzed. The functional relationship between road performance. Firstly, the natural asphalt modified asphalt (TFOT PAV) was prepared after the short term aging of natural asphalt modified asphalt (TFOT). The macroscopical properties of the prepared asphalt binder were tested. It is found that the optimum content of natural asphalt is between 4% and 6%. It is found that the penetration and ductility decrease and the softening point increases after aging. Secondly, infrared spectrum analysis of asphalt binder before and after aging is carried out. The dynamic shear rheological test and frequency scanning analysis show that the complex shear modulus increases and the phase angle decreases after the short term aging of the original asphalt and the modified asphalt. The higher the stability of asphalt binder at high temperature, the stronger the deformation resistance at high temperature. The complex modulus value of natural asphalt modified asphalt binder increases with the increase of frequency, and the phase angle decreases with the increase of frequency. The rates of high frequency region and low frequency region are different. Then thermal analysis and mass spectrometry were used to analyze bituminous binder by thermal analysis and mass spectrometry. The characteristics of decomposition peak of DSC curve and the temperature range of TG curve mass loss were analyzed. The area of decomposition peak of DSC curve of modified asphalt with different content was integrated, and the optimum content of natural asphalt was found to be between 4% and 6% according to the analysis of ionic current strength. For the decomposition peak of DSC curve before and after aging, the area of the peak decreases obviously after short-term aging, which indicates that the thermal property of bituminous binder becomes more stable after short-term aging. The DTG curve is obtained by first order differentiation of TG curve. It is found that the rate of mass loss of bitumen binder has three step changes. Comparing the peak value of DTG curve of non-aging, short-term aging and long-term aging, it is found that the unaging is the largest, and the short-term aging is the second. The long-term aging is relatively small. Finally, from the point of view of thermal analysis and mass spectrometry analysis, the TG-DSC-MS has the consistency, the decomposition peak, the temperature at the maximum loss rate of thermogravimetry and the maximum ion current intensity are corresponding to each other.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U414

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