排水性沥青混合料体积参数变化规律及矿料间隙率预估方法

Change law of volume parameters and predictive method of VMA of porous asphalt mixture

为了对没有压实的混合料试件的矿料间隙率(VMA)进行合理估算,构建了基于体积参数的排水性沥青混合料的沥青用量确定新方法。通过理论分析和室内试验对排水性沥青混合料体积参数的内部关系和变化规律进行研究,揭示排水性沥青混合料矿料间隙率、空隙率和有效沥青用量之间的定量关系;基于矿料间隙率计算模型,考虑矿料级配、矿料堆积特性和棱角特征对VMA的影响,提出基于矿料级配的矿料间隙率经验计算方法。研究结果表明:矿料级配对VMA具有显著性影响,VMA值的大小主要取决于矿料级配,当油石比为4.0%~5.5%时,其变化对VMA没有显著性影响;实测VMA值与经验法计算的VMA值相近,存在良好的线性相关关系;在进行排水性沥青混合料设计时,可根据矿料间隙率、空隙率和有效沥青用量之间的体积关系,应用提出的排水性沥青混合料有效沥青用量确定新方法来确定有效沥青用量。

In order to reasonably estimate the VMA of non-compacted mixture specimen, a new method of determining asphalt content of drainage asphalt mixture was built based on volume parameters. The relationships among volume parameters and change law of volume parameters for porous asphalt mixture by means of theoretical analysis and indoor tests were studied in this paper, which revealed the quantitative relationship among VMA, VV and effective asphalt content of drainage asphalt mixture. Based on the calculation model of VMA, considering the effect of aggregate gradation, aggregate accumulation characteristics and aggregate angular features on VMA, this paper proposed an empirical calculation method for VMA upon aggregate gradation. The results show that the aggregate gradation has a significant influence on VMA, and the value of VMA mainly depends on aggregate gradation. While the asphalt aggregate radio is within 4.0 % to 5.0 %, the change has no significant effect on VMA. Comparing the results of VMA from calculated and measured, which show that they are similar and have a good linear correlation. According to the relationship among VMA, VV and effective asphalt content, the effective asphalt content can be determined by applying the new method in the design process of porous asphalt mixture. 7 tabs, 4 figs, 24 refs.