【作者】 毛宇；

【导师】 郝培文；

【作者基本信息】 长安大学 ， 道路材料科学与工程， 2017， 博士

【摘要】 废旧胎胶粉被广泛应用在路面工程中,既解决了废轮胎污染,也满足了现代公路交通对路面性能的要求。本文采用理论分析与室内试验相结合的方法,研究了裂解-聚合法橡胶颗粒改性沥青及其混合料的技术性能和生产设备及工艺,以期为科学生产和使用裂解-聚合法橡胶颗粒改性沥青提供参考,从而为保证裂解-聚合法橡胶颗粒改性沥青路面使用性能和工程质量提供依据。本文在40-60目的橡胶粉中添加适量裂解剂,经造粒生产出部分裂解的新型橡胶颗粒,具有飘尘少、易于搅拌、加入沥青后系统粘度低等特点。在生产橡胶改性沥青过程中加入聚合改性剂,通过聚合作用使已经部分裂解的橡胶颗粒在沥青中重新适度聚合形成部分交联结构,能够对沥青高、低温性能,抗疲劳性能、耐久性能起到明显改善的作用。论文分析了剪切温度、速率、时间和胶粉掺量对裂解-聚合法橡胶颗粒改性沥青的技术性能影响,结果表明剪切温度越低,胶粉改性沥青粘度越大,胶粉在沥青中越不易分散;剪切温度过高则易引起沥青老化,从而影响沥青性能;剪切速率越小,胶粉颗粒细化越慢,且不易形成稳定的胶粉改性沥青体系;剪切时间越短,胶粉分散效果越差,剪切时间过长时,胶粉易发生降解,从而降低了沥青的使用性能;通过试验确定了裂解-聚合法橡胶颗粒改性沥青的加工工艺为将基质沥青加热到165℃,然后加入裂解橡胶颗粒与聚合改性剂,剪切并升温到185℃并保持,以4500r/min的剪切速率剪切约60min即可。通过常规试验、布氏旋转粘度以及DSR、BBR试验评价了不同橡胶改性沥青技术性能,分析了掺加裂解、聚合改性剂对橡胶改性沥青性能及改性工艺的影响,试验结果表明,随着裂解橡胶颗粒掺量的增加,裂解-聚合法橡胶颗粒改性沥青的粘度、针入度、软化点、延度和弹性恢复均增大,在沥青中掺入20%的橡胶颗粒,其综合性能最优;裂解-聚合法橡胶颗粒改性沥青的高温性能按照SHRP分级达到PG76的要求,具有较好的高温稳定性;裂解-聚合法生产工艺制备的橡胶颗粒改性沥青,粘度与SBS改性沥青相差不大,相较于普通橡胶改性沥青以及SBS改性沥青,裂解-聚合法橡胶颗粒改性沥青的综合性能更好。通过红外光谱吸收法、差示扫描量热法和扫描电子显微镜,分析了裂解-聚合法橡胶颗粒改性沥青的改性机理。结果表明,橡胶粉在沥青中发生了明显的溶胀现象,而经过裂解-聚合工艺后,橡胶粉在沥青中分布更加均匀;橡胶粉裂解-聚合改性后,DSC曲线吸热峰面积减小,其温度敏感性进一步改善;裂解-聚合改性使沥青与胶粉发生了化学反应,表现为二者相容性变好。在对比分析国内外橡胶改性沥青混合料配合比设计方法的基础上,针对干法与湿法制备工艺,分别研究了密级配(AC-16)、间断级配(ARHM-16)裂解-聚合法橡胶颗粒改性沥青混合料的技术性能,并与SBS改性、普通橡胶改性沥青混合料进行对比,结果表明裂解-聚合法橡胶颗粒改性沥青混合料更宜采用间断级配,以充分体现橡胶改性沥青混合料的弹性和抗疲劳性。其中,裂解-聚合法橡胶颗粒改性沥青混合料的高低温性能以及水稳性更加突出,其疲劳性能与SBS改性沥青混合料相当。采用干法工艺时,将橡胶颗粒计入级配曲线中,从而有效避免橡胶颗粒与其他粒径集料发生干涉作用,其路用性能基本与湿法工艺相当。过磨研磨型裂解-聚合法橡胶颗粒改性沥青生产可在原有SBS改性沥青生产设备的基础上进行改造升级。通过在配料罐罐壁铺设环绕式加热管道并取消内设盘管式加热的方式,实现了快速升温;通过将搅拌桨叶形式改造成弧形桨叶的形式,能够形成向下向内的搅拌涡流,从而使橡胶颗粒的添加更加顺畅,减小搅拌阻力,降低能耗;将胶体磨中动磨盘和静磨盘磨刀之间的夹角设置为90℃并使磨盘之间间隙可调,改善了粘度较大的裂解-聚合法橡胶颗粒改性沥青过磨特点,实现了均匀研磨;优化了整个电气系统,实现了改性生产设备自动化操作。结合甘南界至博克图公路,研究了裂解-聚合法橡胶颗粒改性沥青混合料的施工设备及工艺,总结了裂解-聚合法橡胶颗粒改性沥青路面施工中的控制要素。最后,对裂解-聚合法橡胶颗粒改性沥青混合料与普通沥青混合料进行了环境影响分析、全寿命技术经济分析比较,结果表明裂解-聚合法橡胶颗粒改性沥青混凝土在全寿命使用周期内,具有更多的经济优势。更多还原

【Abstract】 The waste tire rubber powdering is widely used in pavement engineering,which not only could solve the problem of waste tires,and also satisfy the requirementson pavement of modern highway transportation.This paper adopted the methods of theory,experiment and statistics analysis to explore and research the characteristic,production equipment and technology of rubber modified asphalt by cracking-polymerizing and its mixture,in order to provide the correct direction for the scientific production and use of rubbermodified asphalt over lapping,and corresponding reference to ensure the pavement performance and the project quality of rubber modified asphalt over lapping.The new rubber particles was produced by adding appropriate amount of cracking agent in rubber powder(0.3-0.45mm)and cracking granulation,which is less dust,easy mixing.The viscosity of rubber modified asphalt can be reduced by adding polymeric modifier in the production process.Through the polymerization,the partially cracked rubber particles forms a partially cross-linked structure in the asphalt,which can obviously improve the asphalt high temperature,low temperature performance,fatigue resistance and durability.Through the analysis of the influence of the shear rate,temperature,time and of powder content on the technical performance of crumb rubber modified asphalt by crackingpolymerizing.The results show that lower the shear temperature,and the greater the viscosity of rubber modified asphalt,and rubber powder is not easily dispersed in asphalt;high shear temperature can easily lead to asphalt aging,thus affecting the performance of asphalt;smaller the shear rate,more slowly powder particle refining,and it is not easy to form stable crumb rubber modified asphalt system;shorter the shear time,less dispersion effect of powder.Powder is easily degradation because of the long shear time,thereby reducing the using performance of asphalt.The processing technology of rubber particles modified asphalt by cracking-polymerizing was determined: firstly,the matrix asphalt is heated to 165℃,then adding cracking rubber particles and the polymeric modifier,and shearing and heating to 185 ℃,and shearing by the rate of 4500r/min about 60 min.Through the conventional test,Brookfield viscosity test,DSR and BBR test,the binder performance of different crumb rubber modified asphalt by cracking-polymerizing was evaluated,and the effect of cracking,polymerization modifier on the properties of rubber modified asphalt and the modification process was analyzed.The results indicate that with the increasing of the content of cracking rubber particles,the viscosity,penetration,softening point,ductility and elastic recovery of crumb rubber modified asphalt by cracking-polymerizing increased,and 20% rubber are added into the asphalt,and its comprehensive performance is the best.The performance at the high temperature of crumb rubber modified asphalt by cracking-polymerizing is up to PG76 in accordance with the requirements of SHRP grade,which has better high temperature stability.The viscosity of rubber particles modified asphalt by cracking-polymerizing has little difference with SBS modified asphalt.Compared with ordinary rubber modified asphalt and SBS modified asphalt,the comprehensive properties of crumb rubber modified asphalt by cracking-polymerizing is better.Through infrared absorption spectroscopy,differential scanning calorimetry and scanning electron microscope,the modified mechanism of crumb rubber modified asphalt by cracking-polymerizing was analyzed.The results showed that the rubber powder has obvious swelling phenomenon in asphalt,and after the process of cracking-polymerizing,and rubber powder is more evenly distributed in asphalt.What’s more,the endothermic peak area of DSC curve is reduced,and the temperature sensitivity of asphalt is further improved.The chemical reactions produces in asphalt and rubber powder,which shows that compatibility between asphalt and rubber powder is better.Based on the comparative analysis of mix design of rubber modified asphalt mixtureat home and abroad,and mix design and road performance dense gradation(AC-16)and the gap gradation(ARHM-16)rubber modified asphalt mixture by cracking-polymerizing were studied respectively by dry-mixing method and wet-mixing method,and compared with SBS and common rubber modified asphalt mixture,it was concluded that the gap gradation was more suitable for mix design of rubber modified asphalt mixture,which fully reflected the elastic properties and anti-fatigue properties of rubber asphalt mixture.The high and low temperature performance,water stability performance of rubber modified asphalt mixture by cracking-polymerizing were more prominent,and the anti-fatigue performance was almost the same as SBS modified asphalt mixture.When using the dry process,the rubber particles included in the grading curve,which avoided interference effect between rubber particles and the aggregate,so the road performance was close to the wet process.Based on production equipment in the original SBS modified asphalt,production equipment of crumb rubber modified asphalt by cracking-polymerizing was transformed and upgraded.By laying in the batching tank wall surrounding heating pipe and cancel internal coil heating mode,rapid warming-up was achieved;The vortex mixing downwards and inwards forms by changing the form of the mixing blade into the arc blade,thereby making rubber particles adding more smoothly,and decreasing the stirring resistance,and reducing the energy consumption;Through setting the included angle between static millstones and moving millstones of colloid mill millstones to 90 degrees and setting the clearance of millstones adjusting,the characteristics of the grinding of crumb rubber modified asphalt by cracking-polymerizing with high viscosity were improved,and the crumb rubber modified asphalt by cracking-polymerizing was ground uniformly.The whole electrical system is optimized,and the automatic operation of the modified production equipment is realized.This paper made research on the construction equipment and technology of rubber modified asphalt mixtures by cracking-polymerizing combined with the test road in Gannan to the hills.Then it summarizes the construction control elements of pavement of crumb rubber modified asphalt by cracking-polymerizing.At last,the environmental impact analysis of rubber modified asphalt mixture by cracking-polymerizing and common asphalt mixture was analyzed and compared.The results shows that rubber modified asphalt mixture by cracking-polymerizing has more economic benefits in the whole life cycle.更多还原