基于多指标的沥青混合料均匀性评价方法研究

Study on Asphalt Mixture Uniformity Evaluation Method Based on Multi-Factors Indexes

针对目前沥青混合料均匀性定义不清、评价指标不健全和均匀等级划分存在的问题,利用规范对物质均匀性的定义和材料力学对物质均匀性的假设,将沥青混合料定义为组分均匀、质量分布均匀和刚度均匀,建立了沥青混合料均匀性多指标评价模型,给出了沥青混合料均匀性计算方法和均匀性等级划分依据。开展了AC-13级配的沥青混合料均匀性实验,测试了沥青混合料的各体单元的毛体积相对密度、弹性模量特征值和沥青含量,研究了沥青混合料均匀性,并与传统均匀性评价进行对比分析。结果表明:基于多指标的沥青混合料均匀性评价方法增加了沥青混合料的组成成分和力学性能指标,评价结果更加客观和准确,AC-13级配的沥青混合料的综合均匀指数为0.896,属于中度均匀;采用传统均匀性方法评价,沥青混合料的压实度和密度变异系数很小,均匀性很好,但合格率仅为63.2%。

In order to solve the problem of unclear uniformity of asphalt mixture,unsound evaluation index,and uniform grade division,the definition of asphalt mixture homogeneity is proposed that the mix has the same structural state consisting of one or several components and has the same mass and elastic modulus within each unit volume,according to the definition of material uniformity and material mechanics assumption of material uniformity.Asphalt mixture homogeneity calculation formula and uniformity classification was determined after establishing the multi-index evaluation model for asphalt mixture homogeneity.Asphalt mixture homogeneity comparative analyzing experiments were conducted between the traditional homogeneity evaluation and the multi-index evaluation methods,including bulk volume relative density,elastic modulus characteristics of body units and asphalt content.It is found that the evaluation results are more objective and accurate under the evaluation method,increasing the composition and mechanical properties,of asphalt mixture homogeneity based on multiple indexes.The comprehensive average index was 0.896 for AC-13asphalt mixture,which is moderate uniform for the asphalt mixture used in this experiment;while,the evaluation result is self-contradictory,because the compaction degree and density variation coefficient of the asphalt mixture is very small,but the pass rate is only 63.2%.