不同层位旧料特性对热再生沥青混合料路用性能的影响研究

发布时间：2018-05-20 08:21

本文选题：厂拌热再生 + 旧料(RAP)　；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充分利用旧沥青路面材料,节约资源,保护环境,在公路沥青路面的养护中得到了越来越广泛的应用。沥青路面回收料(RAP)是再生沥青混合料的原料之一,厂拌热再生工程中一般使用冷铣刨旧料,旧料特性对再生效果和再生混合料的性能有着重要的影响,其性状是进行再生沥青混合料配合比设计的重要依据。基于此,本文对上、中面层冷铣刨旧料中的沥青性能、级配组成和集料性能进行了全面分析,分析了不同旧料掺量的沥青砂浆和混合料的高温稳定性、低温抗裂性、水稳定性和耐疲劳性能,在以上结果的基础上,探究了合理评价旧料性能的试验方法,分析了沥青、集料、砂浆等旧料特性对再生混合料性能的影响。首先,重点运用SHRP计划的实验方法,以宁靖盐高速公路上、中面层冷铣刨旧料中回收的沥青为研究对象,对上、中面层的回收沥青分别进行常规性能及动态剪切流变(DSR)、低温弯曲梁流变(BBR)试验,得出结论沥青路面上、中面层沥青试样的高温等级均提高,低温性能和耐疲劳性能衰退。其次,对旧料的含水率、油石比、级配、集料性质进行试验,得出结论旧料的含水率通常较高,油石比降低；由于冷铣刨刀具对旧料细化的作用,上面层和中面层铣刨旧料大部分筛孔的通过率都超过原级配上限,旧料的级配明显细化。上、中面层旧料的粗集料在车辆荷载的作用下棱角性和洛杉矶磨耗值都有所降低,玄武岩性能衰退的程度比石灰岩大,但玄武岩旧料的耐磨耗性能仍然明显优于石灰岩。接着,通过室内试验分别研究不同旧料掺配比例(100%,50%,30%,0)的沥青砂浆的路用性能,得出结论旧料砂浆的高温性能较新料更好,旧料掺量越高,砂浆的高温性能越好,旧料砂浆的高温动态蠕变试验主要体现了砂浆中沥青的高温性质,与老化沥青的研究结论吻合：旧沥青砂浆的低温性能相比新料有所下降；沥青的老化导致沥青砂浆抗水损害能力明显降低；旧料砂浆耐疲劳性能较低,疲劳寿命对于应力的敏感性也较低。然后,研究铣刨得到的旧沥青混合料、与旧料现有级配相同的新沥青混合料和与旧料初始级配相同的新沥青混合料的路用性能,上、中面层旧沥青混合料的高温性能都比新料有大幅衰退,粗集料对混合料高温性能的影响最大,老化沥青的高温性能变好对混合料也有一定影响。沥青的老化对混合料的低温性能退化贡献最大；旧料的抗水损害能力降低；旧料的耐疲劳性能衰退,旧料的疲劳寿命对于应力的敏感性与新料相比也有所降低。最后,以中面层为例,研究旧料掺量0%、30%、50%、100%的砂浆和相应掺量的混合料性能之间的相关关系,得出结论,对于低温性能、水稳性能和耐疲劳性能,沥青砂浆和沥青混合料相关性显著;对于高温性能,两者相关系数较低。
[Abstract]:The technology of asphalt pavement thermal regeneration can make full use of the old asphalt pavement materials, save resources and protect the environment. It has been more and more widely used in the maintenance of highway asphalt pavement. Asphalt pavement Recycling material (rap) is one of the raw materials of recycled asphalt mixture. Cold milling is commonly used in hot recycling engineering, and the characteristics of the old material have an important impact on the regeneration effect and the performance of recycled mixture. Its character is an important basis for mix design of recycled asphalt mixture. Based on this, this paper makes a comprehensive analysis of asphalt performance, gradation composition and aggregate performance in upper and middle surface layer cold milling old materials, and analyzes the high temperature stability and low temperature crack resistance of asphalt mortar and mixture with different used materials. Based on the above results, the test methods for evaluating the properties of old materials are explored, and the effects of asphalt, aggregate and mortar on the properties of recycled mixtures are analyzed. First of all, using the experimental method of SHRP plan, taking the asphalt recovered from the cold milling used material in the middle surface layer on the Ningjing Salt Expressway as the research object. The normal performance, dynamic shear rheology and low temperature bending beam rheology (BBR) of the recovered asphalt in the middle surface layer were tested, respectively. It is concluded that the high temperature grade of the asphalt specimen of the middle surface layer on the asphalt pavement is improved, and the low temperature performance and fatigue resistance of the asphalt sample are decreased. Secondly, the water content, oil stone ratio, gradation and aggregate properties of used materials are tested, and the conclusion is drawn that the water content of used materials is usually higher, and the oil stone ratio is lower. The pass rate of most of the sieve holes in the upper layer and the middle layer is higher than the upper limit of the original gradation, and the gradation of the old material is obviously refined. On the other hand, under the action of vehicle load, the coarse aggregate of the middle surface layer has lower angularity and Los Angeles wear value, and the decline degree of basalt performance is greater than that of limestone, but the wear resistance of basalt used material is still better than that of limestone. Then, through laboratory tests, the road performance of asphalt mortar mixed with different used materials is studied separately. It is concluded that the high temperature performance of the old mortar is better than that of the new one, and the higher the content of the old material, the better the high temperature performance of the mortar. The high temperature dynamic creep test of the old mortar mainly reflects the high temperature property of asphalt in the mortar, which is consistent with the research conclusion of aging asphalt: the low temperature performance of the old asphalt mortar is lower than that of the new compound; The aging of asphalt results in the decrease of water damage resistance of asphalt mortar, and the low fatigue resistance and the sensitivity of fatigue life to stress of used mortar. Then, the road performance of the old asphalt mixture, the new asphalt mixture with the same existing gradation as the old material and the new asphalt mixture with the same initial gradation with the old material is studied. The high temperature performance of the old asphalt mixture in the middle surface layer is much lower than that of the new asphalt mixture. The coarse aggregate has the greatest influence on the high temperature performance of the mixture, and the high temperature performance of the aging asphalt has a certain effect on the mixture. The aging of asphalt contributes the most to the degradation of the low temperature performance of the mixture; the water damage resistance of the old material is decreased; the fatigue resistance of the old material declines; the fatigue life sensitivity of the old material is also decreased compared with the new compound. Finally, taking the middle surface layer as an example, this paper studies the correlation between the properties of 100% mortar and 100% mortar and the corresponding mixture, and draws a conclusion that, for low temperature performance, water stability and fatigue resistance, The correlation between asphalt mortar and asphalt mixture is significant, and the correlation coefficient is low for high temperature performance.
【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

【相似文献】