A three-dimensional numerical investigation is presented to study the shape effect of cement particles on the ionic diffusivity of hardened cement paste (HCP), whose microstructure is generated based on the random packing models of spherical and polyhedral particles. The microstructure of HCP composed of four phases is first generated and then converted into a voxel-presented one. Based on the digitized microstructure, the diffusivity of HCP can be obtained by a lattice modelling. The reliability of simulations is validated by comparing to experimental data and the shape effect of cement particles on the diffusivity of HCP is discussed. The results indicate that the shape of cement particles significantly affects the ionic diffusivity of HCP due to its effect on the hydration degree: the cement particles with smaller sphericity contribute to the hydration of HCP, which reduces the ionic diffusivity of HCP. This effect decreases as the hydration age elapses and increases with the increasing water-cement ratio. The intrinsic reason causing this effect is illustrated from the microstructural view of HCP: the shape effect has an influence on the volume fractions of three diffusive phases and pore structures.

进行了三维数值研究，研究了水泥颗粒的形状对硬化水泥浆（HCP）离子扩散率的影响，该水泥浆的微观结构是根据球形和多面体颗粒的随机堆积模型生成的。由四相组成的HCP的微观结构首先生成，然后转化为体素表示的相。基于数字化的微观结构，可以通过晶格建模获得HCP的扩散率。通过与实验数据进行比较，验证了仿真的可靠性，并讨论了水泥颗粒的形状对HCP扩散性的影响。结果表明，水泥颗粒的形状因其对水合度的影响而显着影响HCP的离子扩散率：球形度较小的水泥颗粒有助于HCP的水合作用，从而降低HCP的离子扩散率。随着水化年龄的流逝，这种效果会降低；随着水灰比的增加，这种效果会增加。HCP的微观结构说明了造成这种效应的内在原因：形状效应对三个扩散相和孔结构的体积分数有影响。