【作者】 王川；

【导师】 郭荣鑫；

【作者基本信息】 昆明理工大学 ， 材料物理与化学， 2018， 硕士

【摘要】 近年来国家大力建设高速公路事业,大量高速公路建设需要消耗大量天然石料,会造成自然资源匮乏和环境污染问题。钢渣作为产量较大的工业固体废弃物,具棱角性良好、硬度和强度大、磨光值高、耐磨耗损失小等优异的物理力学性能,可作为沥青混合料集料使用。另一方面,钢渣经过1600℃高温生成,其中的f-CaO、f-MgO结构非常致密,水化速率会非常慢,遇水会产生体积膨胀从而降低了钢渣沥青混合料长期体积稳定性能。多年来对钢渣作为道路工程材料的研究和应用表明,钢渣的体积膨胀性是影响其大规模应用的主要障碍。开展钢渣膨胀性抑制方法的深入研究符合工程实际的迫切需求,有重要的学术意义和工程实际意义。基于钢渣膨胀性问题,本文利用改性材料Ⅰ、改性材料Ⅱ对钢渣进行表面改性处理,研究了水侵蚀后改性集料胀裂性、力学性能和改性钢渣沥青混合料试件动态模量变化规律。并通过pH计、ICP-OES和扫描电镜分别测量浸出液pH、浸出液离子浓度、水侵蚀后集料界面过渡区结构变化,分析水侵蚀后改性钢渣性能劣化机理,得到如下主要结论:(1)改性材料Ⅰ、改性材料Ⅱ改性后,两种方法改性后钢渣都具有良好的力学性能。改性钢渣SEM图片表明,ISS(改性材料Ⅰ改性钢渣)表面粗糙、断面和界面过渡区存在大量孔隙,OSS(改性材料Ⅱ改性钢渣)其表面光滑,致密性强,界面过渡区缺陷较少,起到很好的阻隔水的作用。(2)改性钢渣的抗水侵蚀胀裂性能较未改性钢渣提升显著,改性材料Ⅱ改性钢渣的抗胀裂性能最高。两种改性方法提高了钢渣力学性能,水侵蚀后改性钢渣依然保持良好力学性能。改性处理不仅提高了钢渣沥青混合料动态模量,同时降低了水侵蚀后低频动态模量衰减速率,对钢渣沥青混合料高频动态模量影响不大。(3)水侵蚀后,改性层、钢渣发生水化反应,水化产物堆积、填充着改性层和界面过渡区,使界面过渡区结构变得密实,逐渐减少水渗入的通道,有助于增强改性层的阻水能力,不仅有利改善钢渣抗水侵蚀胀裂性能,又有利于维持水侵蚀后抗压、抗磨耗能力。更多还原

【Abstract】 In recent years,the country has vigorously built highways.A large number of highway constructions need to consume a large amount of natural stone,which will cause shortage of natural resources and environmental pollution.Steel slag as a relatively large volume of industrial solid waste,has excellent physical and mechanical properties such as angularity,high hardness and strength,high polishing value,and wear value of Losangeles is small,and can be used as an asphalt mixture aggregate.On the other hand,steel slag is generated at a high temperature of 1600°C.The structure of f-CaO and f-MgO is very dense,and the hydration rate is very slow.When steel slag comes into contact with water,it will produce volume expansion and thus reduce the long-term stability of steel slag asphalt mixture.The research and application of steel slag as a road engineering material over the years has shown that the expansion of steel slags is the most important factor affecting steel slags to be used widely.The study of the method for suppressing the expansion of steel slag conforms to the urgent need of engineering practice,and has important academic significance and practical significance.Based on the problem of expansion of steel slag,in this paper,the surface modification of steel slag is performed using modified material I and modified material II.The modified aggregate expansion and mechanical properties and the dynamic modulus of the modification steel slag asphalt mixture specimens after water erosion were studied.The pH,ICP-OES and scanning electron microscopy were used to measure the pH of the leachate,the ion concentration of the leachate,and the structure change of the aggregate interface after water erosion.The mechanism of deterioration of the modification steel slag after water erosion was analyzed.The following main conclusions were obtained:(1)After modification of modified material I and modified material II,the two kinds of modified steel slag have good mechanical properties.The SEM image of the modified steel slag shows that the surface of the ISS(modified material I modified steel slag)is rough,and there are a lot of pores in the transition zone and the interface.The OSS(modified material II modified steel slag)has a smooth surface,structure is very dense,fewer defects in the interface transition zone,and plays a good effect of water barrier effect.(2)The resistance to water erosion and cracking of the modification steel slag is significantly higher than that of the untreated steel slag,and the modified material II modified steel slag has the highest anti-explosion performance.The two modification methods improve the mechanical properties of the steel slag,and the modified steel slag remains good mechanical properties after water erosion.The modified treatment not only improves the dynamic modulus of the steel slag asphalt mixture,but also reduces the attenuation rate of the low frequency dynamic modulus after water erosion,and has little effect on the high frequency dynamic modulus of the steel slag asphalt mixture.(3)Hydration reaction of modified layer and steel slag after water erosion.The hydration products accumulate and fill the transition zone between the modification layer and the interface,make the structure of the interface transition zone dense,gradually reducing the water infiltration channel,and helping to strengthen the modification layer.The ability to block water not only improves the resistance to water erosion and cracking of steel slag,but also helps maintain the ability to resist pressure and wear after water erosion.更多还原