【作者】 李振；

【导师】 徐世法；

【作者基本信息】 北京建筑工程学院 ， 道路与铁道工程， 2011， 硕士

【摘要】 温拌再生沥青混合料是一种新型“绿色环保型”沥青混合料,它是在热再生技术和沥青温拌技术的基础上发展而来的,结合了废物循环利用和节能环保的优点。由于降低了生产与施工温度,可以降低旧料在生产过程中的短期二次老化;同时在降粘减阻剂的作用下,新沥青的高温粘度降低,从而可以实现较低温度下拌和与压实。添加适当比例旧料(RAP)的温拌再生沥青混合料不仅能实现废物利用,实现较低的生产与施工温度,同时还能保持与普通热拌料基本相当的路用性能。因此,在环境的日益恶化与资源、能源的巨大压力下,温拌再生沥青混合料这种集各种优势于一身的新型道路材料的研究与应用就显得尤为迫切。本文选择了较为常用的温拌技术---沥青降粘减阻剂,分别评价了LTS温拌再生沥青混合料与LTR温拌再生沥青混合料在不同旧料掺量下的压实特性与路用性能,并将两种温拌再生沥青混合料与普通热拌沥青混合料进行了对比分析。本文制备了LTS与LTR两种温拌沥青,研究了加入降粘减阻剂后对沥青本身性能的影响。通过沥青的三大指标(针入度、软化点、延度)以及粘度指标来评价了降粘减阻剂对沥青的影响。试验证明,两种降粘减阻剂都能降低沥青高温粘度,且降粘效果明显,但LTS对沥青其他性能的影响是明显的,而LTR对沥青本身的性能基本没有影响。通过变温度击实马歇尔试验,研究了掺加不同比例旧料(0%、15%、30%、45%以及60%)的两型温拌沥青混合料的压实特性与压实温度的关系,确定了各旧料掺量下的混合料满足规范要求的体积参数下的最低压实温度。试验证明,在相同的旧料掺量下,空隙率随着压实温度的降低而增大;在相同的压实温度下,空隙率随着旧料掺量的增大而增大。其他指标,诸如矿料间隙率、沥青饱和度、毛体积相对密度和稳定度等也与压实温度、旧料掺量有直接的关系。试验证明,不掺加旧料时,两型温拌沥青混合料均能降低拌合与压实温度约20~30℃,但随着旧料掺量的增大,降温幅度会随之减小。当旧料掺量达到60%时,为了保证沥青混合料的压实特性与路用性能而只能采取普通热拌料的拌和与压实温度。在确定了两型温拌沥青混合料掺加不同比例旧料后的拌和与压实温度后,对其进行了性能检验,采用马歇尔稳定度试验、车辙试验评价了其高温性能;采用小梁弯曲试验评价了其低温性能;采用浸水马歇尔试验、冻融劈裂试验评价了其抗水损害性能;采用小梁重复弯曲试验评价了其疲劳性能。针对高旧料掺量下(45%、60%)低温性能与疲劳性能大幅度衰减的情况,采用再生剂对其进行性能改善。结果证明,掺加8%的再生剂能够恢复旧沥青的性能,可恢复至新沥青的性能,混合料的低温性能和疲劳性能也得到大幅改善。温拌再生沥青混合料最大旧料掺量为45%,当旧料掺量为15%、30%时,拌和与压实温度可降低20~30℃左右;旧料掺量为45%时,拌和与压实温度只能维持在热拌沥青混合料相同的温度。即再生混合料料实现温拌的临界掺量为30%,在此掺量下能降低拌和与压实温度20℃,当掺量为45%时,为了确保其路用性能,再生沥青混合料已经不能实现温拌,只能以热拌的形式生产。更多还原

【Abstract】 Warm-Recycled Mix Asphalt (WRMA) is a new type of mixture that can not only reduce the mixing temperature and exhausting gas emissions but also use some reclaimed asphalt pavement, (RAP). It can be mixed, compacted and paved at a relatively lower temperature because of the temperature reduceing agent. Therefore, researching and developing the technology of WRMA will have important significances in the context of energy saving and environmental protection.Two temperature reducing agents LTS and LTR are selected to do the the warm asphalt mixture evaluation and comparison, like the compaction characteristics and pavement performance at different RAP dosages.The binders with LTS and LTR were prepared by high-speed mill, and the influence of additives were evaluated. The penetration test, the softening point test, the ductility test and the brookfield viscosity test for asphalt were conducted to investigate the impact of additives on the properties of asphalt. The research indicated that the additives can reduce the viscosity of base bitumen at high temperature. LTS affects bitumen’s other properties obviously while LTR has minimal impact.The volume parameter of WRMA was studied with different RAP contents (0%, 15%, 30%, 45% and 60%) and compaction temperatures (140℃, 130℃, 120℃, 110℃and 100℃), respectively. The research indicated that when the compaction temperatures decreased, VV of asphalt mixtures increased in the same RAP contents. When the RAP contents increased, VV of asphalt mixtures decreased in the same compaction temperatures. The temperature of mixing and compaction of WRMA could be decreased by 20℃and 30℃when RAP contents is 0%. When RAP content was 60%, the temperature of mixing and compaction was equal to HMA in order to ensure the pavement performance.The pavement performances of WRMA were compared and evaluated by means of Mashall test, rutting test, bending-beam test at low temperature, immersion mashall test, frost thawing and splitting test and crooked fatigue test.Recycling agent was used to improve the low temperature resistance and fatigue resistance when RAP contents were 45% and 60%. The pavement performance restored after at the dosage of 8%.It is concluded that at the RAP ratio of less than 30%, the temperature reduction of 20~30℃can be achieved. Nevertheless, when the RAP ratio is over 45%, conventional handling and application temperature is recommanded to WRMA.更多还原