沥青混合料介电特性与密度关系研究

为研究沥青混合料介电特性与密度的关系，进行不同压实度条件下沥青混合料介电常数的测定试验。试验采用旋转压实成型试件，通过高温介电常数平台测定不同压实度试件的介电常数，应用复合材料多相介电常数模型计算各试件的毛体积相对密度，与室内水中重法测得实际值相比较验证计算结果的准确性。研究表明：不同级配、集料的矿料介电常数并不相同，矿料介电常数应以标准级配及空隙率试件反算求解，不局限于传统7~9的取值范围；通过Rayleigh模型建立沥青混合料介电常数与毛体积相对密度之间的关系，计算结果与水中重法的测定结果误差小于1%，精度较高；旋转压实成型试件在同一深度处压实不均，沥青混合料毛体积相对密度和空隙率相差分别为0.092和3.5%，试件毛体积相对密度随压实深度增加而逐渐减小。

Study on the relationship between dielectric properties and density of asphalt mixture

The tests of dielectric constant of asphalt mixture under different compaction degrees were carried out to study the relationship between the dielectric properties and density of the asphalt mixture. The specimens with different compaction degrees were prepared by gyratory compaction and the dielectric constants were tested on the high-temperature dielectric constant platform. The relative density of bulk volume of specimens was calculated based on the multiphase dielectric constant model of composite material, and then compared with the actual result measured by the water gravity method to verify the accuracy of calculation. The results show that the dielectric constants of mineral aggregates with different gradations and aggregates shall be different. The dielectric constant of mineral aggregate should be calculated based on the specimens with standard gradation and void ratio, without being limited to the traditional values taken from 7 to 9. The relationship between the dielectric constant and the relative density of bulk volume of asphalt mixture was established by the Rayleigh model. It is seen that the deviation between the calculated result and the result measured by the water gravity method is less than 1%. When the compaction is uneven at the same depth of the specimen prepared by gyratory compaction, the errors in the relative density of bulk volume and void ratio of specimen at the same depth could be 0.092 and 3.5%, and the relative density of bulk volume of specimen may decrease gradually with the thickness of compaction.