沥青混合料空隙率与渗透系数相关性试验研究

Experimental Study of Relationship between Voidage and Permeability Coefficient of Asphalt Mixture

为了研究不同试验方法得到的沥青混合料空隙率之间、空隙率与渗透性之间的相关性,选择SMA-13、AC-13、AC-16和AC-20等4种沥青混合料,制备了直径100mm、高50mm的圆柱体试件,分别采用表干法、真空密封法试验得到了4种沥青混合料试件的表干法空隙率Vssd、真空密封法空隙率Vvac和有效空隙率Ve;采用自制的柔性壁变水头渗透仪进行试验,得到4种沥青混合料试件的渗透系数k;对Vssd、Vvac和Ve进行了线性方程拟合研究及双样本等方差假设分析,对Vssd、Vvac、Ve与渗透系数k的关系进行了指数函数拟合研究。结果表明:Vssd与Vvac具有较强的相关性和显著性差异,空隙率越大,两者之间差值越大,数据拟合直线越偏离对角线;Vvac与Ve的关系也具有类似规律;Vssd、Vvac、Ve与渗透系数k之间具有较强的相关性;得到了临界空隙率Vcrit、临界渗透系数kcrit2个参数,参数可作为沥青混合料组成设计、施工质量控制及沥青混合料耐久性评价的指标。

To study the correlation among voidages and between voidage and permeability coefficient obtained from different test methods of asphalt mixture,such four types as SMA-13,AC-13,AC-16 and AC-20 were selected and their samples of diameter 100 mm and height 50 mm were produced.Saturated surface dry method and vacuum sealing method were used to test their bulk specific gravity and compute their voidages,called V ssd and Vvac respectively,and the effective void ratio Ve was gained.Permeability coefficient kwas measured with a flexible wall variable head tester.Linear equation fitting and two-sample equal variance hypothesis were used for Vssd,Vvac and Vc.The results show that there is a strong correlation and significant difference between Vssd and Vvac,and between Vvac and Ve,and that the relationship between voidage and permeability coefficient k is fitted through the exponential function,that is,both have a strong correlation.From the exponential fitting curve,their critical void ratio Vcrit and critical permeability coefficient kcrit are obtained as the evaluation index for asphalt mixture composition design,construction quality control and durability.