This study presents a five-phase mesoscale modeling framework specifically developed to investigate crack propagation and mechanical properties of biochar–cement composites. The multi-phase model includes porous biochar particles with precise geometric construction, sand aggregates, cement matrix, and interfacial transition zone adjunct to both the biochar particles and sand aggregates. The 3D porous biochar library was first proposed and established in this study, which could provide an external interface for describing different pore shapes, wall thicknesses, and pore areas. All the simulation results were experimentally validated using a digital image correlation. Through precise geometric modeling, the unique failure modes and timing of biochar particles within the mortar were identified. This is analogous to the “strong column–weak beam” concept, accounting for the enhanced ductility observed in the biochar–cement composites under compression test. This work can advance the geometric modeling of porous aggregates broadly and elucidate their mesoscopic failure mechanisms in cementitious materials, thus providing new insights for developing high-ductility and lightweight cement composites.

中文翻译：

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介观尺度生物炭-水泥复合材料的多相力学模型


本研究提出了一个五相介观建模框架，专门用于研究生物炭水泥复合材料的裂纹扩展和机械性能。多相模型包括具有精确几何结构的多孔生物炭颗粒、砂骨料、水泥基质以及生物炭颗粒和砂骨料的界面过渡区。本研究首次提出并建立了3D多孔生物炭库，它可以为描述不同的孔隙形状、壁厚和孔隙面积提供外部接口。所有模拟结果均使用数字图像相关性进行实验验证。通过精确的几何建模，确定了砂浆内生物炭颗粒的独特失效模式和时间。这类似于“强柱弱梁”概念，解释了在压缩测试下生物炭水泥复合材料中观察到的延展性增强。这项工作可以广泛推进多孔骨料的几何建模，并阐明其在水泥材料中的细观破坏机制，从而为开发高延展性和轻质水泥复合材料提供新的见解。