Abstract
In asphalt mixture, aggregates account for up to 90% of the total volume and play an important role in the mechanical characteristics of asphalt mixture. The proportions of fine and coarse aggregates in gradation, as well as the function of aggregate particles, are important factors for the skeleton structure performance of asphalt mixtures. However, the existing asphalt mixture design methods are mostly based on empirical methods, where the non-uniformity and complexity of the composition of asphalt mixtures are not fully studied. In this study, the skeleton structure of aggregate mixture and function of aggregate are studied and analyzed using the Discrete Element Method (DEM). The Particle Flow 3D (PFC3D) DEM program is used to perform the numerical simulation. The average contact number and interaction forces by aggregate particles of different sizes are obtained and studied. The skeleton structure of aggregate mixture and function of aggregate particles are further analyzed from the meso-structural perspective.
Highlights
The design of asphalt mixtures is mainly based on macro-scale tests, where the macroscopic physical indexes are used as the main criteria for the design of asphalt mixtures, such as gradation of asphalt mixtures, void ratio, crack resistance, fatigue performance, ageing performance, self-healing properties, structure characteristics, moisture and seepage characterization, etc. [1,2,3,4,5,6,7,8,9,10,11,12]
Asphalt mixture is a system consisting of a variety of aggregates with different particle sizes according to certain proportions
When generating virtual mixtures in PFC3D software, first, the average particle size of each size is taken as the diameter, and the number of particles is calculated according to the total bulk volume of the particle size
Summary
The design of asphalt mixtures is mainly based on macro-scale tests, where the macroscopic physical indexes are used as the main criteria for the design of asphalt mixtures, such as gradation of asphalt mixtures, void ratio, crack resistance, fatigue performance, ageing performance, self-healing properties, structure characteristics, moisture and seepage characterization, etc. [1,2,3,4,5,6,7,8,9,10,11,12]. Asphalt mixture is a system consisting of a variety of aggregates with different particle sizes according to certain proportions. In order to further understand the mechanical properties of asphalt mixtures, it is necessary to study the skeleton structure characteristics and aggregate function of aggregate mixtures inside the asphalt mixtures. Many researchers used DEM to study the properties of the mixture constituents (aggregate and asphalt binder). The discrete element method is used to simulate the mechanical behaviors of aggregate mixture. Further studies are considering the packing characteristics of aggregate with different particle size and morphology [33]. The key particle size is investigated to analyze the skeleton-structure characteristics and the function of coarse and fine aggregates, which provides reference for optimization of aggregate gradation design
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