Study on the Mix Design of Mastic Flow for Filling Based on Deviation Coefficient Method

Abstract

To quantitatively evaluate the skeleton design of the MaFF method, this study addresses five dimensions: gradation control, test method, quantitative model, correction conversion, and design method. First, the deviation coefficient method is proposed based on the Talbot method. Unlike conventional design restricted to n = 0.3–0.7, this method takes the maximum density curve at n = 0.45 as the reference and enables flexible adjustment of Vag by controlling the 4.75 mm sieve passing rate. This provides a theoretical basis for discontinuous gradation design. Second, the wet mixing test is developed to overcome aggregate segregation and inadequate lubrication inherent in the dry tamping method, offering a new detection approach that better reflects the actual skeleton structure in the mixture. The optimum parameters were determined as 2% asphalt content, layered loading, one-sided tamping and 75 blows. Using 11 gradations, the wet mixing tests show that Vag increases from 24.13% to 38.29% as λ increases from 0 to 1.0, with a strong linear correlation (R2 = 0.996). CT scanning validation indicates that the wet method results are 83–86% of those from 3D reconstruction, yielding a recommended reduction coefficient of 0.84. These findings systematically refine the MaFF method into a complete skeleton design framework. For the specific material system investigated (diabase aggregate, ultra-high-viscosity asphalt, maximum nominal particle size of 13.2 mm), this study provides a preliminary technical reference for FMA mix design. However, broader validation across diverse materials and field conditions is required before generalization.