【作者】 黄刚；

【导师】 何兆益；

【作者基本信息】 重庆交通大学 ， 道路与铁道工程， 2013， 博士

【摘要】 沥青路面以其良好的路用性能被交通行业广泛应用。但高温状态下,热拌沥青混合料产生和聚集的沥青烟会危害施工人员身心健康、造成环境污染。本文依托国家自然科学基金研究课题“高温条件下改性沥青烟雾产生机理与抑制技术研究”,开发抑烟复合改性沥青,揭示其在高温条件下对沥青烟的抑制机理,系统研究抑烟复合改性沥青及沥青混合料性能,在确保路用性能的前提下,在生产过程中最大限度地减少沥青烟的释放,实现沥青路面生产全过程的污染控制,为建设资源节约型、环境友好型交通提供技术支撑。研究工作取得以下主要成果：1、系统介绍了目前国内外沥青烟释放危害、沥青烟治理技术和沥青烟测定装置研究现状；基于重量法,提出了一个简单、实用的高温条件下评价抑烟效果的方法；根据物理吸附原理,优选纯净聚丙烯纤维棉作为高性能吸附介质,结合冻干技术,研发了一套集沥青烟产生、收集、排空装置于一体的沥青烟测定装置,试验证明该装置简单,稳定、高效、可靠；2、对影响沥青烟释放关键因素的研究表明,拌合速度、加热温度,加热时间是导致沥青烟释放量发生变化的主要因素,是否搅拌沥青、油源和种类的差异、沥青和空气载体的含水量也对沥青烟释放量产生影响；3、按照沥青阻燃、有机物非极性吸附、物理吸附和有机物非极性同时吸附等原理,针对性的选择了不同类别,可能具有抑烟效果的十一种材料,配制抑烟沥青,根据沥青烟释放量和路用性能,优选出膨胀石墨作为抑烟剂,开发抑烟复合改性沥青。4、红外光谱(FT-IR)、X射线衍射(XRD)、扫描电子显微镜(SEM)和综合热分析(TG-DSC)试验研究证实可膨胀石墨掺入沥青,在高温条件和长时间热拌过程中,产生部分膨胀,石墨层片主要被沥青轻质组分溶胀,轻质组份和多环芳烃吸附于膨胀石墨表面或部分插入膨胀石墨层片间并形核结晶长大,范德华力和晶格能的束缚有效抑制了其在热拌过程中的逸出释放；膨胀石墨中的氧化性膨胀剂在拌合过程中会扩散进入沥青,使沥青一定程度被氧化(老化),导致改性沥青的塑性减弱,表现为改性沥青延度降低,并影响改性沥青软化点,使其有所升高。5、提出制备抑烟复合改性沥青的详细方法；采用“均匀设计”为基础的科学实验设计方法,以控制沥青烟释放量和保证胶结料路用性能为目标,开发基于膨胀石墨、SBS和环氧大豆油的抑烟复合改性沥青,研究和提出了材料最佳组成比例；证明抑烟复合改性沥青抑烟率达到了60%,抑烟性能优良。6、常规沥青试验、RTFOT老化性能试验、Brookfield黏度试验与动态流变试验证明抑烟复合改性沥青感温性小、高温稳定性、低温抗裂性、抗水损性好,优于基质沥青,与SBS改性沥青相当,路用性能良好；7、沥青混合料试验分析证明抑烟复合改性沥青混合料具有较好的高温稳定性,良好的抗水损害性能和较好的抗疲劳性能,满足低温性能使用要求(冬温区、冬冷区)；揭示了抑烟复合改性沥青混合料的黏弹性变化规律,分别建立了轴向应变(轴向应变速率)与加载时间的回归方程,加载蠕变方程、动态模量(相位角)主曲线和主曲线回归方程；8、氧浓度燃烧试验、烟密度试验和混合料无约束、约束燃烧试验分析证明,发生火灾时,抑烟复合改性沥青路面能够发挥阻断沥青路面燃烧的作用；掌握了抑烟复合改性沥青的阻燃机理。9、提出了抑烟复合改性沥青和抑烟复合改性沥青混合料的参考技术指标。本文的系统研究表明,抑烟复合改性沥青及沥青混合料可以大幅降低热拌沥青混合料的沥青烟释放量,路用性能良好,为降低沥青烟的危害提供了一条新的技术途径。更多还原

【Abstract】 Asphalt pavement is widely used throughout the transportation industry for its fine pavement performance. However under the elevated temperature condition, asphalt fume which comes from the HMA harms construction personnel’s physical health and causes environmental pollution. Subject research of nation national natural science fund that is "study on generation mechanism and suppression technique of modified asphalt fume under high temperature" is based on by this paper to exploit composite modified asphalt of fume suppression and reveal mechanism of asphalt fume suppression under the elevated temperature conditions and study the performance of composite modified asphalt and asphalt mixture of fume suppression systematically. Under the precondition the pavement performance is ensured, the aim is to minimize the release of asphalt smoke, to control the pollution during the entire production of asphalt pavement. It provides technical support to build a resource-conserving and environment-friendly traffic construction. Main research results in this paper are obtained as follows.1. The present situation at home and abroad research on the harm of asphalt fume releasing and the technology of asphalt fume suppression and measurement equipment of asphalt fume was introduced. At the base of the gravimetric method, a simple and practical evaluation method on effect of fume suppression was put forward; according to the principle of physical adsorption, pure polypropylene fiber cotton was preferred as superior performance adsorption material. By freeze-drying technology, a measurement equipment which combines generation device of asphalt fume, collection device of asphalt fume with emptier of asphalt fume was researched and developed. The experimental results prove the equipment is uncomplicated, stable, efficient and reliable.2. The systematic research on the key factors which influence the release of asphalt fume shows that mixing speed and the heating temperature and heating time are the main factor that leads to the change of the release amount of asphalt fume; Mixing or not, the different oil source and types of asphalt, the water content in asphalt and water content on the air all influence the release of asphalt fume.3. According to the smoke suppression principle of the asphalt flame-retardant, the nonpolar adsorption principle of organic compounds, the physical adsorption and nonpolar adsorption principle of organic compounds, eleven kinds of material which belong different category and maybe have fume suppression performance were chosen pertinently to be prepared modified asphalt of fume suppression. Expanded graphite (EG) as the best fume suppressant was selected according to the release amount of asphalt fume and road performance, then composite modified asphalt of fume suppression was developed.4. The infrared spectrum test (FT-IR), X-ray diffraction test (XRD), scanning electron microscopy (SEM) test and comprehensive thermal analysis (TG-DSC) test Confirm that after expandable graphite was incorporated into asphalt, in elevated temperature conditions and hot mix process for a long time, the part of EG expand, graphite layer is swelled by light asphalt component. Light asphalt component and polycyclic aromatic hydrocarbon are adsorbed on the expansion graphite surface or part of them insert expansion graphite layer and crystal nucleation is grown up. The van der Waals force and lattice energy can effectively restrain escape and release in the hot mix process.In mixing process oxidative expansion agent of expandable graphite can spread into asphalt, so asphalt is oxidized (aging) in certain extent. These make the modified asphalt plastic abate, the performance is that ductility is reduced, softening point of the modified asphalt may be affected and risen.5. The detailed method to prepare the composite modified asphalt of fume suppression was determined; The "uniform design" as the foundation, method of scientific experimental design was utilized. To control the release amount of asphalt fume and ensure road performance of cementing material as the goal, composite modified asphalt of fume suppression was developed which is based on the expansion graphite, SBS modifier and epitomized soybean oil. The best material composition proportion was studied and put forward. Afterwards it was proved that composite modified asphalt of fume suppression has excellent performance of asphalt fume suppression and its fume suppression rate is60%.6. Conventional asphalt test, performance test after RTFOT aging, Brookfield viscosity test and dynamic shear religious test prove composite modified asphalt of fume suppression has low temperature susceptibility, good high temperature stability, good low-temperature crack resistance, good water stability. Its performance is better than that of the basic asphalt and the same as that of SBS modified asphalt. So its pavement performance is good.7. Tests of asphalt mixture prove conventional indexes of the composite modified asphalt of fume suppression meet the current specification, it has good elevated temperature stability, good resistance to water damage, good resistance to fatigue performance, meets the use requirements (winter temperature area, winter cold area) about the low-temperature performance; The composite modified asphalt mixture of fume suppression’s viscoelasticity change rule is revealed. The regression equations for the axial strain or strain rate of asphalt mixtures and loading time were built. Loading creep equation was built. Dynamic Modulus (phase angle) master curve and master curve regression equation are established.8. Analysis of the oxygen concentration combustion test and smoke density test of asphalt cementing material, unconstrained and constrained combustion test of asphalt mixture prove that composite modified asphalt of fume suppression pavement can pay a role to prevent asphalt pavement combustion. The flame-retardant mechanism of composite modified asphalt of fume suppression is mastered.9. Reference technical indexes of composite modified asphalt and asphalt mixture of fume suppression are put forward.Systematic research in this paper shows that composite modified asphalt of fume suppression and asphalt mixture can decrease asphalt fume emission of HWA greatly and have good pavement performance. It provides a new technical way to decrease harm of asphalt fume.更多还原