紫外光谱法评价乳化沥青破乳过程
Evaluation of emulsified asphalt demulsification process by UV spectrum method

为了研究和评价乳化沥青的破乳过程，将现代分析仪器及化学计量算法应用到道路材料学研究领域，以紫外可见光谱和Lambert-Beer定律为基本原理，采用CR22G Ⅱ高速离心机通过给乳化沥青附加离心场加速破乳，并引入紫外吸光度和乳化剂浓度这2个参数表征乳化沥青的破乳过程。在不同测试条件下，对乳化沥青以及经过集料拌和后的乳化沥青进行破乳过程验证。研究结果表明：乳化沥青破乳模拟方法显著影响破乳试验结果的精度，未经处理的乳化沥青上层清液浑浊，溶液中含有大量悬浮的沥青颗粒，对试验结果产生较大影响，导致紫外光谱测量结果紊乱，无法表征乳化沥青破乳过程；而经过处理后的上层清液含有极少悬浮状沥青颗粒，溶液清澈透明，所得紫外光谱图线性良好，与实际吻合。乳化沥青在高速离心场下能加速破乳，随着时间的推移，体系中的乳化剂浓度不断上升至一个定值，具体在紫外光谱图中表现为吸光度值不断上升直至趋于平稳状态，也即达到破乳平衡状态。对有紫外吸光度的乳化剂采用适当的乳化沥青加速破乳条件，用紫外分光光计法，并将所取上层清液中的乳化剂浓度控制在一定的范围内，根据紫外光谱图及Lambert-Beer定律能够精确描述乳化沥青破乳全过程；该方法可有效区分不同集料/乳化沥青系统的破乳速度。
In order to research and evaluate the demulsification process of emulsified asphalt, modern analysis instruments and chemical measurement algorithm were applied to the field of road materials by omics technology. With UV spectrum and Lambert Beer law as the basic principle, CR22G Ⅱ high-speed centrifuge was adopted to accelerate the demulsification by adding centrifugal field to emulsified asphalt, two parameters, involving UV absorbance and the concentration of emulsifier, were introduced to character the demulsification process of emulsified asphalt. And under different test conditions, the demulsification process of emulsified asphalt and emulsified asphalt after aggregate mixing was verified. The results show that emulsified asphalt demulsification simulation method significantly affects the accuracy of demulsification test results. Untreated emulsified asphalt supernatant is cloudy. The solution containing a large amount of suspension asphalt particles has great influence on the test results, leading to the disorder of the UV spectrum measurement, which can not characterize the emulsification process of emulsified asphalt. And after processing, the supernatant liquid has few slurry asphalt particles, the solution is clear and transparent, and the UV spectra obtains good linear in accordance with the practicality. Emulsified asphalt in high speed centrifugal field can accelerate the demulsification. As time goes on, the concentration of emulsifier in the system continues to rise to a constant value, which is manifested in UV spectrum as the absorbance value continues to rise until it reaches a steady state, that is, reaches the demulsification equilibrium state. For emulsifier with UV absorbance, the use of appropriate emulsified asphalt can accelerate the demulsification conditions to accelerate the demulsification conditions. The concentration of emulsifier in the supernatant is controlled within a certain range by UV spectral light meter. According to the UV spectra and Lambert-Beer law, the whole process of emulsified