不同RAP料掺量热再生改性沥青混合料耐久性能研究

发布时间：2018-05-30 09:53

本文选题：热再生 + 半圆弯曲试验　；参考：《东南大学》2015年硕士论文

【摘要】：沥青路面热再生技术,能够提高资源利用效率,减小损失浪费,保护环境,以尽可能少的资源消耗,创造尽可能大的经济社会效益,所以它在公路沥青路面的养护中得到越来越广泛的应用。目前,出于对热再生技术的可行性和可靠性,尤其是再生沥青路面的耐久性能的担忧,沥青路面热再生技术未得到大规模推广应用。基于此,本文通过室内试验,对不同RAP料掺量的热再生沥青混合料的耐久性能进行评价,希望对我国沥青路面热再生技术评价体系和指标的建立提供一些参考。首先,本文对研究所用的旧料进行了研究：通过抽提筛分得到旧料的级配组成和油石比；为了保证再生料配合比设计时旧料的均匀性,将旧料分为了粗细两档进行处理；对回收得到的旧沥青性能进行了评价,选取现有的再生剂对旧沥青进行了再生研究,发现3%掺量的再生剂可以将老化沥青的性能指标恢复至与原样沥青接近的程度；应用马歇尔配合比设计方法对再生混合料进行了设计。其次,总结了现有的疲劳性能室内评价试验方法,选取半圆弯曲试验作为本文的疲劳试验评价方法,确定了其参数。应用半圆弯曲疲劳试验评价了不同RAP料掺量热再生沥青混合料在单级等幅荷载作用下的疲劳性能,采用数字图像技术对试验中的疲劳裂纹开展过程进行了观测,分别采用裂纹扩展速率和疲劳断裂能评价了热再生沥青混合料的疲劳性能。结果表明,热再生混合料的裂纹扩展速率快于新沥青混合料,且随着RAP料掺量的增加,裂纹扩展速率越快。热再生混合料的单次疲劳破裂能大于新沥青混合料,而总疲劳破裂能小于新沥青混合料,因此热再生混合料的疲劳性能不如新沥青混合料。接着,通过不同加载方式的多级等幅荷载下的疲劳试验对不同RAP料掺量的热再生沥青混合料的疲劳性能进行了评价。研究表明：沥青混合料在应力控制多级等幅荷载下,疲劳损伤据Miner法则线性累积,损伤因子都大于1,说明多级荷载下的疲劳损伤演化呈非线性。30%旧料掺量的热再生沥青混合料有着与新沥青混合料相似甚至更好的疲劳性能,但当RAP料掺量进一步增加时,热再生料的疲劳性能下降明显,为了保证热再生混合料的疲劳性能,应限制其旧料掺量。再次,基于冻融循环条件应用劈裂试验、动态模量试验、动态蠕变试验和半圆劈裂试验全面评价了不同RAP料掺量的热再生沥青混合料的强度、高温性能和低温性能,分析了评价方法和RAP料掺量对热再生混合料性能的影响。最后,综合疲劳性能和水稳定性能两方面的研究,本文认为：为了保证热再生沥青混合料的耐久性能,当采用只具有软化效果类型的再生剂时,其旧料掺量不宜超过30%。
[Abstract]:The technology of asphalt pavement thermal regeneration can improve the efficiency of resource utilization, reduce the loss and waste, protect the environment, consume as little resources as possible, and create as much economic and social benefits as possible. So it is more and more widely used in the maintenance of highway asphalt pavement. At present, due to the concern about the feasibility and reliability of thermal regeneration technology, especially the durability of recycled asphalt pavement, the thermal recycling technology of asphalt pavement has not been popularized and applied on a large scale. Based on this, this paper evaluates the durability of hot recycled asphalt mixture with different RAP content through laboratory test, hoping to provide some references for the establishment of evaluation system and index of asphalt pavement thermal regeneration technology in China. First of all, this paper studies the old materials used in the research: the gradation composition and the oil stone ratio of the old materials are obtained by extracting and sieving, in order to ensure the uniformity of the old materials in the design of the mixture ratio of the recycled materials, the used materials are divided into two stages of thickness for treatment. The performance of the recycled old asphalt was evaluated and the existing regenerating agent was selected to study the regeneration of the old asphalt. It was found that the performance index of the aged asphalt could be restored to the same degree as the original asphalt with the addition of 3% of the regenerating agent. The recycled mixture was designed by Marshall mixture design method. Secondly, the existing indoor fatigue performance evaluation methods are summarized, and the semi-circular bending test is selected as the fatigue test evaluation method in this paper, and its parameters are determined. In this paper, the fatigue performance of heat regenerated asphalt mixture with different RAP content was evaluated by semi-circular bending fatigue test, and the fatigue crack development process was observed by digital image technique. The fatigue performance of hot recycled asphalt mixture was evaluated by crack growth rate and fatigue fracture energy. The results show that the crack growth rate of hot recycled mixture is faster than that of new asphalt mixture, and the faster the crack growth rate is with the increase of RAP content. The single fatigue rupture of the hot recycled mixture is greater than that of the new asphalt mixture, and the total fatigue rupture energy is lower than that of the new asphalt mixture, so the fatigue performance of the hot recycled mixture is inferior to that of the new asphalt mixture. Then, the fatigue performance of hot regenerated asphalt mixture with different RAP content was evaluated by the fatigue test of different loading modes under multistage and equal amplitude loads. The results show that the fatigue damage of asphalt mixture accumulates linearly according to the Miner rule under the stress controlled multistage constant amplitude load. The damage factors are all greater than 1, which indicates that the fatigue damage evolution of hot-regenerated asphalt mixture with a nonlinear content of .30% used material under multistage load has similar or even better fatigue performance than that of new asphalt mixture, but when the content of RAP mixture increases further, the fatigue performance of the mixture is similar to that of the new asphalt mixture. The fatigue performance of hot recycled mixture is obviously decreased. In order to ensure the fatigue performance of hot recycled mixture, the amount of used material should be limited. Thirdly, based on the freezing and thawing cycle conditions, the strength, high temperature and low temperature properties of different RAP mixtures are evaluated by splitting test, dynamic modulus test, dynamic creep test and semi-circular splitting test. The influence of evaluation method and RAP content on the performance of hot recycled mixture is analyzed. Finally, in order to ensure the durability of hot recycled asphalt mixture, it is concluded that in order to ensure the durability of hot recycled asphalt mixture, the amount of the old mixture should not exceed 30% when the recycled agent with only softening effect is used.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U414

【参考文献】