基于红外光谱的沥青结构表征研究

发布时间：2018-06-16 04:48

本文选题：沥青 + 红外光谱　；参考：《武汉理工大学》2014年硕士论文

【摘要】：近年来，随着长寿命沥青路面设计理论的提出，在高等级公路的施工过程中，对沥青路面耐久性的要求越来越高。然而，沥青属于有机材料，众所周知，在自然气候环境中的热、光、氧等的作用下，有机材料易老化；沥青的老化所引起的多种病害，如裂缝、麻面和坑槽等，将大大缩短了沥青路面的使用寿命。为延长沥青路面的耐久性能，必须研究揭示沥青在老化与抗老化过程中的成分与结构的变化规律。红外光谱法是研究沥青组分及其分子结构的最重要和最有效的实验手段之一，但由于沥青成分及其结构的复杂性，迄今沥青红外光谱的研究仍存在评价标准不统一、评价体系混乱等问题。本文利用多种来源不同的基质沥青和不同的改性沥青，系统研究傅里叶变换红外光谱法（FTIR）运用于沥青的各种指标评价体系，以揭示沥青的物理性能、成分及其分子结构之间的关系规律。获得的主要结论如下：（1）分别以沥青红外光谱的全振动谱区(4000~700cm-1)、基团伸缩振动谱区(4000~1400cm-1)、指纹振动谱区(1400~700cm-1)和饱和碳氢伸缩振动谱区(3000-2800cm-1)的总峰面积为基准，计算分析沥青中几个主要官能团的基团指数，发现以4000~700cm-1全振动谱区的峰面积为基准计算的各官能团相对含量，最能正确反映基团含量与沥青物理性能之间的关系规律。（2）在实验室模拟的短期热氧老化和短期紫外老化后，沥青中羰基峰和亚砜基峰的峰面积变化增减不一，单独的羰基峰面积更适合于评价道路沥青的短期老化行为；但对于PAV长期老化，羰基和亚砜基峰的峰面积均随老化时间的增加而增加，同时运用羰基峰和亚砜基峰的面积两个指标评价道路沥青的长期老化情况，更为精准。（3）通过四组分研究，，发现沥青中饱和分、芳香分和沥青质在采取不同的老化方式老化后各自的变化规律相同，老化过程中饱和分没有发生断链和氧化，芳香分发生了缩聚反应形成了稠环化合物。沥青中的胶质在不同的老化方式下有不同的表现：在热氧老化下WAR（芳香指数变化率）和Wn≥4（长链指数变化率）均增加，形成了更多大分子的稠芳环，即转变为沥青质；在紫外老化下WAR和Wn≥4均不变，主要表现为亚砜基官能团指数的变化率增大，表明在紫外光作用下，胶质中的杂原子发生了氧化反应。（4）层状双羟基复合金属氢氧化物（LDHs）具有多级层状结构，其多级层板和层间能产生对紫外线的多重吸收和屏蔽，从而起到对紫外线的阻隔作用；有机化蒙脱土（OMMT）也具有类似的层状结构，OMMT片层可有效阻止氧在沥青中的扩散从而抑制沥青的老化；紫外吸收剂通过自身对紫外线的吸收，来避免或减轻紫外线对沥青分子的直接破坏。利用上述全谱区基准法，对LDHs、OMMT和紫外吸收剂在沥青抗老化过程中的作用，以及改性沥青在老化过程中相关特征基团含量的变化情况进行了评价，进一步证实了全谱基准法的可靠性。
[Abstract]:In recent years, with the development of long life asphalt pavement design theory, the requirement for durability of asphalt pavement is becoming more and more high during the construction of high grade highway. However, asphalt belongs to organic material. It is well known that organic materials are easily aging under the effect of heat, light and oxygen in natural climate environment; many kinds of asphalt aging are caused by the aging of the natural climate environment. Diseases, such as cracks, slots and pit grooves, will greatly shorten the service life of asphalt pavement. In order to prolong the durability of asphalt pavement, it is necessary to study the changes in the composition and structure of Asphalt during aging and aging resistance. The infrared spectroscopy is the most important and effective laboratory for the study of asphalt components and its molecular structure. However, due to the complexity of the asphalt composition and its structure, there are still some problems in the research of the infrared spectrum of bitumen, such as the evaluation standard is not uniform and the evaluation system is confused. In this paper, a variety of different sources of matrix bitumen and different modified bitumen are used in this paper to systematically study the various index evaluation of the Fourier transform infrared spectroscopy (FTIR) used in asphalt. The main conclusions are as follows: 1.
(1) the group exponents of several major functional groups in bitumen are calculated and analyzed with the full vibrational spectral region (4000~700cm-1), the group expansion vibration spectrum region (4000~1400cm-1), the fingerprint spectrum region (1400~700cm-1) and the saturated hydrocarbon expansion vibration spectrum region (3000-2800cm-1), respectively. It is found that the 4000~700cm-1 full vibrational spectrum is found. The relative content of each functional group calculated on the basis of the peak area of the area can best reflect the relationship between the group content and the physical properties of asphalt.
(2) the peak area of carbonyl and sulfoxide peaks in bitumen is not one, but the peak area of the carbonyl group is more suitable for evaluating the short-term aging behavior of asphalt. However, the peak area of carbonyl and sulfoxide base peaks is increased with the increase of aging time for the long-term aging of PAV. It is more accurate to evaluate the long-term aging of paving asphalt by using two indicators of carbonyl peak and sulfoxide peak area.
(3) through the study of four components, it is found that the saturated fraction, aromatic fraction and asphaltene in asphalt have the same changing rules after aging in different aging ways. There is no broken chain and oxidation in the aging process, and the condensation reaction of aromatic fractions has formed a thick ring compound. The gum in asphalt has different aging methods. The expression of WAR (aromatic index change rate) and Wn > 4 (long chain index change rate) increased in the thermal oxygen aging. The thickening aromatic ring of more macromolecules was formed, that is, the transition to asphaltene. Under UV aging, WAR and Wn > 4 are all constant, mainly as the change rate of the sulfoxide functional group index, indicating that under ultraviolet light, the colloid is in the presence of ultraviolet light. The atom of the heteroatom has an oxidation reaction.
(4) layered double hydroxyl complex metal hydroxide (LDHs) has multilayered structure, and its multistage laminates and interlayers can produce multiple absorption and shielding of ultraviolet light, which can prevent ultraviolet radiation. Organic montmorillonite (OMMT) also has a similar layered structure, and the OMMT lamellar can effectively prevent oxygen diffusion in asphalt and suppress the diffusion of oxygen in the asphalt. The effect of LDHs, OMMT and UV Absorbents on the anti aging process of asphalt and the change of the related characteristic group content during the aging process of asphalt in the process of asphalt aging are avoided or mitigated by UV Absorbents. The evaluation results further confirm the reliability of the full spectrum benchmark method.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U414

【引证文献】