Feasibility analysis of utilizing aeolian sands and Gobi gravels in ultra-high performance concrete: insights from mesoscopic numerical simulation

In this study, aeolian sands and Gobi gravels were employed as fine and coarse aggregates, respectively, in the preparation of ultra-high performance concrete (UHPC), and mesoscopic simulation was employed to investigate its mechanical properties. Initially, algorithms were developed for the generation of ellipsoidal-shaped Gobi gravels and straight fibers, respectively. Additionally, methods for determining the overlap between ellipsoid-ellipsoid, cylinder-cylinder, and ellipsoid-cylinder configurations were proposed, and a three-dimensional packing model incorporating aggregates and fibers was constructed. Subsequently, the finite element meshing algorithm suitable for ellipsoidal aggregates was introduced. This algorithm accurately identified the three-phase components of the matrix, aggregates, and interface transition zone (ITZ), establishing a mesoscopic model for UHPC containing mortar matrix, coarse aggregates, ITZ, and fibers. Finally, numerical simulation was employed to assess the mechanical properties of UHPC across a range of Gobi gravel and fiber content conditions, facilitating the determination of the recommended content of coarse aggregates and fibers.