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类型 基础研究 预答辩日期 2018-05-14
开始(开题)日期 2015-12-18 论文结束日期 2018-03-02
地点 九龙湖交通大楼323会议室 论文选题来源 学校自选项目    论文字数 5.5 (万字)
题目 沥青混合料微波吸收增强机理与修复研究
主题词 沥青混合料,微波加热,升温速率,温度场,微波修复
摘要 由于自然环境和车辆荷载形成的沥青路面早期表面和结构破损,可以通过适时的加热修复,以延长路面使用寿命。为了提高沥青路面的微波加热修复效率,大幅节约养护成本,本研究提出了集料表面磁损耗增强原理,并采用三种增强方式对沥青混合料进行了微波加热效率的研究。分别对沥青混合料中各个成分进行改性处理,采用化学共沉淀法对普通玄武岩细集料和粗集料分别进行改性处理;采用共沉淀法对含铁量25%左右的普通钢渣进行改性处理;采用羰基铁粉作为磁损耗吸波剂、炭黑作为电损耗吸波剂、沥青作为基质制备吸波材料对沥青进行改性处理。在此基础上,对制备的吸波材料样品分别进行XRD物相分析和微波加热测试,结果表明改性钢渣和改性玄武岩细集料表面成功生成了磁性纳米Fe3O4,平均晶粒径分别为22nm和30nm。在微波加热2min内,改性玄武岩细集料(MF)和改性玄武岩粗集料(MC)上升的温度几乎是普通玄武岩细集料(BF)和普通玄武岩粗集料(BC)的两倍,且MF的温度略高于MC;改性钢渣的温度较普通钢渣高出40℃。 将吸波材料分别掺入到沥青混合料中以AC-13C级配制备成马歇尔试件和车辙板后,采用自由空间法测试了2-4GHz频率范围内的电磁参数,并使用红外热像仪和红外测温仪分别测试其在微波加热2min过程中的温度变化。结果表明改性玄武岩粗集料沥青混合料(MCAM)、改性玄武岩细集料沥青混合料(MFAM)、改性钢渣沥青混合料(MSAM)和羰基铁粉炭黑改性沥青混合料(AM CIP/CB)的复介电常数实部??相较于普通沥青混合料(BAM)分别增加了11.3%、11.3%、10.6%、1.89%;复介电常数虚部??分别增加了12.79%、12.72%、12.74%和4.41%;复磁导率实部??分别增加了30%、28.7%、27.3%和5.27%。四种改性沥青混合料在微波加热过程中温度随时间是呈线性增长的,且试件内部温度比表面温度在同一时刻高8-13℃左右。MCAM、MFAM、MSAM和AM CIP/CB的表面温度升温速率分别为0.4364、0.4564、0.4356和0.4162,相较BAM的升温速率分别提高了70.9%、78.8%、70.6%和63%。 采用沥青混凝土板模拟微波加热,选择2.5cm、5cm、7.5cm、10cm和15cm深度处测试其平面上的温度场,并采用CST软件对其电磁场和温度场进行模拟,结果显示,在微波加热15min的过程中,同一深度的水平面上不同微波加热时间下的温度差异大部分小于8℃,微波加热在沥青混凝土板的水平方向具有较好的均匀性。沥青混凝土板在深度方向的温度是先升高后降低,且试件底部的温度会略低于表面和中部的温度,其中10cm深度处的温度最高,四种改性沥青混凝土板在此处的温度均超过120℃,满足实际路面养护的要求。CST软件模拟的结果显示温度场的分布与微波能量损耗密度有关,即损耗密度越大,温度越高;本文采用的模型中温度最高的深度是距模型表面11cm深度处的平面。可认为微波加热在沥青混凝土板中相较常规加热方式,具有良好的均匀性和恰当的加热深度。 采用三点弯曲破坏试验和三点弯曲疲劳试验评价了六种沥青混合料的微波加热修复效果,结果显示通过微波加热,沥青混合料的强度不能实现完全恢复,且随着破坏-修复循环次数的增加,沥青混合料的抗弯强度恢复率在逐渐降低。其中抗弯拉强度恢复率和微波修复指数从大到小排序依次是MCAM、MFAM、MSAM、AM CIP/CB、USAM和BAM。在一定范围内,微波可以重复用于沥青混合料的裂缝修复,但不能无限次修复。微波修复指数主要取决于微波加热的时长和沥青混合料的微波吸收性能,当微波加热后六种沥青混合料的修复指数是常温修复的3倍左右。当微波加热相同时长,MCAM和MFAM的微波修复指数相较于BAM提高了41.4%;MSAM的微波修复指数相较于BAM提高了36.2%,而相较于USAM提高了16.1%;AM CIP/CB的微波修复指数相较于BAM提高了37.5%。 六种沥青混合料的路用性能测试结果显示其高温稳定性、低温抗裂性、水稳定性和抗滑性能均能很好地满足规范要求。其中MCAM、MFAM、MSAM和AM CIP/CB的动稳定度和弯拉应变均优于BAM,三种改性方法可以提高沥青混合料的高温稳定性和低温抗裂性;USAM和MSAM的水稳定性会优于其他四种沥青混合料,而六种沥青混合料的抗滑性能没有明显的差异。
英文题目 Study on enhancement mechanism and healing evaluation of microwave absorption of asphalt mixture
英文主题词 Asphalt mixture, Microwave heating, Heating rate,Temperature distribution, Microwave healing
英文摘要 Microwave technology has been applied in asphalt pavement maintenance for years, but microwave heating efficiency of asphalt mixtures needs to be improved. In this paper, the components of asphalt mixtures were modified by three different means. The first was to coat a very thin layer of magnetic Fe3O4 films on the surface of coarse and fine aggregates, by using a chemical co-precipitation reaction. The second one was that steel slag particles with twenty percent iron content were modified by a coprecipitation method for improving the Fe3O4 content on its surface, and then used to completely replace fine aggregates. The third was to prepare a wave-absorbing material employing carbonyl-iron powder as magnetic loss absorbent and carbon black as dielectric loss absorbent with asphalt as matrix. On this basis, X-ray diffraction (XRD) phase analysis and microwave heating properties of prepared microwave-absorbing materials were tested compared with those of control basalt aggregrates and steel slags. XRD spectra results showed that Fe2O3 on the surface of steel slag particles was converted into magnetic Fe3O4 nanoparticles and a very thin layer of magnetic Fe3O4 films was coated on basalt fine aggregates, by using the chemical co-precipitation method. The mean grain sizes of Fe3O4 nanoparticles on the surface of steel slag particles and basalt fine aggregates were 22nm and 30nm, respectively. The heating rates of modified basalt coarse aggregate and fine aggregate were twice than those of basalt coarse aggregate and fine aggregate before modified. The temperature of fine aggregate was a little higher than that of coarse aggregate and the temperature of modified steel slag was 40?C higher than that of ordinary steel slag. The three kinds of modified microwave-absorbing materials were added to prepare Marshell specimens and rutting slabs. Electromagnetic characteristics of the modified asphalt concretes were measured using a free space method in the range of 2-4 GHz. The FLIR thermal infrared camera and infrared thermometer were adopted to test the surface temperature of the asphalt mixture specimens. The results showed that the real part of the complex dielectric constant of asphalt mixtures prepared by adding modified basalt coarse aggregate (MCAM), modified basalt fine aggregate (MFAM), modified steel slag asphalt concrete (MSAM) and carbonyl-iron powder and carbon black (AM CIP/CB) increased by 11.3%, 11.3%, 10.6% and 1.89%, respectively, compared to their control groups (BAM). And the imaginary part of the complex dielectric constant of above asphalt mixtures increased by 30%, 28.7%, 27.3% and 5.27%, repectively. The temperature variation of asphalt concretes was linear with time and the internal temperatures of the asphalt concrete were 8-13?C higher than those of the surface temperatures. The surface temperatures rates of MCAM, MFAM, MSAM and AM CIP/CB were 0.4364?C/s, 0.4564?C/s, 0.4356?C/s and 0.4162?C/s, respectively, after microwave heating for 2min, which were 70.9%, 78.8%, 70.6% and 63% higher than those of BAM. In order to research the microwave heating rate and temperature field of asphalt pavement, temperature sensors were used to measure the temperature distributions at 2.5cm, 5cm, 7.5cm, 10cm and 15cm depth of a 20 cm-depth asphalt concrete slab. An electromagnetic simulation software named CST was also used to measure the microwave power density and the temperature distribution. The results showed that most of the temperature variations at the same depth in different heating times were less than 8?C, indicating a good uniformity of microwave heating in the plane scope of the asphalt concretes. In the 20cm-depth asphalt concrete slab, the temperature increased firstly and then decreased in the depth direction. The temperatures at the bottom of the slab were slightly lower than those in the middle and top layers. The optimal heating depth of the asphalt concrete slab were around 10cm and the highest temperatures of the four kinds of modified asphalt mixture exceeded 120?C within 15min of microwave heating, which can basically meet the temperature requirements for asphalt pavement maintenance. The CST simulation results showed that the temperature distribution is related to the power loss density, that is, where the loss power density is higher, the temperature is higher. The maximum temperature is 11cm depth from the surface in simulation model. The simulation results also demonstrated a good accordance with the laboratory results. Although the temperature distributions were non-uniform in both horizontal and vertical direction, the temperature variations were within acceptable limits. Microwave heating has good uniformity and proper heating depth compared with conventional heating in asphalt concrete slabs. The three point flexural failure tests and three point bending fatigue tests were conducted to evaluate the microwave healing effects of the modified asphalt mixtures. The results showed that the strength recovery of the modified asphalt mixtures was not complete and the strength recovery rate decreased with the breaking-healing cycle during microwave heating process. The strength recovery rates and microwave healing indexes of the six kinds of asphalt mixtures were listed as MCAM, MFAM, MSAM, AM CIP/CB, USAM and BAM in descending order. Microwave heating can be used to repair the cracks in asphalt mixture within certain limits. The microwave healing index mainly depends on the microwave heating time and the microwave absorbing ability of asphalt mixture. When the six kinds of specimens were heated in the same period, the microwave healing indexes of MCAM and MFAM increased by 41.4% compared to that of BAM. The microwave healing index of MSAM increaded by 36.2% compared to that of BAM and by 16.1% compared to that of USAM. The microwave healing index of AM CIP/CB increaded by 37.5% compared to that of BAM. The healing effects of six kinds of asphalt mixtures via microwave heating were three times as high as those at room temperature. The influences of different asphalt mixtures on pavement performance were evaluated through the indexes, such as Marshall Stability, flow value, dynamic stability and so on. The results showed that MCAM, MFAM, MSAM and AM CIP/CB exhibited better dynamic stabilities and strains at low temperature than BAM, indicating that the high-temperature and low-temperature performances of the modified asphalt mixtures can be improved by the three modification methods. Water stabilities of USAM and MSAM were better than those of the other four kinds of asphalt mixtures. All the skid resistances of the six kinds of asphalt mixtures can meet the requests in the Chinese specification
学术讨论
主办单位时间地点报告人报告主题
东南大学交通学院道路与铁道工程研究所 2013.9.24 道路与铁道工程研究所二楼会议室 Steinauer The sensitive road: a step into the future
东南大学交通学院道路与铁道工程研究所 2014.3.19 路与铁道工程研究所二楼会议室 刘为 基于旧沥青路面原位快速修复的电磁场感应吸收效率与结构演化过程研究
东南大学土木学院 2014.5.13 春晖堂会议室 Kent A. Harries The use of FRPin civil infrastructure: Limitations, Opportunities and Innovations
东南大学交通学院道路与铁道工程研究所 2015.3.23 群贤楼会议室 Erik The first engineered self-healing asphalt road: how is it performing?
东南大学交通学院道路与铁道工程研究所 2015.4.5 群贤楼会议室 Dar Hao Chen Sustainable pavement technology-warm mixed asphalt mixture
东南大学交通学院道路与铁道工程研究所 2015.5.15 道路与铁道工程研究所二楼会议室 刘为 感应加热自愈合路面研究
东南大学交通学院道路与铁道研究所 2015.5.22 道路与铁道工程研究所二楼会议室 刘为 竹材用于路面中的可行性分析
东南大学交通学院道路与铁道研究所 2015.5.25 中山院202 John E.Haddock Modifying Laboratory Mixture Design to Improving Field Compaction
东南大学交通学院道路与铁道工程研究所 2015.6.2 道路与铁道工程研究所二楼会议室 刘为 红外涂层综述报告
东南大学交通学院道路与铁道工程研究所 2016.4.11 道路与铁道工程研究所二楼会议室 刘为 基于旧沥青混合料原位快速修复的微波加热应用研究
     
学术会议
会议名称时间地点本人报告本人报告题目
2016年绿色建筑、材料与土木工程国际会议 2016.4.27 香港 Heating characteristics of microwave-absorbing asphalt mixture
2016年国际交通基础设施和材料会议 2016.7.15 西安 钢渣Fe3O4富化及增强沥青混合料微波加热特性研究
     
代表作
论文名称
Photocatalytic degradation of vehicle exhaust on asphalt pavement by TiO2/rubber composite structure
Heating characteristics of microwave-absorbing asphalt mixture
Increasing Microwave Heating Efficiency of Asphalt-Coated Aggregates Mixed with Modified Steel Slag
 
答辩委员会组成信息
姓名职称导师类别工作单位是否主席备注
钱振东 正高 教授 博导 东南大学
江瑞龄 正高 教授级高工 博导 江苏交通控股有限公司
徐庆宇 正高 教授 博导 东南大学
陶永春 正高 教授 博导 南京师范大学
董侨 正高 研究员 博导 东南大学
      
答辩秘书信息
姓名职称工作单位备注
杨若冲 副高 副教授 东南大学