脱硫灰沥青混凝土水稳定性能研究

发布时间：2018-05-18 00:40

本文选题：脱硫灰 + 沥青混凝土　；参考：《武汉理工大学》2014年硕士论文

【摘要】：脱硫灰是燃煤烟气脱硫过程中，脱硫剂CaCO3/Ca(OH)2浆液吸收SO2产生的一种工业副产物。实现脱硫灰的资源化利用，是从根本上解决烟气脱硫工艺中脱硫副产物引起的一系列经济和环境问题的有效途径。本课题将脱硫灰作为无机沥青抗剥落剂应用于沥青混合料中，并与当前常用的抗剥落剂——水泥制备的改性沥青混合料的水稳定性能对比，研究脱硫灰对沥青混合料的水稳定性能的影响。本文采用扫描电子显微镜(SEM)观察脱硫灰的微观形貌，采用荧光分析和X射线衍射(XRD)对脱硫灰进行化学成分分析。通过研究拌合温度下脱硫灰的质量变化和差热分析(TG-DSC)(0-250℃)考察脱硫灰的热稳定性能。采用改进的水煮法和拉伸实验考察脱硫灰改善沥青与集料粘结性能的效果。采用浸水马歇尔实验、冻融循环试验、浸水车辙试验等评价脱硫灰沥青混合料的水稳定性能；脱硫灰沥青混合料的路用性能则通过高温车辙试验、低温三点弯曲试验、四点弯曲试验来考察。以二水硫酸钙和氢氧化钙做填料制备沥青混合料，采用冻融劈裂强度比做指标，探索脱硫灰中的这两种主要组分在对抗水损害中的作用。脱硫灰没有明显的团聚，颗粒分布范围较窄，较为均匀，，主要的颗粒大小在5-10um范围以内，且脱硫灰颗粒的表面呈囊状凸起。脱硫灰的化学成分分析表明脱硫灰的主要成分为CaSO4·2H2O， CaCO3和Ca(OH)2，同时还有CaSO3·0.5H2O。改进的水煮法显示集料表面脱硫灰沥青胶浆的残留比例达到了55.4%，高出普通矿粉胶浆7%，说明脱硫灰的掺入可以提高沥青胶浆的强度。脱硫灰沥青混合料的残留稳定度、冻融劈裂强度比、浸水车辙动稳定度均表现出对普通石灰石矿粉的明显优势。且相较于水泥沥青混合料其水稳定性能也有所提高。高温车辙、低温三点弯曲试验、四点弯曲疲劳试验显示，脱硫灰沥青混合料的高温抗变形能力、低温抗裂性能、抗疲劳能均满足规范要求或与水泥沥青混合料相当。因此脱硫灰应用于沥青混合料中能够显著的提高沥青混合料的水稳定性能，同时使沥青混合料的路用性能不低于传统填料制备的沥青混合料。脱硫灰的两种主要成分中，二水硫酸钙能够改善混合料的水稳定性能，但效果有限，但是它的水化作用是脱硫灰沥青混合料在多次冻融中发生强度回复的主要原因；而氢氧化钙在抗水损害中发挥了主要作用。
[Abstract]:Desulphurization ash is an industrial by-product produced by the absorption of SO2 by desulfurizer CaCO3/Ca(OH)2 slurry in the process of flue gas desulfurization. Realizing the utilization of desulphurization ash is an effective way to solve a series of economic and environmental problems caused by desulfurization by-products in flue gas desulfurization process. In this paper, desulphurization ash is used as inorganic asphalt anti-stripping agent in asphalt mixture, and the water stability of modified asphalt mixture is compared with that of modified asphalt mixture prepared by cement, which is commonly used as anti-stripping agent. The effect of desulphurization ash on the water stability of asphalt mixture is studied. In this paper, scanning electron microscope (SEM) was used to observe the microstructure of desulfurization ash, and fluorescence analysis and X-ray diffraction (XRD) were used to analyze the chemical composition of desulfurization ash. The thermal stability of desulphurization ash was investigated by studying the mass change of desulphurization ash at mixing temperature and differential thermal analysis (DTA). The effect of desulphurization ash on the adhesion between asphalt and aggregate was investigated by improved boiling method and tensile test. The soaking Marshall test, freeze-thaw cycle test, immersion rutting test and so on are used to evaluate the water stability of desulphurized ash asphalt mixture, while the road performance of desulphurized ash asphalt mixture is evaluated by high temperature rutting test, low temperature three-point bending test, etc. Four point bending test to examine. The bituminous mixture was prepared with calcium sulfate dihydrate and calcium hydroxide as fillers. The effect of these two main components in desulphurization ash against water damage was explored by using the ratio of freezing and thawing splitting strength as the index. There is no obvious agglomeration of desulphurization ash, the particle distribution range is narrow and uniform, the main particle size is within 5-10um range, and the surface of desulphurization ash particles is cystic protruding. The chemical composition analysis of desulfurization ash shows that the main components of desulfurization ash are CaSO4 _ 2H _ 2O, CaCO3 and CaOH _ (2) H _ (2), as well as CaSO3 _ (0.5) H _ 2O. The improved water boiling method shows that the residual ratio of desulfurized ash asphalt slurry on aggregate surface reaches 55.4, which is higher than that of ordinary mineral powder paste, which indicates that the strength of asphalt mortar can be improved by adding desulfurization ash. The residual stability, freeze-thaw splitting strength ratio and dynamic stability of soaking rut of desulfurized ash asphalt mixture show obvious superiority to ordinary limestone ore powder. Compared with the cement asphalt mixture, the water stability of the mixture is also improved. The results of high temperature rutting, low temperature three point bending test and four point bending fatigue test show that the high temperature deformation resistance, low temperature crack resistance and fatigue energy of desulphurized ash asphalt mixture meet the requirements of the specification or are equivalent to the cement asphalt mixture. So desulphurization ash used in asphalt mixture can significantly improve the water stability of asphalt mixture, at the same time, the pavement performance of asphalt mixture is not lower than that of asphalt mixture prepared by traditional filler. Among the two main components of desulphurization ash, calcium sulfate dihydrate can improve the water stability of the mixture, but the effect is limited, but its hydration is the main reason for strength recovery of desulfurization ash asphalt mixture in many freeze-thaw. Calcium hydroxide plays a major role in water damage resistance.
【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

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