【作者】 陈辉强；

【导师】 郝培文；

【作者基本信息】 长安大学 ， 道路与铁道工程， 2009， 博士

【摘要】 随着我国山区高速公路的快速发展,公路隧道的数量与规模大幅度增长,沥青路面已经发展成为隧道铺装最主要的结构形式之一。作者通过国内外相关文献调研和本课题组的有关工作,综述了阻燃剂及阻燃技术在高分子领域内的研究进展情况和沥青阻燃技术的最新研究动态,认为通过对无卤环保型沥青阻燃剂进行表面改性,以提高沥青阻燃剂与沥青的相容性,有望发展成为新型的行之有效的沥青阻燃技术。本文采用偶联剂对沥青阻燃剂进行表面改性,研制了新型沥青阻燃剂及阻燃沥青,分析了其阻燃机理,研究了阻燃沥青混合料的技术性能,主要研究内容如下：1以界面理论和相容性原理为基础,研制出了两种活性高、与沥青相容性好、阻燃性能优良的新型沥青阻燃剂：经钛酸酯偶联剂表面改性的沥青阻燃剂(简称为BFR-Ti)和经硅烷偶联剂表面改性的沥青阻燃剂(简称为BFR-Si),确定了偶联剂合理用量。采用红外光谱(FTIR)、热重分析(TGA)及电镜扫描(SEM)等测试手段,对阻燃剂的结构和性能进行了分析。结果表明,当沥青阻燃剂的粒度范围为1000～1500目时,其对应的钛酸酯偶联剂和硅烷偶联剂的合理用量分别为沥青阻燃剂的1.6%和0.9%左右；经偶联剂表面改性之后的沥青阻燃剂,在沥青阻燃剂表面形成了新的化学键,其热稳性得到了有效的改善,“团聚现象”基本消失。2由BFR-Ti和BFR-Si两种沥青阻燃剂制备了BFR-Ti阻燃沥青和BFR-Si阻燃沥青,研究了沥青阻燃剂粒度和用量对阻燃沥青路用性能及燃烧性能的影响,分别确定了沥青阻燃剂的合理粒度范围和用量；研究了阻燃增效剂硼酸锌(ZB)对以上两种沥青阻燃体系的协同作用,并确定了ZB的合理用量。采用红外光谱(FTIR)、热重分析(TGA)及电镜扫描(SEM)等测试手段,对阻燃沥青的结构与性能进行了分析。结果表明,BFR-Ti和BFR-Si的合理粒度范围均为2000～2500目,合理用量均为沥青的9.0%；硼酸锌(ZB)对BFR-Ti阻燃沥青具有显著的阻燃增效作用,且以2.0%的硼酸锌(ZB)取代等量的BFR-Ti后,综合效果最佳,而硼酸锌(ZB)对BFR-Si阻燃沥青的阻燃增效作用并不明显；沥青阻燃剂用量对阻燃沥青的流变性能有一定影响。3通过研究几种阻燃沥青的燃烧行为,分析了阻燃沥青的阻燃机理,并找出了热重分析TGA与锥形量热分析CCT的测试结果之间的相关性,分析了阻燃增效剂ZB对BFR-Ti阻燃沥青的协同作用。结果表明,与SBS改性沥青相比,阻燃沥青的热释放速率(HRR)、质量损失速率(MLR)、有效燃烧热(EHC)以及点燃时间(TIG)等发生了较显著的变化,显示了良好的阻燃性；TGA中的分解温度与相应的CCT中的点燃时间有着较好的相关性,TGA中的高温炭层与CCT中的残炭量及热释放速率同样有着良好的相关性；硼酸锌在BFR-Ti-ZB阻燃沥青的燃烧过程中起到了明显的协同作用,这主要体现在燃烧过程中其烟雾密度和烟雾总量得到了明显的减小；阻燃沥青的燃烧过程中,均有沥青阻燃剂分解吸热、成炭等现象,表明其阻燃机理并不单一。对于BFR-Ti-ZB阻燃沥青而言,由于协同阻燃效应的存在,其阻燃机理虽以凝聚相阻燃机理为主,但兼具协效阻燃和吸热阻燃机理的特征,而其他几种阻燃沥青都是凝聚相阻燃机理和吸热阻燃机理共同作用的结果,但其侧重点不同。4通过对比实验,研究了由SBS改性沥青、BFR-Si阻燃沥青、BFR-Ti-ZB阻燃沥青以及国内常用组成不同混合料的技术性能,并通过实体工程,验证了阻燃沥青的路用性能和实际应用情况。结果表明,与SBS改性沥青相比,阻燃沥青混合料的油石比较大,其路用性能除水稳性有一定提高外,其他路用性能变化不大,均能满足规范要求。更多还原

【Abstract】 With the rapid development of expressways in China, the number and size of highway tunnels have been growing dramatically. As cement pavement has a lot of weaknesses, it has become increasingly unsuitable for modern tunnels and gradually replaced by bitumen pavement in tunnel construction. However, the inflammability of bitumen poses great danger for tunnel operation. Although many extensive researches have been conducted on bitumen flame retardant (BFR), further in-depth studies are still necessary.This Paper starts with a literature review on the background of researches on flame retardant and flame-retarding technology in terms of high polymer and latest developments of BFR technology, which shows that it is possible to develop a new effective BFR through surface modification of halogen-free environmental-friendly flame retardant to improve the compatibility between retardant and bitumen. The Paper then presents a study on the development of new BFR and flame retardant bitumen by using coupling agent to modify the surface of flame retardant. Based on the findings, the Paper studies the flame retarding mechanism and analyzes and tests the performance of flame retardant bitumen mixture. The study mainly covers the following contents:1. Based on interface theory and compatibility principle, two new bitumen flame retardants with high activity, good compatibility with bitumen, and excellent flame retarding performance, are developed by respectively using Titanate coupling agent and Silane coupling agent to conduct surface modification (these two retardants are called BFR-Ti and BFR-Si throughout the Paper). Then FTIR, TGA and SEM are used to test, describe and represent the structure and property of said retardants. Results show that appropriate ratio of Titanate coupling agent to BFR is around 1.6% and that of Silane coupling agent to BFR is around 0.9%. After surface modification, new chemical bonds have been formed on bitumen surface, effectively improving its thermal stability and largely eliminating the occurrence of agglomeration.2. Two flame retardant bitumens are made by mixing bitumen with BFR-Ti and BFR-Si respectively. ZB is then added to test its synergy with the two bitumens and determine the appropriate ratio. FTIR, TGA and SEM are used to test, describe and represent the structure and property of said bitumens. Results show that appropriate granularity range of both bitumens is 2,000-2,500 and ratio of ZB to bitumen is both 9.0%. Results also show that ZB does not produce significant synergy with BRF-Si flame retardant bitumen as a result of chemical reaction between ZB and Silane coupling agent, but the amount of BFR has some relation to the rheological property of flame retardant bitumen.3. Inflammation of several flame retardant bitumens is studied to analyze the flame retarding mechanism, identify the correlation between the results of TGA and CCT, and analyze ZB’s synergy with BFR-Ti flame retardant bitumen. Results show that in terms of inflammation property, compared to SBS modified bitumen, flame retardant bitumens have demonstrated significant changes regarding HRR, MLR, EHC and TIG and proved to be very flame retardant. Results also show that the breakdown temperature in TGA and corresponding TIG has sound correlation, high temperature carbon layer in TGA and residual carbon & HRR in CCT also have good correlation, and BFR-Ti-ZB flame retardant bitumen has shown significant synergy in the course of inflammation. In the course of inflammation, endothermic decomposition and carbonization occur to all flame retardant bitumen, indicating the flame retarding mechanisms is not single. As a result, the main flame retarding mechanisms is condensed phase flame retarding mechanisms, characterized by synergy and endothermic flame retarding mechanisms. The other flame retardant bitumens are the result of combination of condensed phase and endothermic flame retarding mechanisms.4. Tests are conducted to compare the properties of SMA13, AC 13 and GA10 respectively corresponding to SBS modified bitumen, BRF-Si flame retardant bitumen, BFR-Ti-ZB flame retardant bitumen. Real projects are studied to testify the road performance of flame retardant bitumen and its actual applications. Results show that compared to SBS modified bitumen, besides having bigger oil stones and improved moisture stability, flame retardant bitumen mixture boasts similar properties and therefore can meet pavement regulations. In addition, flame retardant bitumen can have satisfactory effect in actual application.更多还原