Han Lu, Gao Weiliang, Tao Yaping, Liu Lulu
School of Transportation Engineering, Huanghe Jiaotong University, Jiaozuo 454000, China.
School of Mechanics and Civil Engineering, China University of Mining & Technology, Xuzhou 221116, China.
Materials (Basel). 2025 May 23;18(11):2439. doi: 10.3390/ma18112439.
The application of construction and demolition waste (CDW) as roadbed filler faces challenges due to the variable mechanical properties caused by fragile recycled brick aggregates. This study elucidates the breakage mechanism of CDW fillers under compaction effort through a combination of standardized laboratory compaction tests and discrete element method (DEM) simulations. Furthermore, the breakage evolution patterns of mixed fills comprising recycled concrete and brick aggregates at various mixing ratios were revealed. A DEM model was developed to characterize recycled concrete and brick aggregates, adopting polygonal clumps for particles >4.75 mm and spherical clumps for finer fractions. The results indicate that particle breakage progresses through three distinct stages: linear fragment stage (0-200 kJ/m, 50% of total breakage), deceleration growth stage (200-1000 kJ/m, 38% of total breakage), and residual crushing stage (1000-2684.9 kJ/m, 12% of total breakage). Recycled concrete aggregates form a skeleton restraining deep cracks, while brick aggregates enhance stability through energy dissipation and void filling. However, exceeding 30% brick content impedes skeleton development. Critically, a 30% brick content optimizes performance, achieving peak dry density with 25% lower compression deformation than concrete-only fillers, while limiting breakage index rise. These results provide a science-based strategy to optimize CDW roadbed design, improving recycling efficiency and supporting sustainable infrastructure.
由于易碎的再生砖骨料导致建筑垃圾（CDW）的力学性能多变，将其用作路基填料面临挑战。本研究通过标准化实验室压实试验和离散元法（DEM）模拟相结合的方式，阐明了CDW填料在压实作用下的破碎机制。此外，还揭示了不同混合比例下由再生混凝土和砖骨料组成的混合填料的破碎演化模式。开发了一个DEM模型来表征再生混凝土和砖骨料，对于粒径大于4.75mm的颗粒采用多边形团块，对于较细颗粒采用球形团块。结果表明，颗粒破碎经历三个不同阶段：线性破碎阶段（0 - 200kJ/m，占总破碎量的50%）、减速增长阶段（200 - 1000kJ/m，占总破碎量的38%）和残余破碎阶段（1000 - 2684.9kJ/m，占总破碎量的12%）。再生混凝土骨料形成一个骨架，抑制深层裂缝，而砖骨料通过能量耗散和孔隙填充增强稳定性。然而，砖含量超过30%会阻碍骨架的形成。至关重要的是，30%的砖含量可优化性能，达到峰值干密度，压缩变形比仅使用混凝土的填料低25%，同时限制破碎指数的增加。这些结果为优化CDW路基设计提供了基于科学的策略，提高了回收效率并支持可持续基础设施建设。
