Micromechanics-based Multiscale Lattice Modeling of Fatigue Cracking in Hot Mixed Asphalt

[摘要] This dissertation presents a novel micromechanics-based lattice procedure designed to characterize the cracking performance of hot mix asphalt (HMA) from its constituent material properties.The approach essentially consists of a series of direct-lattice models integrated with multiscale technique. A typical direct-lattice modeling starts with a preprocessor that discretizes the microstructure of a specimen, which is either physically or virtually fabricated, into a random truss lattice.The mixture performance can be predicted by analyzing such lattice network using a general-purpose finite element program FEP++. The cracking process in HMA is simulated by successive removal of failed links representing microcracks. In this study, a surface energy based failure criterion is developed to trigger the creation and subsequent extension of microcracks. Due to the disparate length scales associated with microcracking and specimen size, the direct-lattice modeling described above would demand unrealistic computational cost for modeling even a laboratory scale HMA specimens.In order to make the procedure more practical, the multiscale approach is implemented.Essentially, multi-scale model considers the effect of different-sized aggregates at different length scales. Such an approach reduces the computational cost significantly, while capturing the mechanical phenomenon at various length scales.Finally, the effectiveness of the proposed multiscale lattice procedure is illustrated by modeling an actual indirect tensile (IDT) test on a thin cylindrical HMA specimen and making quantitative comparisons with experimental measurements, including full-strain fields measured by the digital image correlations (DIC) technique.

[发布机构] University:North Carolina State University

[效力级别] fatigue

[关键词] lattice;fatigue;asphalt