大粒径沥青混合料离析评价指标和方法的研究

Researching on  Evaluation Index and Method of Segregation in Large Stone Asphalt Mixes

研究生：臧永超

指导教师：郭忠印教授

二〇〇八年三月

摘要

随着交通量的快速增长和轴载的加重，沥青路面普遍出现了抗车辙能力不足和排水功能较差等问题。大粒径沥青混合料柔性基层能提高路面的抗车辙能力，同时具备良好的排水功能。但由于公称最大粒径较大和沥青用量小，离析成为影响柔性基层质量的一个主要问题。本文参照国内外对离析的研究成果，对大粒径沥青混合料离析进行了深入的研究。

首先，依据实体工程，分析LSPM柔性基层离析的特征和离析机理；在此基础上，选择两个离析严重的路段进行现场调研和试验，在实验室开展相关室内试验，测定离析混合料的体积指标。

结合LSPM性能试验结论，运用数理统计的方法，根据级配、沥青含量、空隙率和密度指标，按照严重程度将LSPM离析分为三类，提出了不同程度离析的评价标准建议值。并提出大粒径沥青混合料离析评价的研究方法。

其次，选取不同程度离析的LSPM典型级配，通过室内试验分析不同程度离析对LSPM性能的影响，同时验证离析分类的合理性。通过力学计算分析了不同程度离析对沥青路面结构力学响应的影响，并预估离析对沥青路面寿命的影响。

在LSPM离析分类标准的基础上，提出应用离析率作为评价柔性基层整体离析程度的指标，并给出了计算方法和临界值，依据离析率的大小给出了相应的工程处理措施。最后提出大粒径沥青混合料基层离析评价的研究方法。

关键词：大粒径透水性沥青混合料，集料离析，评价指标，沥青含量，空隙率，级配，路面结构响应

ABSTRACT

With the  highway volumes and axle loads' fast increasing, the inadequate rutting  resistance and poor drain ability and etc become the important problems of  asphalt pavement in recent years the use of large stone asphalt mixture in  flexible base can minimize or eliminate the rutting of pavements, and has  high drain ability. But due to biggish nominal size and 10w asphalt contents，segregation become a primary  problem which influences the quality of flexible base. Referring to the  research result of segregation of asphalt mixture at home and abroad, the  segregation of large stone asphalt mixture is deeply researched.

Based on field  investigation of solid project，the paper first analyzes the character and reasons of segregation  that happen in the course of the construction of flexible base. Two pavement  sections are choiced to do field investigation and tests volume indexes are  set out by site sampling and laboratory tests.

Combining the  conclusion of LSPM performance test, and applying the method of the  mathematical statistics, in accordance with the grade、asphalt content、air void and density, segregation  is classified as having no、low and high, advice values of level of segregation are developed.  The research methods of segregation evaluation of large stone asphalt mixture  are set out.

Secondly，by choosing different degrees  typical grade，laboratory  tests are done to analyze the influence of segregation on the performance of  LSPM and verify the classification of segregation the influence of  segregation on mechanics responses of asphalt pavement is analyzed by  mechanic calculation. Then, the influence of segregation on fatigue life of  pavement is predicted.

According to the  criteria of LSPM segregation, the ratio of the segregation is put forward to  appraise the level of segregation of overall flexible base, and calculation  method and the critical value are proposed too. Based on the ratio of the  segregation, it brings forward corresponding measurements to deal with the  project. At last，the  research methods of segregation evaluation of LSAM flexible base are put  forward.
Key Words：Large Stone Porous asphalt Mixes, aggregate segregation,  evaluation index, asphalt content, air void, grade, mechanics response .