考虑均匀性的SMA混合料最佳沥青用量确定方法

Determination method of optimum asphalt content of SMA mixture considering homogeneity

为更为准确地确定SMA混合料最佳沥青用量,利用CT技术识别SMA混合料各组分内部结构特征,分析SMA混合料的马歇尔设计方法中主要体积参数与其内部结构各组分特征的关系,考虑混合料内部结构均匀性,建立SMA混合料最佳沥青用量确定方法,并选用3种混合料类型(SMA-13、SMA-16和SMA-20)对该方法的有效性进行验证.结果表明,基于CT技术获取不同沥青用量条件下的SMA混合料空隙率可以较好地表征通过密度试验所得SMA混合料空隙率,并以此分析计算得到的间隙率和饱和度与马歇尔体积设计方法中的差值平均值分别为0.35%和1.45%;采用建立的最佳沥青用量确定方法与根据现行马歇尔设计方法分析得到的SMA-13、SMA-16和SMA-20三种混合料最佳沥青用量差值分别为0.08%、0.18%和0.15%,表明了该方法的有效性.

In order to determine the optimum asphalt content of stone mastic asphalt（ SMA） mixture precisely,the characteristics of inner structure of components of SMA mixture were identified by using CT technique. The relationship between the inner characteristics of components and the Marshall volumetric parameters for SMA mixture was analyzed,and the homogeneity of inner structure of the SMA mixture was taken into account,and then a determination method of the optimum asphalt content of SMA mixture was established,and three types of SMA mixtures（ SMA-13,SMA-16 and SMA-20）were chosen to verify the method through Marshall design method. Results show that the volume of air voids obtained by using CT technique exhibits a favorable consistency with that measured by the density tests for SMA mixture with different asphalt contents. The average differences between the voids in mineral aggregate,the voids filled with asphalt and those obtained by Marshall design method are 0. 35% and 1. 45%,respectively. The optimum asphalt contents of SMA mixtures（ SMA-13,SMA-16 and SMA-20） are determined based on Marshall design method,and the differences between those and the optimum asphalt contents achieved by the proposed method are 0. 08%,0. 18% and 0. 15%, respectively,which demonstrates the effectiveness of the proposed method.