沥青混合料离析评价方法与评价

指标的研究

Research  on Evaluation Method and Evaluation Index of Asphalt Mixture

研究生：郑晓光

指导教师：郭忠印

二○○七年一月

摘要

近几年来，随着我国国民经济的增长，道路发展日新月异，但是沥青路面的早期损坏也成为关注的一个热点，早期损坏总是以不均匀的方式出现，这些早期损坏现象或多或少都与沥青混合料的离析有关。

当前虽然对沥青混合料离析进行了很多的研究，但是对于离析没有具体的分类，缺乏一个明确的离析分类指标；对于离析的评价方法仅局限于钻芯取样或者视觉观测法，工作效率和准确程度比较低；离析对沥青混合料的力学性能和路用性能影响分析还不是很全面，而且大部分研究还停留在定性分析的阶段上，没有进行量化。

针对于上述问题，论文从沥青混合料离析评价方法和评价指标、离析对沥青混合料性能和路面结构响应影响、离析产生原因及解决措施等几个方面进行了研究。

论文首先对沥青混合料离析进行了现场调研，分析沥青混合料离析在路面上出现的形式，将离析分为5类。对离析区域进行无损检测试验，同时钻芯取样，对芯样进行室内试验，得到芯样的级配、用油量和空隙率等体积指标。

根据芯样级配、沥青含量和空隙率等指标，按照严重程度将沥青混合料离析分为三类，提出了不同程度离析的评价标准建议值。

分析沥青混合料离析与无损检测结果的关系，无损检测主要包括核子密度和构造深度，检验不同程度离析混合料的核子密度和构造深度差异，分别提出了基于构造深度和核子密度的沥青混合料离析评价指标。针对于构造深度评价指标，提出了均匀区域构造深度预估模型。

在以上研究的基础上，选择了不同程度离析的混合料，在室内试验的基础上，全面定量地分析不同程度离析对沥青混合料性能影响，同时验证离析分类的合理性。不同程度离析导致路砥模量变化，通过力学分析来检验不同程度离析对沥青路面结构力学响应的影响。在力学分析的基础上得到沥青各层层底拉应变，同时结合沥青混合料体积参数，通过疲劳方程来预估离析对沥青路面寿命的影响。

在构造深度评价指标基础上，提出了沥青路面均匀性评价程序，使用离析面积指数作为检验路面均匀性是否合格的指标，制定了不同程度离析的处治措施。

论文最后针对于不同类型的离析，从沥青混合料设计、生产、运输和沥青混合料摊铺入手，阐述沥青混合料离析影响因素，提出了离析解决措施。重点研究了沥青混合料温度差异容许标准和转运车在沥青混合料施工中的作用。

关键词：沥青混合料；离析；评价方法；评价指标；钻芯取样：级配；用油量；空隙率；无损检测；构造深度；核子密度；沥青混合料性能；路面结构响应；解决措施；温度差异；红外线温度记录仪：转运车

ABSTRACT

With  the development of our country’s economy, great changes have been occurred in  highway recently，but premature damage also has  become the widespread phenomenon，premature damage  always occurs in the form of non-uniformity, it has something to be with the  segregation of asphalt mixture more or less．

Nowadays  a lot of research has been done about segregation of asphalt mixture，but  there still exist some problems that are not solved．Firstly,  segregation lacks of definite classification，it  need evaluation index．Secondly, current evaluation  methods of segregation are cores and visual identification which are not  accurate．Thirdly, the influence of segregation on  asphalt mixture performance is qualitative and not comprehensive．

On  the basis of these problems，the dissertation’s  emphases are evaluation methods and index of segregation，the  influence of segregation on asphalt mixture performance，influencing  factors and solving measures．

Based  on the research of relevant data and field investigation about segregation of  asphalt mixture，the existing form of segregation is  analyzed．Nondestructive tests are done on the  reign of segregation，and Grade，asphalt  content and air void of different samples are achieved by site sampling and  laboratory tests．

According  to the grade，asphalt content and air void，definitions  of level of segregation are developed；segregation is  classified as having no，low or high．

The  relationship between nondestructive measurements and segregation is analyzed，nondestructive  measurements includes nuclear density gauges and 1aser surface texture measurements  which are used to measure segregation．On the basis of laser  surface texture measurements，the non-segregated  texture can be predicted using various properties of the original job-mix  formula．

According  to the level of segregation，laboratory tests are  done to analyze the Influence of segregation on the performance of asphalt  mixture and verify the classification of segregation．Segregation  induces the variation of modulus of asphaltpavement；the  influence of segregation on mechanics responses of asphalt pavement is analyzed  by mechanic analysis．Fatigue model is used to analyze  the influence of segregation on fatigue life of pavement． 

By  the combining the laser surface texture，an AREA index  can be developed to

determine  the acceptance or non—acceptance of a pavement section．When  a pavement section is acceptable，Remedial actions  are suggested when segregation is present．

Segregation  maybe occurs in the design，production and  placement of hot mix paving mixtures．Segregation in  hot mix bituminous mixtures is a common and persistent problem．However,  the problem can be controlled and even eliminated through proper mix design  and through proper maintenance and operation of plants, trucks，and  paving equipment．In this chapter, the acceptable  standard of temperature differential and the use of material transfer vehicle  are researched especially．

Key  Words：Asphalt mixture；Segregation；Evaluation  method；Evaluation  index；core；Grade；Asphalt  content；Air void；Nondestructive  test；Laser  surface texture：Nuclear density；Performance  of asphalt mixture；Mechanics response；Temperature  differential；Thermal imaging；Material  transfer vehicle